IBCrazy on RCGroups has created an antenna tracker that uses several antennas, one recevier and 2 RSSI modules... It doesn't need the telemetry data it uses RSSI to track the plane. Also, my GCS is going to start outputting control messages and I'm hoping to write some code to run on the old ArduPilot board to actually output to the servos.
Jordi also has a solution in the works and then there's always the ArduStation....
The airborne GPS data is encoded into the video in a part of the signal called the vertical interval. This area is normally used for closed caption etc. There is heaps of room for the data. The video is received on the ground and the GPS data decoded. As the start location of the aircraft is the tracker location, the firmware calculates the azimuth and elevation to the airborne GPS receiver and commands the servos to point to that part of the sky. Normally a diversity video receiver is used in case the tracking antenna loses lock in a fast flyby etc and the GPS signal then is received on the onmi antenna while the tracking servos relock. Not rocket science!
I've read about using the GPS data to achieve antenna tracking. But you would need a data link to pass down the GPS position before you establish the. So it sounds like you need 2 antenna systems, one high gain which requires antenna tracking, and a low gain which doesn't. I am thinking if you use video tracking you can either eliminate the low gain data link, or you can use high gain antennas on both the 2 links and greatly increase your range. I am just wild thinking, not sure if there is a need to do this.
Would you guys consider video tracking the UAV with a telescope and piggyback the antenna on the telescope? That way you can use a directional antenna for the telemetry data link too and it may in theory increase the operational range of your UAV system.
There are also other ways to do this. Some video tx/rx can send it down. this will require more parts and weight on the aircraft though. check out ezosd or ezuhf i think one of those EZ things will also include antenna tracking.
I believe it's coming soon with ardupilot mega though
Basicaly look at the ardustation code, it has some information about antenna tracking.
But here is a simple way to get started
You know the approx 3D position of ur plane as it has GPS on it, When you startup you record the 3D position of ur antenna (could be from the startup location of ur plane if its close enough.
Then you just calculate the bearing and height angle (from coordinates and alt) between the startup position/ and the current location of the aircraft that is being send back via telemetry and send the bearing and angle to the antenna servos to point it in the right direction.
This is something I have also been researching... It would be nice to hear from the wider community if there are any ingenius ways to get this to work :)
Replies
IBCrazy on RCGroups has created an antenna tracker that uses several antennas, one recevier and 2 RSSI modules... It doesn't need the telemetry data it uses RSSI to track the plane. Also, my GCS is going to start outputting control messages and I'm hoping to write some code to run on the old ArduPilot board to actually output to the servos.
Jordi also has a solution in the works and then there's always the ArduStation....
Eagle Tree has a neat system.
The airborne GPS data is encoded into the video in a part of the signal called the vertical interval. This area is normally used for closed caption etc. There is heaps of room for the data. The video is received on the ground and the GPS data decoded. As the start location of the aircraft is the tracker location, the firmware calculates the azimuth and elevation to the airborne GPS receiver and commands the servos to point to that part of the sky. Normally a diversity video receiver is used in case the tracking antenna loses lock in a fast flyby etc and the GPS signal then is received on the onmi antenna while the tracking servos relock. Not rocket science!
Jack
VK2TRF
Would you guys consider video tracking the UAV with a telescope and piggyback the antenna on the telescope? That way you can use a directional antenna for the telemetry data link too and it may in theory increase the operational range of your UAV system.
I believe it's coming soon with ardupilot mega though
But here is a simple way to get started
You know the approx 3D position of ur plane as it has GPS on it, When you startup you record the 3D position of ur antenna (could be from the startup location of ur plane if its close enough.
Then you just calculate the bearing and height angle (from coordinates and alt) between the startup position/ and the current location of the aircraft that is being send back via telemetry and send the bearing and angle to the antenna servos to point it in the right direction.
Thanks