Space Radio Telescope (SRT) Schedule File Version 3.3 J. Ulvestad, Y. Murata, A. Wiercigroch, M. Popov, L. D'Addario December 16, 1996 CONTENTS 1.0 INTRODUCTION 1.1 THREE-STEP SCHEDULING PROCESS 1.2 IMPLEMENTATION DETAILS 2.0 GENERAL FILE STRUCTURE 2.1 DETAILED SPECIFICATION OF FILE STRUCTURE 2.2 HEADER AND COMMENT INFORMATION 3.0 SCHEDULED SPACECRAFT EVENTS 3.1 SCHEDULED SPACECRAFT EVENTS FOR VSOP 3.2 SCHEDULED SPACECRAFT EVENTS FOR RADIOASTRON 4.0 SCHEDULED TRACKING STATION EVENTS 4.1 LOGICAL ORDER FOR TRACKING STATION EVENTS 5.0 GROUND RADIO TELESCOPE EVENTS 5.1 GROUND RADIO TELESCOPE NAMES 6.0 SUMMARY OF SCHEDULED EVENTS 6.1 LISTING OF VSOP SPACECRAFT EVENTS 6.2 LISTING OF RADIOASTRON SPACECRAFT EVENTS 6.3 TRACKING STATION EVENTS 6.4 GROUND RADIO TELESCOPE INFORMATION 7.0 SAMPLE SRT SCHEDULE FILES 7.1 SAMPLE SRT SCHEDULE FILE FOR VSOP 7.2 SAMPLE SRT SCHEDULE FILE FOR RADIOASTRON APPENDIX A CONSTRAINTS OF DSN TRACKING STATIONS APPENDIX B CONSTRAINTS OF GREEN BANK TRACKING STATION ---------------------------------------------------------------------------- 1.0 INTRODUCTION This document describes the specification for the Space Radio Telescope (SRT) Schedule File that will be used to operate tracking stations in conjunction with the VSOP or RadioAstron satellite during SVLBI observations. This schedule file contains a chronologically ordered sequence of events describing spacecraft and tracking-station operations. It is a high-level description of all operations that are necessary to operate the tracking stations and spacecraft. Each file should be small in size (on the order of 100 kilobytes for a 1-week schedule), and is formatted to be computer-readable. It should also be comprehensible by a person, although no person will be required to take any action as a result of interpreting comments in the file. Although this specification has been written to apply to both VSOP and RadioAstron, the specification states that information for the two space radio telescopes will be provided in separate files. This makes it possible to end each file at the conclusion of a tracking pass, which would usually not be possible for a single file including tracking passes for both spacecraft. At times when VSOP and RadioAstron are in orbit simultaneously, it is required that all conflicts between the two in the use of ground resources be resolved before the SRT schedules are distributed. Times of participation of ground radio telescopes (GRTs) are included in the SRT Schedule File for information and should be considered as supplementary data. The SRT Schedule File does not contain all the information necessary to operate each GRT. The current specification includes parameters that will permit basic information about the GRT activities to be derived, without many of the details of setup, recording, and calibration that will have to be supplied locally or via the DRUDG files. The exact form and content of the GRT control files, the mechanism by which they are derived, and the formal interface for those files are not yet determined. Actual scheduling and methods of operation of GRTs currently are being considered by a technical working group of the Global VLBI Working Group. (See Section 1.1 for the current guess at the mechanism for deriving the GRT control files.) ---------------------------------------------------------------------------- 1.1 THREE-STEP SCHEDULING PROCESS Development of the SRT Schedule File is part of a three-step process for creating commands to control each mission element during observations. The description below is the best current estimate of the means by which schedules are created. However, the actual process of schedule creation will probably be different for VSOP and RadioAstron, and the final determination and description of this process is beyond the scope of the current specification. A description of the preliminary plan for VSOP can be found in Section 11.2 of "VSOP Operational Activities, Version 1.5," by Wiercigroch et al. (August 17, 1995). The steps necessary for creating the final command files are described below: 1. Science Schedule - Each Science Operations Group (SOG) will develop a long-term science schedule which will maximize the science performance of the missions. The factors that influence the science schedule include the scientific rankings of proposals, spacecraft constraints, limitations on ground resources, and some (as yet unspecified) amount of interaction with the principal investigators on the proposals. In the event that both VSOP and RadioAstron are in orbit simultaneously, a joint schedule will be developed in order to resolve all conflicts over use of ground resources. An initial science schedule will be developed using automated software. Following this step, some individual observations will be moved in order to take into account operational and other constraints that are not included in detail in the high-level scheduling software. In addition to times of observation by the spacecraft, the science schedule will include (at least) time sequences of operations (start and stop times) for ground telescopes and tracking stations. This science schedule will be the only schedule that contains information about all the mission elements, but it probably will not contain all the detailed information required for operation of the different mission elements. 2. Global Schedules - The Science Operations Group, in consultation with the Satellite Control Group (VSOP) and General Operative Control Group (RadioAstron), will use the scientific schedule to develop schedule files for the ground radio telescopes and for the spacecraft and tracking stations. The current plan for VSOP, as developed at ISAS, is summarized below. The method that will be used for RadioAstron is thought to be similar. Ground radio telescope schedule files will be produced by using the output of the scientific scheduling program and running other existing software such as NRAO-sched. A schedule for the spacecraft and tracking stations will be generated separately, possibly using an additional set of software that includes selection criteria for tracking stations. From that schedule and from other information, the SRT Schedule File will be developed. The latter file, the subject of this document, includes all the information necessary to configure and operate a tracking station for Space VLBI. The SRT Schedule File will contain information about the allocation of ground radio telescopes, but will not contain all the information required to configure and operate ground radio telescopes; that information will be provided to the ground telescopes in DRUDG files or their equivalents. The SRT Schedule File may contain all necessary information for the satellite controllers to generate a spacecraft command file. However, the satellite controllers may choose to create their command file separately, based on their own software and procedures, possibly inherited from other space missions operated by the same organization, rather than relying on a schedule file generated by the RSOG or VSOG. This command file is intimately related to the responsibility for spacecraft health and safety, which belongs to the spacecraft controllers, and should properly be regarded as an internal national issue rather than a subject for international agreements. A predicted spacecraft trajectory is necessary for the generation of pointing and frequency predictions that a tracking station uses to point its antenna at a spacecraft and to generate the correct uplink frequency to establish a two-way phase link. The exchange of such trajectories is the subject of separate interface agreements not covered in this document. Each SRT Schedule File will cover a single week of tracking, for a single spacecraft (either VSOP or RadioAstron), from Monday through Sunday (in UTC). All events required for tracking passes that begin during that time period shall be included. The first tracking session to begin after the midnight crossing between Sunday and Monday will be the first session included in each file. The last session to be included shall be the last one beginning prior to the UTC midnight crossing between Sunday and Monday. Each SRT Schedule File will end at the conclusion of a tracking pass from one of the ground telemetry/phase-transfer stations. The operational methods involved with supply of the SRT Schedule File, including the time by which the file must be supplied, and the procedure for providing updates to the file, have not been finally determined. The current plan (as of September 11, 1995) is that each SRT Schedule File initially should be made available on a particular computer by the SOG no fewer than four weeks before the first day included in the schedule. Later updates may be provided, typically about a week before the first event in the file. At some times, particularly during the in-orbit checkout period, it may be necessary to update a portion of the SRT Schedule File after the beginning of the 1-week file has already been executed. Procedures for such an occurrence remain to be worked out, but in no case will a tracking station be required or expected to alter a tracking session after execution of that session has begun. 