A Novel Approach To Improve Vehicle Speed Estimation Using Smartphone's INS/GPS Sensors

In recent times, number of researchers have investigated vehicle tracking applications by fusing the measurements done by accelerometers, as part of inertial navigation system (INS), and GPS (Global Positioning System). However, the sensors in recreational devices like mobile phone have limitations in measurement accuracy and reliability. Usually, sudden changes in vehicle speed are not always captured well by GPS. Accelerometers, on the other hand, suffer from multiple noise sources. In this paper, we investigate the noise performance of accelerometers, available in a few smartphones. Then, we apply the noise analysis for the purpose of estimating the moving vehicle speed. A number of experiments were carried out to capture the vehicle’s position & speed from OBD2, GPS as well as 3-axes accelerometer. We demonstrate a method by which the phone’s orientation is compensated for while calculating speed from the measured acceleration. Further, a new method of INS/GPS fusion is proposed which enhances the accuracy of speed estimation. It is envisaged that with increasing estimation accuracy, the application of multi-sensor fusion in autonomous vehicles will be greatly enhanced Keywords-component; GPS; Allan Variance; OBD2; speed correction; accelerometer