AMSAT OSCAR-13 TELEMETRY BLOCK FORMAT Compiled by DB2OS for AMSAT-DL 01Sep88 Edits by James Miller G3RUH AO-13 TELEMETRY SYSTEM Oscar-13 transmits most of its telemetry at 400 bps using PSK. Frequencies used are the General Beacon on 145.810 MHz, 435.656 MHz or 2400.646 MHz. Sometimes the stronger Engineering Beacon may be heard for a few minutes on 145.983 MHz or 435.677 MHz. [Note: 435 MHz TX is now defunct]. MODULATION FORMAT The spacecraft digital information at 400 bits/sec is first differentially encoded so that a message "1" is represented by a change in the data stream, and a message "0" by no change. This data is then exclusive-ored with its 400 Hz clock to create Manchester coding. Finally this stream is passed through a gentle low pass filter (3 db point = 560 Hz) to remove extraneous sidebands and then balanced modulated onto the RF carrier to create PSK. Differential encoding is used, similar to packet radio systems, to ensure that channel and decoder polarity inversions are of no consequence; it's the changes that matter, not the absolute polarity. BLOCKS AMSAT OSCAR-13 (like all P3-Satellites) transmits 512 byte blocks preceded by a four byte synchronisation sequence (hex 39 15 ED 30), and followed by a two byte checksum (CRCC) and then a 3 second pause consisting of hex 50. A byte consists of 8 bits and is transmitted serially, MSB first. Blocks are identified according to the first byte of the block (followed by space, coded as #20). K, L, M, N blocks are message blocks (flying mailbox) from one command station to another, but also used for broadcast. All characters use ASCII representation. Bit 7 set to 1 may be used to indicate highlighted character display. No CR/LF will be transmitted, they should be inserted at the ground after 64 received characters! Q blocks carry 128 logical telemetry channels in compressed data format. Y blocks carry 64 plain text analog telemetry channels and will be sent infrequently (less than Q-blocks). It is proposed to use the Q-blocks for decoding, since Y-Blocks may be withdrawn in the feature. Q-Block format: Q HI, THIS IS AMSAT OSCAR 13 hh:mm:ss dddd #hhhh #hhhh #hhhh ddd ddd ddd ddd ddd ddd ddd 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF Line specification: Line 0: Byte pos.= 0 2 48 58 hh:mm:ss dddd U T C AMSAT day number 1 January 1978 = 0 Line 1: Byte pos.= 0 8 16 #hhhh #hhhh #hhhh safety transponder command information status number word (Syspage (see below) byte #5E) Safety Information Word (Emergency Flags): bit significance 0..7 as Syspage byte #56 8 Low Power, QRP mode 9 Extremly low power, QRPP mode 10 Command loss (Watchdog) 11 High temperature (battery or transponder) 12 Sunangle exceeds limit (~50 degrees) 13..15 not used Line 2: Byte pos.= 0 4 8 12 16 20 24 ddd ddd ddd ddd ddd ddd ddd 2MUX0 2MUX1 2MUX2 2MUX3 2MUX4 2MUX5 2MUX6 (Syspage #40 #41 #42 #43 #44 #45 #46) Line 3: empty, blank line. Line 4: Byte = 0 10 20 30 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF Line 5: Byte = 40 50 60 70 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF Line 4 and 5 are the telemetry channels #00 to #7F of the INTERMEDIATE EVENT SYSPAGE buffer. Up to 8 (*) events stored, 128 bytes per event. The buffers are read out cyclically, one event at a time. The time recorded and the event counter identify the particular event. (*) Note: This can be altered by command ground control. Line 6: Byte = 0 10 20 30 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF Line 7: Byte = 40 50 60 70 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF Line 6 and 7 are the SYSPAGE logical telemetry channels #00 to #7F, normally used to display realtime telemetry. Decode according to the OSCAR-13 telemetry