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.
Replies
Grant,
RF Design has a SiK git repo here, which seems to be a fork from the DroneCode one here.
The RF Design binaries are kept here.
Fantastic - thanks Greg!
No, actually your SiK v2.5 is the latest Multipoint networking firmware. I don't know much about it other than it should allow multiple telemetry modules on the same frequency. At one point it was experimental which is why I kept my 3DR and RFD900 modules at SiK v1.9.
Perhaps someone else knows more about the newer Multipoint networking firmware.
Is anyone running the tracker via a small computer like BeagleBone or RPi? I'm trying to get MAVProxy working on my Beaglebone, and have done so successfully, however the tracker module will not show up when doing a "module --list".
Thanks
-Ted
I got my two RFD900 units and new 915MHz v2 unit mounted and tested. The idea is that a single one can increase your telemetry range significantly to your fleet. I had a second ground unit in the Antenna Tracker so I used the air antennas and Pixhawk cable on that setup. The laptop cable has an FTDI adapter built-in so I mounted the RFD900 to the top using some Velcro.
I left the 3DR 433MHz telemtry unit on the AT but it is unplugged for now until the MavLink collisions are fixed.
Everything works fine so I hope to try some range tests this weekend. This experiment should make my telemetry link much stronger and make the 5.8GHz video link the weakest one...hence the need for the Antenna Tracker.
Are you using 3DRadio in the copter and RFD900 on the ground?
From radio point of view you can extend the range in numerous ways:
1. Increase TX power on both ends
2. Increase antenna gain on both ends
3. Increase receiver sensitivity on both ends
If you in fact used 3DRadio in combination with RFD900 your range will be better but not as good as it would be using 2 RFD900s. RFD900 has 1000mW of TX power and it will be able to transmit your data far far away. 3DRadio will be able to receive these messages as long as the signal is within its sensitivity range. 3DRadio on the other hand only has 100mW of TX power and it will send it's messages to relatively lower distance. You may get to a point where 3DRadio will still receive messages from RFD900, but not the other way around. The reason you get a better range than with 2 3DRadios is mostly due to RFD900s sensitivity, antenna diversity and greater TX power which essentially increases the SNR (Signal to Noise Ratio) - copter (ESCs, Motors, BECs etc) generates a lot of RF noise (in fact a lot more than you can expect in the ground station) that affects 3DRadios sensitivity.
Other than that - very nice setup. If only there were RFDs at 433MHz or 868MHz... 900MHz is not an option in my country :(
Hi Jakub,
The idea is to use an RFD900 at the ground station (or common denominator) and use the 3DR radio on the MRC in the air. Since I have 10 APM/Hawk MRCs, it provides the biggest improvement for the cost. My flight paths are never more than 2km (or 1 mile). Some of the FPVers have been flying up to 9.6km (or 6miles) with this configuration.
When you say RFDs at 868Mhz you mean like these?
http://store.rfdesign.com.au/rfd-868-modem/
:-)
Thanks, Grant.
If you're interested - I'm making something like this (3DR Radio/SiK compatible, 433/868/915MHz):
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