3. Local commands - Each mission element that receives the SRT Schedule File or DRUDG files will extract the events relevant to that element. It then will generate a local set of commands specific to the particular element that will accomplish the tasks assigned in the relevant schedule file. ---------------------------------------------------------------------------- 1.2 IMPLEMENTATION DETAILS Each event is marked with the UTC date and time, to the nearest second, at which it is intended to occur. It is the responsibility of the appropriate mission element to enable the event to occur at this time. Determination of the actions needed in preparation for the event (e.g., hardware initialization) and scheduling of those actions is a local responsibility and is not covered in the SRT Schedule File. As stated previously, each SRT Schedule File will cover one week of tracking. Within that file, there will be a large number of different tracking sessions (or "passes"), where a tracking session is defined to be the interval during which a spacecraft is continuously tracked, with telemetry and/or phase and Doppler data being received by a particular tracking station. Each file will begin with the beginning of a particular tracking session; no session will be split between two different SRT Schedule Files. At the beginning of each schedule file, the satellites and all tracking stations are assumed to be in an unknown state, so that all parameters must be specified. At the beginning of each succeeding tracking session within the same SRT Schedule File, the tracking station is assumed to be in an unknown state, since the scheduler has no way of knowing what other activities the tracking station has undertaken since the previous session. Therefore, all tracking-station parameters must be specified for each tracking session. The spacecraft, however, is assumed to remain in the same state given previously, until new values are specified for its state parameters. At the time of the beginning of a tracking session, it is the responsibility of the tracking station to know the status of the tapes or cassettes mounted on the wideband recording system(s). This status includes such information as the sections of tape that have not yet been recorded, and the destination correlator for the currently mounted tapes/cassettes. The SRT Schedule File must specify the recording configuration and the destination correlator for each tracking session, but it does not otherwise govern the details of tape-handling at the tracking stations. The SRT Schedule File will consist of ASCII text in a pre-determined format. Each item is described by a scheduled event and a set of parameters. The number of parameters that are included will differ for the different types of events. It is expected that the SRT Schedule File will be fairly terse. Occasional comment lines may be inserted, and are indicated by beginning with a '#' character. These comments may be inserted in the appropriate time sequence to note special conditions (e.g., rapid turnarounds of the phase link from one station to another). The comments are for information purposes only and should not be used to specify any action that must be taken by a mission element. In addition, several lines beginning with a '$' symbol will be used to communicate header information about a particular file (see Section 2.2 below). For each mission element, a schedule conversion program is necessary to convert the SRT Schedule File into a local set of commands. That conversion program is the responsibility of the local mission element. It will translate relevant schedule events into a set of local commands, and will also specify activities necessary for initialization and testing. In general, tape handling will be a local decision, since it may depend on details of other station activities that are not known by the SOG. However, the SRT Schedule File will include a provision for forcing the mounting of a new tape or the dismounting of an old tape in special circumstances, such as when it is desired to make a rapid fringe check by transporting a tape to some correlation facility as soon as possible after a particular observation. ---------------------------------------------------------------------------- 2.0 GENERAL FILE STRUCTURE Except for comments and header information (see Section 2.2), each line of the SRT Schedule File will contain three fields. The three fields are specified with fixed formats beginning in predetermined columns. All alphabetical characters must be supplied in upper case. The first field is the UTC at which an event should occur, specified by day-of-year (January 1 is day 001) followed by hours, minutes, and seconds. Each time is specified as DDD:hh:mm:ss, and occupies columns 1 through 12. The second field will be an element identification, either a spacecraft, tracking station, or telescope. When possible, these specifications are consistent with those in common usage elsewhere in VLBI. For all ground radio telescopes listed in the VSOP Announcement of Opportunity and Proposer's Guide, the identifiers are identical to those used in that guide. A maximum of eight characters is allowed. The element name occupies columns 16 through 23. Columns 24 through 26 are left blank, enabling expansion of the element names by several characters if desired at some future date. The third field is an event identification, together with associated parameters. The scheduled event is a 6-character identification beginning in column 27, followed by an '=' sign in column 33 and a list of parameters. ---------------------------------------------------------------------------- 2.1 DETAILED SPECIFICATION OF FILE STRUCTURE The detailed specification of the structure of the SRT Schedule File is given below. Recall that lines beginning with '#' are comment lines: 1 2 3 4 5 6 123456789012345678901234567890123456789012345678901234567890 DDD:hh:mm:ss ELEMENTS EVENTA=parm1,parm2,.... | | | | | | | | | +---- Parameters of event. See below. | | | +----------- Scheduled event (within 6 characters) | | +---------------------- Element(within 8 characters): | | VSOP_SC, RA_SC, MADRD_TS, | | TDBIN_TS, GOLDS_TS, PUSHN_TS, | | GBANK_TS, USSUR_TS, EVPAT_TS, | | USUDA_TS, Ground radio telescopes. | +------------------------------ Time +------------------------------------- Day Number. Year should appear in Header ---------------------------------------------------------------------------- 2.2 HEADER AND COMMENT INFORMATION Each file should contain three lines of header information, two at the beginning and one at the end of the file. The headers will begin with a '$' symbol. The first line of the file will give the time span to be covered by the file, specifying the first and last times included in the file. (The reason for including both start and stop time on the first line is so that a human can quickly look at the file and know the exact time period covered by the SRT Schedule File.) The second line gives the total number of lines in the file, including headers and comments, so that the recipient can check to see that no lines have been lost in transit or accidentally deleted. Comment lines should follow, giving information about the construction of the file. Following the entire set of events, the third "header" line should be an end-of-file notation. Thus, the structure of the SRT Schedule File shall be as follows: $SPACE_VLBI START=1996:323:01:00:00 STOP=1996:330:02:00:20 $NUM_OF_LINES=583 # Created by Y.Murata 1996:285:12:00:00 # Modified by H.Kobayashi 1996:290:12:00:00 323:01:00:00 VSOP_SC PWR_ON=KTX . . . 330:02:00:20 VSOP_SC SET_TS=USUDA $END_OF_FILE ---------------------------------------------------------------------------- 3.0 SCHEDULED SPACECRAFT EVENTS The following subsections contain the spacecraft events for VSOP and RadioAstron. A number of events have the same format and meaning for the two spacecraft, although the set of allowed parameters may be different because of the different equipment aboard the satellites. The common events are NDMODE, ON_SRC, ON_TS, PCALSW, REFMOD, SET_TS, and SSFMOD. The events are listed in the same general order that they might be expected to be listed in the SRT Schedule File. A '/' symbol is used to separate different possible values for a given parameter in the specification of each individual event. A ',' separates different parameters for the same event. ---------------------------------------------------------------------------- 3.1 SCHEDULED SPACECRAFT EVENTS FOR VSOP The following sections describe the satellite-related events scheduled for VSOP. Each event has a fixed number of parameters. If two or more instruments are switched on or off on the spacecraft, multiple records are used, one for each event. ---------------------------------------------------------------------------- NAME PWR_ON - power on instrument PWROFF - power off instrument SYNOPSIS PWR_ON=instrument ~~~~~~~~~~ PWROFF=instrument ~~~~~~~~~~ DESCRIPTION Power on and off of 18 observation instruments on board. Instruments are as follows: KTX Ku-band transmitter for down link signal. KRX Ku-band receiver for up-link signal KMOD Ku-band modulator. LOGEN Local generator for L-, C- and Ka-band down converter. REFDIV Reference signal divider. 22LNA Ka-band low noise amplifier 5LNA C-band low noise amplifier 16LNA L-band low noise amplifier CAL Calibration unit for L-, C- and Ka-bands. This unit includes noise sources and comb-tone signals for all bands. 