Using Andruav as 3G/4G Telemetry for APM ArduPilot


This is my third article about Andruav, last one was a couple of weeks ago that was about the Telemetry feature in Andruav.

Since then some updates has been done to telemetry that I want to mention it here.

Andruav Telemetry has taken one more step forward. Now it can use USB besides Bluetooth when connecting to Flight Control Board (FCB). Also communication between drone and GCS has been extended so that  Andruav GCS can detect multiple telemetries on different drones and switch between them as shown in above video. Also protocol overhead has been reduced, which allows it now to work with less bandwidth up to 25%.

The video shows the below setup configuration:

We have two Andruav mobiles, one of them on Quad which is the  Drone-Mode Andruav and the other on land in pilot's hand which is GCS-Mode Andruav , The Quad has  Ardupilot board, the board is connected to Drone-Mode Andruav using USB cable - it can also use a Bluetooth connection-. 

On ground we have GCS-Mode Andruav mobile, and another mobile that runs Droid Planner, BTW you may use a laptop with Mission Planner on it.

The video starts actually showing when everything is connected and then make a playback showing from the beginning how to make such connection.

I want here to mention three things:

1- My english language is bad :( sorry .... I need to work on it.

2- When trying to make this type of connection you need Andruav GCS to have access to both a wi-fi and Internet, so you have two options:

     a. Andruav GCS is connected to a wi-fi that can access Internet as well.

     b. Andruav GCS has 3G/4G connection, and here you need to enable Wi-Fi Tethering so that the third mobile can connect to Andruav GCS. 

     In my demo all mobiles where connected to Wi-Fi router, however both Andruav  mobiles are connected and communicated through a server in server.

 3- If you see the last part of the video you will find that Andruav Camera Shooting and HUD info are working and independent of the telemetry feature that works in parallel.

Have a safe flight :)

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Comment by Johnatan on January 3, 2015 at 1:40pm

First of all thanks for the great job but I think you should try to solve this issues:

1. In current version each drone should carry an android phone which is neither cheap nor light weight.

2. Any data must travel through server which rises security and latency issues.

And one question:

How the device in drone side is going to detect any connection issues and enable "fail-safe mode"?

Comment by MHefny on January 3, 2015 at 6:40pm

Thank you for the feedback.

1- yes however mobiles behaves as camera, GPRS module, Emergency module "send SMS with GPS when lost", also Andruav can be used separately as HUD & Remote shooting. if you add all of this in one device mobile price might be acceptable.  especially that there is no wiring and hassle, also there is no on ground complex antennas.

2.1 regarding security concerns it is planned to encrypt the code using a key that the user only knows, so no one on server side can interact. expected to be available in the very near future -especially after you raise this concern-.

2.2 the 3G nature enforce you to use a server in-between, so this is something we have to deal with and try to minimize the impact that is why I upgraded the protocol since version 1.0.18 -we are now in 1.0.19 and working on 1.0.20- to send binary data for images and telemetry instead of Base64 that is up to 25 faster. I tested the link with slow net as low as 256K and it was working very well, however Ardu telemetry works starting from 512K well. normal mobile speed here in egypt-that is considered slow network is 4 to 10 M- and that is more than enough as long as we dont stream video.

However  still it is unsafe to use remote control from DroidPlanner or EZ-GUI, but for a normal UAV trip with long range, Andruav is great to track your trip. 

3- for fail safe it is board setting with Droidplanner, Andruav till this version does not interact with Mavlink packets or multiwii packets. however it is planned to do so, as part of drone-to-drone tracking feature. 

the only failsafe available now is that it sends SMS with GPS location when connection is lost - a feature you need to enable in the settings menu-.

I do hope you can find time to test the system, and thanks for your fruitful feedback.

Comment by Simon Wunderlin on January 4, 2015 at 5:42am

This is pretty cool, thanks for posting! However, I disagree with 2.2, depending on your provider, you can get an internet exposed device. 



Comment by MHefny on January 4, 2015 at 6:29am

Here in Egypt I use Vodafone, and they dont give real IPs on mobiles. I think this is common for mobile providers. 

A direct link can be established if I have static IP at home and made the mobile connects to it, even using USB stick with SIM card, we dont get real IP here. still it may vary from a provider to another, which make it unreliable to depend on.

Thanks :)

Comment by Stuart Brookes on January 4, 2015 at 8:41am

Very cool. Just be aware that when making connection to apm using usb restarts it effectively killing it if its flying. This doesn't happen on the telemetry port. 

Comment by MHefny on January 4, 2015 at 6:22pm

@Stuart Brookes Thanks for the feedback ... this is very important issue ... 

I am working on supporting FTDI so that I can connect a serial port in Telemetry port.

another ready solution is to use BT connected in Telemetry port, however not as reliable as wiring.

Comment by Oscar Avellaneda-Cruz on January 5, 2015 at 1:52am

@MHefny beautiful work man! Keep it up. I need to get a pair of Android phones to get this going.
Have you had any feedback on which devices work best?

@Stuart Brooks, does this apply to Pixhawk as well? Or is this just universal to the way the code and hardware interact.

Comment by MHefny on January 5, 2015 at 3:15am

@Oscar Thanks :)

Well it depends on what part of Andruav do you want to use. For a telemetry you need an Android 4+  to allow a USB Host. 

if you want to have IMU data without the board using the FPV button then you need a mobile with gyro "best" or at least compass & accelerometer.

typically a cheap mobile will do the job :)

Comment by MHefny on January 5, 2015 at 3:52am

@Johnatan  Data encryption has been implementedas an option. now from server side you cannot tell what navigation data is being communicated between Drones & GCS.

Also Telemetry data is encrypted.

Comment by Stuart Brookes on January 5, 2015 at 6:25am
Hi Oscar, I am not sure if its APM specific, but it's easy to test if you have pixhawk (I don't). With props off arm and spin up you copter and plug in (can be prw plugged in if easier) and then connect hitting the button in mission planner. If it stops the issue is there.


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