---
meta:
id: opssat1
endian: be
doc-ref: 'https://github.com/esa/gr-opssat/blob/master/docs/os-uhf-specs.pdf'
doc: |
:field dest_callsign: ax25_frame.ax25_header.dest_callsign_raw.callsign_ror.callsign
:field src_callsign: ax25_frame.ax25_header.src_callsign_raw.callsign_ror.callsign
:field src_ssid: ax25_frame.ax25_header.src_ssid_raw.ssid
:field dest_ssid: ax25_frame.ax25_header.dest_ssid_raw.ssid
:field rpt_callsign: ax25_frame.ax25_header.repeater.rpt_instance[0].rpt_callsign_raw.callsign_ror.callsign
:field ctl: ax25_frame.ax25_header.ctl
:field pid: ax25_frame.payload.pid
:field priority: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.priority
:field source: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.source
:field destination: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.destination
:field destination_port: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.destination_port
:field source_port: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.source_port
:field reserved: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.reserved
:field csp_hmac: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.hmac
:field csp_xtea: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.xtea
:field csp_rdp: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.rdp
:field csp_crc: ax25_frame.payload.info.payload_dscrm.opssat_payload.header.crc
:field board_temperature: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.board_temperature
:field pa_temperature: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.pa_temperature
:field last_received_rssi: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.last_received_rssi
:field last_received_rf_error: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.last_received_rf_error
:field number_of_tx_packets_since_reboot: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.number_of_tx_packets_since_reboot
:field number_of_rx_packets_since_reboot: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.number_of_rx_packets_since_reboot
:field number_of_tx_bytes_since_reboot: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.number_of_tx_bytes_since_reboot
:field number_of_rx_bytes_since_reboot: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.number_of_rx_bytes_since_reboot
:field active_system_configuration: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.active_system_configuration
:field reboot_number: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.reboot_number
:field reboot_cause: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.reboot_cause
:field last_valid_packet_timestamp: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.last_valid_packet_timestamp
:field background_rssi_level: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.background_rssi_level
:field tx_duty_time_since_reboot: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.tx_duty_time_since_reboot
:field total_tx_packets: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.total_tx_packets
:field total_rx_packets: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.total_rx_packets
:field total_tx_bytes: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.total_tx_bytes
:field total_rx_bytes: ax25_frame.payload.info.payload_dscrm.opssat_payload.beacon_data.total_rx_bytes
seq:
- id: ax25_frame
type: ax25_frame
doc-ref: 'https://www.tapr.org/pub_ax25.html'
types:
ax25_frame:
seq:
- id: ax25_header
type: ax25_header
- id: payload
type:
switch-on: ax25_header.ctl & 0x13
cases:
0x03: ui_frame
0x13: ui_frame
ax25_header:
seq:
- id: dest_callsign_raw
type: callsign_raw
- id: dest_ssid_raw
type: ssid_mask
- id: src_callsign_raw
type: callsign_raw
- id: src_ssid_raw
type: ssid_mask
- id: repeater
type: repeater
if: (src_ssid_raw.ssid_mask & 0x01) == 0
doc: 'Repeater flag is set!'
- id: ctl
type: u1
repeater:
seq:
- id: rpt_instance
type: repeaters
repeat: until
repeat-until: ((_.rpt_ssid_raw.ssid_mask & 0x1) == 0x1)
doc: 'Repeat until no repeater flag is set!'
repeaters:
seq:
- id: rpt_callsign_raw
type: callsign_raw
- id: rpt_ssid_raw
type: ssid_mask
callsign_raw:
seq:
- id: callsign_ror
process: ror(1)
size: 6
type: callsign
callsign:
seq:
- id: callsign
type: str
encoding: ASCII
size: 6
ssid_mask:
seq:
- id: ssid_mask
type: u1
instances:
ssid:
value: (ssid_mask & 0x0f) >> 1
ui_frame:
seq:
- id: pid
type: u1
- id: info
type:
switch-on: '_parent.ax25_header.src_callsign_raw.callsign_ror.callsign'
cases:
'"DP0OPS"': opssat_payload_dscrm
opssat_payload_dscrm:
seq:
- id: payload_dscrm
doc: |
h(x) = 1 + x^3 + x^5 + x^7 + x^8
x8 + x7 + x5 + x3 + 1
10^8 + 10^7 + 10^5 + 10^3 + 1 = 1 1010 1001
mask = 0x1A9 & 0xFF = 0xA9
seed = 0xFF
length = 8 - 1 = 7, (1 << 7) == 128!
scrambler(mask, seed, length)
process: satnogsdecoders.process.scrambler(0xa9, 0xff, 7)
size-eos: true
type: opssat_payload
opssat_payload:
seq:
- id: opssat_payload
type: cube_sat_protocol
- id: crc_32c
type: u4
- id: rs_block
type: u1
repeat: expr
repeat-expr: 32
csp_header:
seq:
- id: raw_csp_header
type: u4
instances:
priority:
value: '(raw_csp_header >> 30)'
source:
value: '((raw_csp_header >> 25) & 0x1F)'
destination:
value: '((raw_csp_header >> 20) & 0x1F)'
destination_port:
value: '((raw_csp_header >> 14) & 0x3F)'
source_port:
value: '((raw_csp_header >> 8) & 0x3F)'
reserved:
value: '((raw_csp_header >> 4) & 0x0F)'
hmac:
value: '((raw_csp_header & 0x08) >> 3)'
xtea:
value: '((raw_csp_header & 0x04) >> 2)'
rdp:
value: '((raw_csp_header & 0x02) >> 1)'
crc:
value: '(raw_csp_header & 0x01)'
csp_beacon_data:
seq:
- id: board_temperature
type: s2
- id: pa_temperature
type: s2
- id: last_received_rssi
type: s2
- id: last_received_rf_error
type: s2
- id: number_of_tx_packets_since_reboot
type: u4
- id: number_of_rx_packets_since_reboot
type: u4
- id: number_of_tx_bytes_since_reboot
type: u4
- id: number_of_rx_bytes_since_reboot
type: u4
- id: active_system_configuration
type: u1
- id: reboot_number
type: u2
- id: reboot_cause
type: u4
- id: last_valid_packet_timestamp
type: u4
- id: background_rssi_level
type: s2
- id: tx_duty_time_since_reboot
type: u1
- id: total_tx_packets
type: u4
- id: total_rx_packets
type: u4
- id: total_tx_bytes
type: u4
- id: total_rx_bytes
type: u4
cube_sat_protocol:
seq:
- id: header
type: csp_header
- id: beacon_data
type: csp_beacon_data
if: '(header.destination == 10) and (header.priority == 3) and (header.source == 5) and (header.destination_port == 31)'