22DC Ka-band down converter 5DC C-band down converter 16DC L-band down converter IFSW IF switch IRMA Image rejection mixer of channel-A IRMB Image rejection mixer of channel-B SSF Sampler and Synchronous Formatter. This unit includes level detector for each channel. SYNTHA Synthesizer for IRMA SYNTHB Synthesizer for IRMB Following groups of instruments are also allowed. OBS22 22LNA, and 22DC OBS5 5LNA, and 5DC OBS16 16LNA and 16DC OBSA SYNTHA, and IRMA OBSB SYNTHB, and IRMB OBSS CAL, IFSW, and SSF OBSLNK KRX, REFDIV, LOGEN, KMOD, and KTX OBSBE KKRX, REFDIV, LOGEN, KMOD, KTX, SYNTHA, IRMA, SYNTHB, IRMB, CAL, IFSW, SSF The instruments in the same group are expected to switch on and off in the same time. EXAMPLES 233:12:30:45 VSOP_SC PWR_ON=KTX 233:12:30:45 VSOP_SC PWR_ON=KRX 233:12:30:45 VSOP_SC PWR_ON=KMOD 233:12:30:45 VSOP_SC PWR_ON=LOGEN 233:12:30:45 VSOP_SC PWR_ON=REFDIV or 233:12:30:45 VSOP_SC PWR_ON=OBSLNK ---------------------------------------------------------------------------- NAME KRXPLL - search width of KRX phase lock loop SYNOPSIS KRXPLL=WIDE/NARROW DESCRIPTION Parameter should be WIDE or NARROW EXAMPLES 233:12:30:45 VSOP_SC KRXPLL=NARROW ---------------------------------------------------------------------------- NAME KRXSWP - switch of sweep mode of phase lock loop SYNOPSIS KRXSWP=ON/OFF DESCRIPTION Parameter should be ON or OFF EXAMPLES 233:12:30:45 VSOP_SC KRXSWP=ON ---------------------------------------------------------------------------- NAME REFMOD - set reference signal divider mode SYNOPSIS REFMOD=INT/EXT DESCRIPTION Parameter should be INT or EXT. REFMOD uses internal signal generator on board in INT mode and uses signal from tracking station in EXT mode. EXT mode is used for normal VLBI observation. EXAMPLES 233:12:30:45 VSOP_SC REFMOD=EXT ---------------------------------------------------------------------------- NAME PCALSW - switch of phase calibration signal. SYNOPSIS PCALSW=ALL,ON/OFF DESCRIPTION The ALL parameter has been included for consistency with the RadioAstron event, which is used to turn on the tones for only one frequency band at a time. The second parameter should be ON or OFF. PCALSW=ON starts comb-tone signals for phase calibration in all three bands (Ka, C, and L). PCALSW=OFF ends them. The default for VSOP generally will be PCASLW=ON for all continuum observations and PCALSW=OFF for all spectral line observations. EXAMPLES 233:12:30:45 VSOP_SC PCALSW=ALL,ON ---------------------------------------------------------------------------- NAME NDMODE - noise source switch mode. SYNOPSIS NDMODE=K/C/L,ON/OFF/AUTO,HIGH DESCRIPTION NDMODE needs three parameters. One is K, C, or L, which selects the noise source, and another is the control mode of noise source. ON/OFF keeps the noise source on/off. AUTO keeps on switching on/off with a 500 msec period. The third parameter refers to high or low power of the noise diode, and is included for consistency with the RadioAstron event. The VSOP noise diode has only one power setting, which roughly doubles the system temperature, so the last parameter should always be set to "HIGH." EXAMPLES 233:12:30:45 VSOP_SC NDMODE=K,OFF,HIGH 233:12:30:45 VSOP_SC NDMODE=L,AUTO,HIGH ---------------------------------------------------------------------------- NAME DC_ATT - control attenuator in down converter SYNOPSIS DC_ATT=K/C/L,[0-31] DESCRIPTION DC_ATT needs two parameters. One is K, C, or L which selects the band; the other is the level of the attenuator with the number from 0 to 31 (32 levels). 0 is lowest attenuation level and 31 is the highest. EXAMPLES 233:12:30:45 VSOP_SC DC_ATT=L,22 233:12:30:45 VSOP_SC DC_ATT=K,15 ---------------------------------------------------------------------------- NAME IFSLCT - select IF of A/B channel SYNOPSIS IFSLCT=K/C/L,K/C/L DESCRIPTION Select IF band for channel A and B. First parameter shows the IF band to be connected to channel A, and second paremater shows the IF band for channel B. EXAMPLES 233:12:30:45 VSOP_SC IFSLCT=K,K ---------------------------------------------------------------------------- NAME CRSSCN - cross scan control event SYNOPSIS CRSSCN=START,a,b1,b2,t CRSSCN=STOP DESCRIPTION CRSSCN=START starts a cross scan (for the purposes of checking the SRT pointing) with the parameters a, b1, and b2. The boresighting pattern includes (1) a nominal pointing position, (2) 4 points offset from the nominal position by the same amount, separated from one another by 90 degrees in azimuth, and (3) a distant off-source position. 'a' is the angular offset from the nominal position of the 4 points sampling the power at different azimuths. 'b1' and 'b2' specify the position offset of the more distant off-source point from the center, based on the satellite coordinate system (x,y). Units of 'a', 'b1', 'b2' parameters are arcseconds. 't' shows how long the attitude stays each position in seconds. 't' should be multiples of 32 seconds form the limitation of the attitude control system. CRSSCN=STOP stops the cross scan. EXAMPLES 233:12:30:45 VSOP_SC CRSSCN=START,190,1000,-1000,64 233:12:30:45 VSOP_SC CRSSCN=STOP ---------------------------------------------------------------------------- NAME SSFMOD - set mode of formatter on board (SSF) SYNOPSIS SSFMOD=SamplingRate,NumberOfBBC,SamplingBits,AB/A/B DESCRIPTION SSFMOD sets sampling mode of SSF. Parameters are selected as follows: SamplingRate 32/64 (Msps) NumberOfBBC 1/2 SamplingBit 1/2 (bit) Channel Allocation AB/A/B Allowed combinations of parameters are (32,2,2,AB), (64,2,1,AB), (64,1,2,A) and (64,1,2,B). The mode (32,2,2,AB) will be the normal mode for international scientific observations. Different combinations are allowed for RadioAstron. EXAMPLES 233:12:30:45 VSOP_SC SSFMOD=32,2,2,AB ---------------------------------------------------------------------------- NAME TLMFMT - change VSOP satellite (S-band) telemetry format SYNOPSIS TLMFMT=, is one of AOCS - Attitude control system telemetry output mode STTM - Star tracker mapping results OBS - Ku link antenna tracking data GPS - GPSR data HK - High sampling rate output of Temperature/Voltage data. RDHU, RACS, RSTT, RAPE, RGPS, RSTC, RHCER - On board RAM checking mode. ANT - Antenna deployment mode. Not used after IOC. LNCH - Launch mode. Not used after launch. is one of H, M, L. H: Bit rate is High. Satellite uses 8 kbit/s clock. M: Bit rate is Medium. Satellite uses 1 kbit/s clock. L: Bit rate is Low. Satellite uses 256 bit/s clock. DESCRIPTION Change S-band telemetry mode and format. In the normal operation, AOCS, OBS, GPS and HK modes may be switched. STTM is used to get star tracker mapping results. When the VSOP satellite has a link with the tracking station, must be set to H, in order for the planned telemetry records to appear in the Ku-band downlink header. (Otherwise, the frame repetition sequence and period are different.) The VSOG will use lower bit rate modes just for getting data with low sampling rate (long play mode) using the onboard data recorder. RDHU, RACS, ... are used for onboard RAM checking, but they may not appear in this schedule file. ANT and LNCH are used only in initial phase. EXAMPLES 233:12:30:45 VSOP_SC TLMFMT=AOCS,H ---------------------------------------------------------------------------- NAME DR_REC - start on-board data recorder for telemetry data SYNOPSIS DR_REC=ONCE/CYCLE DESCRIPTION DR_REC starts the data recorder for the telemetry data. VSOP data recorder has 2 modes. One is ONCE mode which records data ONCE. When the recorder becomes full, the data recorder automatically stops. Another mode is CYCLE. In this mode, the data recorder overwrites the old data after it uses all the data area. EXAMPLES 233:12:30:45 VSOP_SC DR_REC=ONCE ---------------------------------------------------------------------------- NAME DRSTOP - stop on-board data recorder for telemetry data SYNOPSIS DRSTOP DESCRIPTION DRSTOP stops the data recorder for the telemetry data. EXAMPLES 233:12:30:45 VSOP_SC DRSTOP ---------------------------------------------------------------------------- NAME SETFRQ - set frequency of SYNTH-A/B for IRM SYNOPSIS SETFRQ=A/B,frequency DESCRIPTION SETFRQ sets the frequency of synthesizer for IRM. Observation frequency is a function of the parameters of SETFRQ and IFSLCT. The unit of frequency is megahertz. EXAMPLES 233:12:30:45 VSOP_SC SETFRQ=A,550 233:12:30:45 VSOP_SC SETFRQ=B,582 ---------------------------------------------------------------------------- NAME ANTMOV - begin moving space telescope to source SYNOPSIS ANTMOV=SRC_NAME,hhHmmMss.sssS,+ddDmmMss.ssS,Epoch,Attitude ~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~ ~~~~~~~~ DESCRIPTION ANTMOV is the time that the space radio telescope is scheduled to begin moving to the source designated by SRC_NAME. The source name should be within 12 characters. (hhHmmMss.sssS) and (+ddDmmMss.ssS or -ddDmmMss.ssS) show right ascension and declination at a certain Epoch (1950 or 2000 are allowed). Attitude should be 0 or 180, which indicates the selection of one of the two possible attitudes of the satellite. An attitude of 180 degrees indicates that the Sun shines on the side of the spacecraft where the base of the Ku link antenna is located, while an attitude of 0 degrees indicates that the Sun shines on the opposite side. EXAMPLES 233:12:30:45 VSOP_SC ANTMOV=ORION-KL,05H32M47.032S,-05D24M24.25S,1950,0 ---------------------------------------------------------------------------- NAME OBSCOD - VSOP observation code SYNOPSIS OBSCOD= DESCRIPTION Specify VLBI observation code. Code has 5 or 6 characters, and is defined by Long-term schedule. This code is identical with the experiment code in the GRT schedule file. These records are inserted for every