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ossi1beacon
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Listening OSSI-1 Satellite Beacon

Information are being updated now. Please, check often!!

Beacon Information

  • Frequency: 145.980 MHz
  • Modulation: CW (OOK)
  • Data Rate: 12 WPM
  • RF Power : 80~100mW
  • Signal Period: It keeps beaconing
  • Orbit: elliptical orbit (expect lots of doppler shift!)

Equipment to Listen

Radio: if you're an ham amateur operator, your radio should support “CW Mode” to listen to the OSSI-1 Beacon.

Good software to decode Morse:

  1. Hook your VHF antenna to your radio
  2. Set your radio frequency to 145.980 MHz
  3. Connect the audio output of the radio to computer audio input
  4. Open up the software and set to CW decode mode
  5. Wait for the satellite (this is hard for beginners who cannot use TLE to know where the satellite is)
  6. And try adjust the radio frequency for doppler effect. ( expect lots of doppler effect!!!!)

I will upload more kind tutorial soon.

OSSI-1 Satellite TLE (Two Line Element)

OSSI-1's TLE is calculated on 20th Apr 2013 after Russian side provided the data based on geocentric equatorial coordinate

OSSI-1
1 39137U 13015H   13109.61683023  .00218796  18651-4  10338-2 0    37
2 39137 064.9052 032.9523 0221255 060.5813 013.8697 15.55037421    35


As the satellite is launched yesterday (19th Apr 2013), it should be near BION-M1 Satellite-the carrier of OSSI-1 satellite.

BION-M1's TLE is known as below for now (20th Apr 2013):

BION-M1
1 39130U 13015A   13109.86774677 -.00001982  62674-5  00000+0 0    38
2 39130 064.8855 032.0365 0223088 061.7172 336.4641 15.54458396    63

Beacon Format

  • OS0 Packet - “OS0 DE OSSI1 ANYOUNG”
  • OS1 Packet - “OS1 XYXYXYXYXYXYXYXY”
  • OS2 Packet - “OS2 XYXYXYXYXYXYXYXYXYXY”
  • OS3 Packet - “OS3 XYXYXYXYXYXYXYXYXYXY”
  • OS4 Packet - “OS4 XYXYXYXYXYXYXYXYXYXY”
  • OS5 Packet - “OS5 XYXYXYXY”

What does XY means?

To send a byte value from 0 ~ 255, a byte is again formated into to hex numbers.

For example:

  • data value = 255 → XY = FF
  • data value = 0 → XY = 00
  • data value = 43 → XY = 2B

For data value = 43, what you hear from morse code is 2 and B

So for OS1 Packet, we have 8 XY's. This means OS1 Packet has 8 data values.

OS0 Packet: Hello Data

Fixed Data. If the system suffers from the failure, this is the only message you' going to hear. ANYOUNG means hello in Korean.

OS0 DE OSSI1 ANYOUNG

OS1 Packet: Status Data

This packet tells us the basic status information of the OSSI-1 Satellite:

  • OS1: Packet Header
  • Space: There is a space between the header and the data
  • Operation Mode: satellite operation mode
  • Module On Status: which modules are on now
  • EPS Status: Status of the EPS module
  • Error Status: Last Error Occured
  • OBC Tick Count 3: 32 bit Tick Counter of the OBC since it's working divided into 4 bytes - MSB
  • OBC Tick Count 2: 32 bit Tick Counter of the OBC since it's working divided into 4 bytes
  • OBC Tick Count 1: 32 bit Tick Counter of the OBC since it's working divided into 4 bytes
  • OBC Tick Count 0: 32 bit Tick Counter of the OBC since it's working divided into 4 bytes - LSB

Operation Mode

The data will be one of the below

  • BOOT_MODE = 0
  • DEPLOY_MODE = 1
  • NORMAL_MODE = 2
  • LED_MODE = 3
  • SAFE_MODE = 4
  • RECOVERY_MODE= 5
  • TEST_MODE = 6

Module On Status

The data will be OR-ed from the below to show the status at the same time

  • COMMS_ON = 0x01
  • BEACON_ON = 0x02
  • LED_ON = 0x04

EPS Status

The data will be OR-ed from the below to show the status at the same time.
Tricky to decode as the below using upper and lower 4 bits to show the status

  • BATTERY_MODE = 0x01
  • SUPERCAP_EN = 0x02
  • SUPERCAP_PATH_ON = 0x04
  • BATTERY_CHARGED = 0x08
  • BATTERY_FAULT = 0x10
  • SUPERCAP_CHARGER_EN = 0x20
  • SUPERCAP_CHARGED = 0x40

Error Status

Last saved error

OBC Tick Count

The OBC saves the tick count in second unit.
It uses 32 bit variable, so to send the count in morse code, it got divided into 4 bytes and then again into hex format.
Tick Count 3 is the MSB

OS2 Packet: VI Data

Voltages and currents of the OSSI-1 Satellite:

  • OS2: Packet Header
  • Space: There is a space between the header and the data
  • Solar Voltage: Voltage of solar panels befor going into EPS module
  • Battery Voltage: Voltage of the Lithium-Ion Battery
  • Bus Voltage: Voltage of the system after the EPS module (unregulated)
  • Supercap Volate: Voltage of the supercapacitor on board
  • -X Solar Panel Current: Current of the -X Solar Panel
  • -Z Solar Panel Current: Current of the -Z Solar Panel
  • +Z Solar Panel Current: Current of the +Z Solar Panel
  • -Y Solar Panel Current: Current of the -Y Solar Panel
  • +Y Solar Panel Current: Current of the +Y Solar Panel

While I'm working on filling out the rest, please check the link below:
https://docs.google.com/spreadsheet/ccc?key=0AjtQ6cJ4QOqJdGpHNnRtUWZJV0w4TTFKRU9WYTZqc3c#gid=1

ossi1beacon.txt · Last modified: 2013/04/21 10:21 by ossi