decoding document. Bytes are expressed directly, not as character values. In Y-Blocks only SYSPAGE channels #00 to #3F (analog channels) are transmitted in ASCII (16 channels per line, 4 bytes per channel)!! Example for Y-Blocks: Y HI, THIS IS AMSAT OSCAR 13 19:22:41 3894 #00A6 #0020 #0193 64 1 255 166 19 230 0 193 7 147 7 193 7 164 117 200 7 130 25 118 7 149 32 7 7 133 7 13 7 131 112 14 7 131 7 112 7 131 7 155 129 134 148 191 145 132 142 75 145 132 7 228 129 127 7 179 129 126 128 62 141 132 7 13 127 124 7 208 133 125 7 ---------------------------------------------------------------------------- Logical Telemetry Channels SYSPAGE This document describes the decoding of the 128 logical telemetry channels of the AMSAT Phase 3C satellite, OSCAR-13. Bytes are counted in the followings ways: C - unsigned count (0 to +255) Cs - signed count (-128 to +127, 2s complement) Cx - signed count (+63 to -192, #3F=+63, #FF=-1, #80=-128, #7F=-129, #40=-192, modified 2s complement) All temperature channels are decoded identically using the following decoding relationship: Temp: T = (C-120)/1.71 Celsius Current channels are linear, but have different calibrations for 1A, 2.5A and 5A max. current: 1A: I = (C-15)*4.854 mA 2.5A: I = (C-15)*12.135mA 5A: I = (C-15)*24.27 mA Channel identification and decoding equations: Byte Channel Calibration Remarks 00 Uin-BCR U=(C-10)*167mV U-Panel: +0.6V @ 0.35A +0.7V @ 1A 01 Tx-PWRout-L Average power=(261-C)^2 / 724 Watts rectified envelope voltage. 02 T-Rx-U Temp Mode-B reveiver temperature. 03 --- 04 Uout-BCR U=(C-10)*79.5mV BCR output voltage. 05 --- 06 T-TX-U Temp Mode-B transmitter temperature. 07 I-14V-ST 5A Transponder separation bus. 08 U-10V-C U=(C-10)*53.2mV Computer supply 09 Press He-Hi off Helium tank pressure. 0A T-IHU Temp Integrated Housekeeping Unit 0B I-14V-S 1A Separation bus, 14V that supplies torquer and LIU. 0C BCR-Oscill1 >~6=OK BCR status. No count = not working. Typically C=80. 0D Press He-Lo off Helium regulator output. 0E T-BCR Temp Battery Charge Regulator. 0F I-10V-C 1A 10V continuous power supply. 10 BCR-Oscill2 As channel 0C 11 Press Tank off N2O4 tank pressure. 12 T-SEU Temp Sensor Electronics Unit 13 IbatCharge 2.5A Positive Current to battery. 14 L-Sensor (A) U=(C-10)*8.53mV Light-Sensor Antenna Side. 15 Motor Valve off 16 T-ABAT1 Temp Auxiliary battery 1 17 I-BCR-OUT 5A 14V line to battery and other consumers. 18 L-Sensor (M) U=(C-10)*8.53mV Light-Sensor Motor Side. 19 --- 1A T-ABAT2 Temp Auxiliary battery 2 1B I-BCR-IN Equivalent to total current of all panels, 1C Spin rate (C>131, Spin rate=479/(C-109)-2 rpm )pre-launch (C<=131, Spin rate=(131-C)*0.85+20 rpm)formulas Spin rate = (141.54 - C*0.968)rpm (post-launch formula) Sensor angular position oscillator. Lock indication channel #47 1D Rx-L-AGC Gain reduction=(C-75)^2 / 1125 dB 1E T-MBAT Temp Mean battery (normally in use) 1F I-Panel6 1A Solar panel 6 20 Tx-PWRout-U Average power=(287-C)^2 / 1796 Watts As channel 01. 21 T-He-Tank Temp 22 T-Panel1 Temp 23 I-Panel5 1A 24 Rx-U-AGC Gain reduction=(C-71)^2 / 2465 dB 25 T-Tx-L Temp Mode-JL transmitter. 26 T-Panel3 Temp 27 I-Panel4 1A 28 --- 29 T-Rx-L Temp Mode-L receiver. 2A T-Panel5 Temp 2B I-Panel3 1A 2C U-14V-ST U=(C-10)*66.8mV Transponder separation bus. 2D T-RUDAK Temp RUDAK temperature. 2E T-top Temp Arm 1, Antenna side. 2F I-Panel2 1A 30 U-9V-U U=(C-10)*54mV Internal 9 volt bus from Mode-B transponder. 31 T-wall-arm2 Temp 32 T-bottom Temp Arm 1, Motor side. 33 I-Panel1 1A 34 --- 35 T-wall-arm1 Temp 36 T-N2O4 Temp 37 --- 38 U-ABAT U=(C-10)*78.5mV Auxiliary battery. 39 T-S-xpnder Temp Mode-S transponder. 3A T-L-Sensor Temp Light sensor antenna side. 3B --- 3C U-9V-L U=(C-10)*45.4mV As channel 30, Mode-L 3D T-AZ50-Tank Temp 3E T-nutation damper Temp Arm 3. 