figuring out the Antenna Tracker

Not many people know but we have an piece of open source software for controlling an Antenna Tracker. It's been built by Tridge (Arduplane lead developer) for use in the outback challenge.

Sadly we have no documentation and, as far as I know, nobody except Tridge has used it. Still given Tridge's track record on building great software I suspect it works well and if it doesn't, I'm sure we can fix it. So to not let this piece of code go to waste, I'd like some help from people who are interested to give it a try and help me figure out how it works.

Here's the little that I know:

It runs on any of our supported board (APM1, APM2, PX4, Pixhawk, Flymaple and perhaps VRBrain)
For APM1/APM2 users building the code is as easy as opening our hacked ArduinoIDE and selecting File > SketchBook > Tools > AntennaTracker and then building in the normal way. For PX4/Pixhawk, our autobuilder doesn't automatically build a binary but I can provide one if people are interested.
It can control a Pan and Tilt gimbal like this or this found on servocity.com.
It may or may not require a GPS
It must somehow receive vehicle position updates from the ground station which has the telemetry radio that is connected to the vehicle. Maybe through a USB cable. Tridge probably uses the python ground station, MAVProxy, to passthrough the vehicle position data to the AT but perhaps we can get MichaelO to build out a similar feature in Mission Planner.
I imagine this antenna tracker could also be used to keep a camera focused on the vehicle which might be good for easing the burden on creating videos of our vehicles.

So if you want to give it a try please do and stick any findings, questions or issues below. Alternatively Issues can go into the issues list.

I'll start sticking things into the wiki as they become clear.

Ok, so I did a bit of work today on the Tracker and pushed out a new version 0.5 with the following features:

add SERVO_TEST mode which adds support for the "test" buttons on the MP's antenna tracker extended tuning page
add DISTANCE_MIN parameter (default to 5m). Vehicles must be at least this distance away for the tracker to track them. Set to zero to follow regardless of distance.
add SYSID_TARGET parameter to specify which vehicle to follow which is useful for the unlikely case where there are multiple vehicles flying and sharing the same network. This param defaults to zero which means track the first vehicle. To set it to a particular vehicle, make it match the vehicle's SYSID_THISMAV parameter.
send request to vehicle for position updates at 1hz. This should improve reliability a bit especially when used with copter which won't sent position data unless it receives this request from someone (previously we relied on the GCS sending this message).
Listens for vehicle position updates on all channels (not sure if there was actually a problem in this area or not)
bug fix for LED on pixhawk. It now correctly flashes blue or green instead of yellow during the time before it gets a position update from the vehicle

Hopefully this will help resolve some of the problems people have been having.

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Randy April 27, 2015 at 1:14am
Ok, so I did a bit of work today on the Tracker and pushed out a new version 0.5 with the following features:
- add SERVO_TEST mode which adds support for the "test" buttons on the MP's antenna tracker extended tuning page
- add DISTANCE_MIN parameter (default to 5m). Vehicles must be at least this distance away for the tracker to track them. Set to zero to follow regardless of distance.
- add SYSID_TARGET parameter to specify which vehicle to follow which is useful for the unlikely case where there are multiple vehicles flying and sharing the same network. This param defaults to zero which means track the first vehicle. To set it to a particular vehicle, make it match the vehicle's SYSID_THISMAV parameter.
- send request to vehicle for position updates at 1hz. This should improve reliability a bit especially when used with copter which won't sent position data unless it receives this request from someone (previously we relied on the GCS sending this message).
- Listens for vehicle position updates on all channels (not sure if there was actually a problem in this area or not)
- bug fix for LED on pixhawk. It now correctly flashes blue or green instead of yellow during the time before it gets a position update from the vehicle
Hopefully this will help resolve some of the problems people have been having.
- Andre > Randy April 27, 2015 at 4:55pm
  
  Rand,
  
  as Jakub describes, most important are the Basics like Servo_test and to use ´continuous rotation servos´.
  
  Please can you implement this?
  - Christian Thalhammer > Andre April 28, 2015 at 11:40pm
    
    Servo_test mode seems to be work fine on v0.5. Thanks Randy
- Sebastian Schürmann > Randy April 27, 2015 at 11:49am
  
  Hi,
  
  if I upload Tracker 0.5 to one of my APM 2.5 I cant connect to it anymore. Uploading Arduplane or copter and all is fine again. Any ideas?
  - Developer
    
    Randy > Sebastian Schürmann April 28, 2015 at 1:32am
    
    Sebastian,
    
    I uploaded ver 0.5 to my APM2.5 and it seems fine. I had to initially unplug and plug in the board again after the firmware upload for it to work. And it also may have needed some time (30sec or so) to erase all the parameters and dataflash.. but it eventually worked.
    
    Maybe is someone else has an APM2.5 or 2.6 they could give it a try and report back so we can break the tie?
    - Sebastian Schürmann > Randy April 28, 2015 at 1:43am
      
      The APM2.5 I was testing with has its internal compass deactivated. I tested without the external gps/compass module and this seems to have messed up things. Now I connected the gps/compass module and I am able to configure the APM with missionplanner again.
      
      Sorry for taking up your time, Randy
      - Developer
        
        Randy > Sebastian Schürmann April 28, 2015 at 3:44am
        
        All's well that ends well. Good stuff. It definitely needs a compass!
      - Jakub Oller > Sebastian Schürmann April 28, 2015 at 1:52am
        
        I had this problem myself. The firmware fails to boot without a compass.
  - Developer
    
    Randy > Sebastian Schürmann April 27, 2015 at 10:11pm
    
    Sebastian, Ok, thanks for the report, I'll have a look.
- 3qs7z40lxxok2 > Randy April 27, 2015 at 2:39am
  
  cool will test it out later on tonight

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figuring out the Antenna Tracker

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