pARK working on iPhone 3GS

Question

I have been building on top of the iphone augmented reality framework found here but sadly, on mobiles without gyro (namely the 3GS) it doesn't work (as it states.)

Does anyone know of a fix to make it work with the motion sensors and compass heading instead ? Or would anyone be so bounty-hungry to provide the codes to a such framework ?

I will need a way to either make the vectors work, and if it is not possible, I will need to push through and just use heading only.

Answer 1

CoreMotion do work in devices like 3GS. However, this Framework pARk is for devices with gyroscopes (Runtime Requirements: iPad 2 or iPhone 4 running iOS 5.0 or later)

Gyroscope is a fundamental piece of inertial navigation systems (INS) and thus without it you'll have a severe loss in precision.

Check the paper: "Usability of apple iPhones for inertial navigation systems" for a comparison of the performance of iPhone 3GS and iPhone 4. The author's conclusion is:

However, the tests show that even with the use of filters it is challenging to build a precise INS using sensors from common devices because of their inaccuracies and high error rate. The results show that the iPhone 4 can provide tolerable results for a short time, but then the deviation becomes too high because of the error rate. Currently we are implementing a multi-dimensional Kalman filter to examine possible enhancements. Furthermore we try to improve the system by using more sensors from the iPhone 4, e.g. light sensors and camera.

I believe you should think your app to support only iPhone4 or newer.