3F --- 40 ES-Sensitivity 2MUX0 Earth Sensor sensitivity threshold. bit significance 0 LSB 20mV 1 37mV Hysteresis 200mV 2 75mV Threshold 600mV 3 150mV 4 300mV 5 600mV 6 1.2V 7 MSB 2.4V 41 Antenna/SERI 2MUX1 Antenna relays and SERI resistors. bit significance 0 LSB Hi-gain 2m to U 1 Hi-gain 70cm to L 2 --+ SERI-1 load resistor for 3 -+| SERI-2 both Light-Sensors || resistance 00 7.5 Ohm 01 3.9 Ohm 10 2.3 Ohm 11 5.9 Ohm 42 RUDAK-Status 2MUX2 IN-B (ex Motor-PWR). C=82, Standard-ROS (S) C=78, Emergency-ROS (N, Not-ROS) C=80, Primitive-ROS (P) 43 S&RUDAK-CNTL 2MUX3 Mode-S and RUDAK interface. bit significance 0 LSB RUDAK OFF 1 " NMI/ 2 " Byte Clock 3 " Byte count reset 4 --- 5 Mode-S Beacon ON 6 " Squelch defeated 7 MSB " Squelch Hi Sensitivity 44 BCR-Sin 2MUX4 Array voltage offset. U=29.1+(Cs*100)mV (16.3V...41.8V) 45 BCR-Sout 2MUX5 Battery knee voltage offset. U=14.98+(Cx*20)mV (11.14...16.2V = 192...63) 46 BCR-relays 2MUX6 bit significance 0 LSB BCR-2 ON 1 Auxiliary battery charging 2 Auxiliary battery connected, Main battery disconnected. 47 SS-1 C=255 or C=0, PLL locked Sun-Sensor angular position oscillator, Slit antenna side. 48 SS-2 Time offset from SS-1 49 Flag-SS C=1, SS-1 Sun sensor data. C=2, SS-2 4A SPIN-RAW Raw spin count (1/256). 4B Sensor-control bit significance (OUT4) 0 LSB --+ MUX-CTRL for sensor elec. module 1 -+| || 00 - Sun data 01 - spin ref./spin counter 10 - ES lower beam 11 - ES upper beam 2 Earth sensor positive edge select. (Strobes value of spin count at transition.) 3 Motor Instrumentation ON. (Pressure sensors, motore valve indicator.) 4 0.3V Sun Sensor Sensitivity 5 0.6V " " " 6 1.2V " " " 7 MSB 2.4V " " " (Max threshold #F = 1 solar constant) 4C SS-correction 4D Last ES-A Z last ES-pulse Antenna side. 4E " O# (Orbit number and MA value) 4F Last ES-M Z last ES-pulse Motor side. 50 " O# (Orbit number and MA value) 51 Lockoutrange Within +- C counts from sun sensor pip, earth sensor handler ignores data (Spin count 1 circle= 256 counts.) 52 ES-A Strobed spin count at edge selected, Antenna Side beam. 53 Update Flag1 Indicates update,Antenna Side beam. 54 ES-M As channel 52 Motor Side beam. 55 Update Flag2 As channel 53 " " " 56 S/C STATUS bit significance 0 LSB LIU power ON 1 S/A plug status 0=Safe, 1=Arm 2 RUDAK-out (lock) 3 Mode-S Squelch open 4 --- 5 Memory Softerror Counter 6 " " " 7 MSB " " " 57 --- 58 --- 59 --- 5A --- 5B N no of 20ms per dot, morse speed. 5C n running count of units for morse. 5D --- 5E TRANSPONDER bit significance (OUT7) 0 LSB GB OFF 1 GB FSK (1=+170Hz) 2 DPSK OFF 3 EB ON 4 --+ PSK source 5 -+| for GB (EB: don't care) || 00 - no PSK 01 - ranging 10 - EB source 6 Low power transponder ON 7 MSB Passband OFF (Beacons and Mode-J +3dB) 5F --- 60 MODUS bit significance (magnet control) 0 magnet system ON 1 undespun magnet 61 M-Soll magnet vector desired angle to the despun sun (clockwise as seen from top, 1 circle = 256) 62 M-Out bit significance (OUT3, also L,S,J control) 0 LSB polarity Arm 1 1 polarity Arm 2 2 polarity Arm 3 3 Magnet power ON 4 Mode-J ON 5 --- 6 Mode-S ON 7 MSB Mode-L ON 63 O-FRAC-lo Fractional Z increment in 20ms 64 O-FRAC-hi Counts down to 0 from preset value. 255th Z has different value of O-FRAC. ~8046 counts/Z. 65 O/256 Z from perigee 66 O#-lo Orbit number 67 O#-hi 68 UHR 10ms UTC 69 sec 6A min 6B hour 6C day 1st January 1978 = AMSAT day 0. 6D 256day 6E SU0 10ms IPS stopwatch 0. 6F sec 70 min 71 min*256 72 SU1 10ms IPS stopwatch 1. 73 sec 74 min 75 min*256 76 SU2 10ms IPS stopwatch 2. 77 sec 78 min 79 min*256 7A SU3 10ms IPS stopwatch 3. 7B sec 7C min 7D min*256 7E Event-Lo Used as event ID word in 7F Event-Hi intermediate buffer.