tracking pass and when the spacecraft will start an observation. If the pass is only for Doppler data acquisition, OBSCOD is DOPLER. EXAMPLES 233:11:00:00 VSOP_SC OBSCOD=V011A 233:12:30:45 VSOP_SC OBSCOD=DOPLER ---------------------------------------------------------------------------- NAME ON_SRC - space telescope is expected to see the source SYNOPSIS ON_SRC=SRC_NAME,hhHmmMss.sssS,+ddDmmMss.ssS,Epoch,Attitude ~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~ ~~~~~~~~ DESCRIPTION ON_SRC defines when the space radio telescope is expected to see the source designated by SRC_NAME. All parameters should be the same as ANTMOV, including source position, epoch of the position, and spacecraft attitude. EXAMPLES 233:12:40:45 VSOP_SC ON_SRC=ORION-KL,05H32M47.032S,-05D24M24.25S,1950,0 ---------------------------------------------------------------------------- NAME SET_TS - start to point Ku link antenna toward selected tracking station SYNOPSIS SET_TS=USUDA/GOLDS/MADRD/TDBIN/GBANK, N/P DESCRIPTION SET_TS starts to move the Ku link antenna toward selected tracking stations. USUDA -> Usuda, MADRD -> Madrid, GOLDS -> Goldstone, GBANK -> Green Bank, TDBIN -> Tidbinbilla. Note that the names of the tracking stations here are different from the names that are used when those tracking stations are the operational elements. N / P specifys the mode of azimuth, elevation angle definition. N means normal mode whicn uses 0 < (elevation angle) < 90, and P means plunge mode which uses 180 < (elevetion angle) < 360. EXAMPLES 233:12:40:45 VSOP_SC SET_TS=GBANK,P ---------------------------------------------------------------------------- NAME ON_TS - Ku link antenna expected to point to selected tracking station SYNOPSIS ON_TS =USUDA/GOLDS/MADRD/TDBIN/GBANK, N/P DESCRIPTION ON_TS indicates the expected time that the Ku link antenna should be pointed at the selected tracking station, and ready to "track" that tracking station. USUDA -> Usuda, MADRD -> Madrid, GOLDS -> Goldstone, GBANK -> Green Bank, TDBIN -> Tidbinbilla. N / P specifys the mode of azimuth, elevation angle definition. N means normal mode whicn uses 0 < (elevation angle) < 90, and P means plunge mode which uses 180 < (elevetion angle) < 360. EXAMPLES 233:12:42:00 VSOP_SC ON_TS =GBANK,P ---------------------------------------------------------------------------- NAME OFF_TS - control link antenna pointing SYNOPSIS OFF_TS - has no parameters DESCRIPTION OFF_TS releases link antenna attitude system EXAMPLES 233:12:30:45 VSOP_SC OFF_TS ---------------------------------------------------------------------------- 3.2 SCHEDULED SPACECRAFT EVENTS FOR RADIOASTRON The following sections describe the satellite-related events scheduled for RadioAstron. Each event has a fixed number of parameters. If two or more instruments are switched on the spacecraft, multiple records are used, one for each scheduled event. ---------------------------------------------------------------------------- NAME RVSLCT - connects given receiver output to selected Formatter input and switches chosen receiver ON. SYNOPSIS RVSLCT=PR/PL/LR/LL/CR/CL/KR/KL,1/2 DESCRIPTION RVSLCT needs two parameters. One is receiver designation: PR - 92-cm with right polarization; PL - 92-cm with left polarization; LR - 18-cm, right polarization; LL - 18-cm, left polarization; CR - 6-cm, right polarization; CL - 6-cm, left polarization; KR - 1.35-cm, right polarization; KL - 1.35-cm, left polarization. Second parameter nominates input channel of the IF system (Formatter) 1 or 2. Two subsequent RVSLCT events are needed to form the necessary receiver configuration. Any combination of observing frequencies is possible, but different polarization must be connected to two Formatter channels. EXAMPLES 233:12:30:45 RA_SC RVSLCT=CR,1 233:12:30:50 RA_SC RVSLCT=KL,2 This determines dual-frequency observation at 6-cm with right polarization and at 1.35-cm with left polarization. 233:12:30:45 RA_SC RVSLCT=LR,1 233:12:30:50 RA_SC RVSLCT=LL,2 This determines two-polarization observations at 18-cm. ---------------------------------------------------------------------------- NAME REFMOD - set reference signal divider mode SYNOPSIS REFMOD=INT/EXT DESCRIPTION Parameter should be INT or EXT. REFMOD uses internal signal generator on board in INT mode and uses signal from station in EXT mode. EXT mode is used for normal VLBI observations. EXAMPLES 233:12:30:45 RA_SC REFMOD=EXT ---------------------------------------------------------------------------- NAME SSFMOD - set mode of formatter on board (SSF) SYNOPSIS SSFMOD=SamplingRate,NumberOfBBC,Bandwidth,SamplingBits, A/B/C/D/AB/AC/AD/BC/BD/CD/ABCD DESCRIPTION SSFMOD sets sampling mode of SSF. Parameters are selected as follows: SamplingRate 4/8/16 (Msps) NumberOfBBC 1/2/4 SamplingBits 1/2 (bit) Channel Allocation A/B/C/D/AB/AC/AD/BC/BD/CD/ABCD Allowed combinations of parameters are: 4/8/16,1,1/2,A/B/C/D 4/8,2,1/2,AB/AC/AD/BC/BD/CD 16,2,1,AC/AD/BD 8,4,1/2,ABCD Letters A,B,C, and D define LO-frequencies of IF-system: A 500 MHz B 508 MHz C 516 MHz D 524 MHz EXAMPLES 233:12:30:45 RA_SC SSFMOD=16,2,1,AC ---------------------------------------------------------------------------- NAME SCISYS - control power ON/OFF to scientific equipment SYNOPSIS SCISYS=ON/OFF DESCRIPTION SCISYS - switches power ON/OFF to scientific equipment selected by the scheduled events specified above: RVSLCT, REFMOD, and SSFMOD EXAMPLES 233:12:30:45 RA_SC SCISYS=OFF ---------------------------------------------------------------------------- NAME PCALSW - switch ON/OFF phase calibration signal to given frequency. SYNOPSIS PCALSW=P/L/C/K,ON/OFF DESCRIPTION First parameter define frequency band, second should be ON or OFF. The format is the same as the VSOP event, although the first parameter specifies a single frequency rather than all frequencies, as is the case for VSOP. EXAMPLES 233:12:30:45 RA_SC PCALSW=C,ON ---------------------------------------------------------------------------- NAME NDMODE - noise source switch mode. SYNOPSIS NDMODE=P/L/C/K,ON/OFF/AUTO,HIGH/LOW DESCRIPTION NDMODE needs three parameters. First is K, C, L, or P, which selects source, and the second is control mode of noise source. ON/OFF keeps source on/off. AUTO keeps on switching on/off with the frame frequency (normally 400 Hz). The third parameter defines noise power level: HIGH - about T(sys), LOW - about 10% of T(sys). EXAMPLES 233:12:30:45 RA_SC NDMODE=K,ON,HIGH 233:12:30:45 RA_SC NDMODE=L,AUTO,LOW ---------------------------------------------------------------------------- NAME OBSCOD - RadioAstron observation code SYNOPSIS OBSCOD= DESCRIPTION Specify VLBI observation code. Code has 5 or 6 characters, and is defined by Long-term schedule. This code is identical with the experiment code in the GRT schedule file. These records are inserted for every tracking pass and when the spacecraft will start an observation. If the pass is only for Doppler data acquisition, OBSCOD is DOPLER. EXAMPLES 233:11:00:00 RA_SC OBSCOD=R020A 233:12:30:45 RA_SC OBSCOD=DOPLER ---------------------------------------------------------------------------- NAME ON_SRC - defines when RA-antenna must be on the given source. SYNOPSIS ON_SRC=SRC_NAME,hhHmmMss.sssS,+ddDmmMss.ssS,Epoch,Attitude ~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~ ~~~~~~~~ DESCRIPTION ON_SRC defines when RA-antenna must be pointed toward the direction set by parameters. SRC_NAME is source name to observe. It should be within 12 characters. (hhHmmMss.sssS) and (+ddDmmMss.ssS) show right ascension and declination at a certain Epoch (1950 or 2000 are allowed). Attitude is included for consistency with the VSOP event, and should be defined by the RADIOASTRON Project. EXAMPLES 233:12:30:45 RA_SC ON_SRC=ORION-KL,05H32M47.000S,-05D24M24.25S,1950,0 ---------------------------------------------------------------------------- NAME OFFSRC - control spacecraft pointing SYNOPSIS OFFSRC - event has no parameters DESCRIPTION OFFSRC - releases Attitude Control System from source tracking, EXAMPLES 233:12:30:45 RA_SC OFFSRC ---------------------------------------------------------------------------- NAME SET_TS - points link antenna toward selected tracking station SYNOPSIS SET_TS=USSUR/GOLDS/MADRD/TDBIN/GBANK DESCRIPTION SET_TS points link antenna toward selected tracking stations. USSUR -> Ussurijsk, MADRD -> Madrid, GOLDS -> Goldstone, GBANK -> Green Bank, TDBIN -> Tidbinbilla. EXAMPLES 233:12:30:45 RA_SC SET_TS=GBANK ---------------------------------------------------------------------------- NAME ON_TRK - link antennas expected to point to selected tracking station SYNOPSIS ON_TRK=USSUR/GOLDS/MADRD/TDBIN/GBANK DESCRIPTION ON_TRK indicates the expected time that the Ku/X link antenna(s) should be pointed at the selected tracking station, and ready to "track" that tracking station. USSUR -> Ussurijsk, MADRD -> Madrid, GOLDS -> Goldstone, GBANK -> Green Bank, TDBIN -> Tidbinbilla. EXAMPLES 233:12:30:45 RA_SC ON_TRK=GBANK ---------------------------------------------------------------------------- NAME OFF_TS - control link antenna pointing SYNOPSIS OFF_TS - has no parameters DESCRIPTION OFF_TS releases link antenna attitude system EXAMPLES 233:12:30:45 RA_SC OFF_TS ---------------------------------------------------------------------------- NAME OBSERV - start or finish transmission of science data to current tracking station SYNOPSIS OBSERV=ON/OFF DESCRIPTION Parameter should be ON or OFF EXAMPLES 233:12:30:45 RA_SC OBSERV=ON ---------------------------------------------------------------------------- NAME LINKTR - switch ON/OFF transponder to establish UP/DOWN link with current tracking station. SYNOPSIS LINKTR=ON/OFF DESCRIPTION Parameter should be ON or OFF EXAMPLES 233:12:30:45 RA_SC LINK=ON ---------------------------------------------------------------------------- NAME BRST_1 - defines the boresighting procedure in scanning mode. SYNOPSIS BRST_1=NumberOfScans,ScanRep,Range,Spacing,Velocity DESCRIPTION BRST_1 provides cross-scanning boresighting. It needs four parameters: NumberOfScans 1-5 ScanRep 1-4 Range 0.5-20 degrees Spacing 2-120 arcmin Velocity 0.017-1.0 deg/s Note: ON_SRC event must precede BRST_1 EXAMPLES 233:12:30:00 RA_SC ON_SRC=CAS-A,23H21M10.600S,58D33M06.00S,1950,0 233:12:30:45 RA_SC BRST_1=3,2,2,10,0.007 ---------------------------------------------------------------------------- NAME BRST_2 - defines the boresighting procedure in cross-points. SYNOPSIS BRST_2=Spacing,IntTime DESCRIPTION BRST_2 provides integration in five fixed directions relative to the source position. There are two parameters: Spacing 2-120 arcmin IntTime 1-10 min EXAMPLES 233:12:30:00 RA_SC ON_SRC=CAS-A,23H21M10.600S,58D33M06.00S,1950,0 233:12:30:45 RA_SC BRST_2=10,2 ---------------------------------------------------------------------------- NAME TMFORM - defines housekeeping telemetry transfer into science data stream headers SYNOPSIS TMFORM=ON/OFF DESCRIPTION TMFORM with ON parameter starts transfer of housekeeping telemetry into science data header, OFF parameter stops transfer of housekeeping telemetry into science header. EXAMPLES 233:12:30:45 RA_SC TMFORM=ON ---------------------------------------------------------------------------- NAME ORBMES - determines range/range-rate orbit measurements made in C-band SYNOPSIS ORBMES=ON/OFF DESCRIPTION ORBMES: ON-parameter means that orbit measurements shall start; OFF-parameter designates the end of the measurements. EXAMPLES 233:12:30:45 RA_SC ORBMES=ON 233:12:40:45 RA_SC ORBMES=OFF ---------------------------------------------------------------------------- NAME COMSES - determines command transmission session SYNOPSIS COMSES=ON/OFF DESCRIPTION COMSES: ON-parameter means that command session shall start; OFF-parameter designates the end of the session. EXAMPLES 233:12:30:45 RA_SC COMSES=ON 233:14:40:00 RA_SC COMSES=OFF ---------------------------------------------------------------------------- NAME TECSER - determines time for spacecraft technical service (e.g., reaction wheels unloading or battery charging) SYNOPSIS TECSER=ON/OFF DESCRIPTION TECSER: ON-parameter means that technical service shall start; OFF-parameters designates the end of the service. EXAMPLES 233:12:30:45 RA_SC TECSER=ON 233:13:40:00 RA_SC TECSER=OFF ---------------------------------------------------------------------------- 4.0 SCHEDULED TRACKING STATION EVENTS The scheduled events necessary for each tracking station are summarized below. The format of the event descriptions is the same as that used for the spacecraft. These are listed in an order that approximates the order in which they might be included for a single tracking pass. ---------------------------------------------------------------------------- NAME RISESC - spacecraft rise time SYNOPSIS RISESC=VSOP/RASTRON DESCRIPTION Parameter (spacecraft name) should be either VSOP or RASTRON. This item is required by NASA DSN operations in order to allocate the time on the tracking antennas, but not by Green Bank, so it should be specified for ALL stations for consistency. The rise time refers to the time when the spacecraft should rise above the horizon mask of the particular tracking antenna. The parameter name is different from that used when the spacecraft is the active element. EXAMPLE 323:12:45:30 MADRD_TS RISESC=VSOP ---------------------------------------------------------------------------- NAME BGN_DL - begin downlink from spacecraft SYNOPSIS BGN_DL=VSOP/RASTRON DESCRIPTION Parameter (spacecraft name) should be either VSOP or RASTRON. Tracking station antenna should acquire a downlink signal from the spacecraft, but should not uplink a phase signal. EXAMPLE 323:12:46:00 MADRD_TS BGN_DL=VSOP ---------------------------------------------------------------------------- NAME BGN2LK - begin establishing two-way phase link (beacon on) SYNOPSIS BGN2LK=VSOP/RASTRON DESCRIPTION Parameter (spacecraft name) should be either VSOP or RASTRON. This event provides the time when the tracking station beacon should be turned on to begin establishment of a two-way link. EXAMPLE 323:12:46:00 MADRD_TS BGN2LK=VSOP ---------------------------------------------------------------------------- NAME OBSCOD - VSOP observation code SYNOPSIS OBSCOD= DESCRIPTION Specify VLBI observation code. Code has 5 or 6 characters, and is defined by Long-term schedule. This code is identical with the experiment code in the GRT schedule file. These records are inserted for every tracking pass and when the spacecraft will start an observation. If the pass is only for Doppler data acquisition, OBSCOD is DOPLER. EXAMPLES 233:12:30:45 GBANK_TS OBSCOD=V011A 233:12:30:45 GOLDS_TS OBSCOD=DOPLER ---------------------------------------------------------------------------- NAME CALMES - specifies the times when tracking stations should extract and measure the phase calibration tones in the downlink data SYNOPSIS CALMES=BEGIN/AUTO/END,integration,interval ~~~~~~~~~~~ ~~~~~~~~ DESCRIPTION CALMES specifies the times at which phase calibration tones should be extracted and measured. The first parameter may be BEGIN, AUTO, or END. The value BEGIN means that a single set of tones will be extracted one time, while the value AUTO means the tones will be extracted periodically at the requested interval. The value END represents the end of the periodic cal-tone extraction. The "integration" parameter gives the integration time, in integer seconds, for a single set of tone extractions. The "interval" parameter gives the reporting interval, in integer seconds, between tone extractions for the case of periodic extraction. If no "END" event is specified, it is assumed that the tone extraction stops when the tracking link ends. Each design of tracking station (DSN, Usuda, Green Bank, Ussurijsk) has a different method and capability for measuring and/or reporting phase calibration tones. Information about which tones to extract and a sequence of multiplexing through the different tones must be supplied for each station. This would be done according to a default configuration resident at the tracking station, which will not change for a given SRT observing mode, and therefore need not be specified separately in the SRT Schedule File. EXAMPLES 323:12:46:00 GBANK_TS CALMES=AUTO,10,60 323:13:48:00 GBANK_TS CALMES=END,10,60 ---------------------------------------------------------------------------- NAME COREL1 - tells name of first destination correlator COREL2 - tells name of second destination correlator COREL3 - tells name of third destination correlator SYNOPSIS COREL1=name ~~~~ COREL2=name ~~~~ COREL3=name ~~~~ DESCRIPTION In a few instances, data may be recorded on two or three tape drives simultaneously for shipment to different correlators or so that one tape might be used for fringe verification while another is shipped to a correlator. This may be the case at the DSN or Green Bank, where both VLBA drives might be used simultaneously. At Usuda or Ussurijsk, one recording may be made on a VLBA tape and the other on a VSOP cassette or an S2 system. In most instances, only COREL1 will be used, while COREL2 and COREL3 will not be required. Possible correlator names are as follows: VLBA - VLBA correlator in Socorro NAO - VSOP correlator at NAO in Mitaka EVN_JIVE - EVN_JIVE correlator in Dwingeloo ATNF - S2 correlator at Australia Telescope National Facility MOSC - S2 correlator in Moscow CANADA - S2 correlator in Canada HSTK - Mark 4 correlator at Haystack Observatory NULL - no data recorded for correlator EXAMPLES 323:12:46:00 MADRD_TS COREL1=EVN_JIVE 323:12:46:00 MADRD_TS COREL2=NAO 323:12:46:00 MADRD_TS COREL3=CANADA 323:22:00:20 USSUR_TS COREL1=MOSC 323:22:00:20 USSUR_TS COREL2=VLBA ---------------------------------------------------------------------------- NAME CNFIG1 - specifies the configuration for recording the wideband VLBI data for COREL1 CNFIG2 - specifies the configuration for recording the wideband VLBI data for COREL2 CNFIG3 - specifies the configuration for recording the wideband VLBI data for COREL3 SYNOPSIS CNFIG1=number ~~~~~~ CNFIG2=number ~~~~~~ CNFIG3=number ~~~~~~ DESCRIPTION The recording configuration will be specified by a 3-digit number corresponding to a specific distribution of data to the recording medium. In most cases, only CNFIG1 will be needed. The configuration codes specify requirements on formatter set-up. For VSOP data and VLBA recording systems, the different aspects of the configurations (barrel roll, sequence of head positions, track assignments) are given in the memo "Recording VSOP Data (Mode 128-2-2) on VLBA Tapes, Version 3.0," by Ulvestad and Romney, April 1996. The configuration codes are allocated as given below. Only a few of the allocated numbers will be used for VSOP, with more used for RadioAstron. 