RotatorPositioner

Firmware for a device that gets the antenna orientation from a BNO055 sensor and distributes it to local LAN via MQTT

Emitted Messages

MQTT

MQTT payloads are composed of JSON objects. There are three topics (to date):

• antenna/orientation This topic carries the antenna orientation data (example):

  {
    "dateTime" : "Thursday, 19-Feb-2026 09:32:40 UTC",
    "ts" : 1771493560427,
    "azimuth" : 47.33,
    "elevation" : 19.13,
    "revolutions": -1,
    "units" : {
      "ts" : "milliseconds",
      "orientation" : "decimal degrees"
    }
  }

• antenna/status Transmits system information (will be expanded on):

  {
    "dateTime" : "Thursday, 19-Feb-2026 09:35:11 UTC",
    "ts" : "1771493711925",
    "bssid" : "B8:69:F4:81:8D:E6",
    "temperatureC": 27
  }

• antenna/calibration Calibration data for the evaluation of the quality of orientation data:

  {
    "dateTime" : "Thursday, 19-Feb-2026 09:37:37 UTC",
    "ts" : "1771493857399",
    "system" : 0,
    "gyro" : 3,
    "accelerometer" : 1,
    "magnetometer" : 0
  }

  Calibration is better when values are higher (0..3).

  Serial Output (NMEA)

  Serial output data is formatted as an NMEA-sentence with a checksum value calculated over the data of the sentence (as per NMEA-specification).

  $PANT,TRK,1771493857399,ms,47.33,dd,19.13,dd,-1,revs,29,c,0,3,1,0*<HH>\r\n   
  

  • "$" : Start of Sentence identifier
  • "PANT,TRK": The Talker and Payload identifier
    • "P": proprietory message,
    • "ANT": antenna,
    • "TRK": tracker
  • "1771493857399": Timestamp
  • "ms": Timestamp is in milliseconds
  • "47.33": Azimuth angle (0..360)
  • "dd": Decimal degrees
  • "19.13": Elevation angle (0..90)
  • "dd": Decimal degrees
  • "-1": Revolutions (if < 0 or > 360)
  • "revs": Revolutions
  • "29": Temperature
  • "c": Celsius
  • "0,3,1,0": Calibration quality indicators
  • "*": End of Sentence identifier
  • : Checksum
  • ",": Field separator

Checksum field is the 8-bit exclusive OR (no start or stop characters) of all characters in the sentence. Checksum consists of 2 characters and is represented as a hex number.