White Star Satellite Telemetry V1

Telemetry Content: Telemetry Contents Google Spreadsheet

Diagram of Telemetry version a.yfrog.com_img204_1735_wz7r.th.jpg

This specification is ONLY RELEVANT AT THE ARROW MARKED IN THE DIAGRAM. After ground post-processing of the received data, and before entry into the permanent storage/distribution database.

Each transmitted data batch of collected samples must be of the same Version and Channel Bitmask.

Header

Delineation

Comma Separated header items

Content Explanation

  1. Telemetry Speed Dial: Telemetry Version of header/data to follow.
  2. Channel Bitmask: Binary 1 bits represent the presence of channel raw data in this sample capture.
    1. Directly 1 to 1 mapped to channel number. i.e. bit 37 is Channel 37.
  3. Batch Number: This is an incrementing counter that will be applied to every transmission from the balloon. Any transmission may contain multiple backlogged sample captures that are batched together. Thus this identifies which batch this sample was sent in.
  4. Sample Capture Time Balloon Epoch: This is the time, in Balloon Epoch, at which the current sample was captured. Transmissions may arrive out of order, this should be used to order the sample captures correctly.

Format

  1. Telemetry Version: Fixed length decimal Ascii number. The format of this will remain constant for all telemetry versions.
  2. Channel Bitmask: Fixed length Hexadecimal ascii number representing [Binary 96 bits = 12bytes = 24 hex digits]. Nibble order is Least Significant Nibble First.
  3. Batch Number: Non-fixed length decimal Ascii number
  4. Sample Capture Time UTC: 6 decimal ascii numbers, HHMMSS
Bitmap Hex Example

Example Hex ASCII bitmap: 483FA937D28B86CA25F02003

   HEX: 4    8    3    F    A937D28B86CA25F02003
   BIN: 0100 1000 0011 1111 10101001 00110111 11010010 10001011 10000110 11001010 00100101 11110000 00100000 00000011
           ^    ^   ^  ^
           |    |   |  |
 Channel:  3    7   10 12
  
 Example Channel Values: 0=off, 1=off, 2=on, 3=off, ..., 127=off

Raw Channel Data

ATC Short Reports

These will be to ensure the ATC critical data gets through when messages are slow.

Report A 6bytes:

Byte0 Byte1 Byte2 Byte3 Byte4 Byte5
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
Lon Lon Lon Altitude Alt1b Alt0b 0 0 Epoch11b Epoch10b Epoch9b Epoch8b Epoch (Lower 8 bits)

Report B 6bytes:

Byte0 Byte1 Byte2 Byte3 Byte4 Byte5
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
Lat0 Lat1 Lat2 Speed 0 0 GPSQuality 1 Epoch11b Epoch10b Epoch9b Epoch8b Epoch (Lower 8 bits)

GPSQuality is binary

  • 0 = FIX VALID
  • 1 = NO FIX

Epoch must be multiplied by 60 on the ground. Accuracy is +/- 60 seconds.

Command Confirmation Reports

These will be produced when manual ground commands need immediate confirmation.

Confirmation Name Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Cutdown Timer Length Change command executed at time X 0xFF 0x00 Timer Length Byte 0x00 EpochMinute Byte 0 EpochMinute Byte 1
CUTDOWNOW Began at time X 0xFF 0x01 0x4E 0x4F EpochMinute Byte 0 EpochMinute Byte 1
CUTDOWNLATER timer began ticking at time X 0xFF 0x02 0x4F 0x48 EpochMinute Byte 0 EpochMinute Byte 1
telemetry/satellite/v1.txt · Last modified: 2012/03/15 15:01 by steamfire
 
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