001-099 VSOP recording on VLBA recorder 101-199 RadioAstron recording on VLBA recorder 201-299 VSOP recording on VSOP recorder 301-399 RadioAstron recording on VSOP recorder 401-499 VSOP recording on S2 recorder 501-599 RadioAstron recording on S2 recorder The meaning of the above codes for RadioAstron has not been specified. Although it is logically driven by the formatters (if any) and correlators, the required correspondence between spacecraft observing modes and recording set-ups has not yet been specified formally. The meaning of the codes for VSOP has been determined, and is provided below: 001 VSOP data recorded on 16 tracks, as it would be fanned out by the VLBA formatter at a ground radio telescope. This specification also includes a default track assignment and the use of the barrel-roll feature on VLBA recorders. 002 VSOP data recorded on 32 tracks. This specification also includes a default track assignment and the use of the barrel-roll feature on VLBA recorders. 201 VSOP data recorded in serial format on a VSOP recorder at 128 Mb/s. Since only tracking stations and correlators located in Japan are currently expected to record/decode data on VSOP-style cassettes, the precise specification of the method of recording is a matter internal to Japan. 401 Record VSOP 128 Mb/s data at DSN ground tracking station (S2 internal record mode 8d16-2). 402 Record VSOP 128 Mb/s data at NRAO ground tracking station (S2 internal record mode 8n16-2). 403 Record VSOP 128 Mb/s data at Usuda ground tracking station (S2 internal record mode 16x8-2). EXAMPLES 323:12:46:00 MADRD_TS CNFIG1=001 323:12:46:00 MADRD_TS CNFIG2=002 323:12:46:00 MADRD_TS CNFIG3=401 323:22:00:20 USSUR_TS CNFIG1=503 323:22:00:20 USSUR_TS CNFIG2=103 ---------------------------------------------------------------------------- NAME BGNRC1 - Specifies time to begin recording wideband VLBI data, whether or not a new tape must be mounted, and the type of recorder to be used, for COREL1. The type of recorder should agree with the numerical code given as the parameter for the CNFIG1 event. BGNRC2 - Same as BGNRC1, for COREL2. Required only if COREL2 and CNFIG2 are specified. BGNRC3 - Same as BGNRC1, for COREL3. Required only if COREL3 and CNFIG3 are specified. SYNOPSIS BGNRC1=MOUNT/LOCAL,VLBA/VSOP_T/S2 BGNRC2=MOUNT/LOCAL,VLBA/VSOP_T/S2 BGNRC3=MOUNT/LOCAL,VLBA/VSOP_T/S2 DESCRIPTION The possible values for the first parameter are MOUNT to force a new tape to be mounted or LOCAL for local control at the tracking station. The second parameter specifies the recorder type of VLBA, VSOP_T, or S2, and should agree with the value given by the corresponding CNFIGn event. If MOUNT is specified without a previous DISMOUNT being issued for the same station, the station still must dismount the previous tape before mounting a new one. Note that tape-handling decisions should, in general, be made locally, and the MOUNT action should be reserved for special circumstances such as mounting a new tape to be used for a rapid fringe search. See JPL SVLBI Memo No. 145, "Requirements for tape-handling at 11m tracking stations," by J. Ulvestad (February 22, 1993), for further information about local tape-handling decisions. EXAMPLES 323:12:46:40 MADRD_TS BGNRC1=MOUNT,VLBA 323:12:46:00 MADRD_TS BGNRC2=MOUNT,VLBA 323:12:46:00 MADRD_TS BGNRC3=MOUNT,S2 323:16:00:05 USUDA_TS BGNRC1=LOCAL,VSOP_T 323:22:00:20 USSUR_TS BGNRC2=LOCAL,VLBA ---------------------------------------------------------------------------- NAME ENDRC1 - End recording of VLBI data for COREL1 ENDRC2 - End recording of VLBI data for COREL2 ENDRC3 - End recording of VLBI data for COREL3 SYNOPSIS ENDRC1=DISMOUNT/LOCAL,VLBA/VSOP_T/S2 ENDRC2=DISMOUNT/LOCAL,VLBA/VSOP_T/S2 ENDRC3=DISMOUNT/LOCAL,VLBA/VSOP_T/S2 DESCRIPTION The possible values of the first parameter are DISMOUNT or LOCAL, while the values for the second parameter are the same as those used for BGNRCn. In some instances, a tracking station may be asked to begin recording on two drives simultaneously, but to end those recordings at different times. Logically, the type of recorder used is superfluous, since it must be the same as that specified in BGNRCn. However, it should be specified as a consistency check. ENDRC2 is only needed if BGNRC2 has been specified. ENDRC3 is only needed if BGNRC3 has been specified. EXAMPLES 323:15:30:00 MADRD_TS ENDRC1=DISMOUNT,VLBA 323:15:30:00 MADRD_TS ENDRC2=DISMOUNT,VLBA 323:15:30:00 MADRD_TS ENDRC3=DISMOUNT,S2 324:02:00:10 USSUR_TS ENDRC1=LOCAL,S2 324:02:30:00 USSUR_TS ENDRC2=LOCAL,VLBA ---------------------------------------------------------------------------- NAME END2LK - End both uplink and downlink segments of two-way link with spacecraft SYNOPSIS END2LK=VSOP/RASTRON DESCRIPTION This event specifies the end of both the uplink and downlink portions of a 2-way link with the spacecraft. The parameter for this scheduled event should be either VSOP or RASTRON. EXAMPLE 323:15:35:00 MADRD_TS END2LK=VSOP ---------------------------------------------------------------------------- NAME END_UL - End uplink portion of 2-way link SYNOPSIS END_UL=VSOP/RASTRON DESCRIPTION This scheduled event ends the spacecraft uplink portion of a 2-way link, converting the tracking to a downlink-only (1-way) pass. It can have either VSOP or RASTRON as its parameter. In general, changing from 2-way to 1-way links will require initialization of a new tracking session, so this parameter will be used very rarely (or never). EXAMPLE 323:15:35:00 MADRD_TS END_UL=VSOP ---------------------------------------------------------------------------- NAME END_DL - End spacecraft downlink (no uplink involved) SYNOPSIS END_DL=VSOP/RASTRON DESCRIPTION This scheduled event ends the spacecraft downlink portion of a 1-way link. It can have either VSOP or RASTRON as its parameter. EXAMPLE 323:15:35:00 MADRD_TS END_DL=VSOP ---------------------------------------------------------------------------- NAME SET_SC - setting time for spacecraft SYNOPSIS SET_SC=VSOP/RASTRON DESCRIPTION As with RISESC, this event is needed by DSN operations for time allocation purposes. EXAMPLE 323:15:37:00 MADRD_TS SET_SC=VSOP ---------------------------------------------------------------------------- 4.1 LOGICAL ORDER FOR SCHEDULED TRACKING STATION EVENTS The scheduled tracking station events should occur in a certain order to be properly interpreted. The ordering generally is important for those events related to recording of the data. These events should occur in the following sequence: 1) CORELn 2) CNFIGn 3) BGNRCn All the local tape decisions must be made before the beginning of recording actually occurs, and these decisions are driven by the parameters for CORELn and CNFIGn. Therefore, BGNRCn must follow the other two events. The local program must determine whether a tape change will be needed, and must execute any necessary tape change in advance of the beginning of recording. The scheduled event to initialize the tracking session (BGN2LK) or to initialize a 1-way downlink (BGN_DL) always should precede all other events associated with that tracking session, except for the spacecraft rise time (RISESC), and the end of the link (END2LK or END_DL) should follow all other events associated with the particular tracking session, except SET_SC. Some tracking sessions will be used only for establishing a two-way phase link to acquire Doppler data, with no VLBI recording taking place. In such circumstances, the scheduled events used to specify the beginning of recording need not be included in the schedule file. ---------------------------------------------------------------------------- 5.0 GROUND RADIO TELESCOPE EVENTS As stated in Section 1, the SRT schedule file will include a description of the Ground Radio Telescope (GRT) activities, for information purposes only. Two event specifiers will be used, one when the telescope begins observing, and one when it stops observing. These events are described below. ---------------------------------------------------------------------------- NAME GRT_ON - ground radio telescope begins observing SYNOPSIS GRT_ON=source,freq,correlator ~~~~~~ ~~~~ ~~~~~~~~~~ DESCRIPTION The parameter values tell the source name, which should be the same as that used for the Space Radio Telescope, the frequency band (P, L, C, or K), and the destination correlator (in the same form as that used for the events COREL1 COREL2, and COREL3). In many cases, the GRTs may slew to calibrator sources, particularly when the SRT is not observing. The VSOG and RSOG should determine whether to include these details in the SRT Schedule File. EXAMPLE 323:11:30:00 VLBA_SC GRT_ON=ORION-KL,L,VLBA ---------------------------------------------------------------------------- NAME GRTOFF - ground radio telescope stops observing SYNOPSIS GRTOFF=source,freq,correlator ~~~~~~ ~~~~ ~~~~~~~~~~ DESCRIPTION The parameter values should have the same values as for GRT_ON. The VSOG and RSOG should determine whether to include the details of calibration observations in the SRT Schedule File. EXAMPLE 323:19:20:00 VLBA_SC GRTOFF=ORION-KL,L,VLBA ---------------------------------------------------------------------------- 5.1 GROUND RADIO TELESCOPE NAMES The codes for ground radio telescope names are identical to those given in the VSOP Proposer's Guide for telescopes that are included in that Proposer's Guide, with the exception of individual names for the 10 VLBA telescopes. The EVN and VLBA are included as arrays in case it should be found convenient to specify these arrays as such rather than giving the names of each individual telescope. Additional telescope names that may be needed for RadioAstron are included, but are subject to possible