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The structure of CORONAS-Photon onboard telemetry and command systems

The structure of CORONAS-Photon onboard telemetry and command systems Alexander Glyanenko, IAF MEPHI, Moscow, Russia. Organization of electrical links onboard the satellite. O nboard control.

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The structure of CORONAS-Photon onboard telemetry and command systems

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  1. The structure of CORONAS-Photon onboard telemetry and command systems Alexander Glyanenko, IAF MEPHI, Moscow, Russia.

  2. Organization of electrical links onboard the satellite

  3. Onboard control Control of onboard equipment (OE) spacecraft is made by an onboard complex of control (OCC) which provides: - Reception from a ground complex of management (GCM) and direct delivery to SD single and pulse commands of control (PCC) with rate is not more often, then 1 command in 2 sec; - Reception from GCM frames of Control Data (FCD) with rate 1-2 per sec and their delivery as SD messages with volume up to thirty 16-th digit information words with set with GCM rate (0÷2000 ms). FCD are transferred aboard spacecraft by files. One file can contains from 1 up to 16 phrases (maximum). Each phrase will consist of 32 16-bits words. First and last words of a phrase are service - heading and the control sum of a phrase. Other words - details (if the data do not fill all of 30 words, other words are filled by zero). In total aboard spacecraft for a communication session can be transferred up to 56 Kbit information, i.e. no more than seven full (16 phrases) FCD files; - Program control of SD with delivering (under the programs incorporated in OCC or under tasks from GCM in FCD) program pulse commands (PC) and program code commands of management; - Delivery of phrases of the service information in volume up to thirty words of the data (without taking into account service words).

  4. Onboard control

  5. Commands • program pulse commands: • Pulse with duration 0,1  0,3 sec, Ucom= +27(-3/+7)V. Attention! Ground line for command must be decoupled with ground line of satellite power supply and with case of device! • Dry contacts – pulse on/off with duration 0,1  0,3 sec, or type of switch on/ switch off. (Example – shadow/light) • New type of command – bad/good (give us information about presence of satellite in high breadths.

  6. Commands

  7. Onboard Power Supply Power Supply • +27 (-3/+7)V • Umax=34,6 V (T<5s) Attention! Ground line for power supply must be decoupled with ground line of satellite command and with case of device!

  8. Scientific telemetry System (SSRNI) • SSRNI is system, which provides: • Data acquisition from scientific devices and Satellite Telemetry System (Scientific Data) • Storage data in mass memory and transmission this data to ground station • Transmission of onboard time code (KBV) to scientific devices • Transmission of control word (UKS) to scientific devices

  9. Scientific telemetry System (SSRNI) Reception of the scientific information from Scientific Devices (SD)to SSRNI system is carried out by frames on 960 bits in a consecutive code. Link speed for one channel- 62.5 kbits/sor 125 kbits/s.

  10. SSRNI Data Interface with scientific device • All scientific devices (SD) in SSRNI has unique personal number (Number of SSRNI Channel). Data and Control Cannels of SSRNI has the same number • SSRNI has 24 independent channels for SD. • Total volume of mass memory in SSRNI is 1,5 GB. The memory allocation between SD is installed according to quotas. Quota is the maximum volume of Data, which may be stored in mass memory for one session of observations. If volume is exceeded, no more data from SD can be stored in SSRNI in current session.

  11. SSRNI Data Interface with scientific device 4. Fixed volume for data from STS – 55 Mbits 5. Internal SSRNI data 1/64 from total data Volume. 6. In case of internal SSRNI error-free coding volume of mass memory decreases as 16:11 7. 4 different quota tables, working table can be changed by commands from Earth. 8. Possibility to create special quota table for one session.

  12. SSRNI Data Interface with scientific device Quota requests (preliminary)

  13. SSRNI Control and Time Interface with SD For maintenance of time binding the scientific devices data and for control of scientific devices SSRNI provides delivery on the special multiplexed line with time division of special sendings of the consecutive code containing or the data on a code of onboard time (KBV), or control information (UKS). Each types of information sendings is synchronized by a corresponding signal of support («Synchro KBV» and «Synchro UKS»). System SSRNI receives from Onboard Time System a 38-digit consecutive code of onboard time scale (OTS), as sequence of pulses with clock frequency 125 KHz, accompanied by labels “1 ms” and "1sec". System SSRNI carries out transformation of OTS code to format KBVand gives out to scientific devices. KBVrepresents a 32-bit consecutive potential binary code in support synchronization pulses62.5 KHz(signal “Clk U-K") and a signal Synchro KBV (a label – 1 ms) and labels 1 sec. Senior category KBVis given out to the first.

