Periodicity

[valentinb]

Would it be possible to increase the periodicity of the signal so that we can be closer to the IdentificationWG conclusions ?

I know that it's conflicting with #5...

[yohanboniface]

Quoting Paweł on this topic:

How often should the position be reported ? The limit is by the channel capacity and the 1% duty cycle required on the 868MHz band. In general, if the drone is moving on a predictable trajectory, it could transmit less often and when doing complicated maneuvers more often. As well a drone on the ground, in particular on an airfield with lots of other drones should as well lower its position reporting frequency.

[pjalocha]

I speak from practical experience with OGN network. I have seen situations with like 100 of gliders at one airfiled and the transmissions would make a huge "noise" at the local reciever. It would be enough that in such situation the gliders/drones would reduce their position reporting frequency as they all stand on the runway anyway, thus give change to report to those who fly in vicinity.

As well for reporting on the APRS we don't report every position but we check if the path predicts well: if so, we skip the positions as long as the prediction error is small. However when the flight parameters are out of "normal" envelope like high sink or high turn rate, we report every position as this data can be very significant is case there is something wrong going on.

[optimaltracking]

The period can not be too small. Imagine a drone is flying in a forbiden location. A policeman is driving at 90 km/h. we have to be sure that a message will be sent when he is in the range. 90hm/h = 30 m/s. A message every 5 to 10 second is perfect

[Benbenbeni]

Specifications given by the working group are not frozen then ?

[pjalocha]

We could give general rules, while the actual algorithm needs to be fine tuned, for example the rules could be:

• send position at least every 5 seconds in flight and every 20 seconds on the ground
• upper the rate when doing complicated manoeuvres (short predictability)
• lower the rate when on a predictable path
• upper the rate during tight turns, high sink/climb rate, abnormal attitudes
• upper the rate when in proximity of others
• lower the rate when high radio traffic