later change by the RSOG. The current list of names is given below, in alphabetical order according to the accepted telescope name (not the coded designation): ---------------------------------------------------------------------------- Code Telescope AR Arecibo 305m BL Bear Lake AT Narrabri (Australia Telescope Compact Array) CD Ceduna EB Effelsberg EV Evpatorija GM Giant Metre-Wave Radio Telescope GO Goldstone GB Green Bank 43m HH Hartebeesthoek HO Hobart JB26 Jodrell Bank Mark 2 JB76 Jodrell Bank 76m KA Kashima KL Kalyazin MC Medicina MH Metsahovi MP Mopra NO Nobeyama NT Noto ON85 Onsala 25m ON60 Onsala 20m OO Ooty PA Parkes PU Puschino RO Robledo (Madrid) SH Shanghai SM Simeiz TI Tidbinbilla TR Torun UR Urumqi US Ussurijsk UD Usuda YL VLA WB Westerbork BR VLBA Brewster station FD VLBA Fort Davis station HN VLBA Hancock station KP VLBA Kitt Peak station LA VLBA Los Alamos station MK VLBA Mauna Kea station NL VLBA North Liberty station OV VLBA Owens Valley station PT VLBA Pietown station SC VLBA Saint Croix station ---------------------------------------------------------------------------- 6.0 LIST OF SCHEDULED EVENTS Below, we list, in alphabetical order, the individual scheduled events for spacecraft, tracking stations, and ground telescopes. These are the only events that will be included in the SRT Schedule File. ---------------------------------------------------------------------------- 6.1 VSOP SPACECRAFT EVENTS ANTMOV - spacecraft telescope begins moving to radio source CRSSCN - cross scan control event DC_ATT - control attenuator in down converter DR_REC - start on-board data recorder DRSTOP - stop on-board data recorder IFSLCT - select IF of A/B channel KRXPLL - search width of KRX phase lock loop KRXSWP - switch of sweep mode of phase lock loop NDMODE - noise source switch mode OBSCOD - observation code for spacecraft OFF_TS - release link antenna pointing ON_SRC - defines when space telescope is expected to be on source ON_TS - Ku link antenna is expected to point to tracking station PCALSW - switch of phase calibration signal PWROFF - power off instrument PWR_ON - power on instrument REFMOD - set reference signal divider mode SETFRQ - set frequency of SYNTH-A/B for IRM SET_TS - start to point Ku link antenna toward selected tracking station SSFMOD - set mode of formatter on board (SSF) TLMFMT - change VSOP satellite telemetry format ---------------------------------------------------------------------------- 6.2 RADIOASTRON SPACECRAFT EVENTS BRST_1 - boresighting procedure in scanning mode BRST_2 - boresighting procedure in cross-points mode COMSES - command transmission session LINKTR - switch spacecraft transponder on or off NDMODE - define switching mode for noise source OBSCOD - observation code for spacecraft OBSERV - start or finish transmission of science data OFFSRC - release space telescope from pointing at source OFF_TS - release link antenna pointing ON_SRC - defines when space telescope must be on source ON_TRK - Link antenna(s) is (are) expected to point to tracking station ORBMES - range/range-rate measurements at C band PCALSW - switch phase calibration on or off for given frequency REFMOD - set reference signal divider mode RVSLCT - selects receiver/formatter combination and turns receiver on SCISYS - power scientific equipment on or off SET_TS - point link antenna to tracking station SSFMOD - set mode of formatter on board TECSER - spacecraft technical service TMFORM - housekeeping telemetry transfer into science headers ---------------------------------------------------------------------------- 6.3 TRACKING STATION EVENTS BGN2LK - begin establishing two-way phase link (beacon on) BGN_DL - begin one-way downlink (no beacon) BGNRC1 - Specifies time to begin recording wideband VLBI BGNRC2 - Same as BGNRC1, for COREL2. BGNRC3 - Same as BGNRC1, for COREL3. CALMES - begin or end single or periodic extraction of phase-cal tones CNFIG1 - specifies the configuration for recording for 1st correlator CNFIG2 - specifies the configuration for recording for 2nd correlator CNFIG3 - specifies the configuration for recording for 3rd correlator COREL1 - tells name of first destination correlator COREL2 - tells name of second destination correlator COREL3 - tells name of third destination correlator END2LK - end both uplink and downlink portions of a two-way link END_DL - end one-way downlink END_UL - end uplink portion of 2-way link, and convert to 1-way downlink ENDRC1 - End recording of VLBI data for COREL1 ENDRC2 - End recording of VLBI data for COREL2 ENDRC3 - End recording of VLBI data for COREL3 OBSCOD - Observation code for tracking session RISESC - spacecraft rise time SET_SC - setting time for spacecraft ---------------------------------------------------------------------------- 6.4 GROUND RADIO TELESCOPE INFORMATION GRT_ON - ground radio telescope begins observing GRTOFF - ground radio telescope stops observing ---------------------------------------------------------------------------- 7.0 SAMPLE SRT SCHEDULE FILES Below, we give two sample SRT Schedule Files, one for VSOP and one for RadioAstron, created according to the rules and specifications given above. ---------------------------------------------------------------------------- 7.1 SAMPLE SRT SCHEDULE FILE FOR VSOP $SPACE_VLBI START=1996:351:12:00:30 STOP=1996:358:00:38:20 $NUM_OF_LINES=583 # Created by Y.Murata 1996:315:12:00:00 # Modified by H.Kobayashi 1996:320:12:00:00 351:12:00:30 VSOP_SC OBSCOD=VT02A 351:12:00:30 VSOP_SC PWR_ON=OBSLNK 351:12:00:30 VSOP_SC PWR_ON=OBS22 351:12:00:31 VSOP_SC PWR_ON=OBSS 351:12:00:31 VSOP_SC PWR_ON=OBSA 351:12:00:31 VSOP_SC PWR_ON=OBSB 351:12:01:33 VSOP_SC KRXSWP=OFF 351:12:01:33 VSOP_SC KRXPLL=NARROW 351:12:01:33 VSOP_SC REFMOD=EXT 351:12:01:33 VSOP_SC DC_ATT=K,21 351:12:01:34 VSOP_SC IFSLCT=K,K 351:12:01:34 VSOP_SC SSFMOD=32,2,2,AB 351:12:01:34 VSOP_SC SETFRQ=A,550 351:12:01:34 VSOP_SC SETFRQ=B,516 351:12:01:35 VSOP_SC TLMFMT=AOCS,L 351:12:01:35 VSOP_SC DR_REC=CYCLE 351:12:11:03 VSOP_SC ANTMOV=0528+134,05H28M07.000S,+13D29M42.25S,1950,0 351:12:15:00 VLBA_SC GRT_ON=ORION-KL,L,VLBA 351:12:15:00 VLBA_MK GRT_ON=ORION-KL,L,VLBA 351:12:15:00 VLA GRT_ON=ORION-KL,L,VLBA 351:12:19:03 VSOP_SC ON_SRC=0528+134,05H28M07.000S,+13D29M42.25S,1950,0 351:12:19:04 VSOP_SC DRSTOP 351:12:19:04 VSOP_SC TLMFMT=OBS,H 351:12:20:45 VSOP_SC PCALSW=ALL,ON 351:12:20:45 VSOP_SC SET_TS=USUDA,N 351:12:23:45 VSOP_SC ON_TS =USUDA,N 351:12:25:32 USUDA_TS RISESC=VSOP 351:12:28:45 USUDA_TS BGN2LK=VSOP 351:12:28:45 USUDA_TS OBSCOD=VT02A 351:12:28:45 USUDA_TS CALMES=AUTO,10,60 351:12:29:10 USUDA_TS COREL1=NAO 351:12:29:10 USUDA_TS CNFIG1=002 351:12:29:10 USUDA_TS BGNRC1=LOCAL,VLBA 351:12:30:45 VSOP_SC NDMODE=K,AUTO,HIGH 351:12:32:45 VSOP_SC NDMODE=K,OFF,HIGH 351:13:00:34 VSOP_SC NDMODE=K,AUTO,HIGH 351:13:02:35 VSOP_SC NDMODE=K,OFF,HIGH 351:13:34:05 VSOP_SC NDMODE=K,AUTO,HIGH 351:13:36:07 VSOP_SC NDMODE=K,OFF,HIGH 351:14:02:05 VSOP_SC NDMODE=K,AUTO,HIGH 351:14:04:13 VSOP_SC NDMODE=K,OFF,HIGH 351:14:28:45 USUDA_TS CALMES=END,10,60 351:14:30:52 USUDA_TS ENDRC1=LOCAL,VLBA 351:14:30:52 USUDA_TS END2LK=VSOP 351:14:34:24 USUDA_TS SET_SC=VSOP 351:14:35:00 VSOP_SC OFF_TS 351:14:42:00 VSOP_SC SET_TS=GOLDS 351:14:45:00 VSOP_SC ON_TS =GOLDS 351:14:52:14 GOLDS_TS RISESC=VSOP . . . 357:23:10:00 GOLDS_TS RISESC=VSOP 357:23:12:00 GOLDS_TS BGN2LK=VSOP . . . 358:00:35:07 GOLDS_TS ENDRC1=LOCAL,VLBA 358:00:35:07 GOLDS_TS ENDRC2=LOCAL,S2 358:00:35:10 GOLDS_TS END2LK=VSOP 358:00:38:20 GOLDS_TS SET_SC=VSOP 358:00:39:00 VSOP_SC OFF_TS $END_OF_FILE ---------------------------------------------------------------------------- 7.2 SAMPLE SRT SCHEDULE FILE FOR RADIOASTRON Note that the following schedule begins with a U.S. tracking station employing a VLBA recorder and an S2 recorder, even though there are no confirmed plans to install S2 recorders in any U.S. tracking stations. $SPACE_VLBI START=1997:349:03:00:00 STOP=1997:356:02:00:20 $NUM_OF_LINES=455 # Created by V.Yakimov 1997:325:12:00:00 # Modified by V.Yakimov 1997:340:12:00:00 # Note power to RadioAstron equipment turned on before observation # takes place. Lead time invented by JU - may really be longer # or shorter for receivers to settle. 349:13:45:00 RA_SC RVSLCT=LR,1 349:13:45:00 RA_SC RVSLCT=LL,2 349:13:45:00 RA_SC SSFMOD=16,2,1,AC 349:13:45:00 RA_SC REFMOD=EXT 349:13:45:00 RA_SC SCISYS=ON 349:14:54:00 RA_SC PCALSW=L,ON 349:14:54:00 RA_SC NDMODE-L,AUTO,LOW 349:14:54:15 RA_SC LINKTR=ON 349:14:54:15 RA_SC TMFORM=ON 349:14:54:30 RA_SC ON_SRC=3C273,12H29M06.700S,+02D03M08.60S,2000,0 349:14:54:30 RA_SC OBSCOD=R022A 349:14:55:00 US GRT_ON=3C273,L,MOSC 349:14:55:00 PA GRT_ON=3C273,L,MOSC 349:14:55:00 TI GRT_ON=3C273,L,VLBA 349:14:59:40 RA_SC ON_TRK= MADRD 349:15:00:00 MADRD_TS RISESC=RASTRON 349:15:02:00 MADRD_TS BGN2LK=RASTRON 349:15:02:00 MADRD_TS OBSCOD=R022A 349:15:02:00 MADRD_TS CALMES=BEGIN,10,60 349:15:02:00 MADRD_TS COREL1=VLBA 349:15:02:00 MADRD_TS COREL2=MOSC 349:15:02:00 MADRD_TS CNFIG1=103 349:15:02:00 MADRD_TS CNFIG2=503 349:15:02:30 MADRD_TS BGNRC1=LOCAL,VLBA 349:15:02:30 MADRD_TS BGNRC2=LOCAL,S2 . . . 355:23:00:00 GBANK_TS BGN2LK=RASTRON . . . 