  14. SSRNI Control and Time Interface with SD The system SSRNI carries out transformation of the commands received on channel 1553b from onboard satellite computer, to 16-th digit control code words (UKS) and gives out to scientific devices. UKSrepresents 16-th digit code which is given out under the consecutive circuit accompanied by clock pulses (signal “Clk U-K") and a strobe («Synchro UKS»). The strobe of the data is individual for each scientific device. The number of independent outputs of the control information corresponds to number of SD. The first bit of UKS is older bit.

  15. SSRNI Control and Time Interface with SD

  16. SSRNI Control and Time Interface with SD Format of UKS from SSRNI to SD

  17. SSRNI Control and Time Interface with SDFormat of UKS from SSRNI to SD

  18. For the control of all scientific devices (SD) of CORONAS-Photon the next resources are available: • Up to 160 pulse commands with duration 0,10,3 sec and amplitude that is equals to satellite power; “dry contacts” – pulse on/off and (switch on)/(switch off) type (OCC→BUS-FM). • Special commands “shadow/light” and “bad/good’ (location of the satellite in high latitudes or in the SAA region), (OCC→BUS-FM). • 16-bits digital commands (UKS) to operate by scientific devices (OCC→SSRNI by 1553b-channel). For data acquisition in CORONAS-Photon project the next resources of two telemetry systems are used by SD: • Satellite Telemetry System (STS) – 131 digital, 34 analogs and 21 thermo-sensors; • Scientific Telemetry System (SSRNI) with the next possibilities: • Up to 24 individual information channels for SD with link speed for one channel - 62.5 kbits/s or 125 kbits/s • Total mass memory up to 1.5 GB, the memory allocation between SD’s is installed according to quotas. • Additional data from STS throw OCC to SSRNI by 1553b–channel; • Ground data link with link speed 7.68 Mbits/s or 15,36 Mbits/s at frequency 8,2 GGz (depending on coding algorithm in the link session). Including into operational network units not only from scientific complex, but all needed units from satellite systems. It is allowed to realize a flexible, convenient infrastructure for management and data acquisition from scientific equipments and to expand opportunities of experiment.

  19. Thanks you for attention

  20. SSRNI Data Interface with scientific device Data exchange between SD and SSRNI realises by the frames with volume 960 bits. For transfer information SD should generate a signal «Data Ready» (DR) after will save up and it will be ready to transfer at least one frame of the information (960 bits). When SSRNI begin to read data from SD, it generate signal «Receive Data» (RD) and serial synchronization pulses «Clk Data». Signal DRshould be established during a delay of reading data and during time of transfer of a frame (frames). SD must change it’s information on log”0”log”1” edge of pulse «Clk Data». The signal DR can be removed (be taken off) by SD at any time after the beginning of a transmitting of last frame, but not later than front of a pulse «Clk Data» of the last bit. Delivery of a signal «Clk Data» is accompanied by a signal «Receive Data», generated by SSRNI. Signal RDis established for the period of transfer of each frame. System SSRNI removes signal RDin intervals between accepted files. Maximal time of a pause between accepted files for one SDdoes not exceed 24 ms. Data exchange between SD and SSRNI

  21. The parameters of signals «Data Ready» and «Data» formed SD: Level of log. «1» - from +2,7up to + 5,5 V; Level of log. «0» - from 0 up to + 0,5 V; Duration of edges - no more than 0,5 mks; Load on each signal: Resistance - not less than 10 KOm; Capacity (incl. capacity of cable) - no more than 500 pF. Everyone from signals «Data Ready» and «Data» should be transmitted simultaneously by two outputs (Out1 and Out2) rather common wire. The question about galvanic decoupling between SD and SSRNI for separate instruments should be decided as agreed with MEPhI. Parameters of signals «Receive Data» and «Clk Data», formed by SSRNI: Level of log. «1» - from +2,7up to + 5,5 V; Level of log. «0» - from 0 up to + 0,5 V; Duration of edges - no more than 0,5 mks; Porosity of pulses «Receive Data» and «Clk Data» (during transmission of the block) - 20,1; Load on each signal: Resistance - not less than 10 KOm; Capacity (incl. capacity of cable) - no more than 500 pF. Everyone from signals «Receive Data» and «Clk Data» should be transmitted in parallel on two independent lines. Parameters of SSRNI and SD signals(Data Channel)

