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.

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IMO, unless you are mapping very large "lawnmower" runs, close in, you are better off with a BiQuad antenna. Almost the same gain as a small Yagi but the beam width is broader. 

Further, the costs of larger servos and P&T assemblies with bearings is fairly steep. Then add the field set up time and calibration.

Not trying to rain on anyone's parade, just passing on a bit of been there done that, knowledge.

Btw, the airborne GPS is used in conjunction with MAVLink messages embedded in the  telemetry to provide the GPS location of the plane. The tracker takes that data and points the antenna accordingly to the correct azimuth and elevation.

Steven,

Do you have any links to those types of antennas?  As a minimum I'd like to add that info to the wiki's telemetry section here.

We are lot of people who want an easy-to-use antenna tracker. 

I don't understand why this stuff did not exist in 3DR shop because of frequency/power we are allowed to use in many countries. 

I've got an Ardustation Mega (2560) with LCD and it's works...certainly not perfect...but it's 'works'.

(with Ctrl+F Mavlink feed from mission planner, even with X-plane for testing/debugging Or 3DR telemetry OR openLRS with Serial-passthrought (flipflap version) )

I've seen this stuff  'Mavlink Auto Antenna Tracker'  from CUAV but it's seems not to be real...

Product :  http://item.taobao.com/item.htm?spm=a1z10.5.w4002-2343226222.87.M9S...

Video presentation :  http://www.tudou.com/programs/view/YFwc1FnSj1U/?resourceId=0_06_02_99 

This stuff seems to have compass. 

If only we could find a working MAAT like this, finally, many Arduplane/copter/rover users will be happy....

I will be happy to test Antenna Tracker 1.01 (via MP) but I've no MPU/Baro/compass on my Ardustaton Mega...

Perhaps when I'll bought Pixwhawk, my APM  will become Antenna Tracker ? 

Hi Randy,

Although I was referring to a video down link and using a BiQuad, the same would apply for a Telemetry down link.

There are three links, two for a ready made BiQuad and one for building your own (DIY)

http://www.readymaderc.com/store/index.php?main_page=product_info&a...

http://www.readymaderc.com/store/index.php?main_page=product_info&a...

http://www.rcgroups.com/forums/showthread.php?t=1328260

Hope this helps,

Steven

Looks like someone hacked a MyFlyDream antenna tracker to use MAVLink messaging. Eventually, this slip ring type trackers get dirty and have electrical open circuits here and there. But it is a nice effort for a mere $300. Does it include everything, including P&T?

Yes, you need a compass on the tracker to tell it which way is North during initial set up. There may be auto calibrating ones now. They will still need a compass to orient North and you will need to be somewhat level to have correct elevation. Slip rings are very handy for providing >360 degree rotation. If you've ever tried a tracker without them, you know exactly what I mean. :-)

Actually, in my home made tracker I fitted a a tilt compensated compass. I can just drop the unit down anywhere :-)

I can pick up the base unit while its busy tracking :-)

Built and programmed in about a week. Its a bit rough but it works. Got bored one weekend and decided to see if I could get one to work. Haven't really used it, just a wee exercise to keep the old grey matter churning.

So does the APM tracker needs a GPS? It seems it would not unless the GCS is mobile.
Sounds like it needs it's Mag, IMU, and Gyros for attitude info.
What about baro? Is there a way to feed the baro info into the GCS so it can update the GND_ALT_OFFSET?

Good job here!

Very cool. Almost makes me want to build one...:-)

Steven,

Thanks for that, I'll add it to the wiki.  Coincidentally I have exactly the same antenna as the top one you've linked to although I haven't tried it yet.  It's true that it's got something like a 52 degree beam meaning you don't have to be too accurate to get good distance.

Mike that looks awesome! Is the code available anywhere or a build guide? I'd definitely like to build one!

@iskess,

I use a GPS but it shouldn't be completely necessary.  It's not documented on the wiki yet but there are some parameter that allow you to manually sets the location of the tracker.  I can't remember the names of the parameters immediately but hopefully you can find them in the full parameters list.  Anyway, just set those to the tracker's location and it should work.

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