356:01:55:00 GBANK_TS END2LK=RASTRON 356:01:55:07 GBANK_TS ENDRC1=LOCAL,VLBA 356:01:55:07 GBANK_TS ENDRC2=LOCAL,S2 356:02:00:20 GBANK_TS SET_SC=RASTRON $END_OF_FILE ---------------------------------------------------------------------------- APPENDIX A: CONSTRAINTS OF DSN TRACKING STATIONS (JSU, 5/17/96) This appendix describes the constraints on the SRT Schedule File for VSOP tracking, as imposed by the implementation of the DSN 11-m subnet. (1) Parameter Changes No parameters of a given tracking pass can be changed during the tracking pass, with the exception of starting and stopping recorders. If the station configuration is to be changed, this should be done by ending a tracking pass and beginning a new tracking pass. Examples of items that can only be changed by initiating a new tracking pass include changes between 1-way and 2-way tracking, changes between 16-track and 32-track recording, and changes in phase-calibration extraction. (2) Phase Calibration Tones Extracted The DSN stations currently have only 1-bit tone extraction. At any time that the SRT Schedule File requests extraction of phase calibration tones, the following method will be followed: For the standard VSOP international mode (two 16-MHz channels, each with 2-bit sampling), the 16 tone extractors are configured so that 8 of them can extract tones from a single A/D converter (sign bit) of Channel A, while the other 8 can extract tones from a single A/D converter of Channel B. These A/D channels actually contain undersampled data, but all extractors are set up to the A/D channels containing samples from times 0,4,8,12,... 4n, so that there is no additional phase offset between tones because of a time offset between data from different A/D channels. The current plan is that the DSN stations will be configured to extract tones at the frequencies of 1, 3, 5, 7, 9, 11, 13, and 15 MHz within each channel. This set of tones should enable appropriate linear combinations to be made to reduce the effects of aliasing, although the current plan is that JPL will not make such linear combinations. The selection of tones can be changed if requested by the VSOG. The final set of frequencies will be defined elsewhere, and cannot be selected for individual tracking passes using the SRT Schedule File. No special provision has been made to extract different tones for the other VSOP (non-VLBA-compatible) observing modes. If such observing modes are used, it is assumed that tone extraction will be performed by the VSOP correlator. (3) Phase Calibration Integration Time The DSN can support three different reporting intervals for phase calibration tones: 2, 10, and 60 seconds. These correspond to tone integration times of 1, 9, and 9 seconds respectively. During discussions held during March 1996, the VSOP Project stated that no tone reporting intervals shorter than 60 seconds would be requested. Therefore, for any tracking pass when the DSN is asked to extract tones, it will extract tones with a 9-second integration time, reporting them at 60-second intervals. The DSN also can turn off the process of tone extraction for a tracking pass if no tone extraction is requested. As stated in (1) above, there is no capability to turn tone extraction on and off during a tracking pass, but the extraction must be either "on" or "off" for the entire tracking session. (4) Doppler Modes The DSN tracking stations support two Doppler tracking modes. In the "Doppler-only" mode, a 4-kHz filter (+/- 2 kHz from nominal) is employed, and no phase residuals are measured; therefore no Delta-t file can be created. In the "Full-phase" mode, a 400-Hz filter (+/- 200 Hz from nominal) is employed, and the full set of phase residuals is extracted, enabling creation of a Delta-t file. Selection between these two modes will be made based on the presence or absence of wideband data recording during a tracking pass. If no wideband recording is requested (i.e., there is no entry of type BGNRCn), the Doppler-only mode will be employed. If wideband recording is requested, the Full-phase mode will be used. If the VSOG would like measurement of phase residuals during a pass that does not include any scientific observing by the spacecraft, they must specify a short recording session at the beginning of that tracking session. (5) Formatter Mode The stations contain only a single formatter. Therefore, only a single configuration of that formatter is possible. It is not possible to record two VLBA tapes, one in 16-track mode and one in 32-track mode. Either the 16-track or the 32-track mode must be selected for both tapes. (6) Correlator and Configuration Selection A BGNRCn entry must have corresponding CNFIGn and CORELn entries preceding the BGNRCn entry. The selected correlator and configuration must correspond to the type of tape recording made. Possible combinations are the following: BGNRCn CNFIGn CORELn ------ ------ ------ VLBA 001 VLBA, NAO, EVN_JIVE, HSTK VLBA 002 NAO VSOP_T 201 Not possible for DSN tracking stations S2 401 NAO, EVN_JIVE, CANADA, ATNF, MOSC S2 402 NAO, EVN_JIVE, CANADA, ATNF, MOSC S2 403 NAO, EVN_JIVE, CANADA, ATNF, MOSC (7) Markers for Tracking Passes The beginning of a tracking pass is marked by either the BGN2LK entry or the BGN_DL entry, while the end is marked by either the END2LK or the END_DL entry. All setup and operations information for the tracking pass must be included between the markers of the beginning and the end of the pass, including the observation code and all information about recorders. (8) Set-up and Acquisition Time A minimum of ONE MINUTE should be allowed between tracking passes in order to allow for reconfiguration. Pre-pass tests at the DSN stations are carried out automatically, depending on the amount of time available. After the beginning of the tracking pass, no extra period of time needs to be allowed for signal acquisition. For example, wideband data recording can be commanded to begin immediately after the command to begin the link to the spacecraft. (9) Tape Management The VSOG should request that tape changes be forced no more than twice per day, either because of a change of correlators or because of a desire to remove a tape for tests such as rapid fringe checks. Local tape management is determined based on the parameters in the BGNRCn and ENDRCn commands, as well as by the choice of correlators. When LOCAL control of tapes is specified, no tape will be allowed to remain on the recorder longer than about 3 days. When a tracking pass requests a correlator different from the one used in the previous pass, the old tape will be dismounted and a new tape will be mounted. (10) Tape Recording Capability A total of 10 arrays of start and stop times may be used during a given tracking pass. These 10 entries may be allocated in various ways, depending on the combination of recorders that is used. In general, there are more constraints on the use of VLBA tapes than on the use of S2 tapes, because the VLBA tape usage is constrained within the station software, while the S2 requests are simply passed on to "external" software supplied by the Canadian Space Agency. Note that recorder numbers specified in the SRT Schedule File are taken to refer to "logical" recorders, not to "physical" recording systems. For example, if the entry BGNRC1 is received for a VLBA recorder, this may be implemented on either of the two VLBA recorders, depending on the dynamic tape allocation performed at the stations. (a) Option A: 1 VLBA Recorder A maximum of 10 start and stop times (i.e., 10 BGNRC1 and 10 ENDRC1 entries) is allowed. (b) Option B: 1 S2 Recorder A maximum of 9 start and stop times is allowed. The 10th possible entry must be reserved for internal DSN use in order to initialize various processes related to data recording and phase residual extraction. Some operation of a VLBA recorder is necessary during the tracking session for this initialization, but the specification of VLBA recorder operation will be handled internally within JPL, and does not need to be supplied in the SRT Schedule File. (c) Option C: 2 VLBA Recorders A maximum of 5 start and stop times is allowed for each recorder. All tape activity must be simultaneous; i.e., the BGNRCn and ENDRCn entries must be simultaneous for the two tapes. The tracking session will begin with a new tape mounted on each recorder, and will end with both tapes being dismounted for mailing to the desired correlator. If it is desired to have simultaneous recording for only part of a period of spacecraft visibility, that visibility period must be broken into two tracking sessions, one that has simultaneous recording and one that does not. (d) Option D: 1 VLBA Recorder and 1 S2 Recorder A total maximum of 10 starts and stops is allowed. The tape activities do not need to be simultaneous, so it is possible to use 1 start/stop for the VLBA tape and 9 for the S2 tape, or 9 for the VLBA tape and 1 for the S2 tape, or anything in between. (e) Option E: 2 VLBA Recorders and 1 S2 Recorder A total maximum of 10 starts and stops is allowed. The 2 VLBA tapes must operate simultaneously; new tapes will be mounted at the start of the session, and both tapes will be dismounted at the end (see Option C above). The activities of the S2 recorder are not constrained. Therefore, it is possible to have 1 start and stop for each VLBA tape and 8 starts and stops for the S2 tape, or 4 starts and stops for each VLBA tape and 2 for the S2 tape, or some combination in between. ---------------------------------------------------------------------------- APPENDIX B: CONSTRAINTS OF GREEN BANK TRACKING STATION (TBS) This appendix describes the constraints on the SRT Schedule File for VSOP tracking, as imposed by the implementation of the Green Bank Earth Station ----------------------------------------------------------------------------