Low cost positioning by matching altitude readings with crowd-sourced route data

Detecting and tracking the position of a mobile user is an increasingly important feature in many mobile applications. In this work we study how cheap and energy-efficient air pressure sensors measuring the altitude could be used, as a complement to the dominant GPS system. The cornerstone of our approach is that a huge amount of route data, collected with GPS devices, is available in various cloud services. The location detection and route tracking task thus becomes a question of matching the collected altitude traces with the altitude curves of stored data to find the best matching routes. Here we build a prototype system of crowd-sourced database containing only altitude data. How accurately this stored altitude data could be matched with the collected altitude traces is the key question of our study. © 2012 ACM.