you also could download form wandoujia platform, this is [download link]:https://github.com/chaz1942/FpvHud/blob/master/app/app-release.apk
what is this app done? This app get some import infomation(such as speed, altitude, heading, roll, pitch and jaw) to display at screen. It is very easy to read. HUD is this app function point, the version is 1.0. I will put more function point in it. I will show you some image about my app.
this image is app UI interface. On the top is Heading scope, left is speed scope and right is alititude scope. In the center of screen is flight path direction. This are three horizontal parallel lines, it show pitch and roll.
The picture above is show that UAV now is roll to right. The angle of roll is the parallel line with screen's x axis.
This picture above is shown that UAV's speed, this speed is (x^2 + y^2)^1/2