  22. SSRNI Control and Time Interface with SD

  23. SSRNI Control and Time Interface with SD For maintenance of time binding the scientific devices data and for control of scientific devices SSRNI provides delivery on the special multiplexed line with time division of special sendings of the consecutive code containing or the data on a code of onboard time (KBV), or control information (UKS). Each types of information sendings is synchronized by a corresponding signal of support («Synchro KBV» and «Synchro UKS»). System SSRNI receives from Onboard Time System a 38-digit consecutive code of onboard time scale (OTS), as sequence of pulses with clock frequency 125 KHz, accompanied by labels “1 ms” and "1sec". System SSRNI carries out transformation of OTS code to format KBVand gives out to scientific devices. KBVrepresents a 32-bit consecutive potential binary code in support synchronization pulses62.5 KHz(signal “Clk U-K") and a signal Synchro KBV (a label – 1 ms) and labels 1 sec. Senior category KBVis given out to the first.

  24. SSRNI Control and Time Interface with SD The system SSRNI carries out transformation of the commands received on channel 1553b from onboard satellite computer, to 16-th digit control code words (UKS) and gives out to scientific devices. UKSrepresents 16-th digit code which is given out under the consecutive circuit accompanied by clock pulses (signal “Clk U-K") and a strobe («Synchro UKS»). The strobe of the data is individual for each scientific device. The number of independent outputs of the control information corresponds to number of SD. The first bit of UKS is older bit.

  25. SSRNI Control and Time Interface with SD

  26. SSRNI Control and Time Interface with SD • Details of transmission sinchronisation

  27. Parameters of UKS-channel signals : Level of log. «1» - from +2,7up to + 5,5 V; Level of log. «0» - from 0 up to + 0,5 V; Duration of edges - no more than 0,5 mks; Frequency of signal “Clk U-K" - 62,5 KHz; Porosity of signal "Clk U-K" - 2±0.1; Duration of a signal «Synchro UKS» - 256 mks; Load on each signal: Resistance - not less than 10 KOm; Capacity (incl. capacity of cable) - no more than 500 pF. Parameters of KBV-channel signals, and also signals «Clk U-K», “Synchro KBV» («1 ns») and «1 sec» formed by system SSRNI: Level of log. «1» - from +2,7up to + 5,5 V; Level of log. «0» - from 0 up to + 0,5 V; Duration of edges - no more than 0,5 mks; Frequency of signal “Clk U-K" - 62,5 KHz; Porosity of signal "Clk U-K" - 2±0.1; Duration of a signal «Synchro UKS» - 512 mks; Duration of a signal «1 sec»-512 mks; Loading on each signal: Resistance - not less than 10 KOm; Capacity (incl. capacity of cable) - no more than 500 pF. Pulses of signal "Clk U-K" are transferred only during transfer of code KBV. Parameters of SSRNI and SD signals(Control and Time Channels)

  28. Recommended circuits of interfaces SSRNI and SD

  29. Recommended circuits of interfaces SSRNI and SD

  30. Format of UKS from SSRNI to SD

  31. Format of UKS from SSRNI to SD Notes: • 1. The control sum of the message is formed SSRNI by addition on the module 2 (excluding OR) for all words #3 - #(N+3). • 2. Formats and structure of words transmitted on devices are defined by developers of devices. • 3. If during a communication session meet M information blocks for one device, SSRNI forms M separate messages with a format determined in Table 1.5.3 for the given device. • 4. The order of delivery UKS-NA in SD coincides with order of reception UKS-NA on 1553b (MKO). • 5. If in a field Number of words for the device is value 0, the given message will consist only of a marker, heading and the control sum. The period of message UKS-NA delivery is defined by the interface and cannot be less than 1 мs.

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