Now french operators of more than 800g weighted uavs need to have on board a signalisation device emitting some required data for law enforcement units.
It only consist of a classic wifi 802.11n frame broadcasted from air device on the 2400 – 2483.5Mhz band ( mostly channel 6 ) containing those data:
- Frame Control fields:
- Frame type : 0
- Frame Subtype : 6
- More Fragment : 0
- Retry : 0
*Fields of frames after frame Control one needs:
- Adress 1 : FF.FF.FF.FF (broadcast),
- Adress 2 : mac Adress of the emitting device
- Payload header is 15 bytes total containing:
protocol number, 2 bytes, value: 1.
protocol version, 1 byte, value: 1.
timestamp, 6 bytes YYYYMMDDHHMMSS
frame number, 2 bytes, Zeroed at uav power up.
mandatory data size , 2 bytes
optional data size: 2 bytes
Then the payload:
drone ID, 30 bytes containing those 3 fields:
. Constructor trigram, 3 bytes
. Uav model id or signalement device id: 3 bytes
. Uav or signalement device serial number, 24 bytes
( in case of less than 24 characters zero ore placed at the front. )
UAV position when message is sent, 10 bytes containing:
. Latitude, 4 bytes, first part sign bit (MSB) and it’s decimal, then exposant is index to 5.
Then all data have 5 decimals: XXX.XXXXX
. Longitude, 4 bytes, …
. Altitude, 2 bytes, in meters, absolute from zero sea level.
Ground speed, 1 byte, m/s
Route, 2 bytes, 0° to 359°
Frame needs to be broadcasted every 3sec max and each 30 meters max.
Would it be possible to integrate this feature to Herelink natively?
For now we have to use some external signalisation device but it add some weight on board but would be legitimate to handle this from HL air unit directly if capable.