Armageddon421's Hackingblog

Android dead reckoning

by on Feb.13, 2014, under quickhack, Random

One of our lecturers gave us the excercise to to over the winter holidays to write an android app in qt that reads and logs sensor and GPS data, does some calculations on them and displays the refined result on a map.

Reading out GPS and sensors from within qt proved difficult, and displaying a map was also not exactly the easiest task at all. Two weeks before the deadline, he lifted the qt-restriction. Naturally, I started the project in android studio two days before the deadline.

In the videos below you can see the result. The data has been recorded with my smartphone placed in the center console of my car.

I found out we also had to do a height profile, so I hacked this together last-minute:

It was fun playing around with dead reckoning. If anyone is interested I might post about how it works or even try to implement some proper algorithms, since this is just a quick mockup rather than anything useful. For example there is no real calibration or gravity compensation of any kind.

This was also the first time I tried to use fragments in android, which proved quite difficult because I didn’t quite read up enough to understand how they work and how to deal with their lifecycles. I obviously managed to get it to work somehow, though, but it might not be exactly the prettiest solution.



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