Data Acquisition using Smart Phone Applications

Abstract

There are numerous publically available smart phone applications designed to track the speed and position of the user. By accessing the phones built in GPS receivers, these applications record the position over time of the phone and report the record on the phone itself, and typically on the application's website. These applications range in cost from free to a few dollars, with some, that advertise greater functionality, costing significantly higher. This paper examines the reliability of the data reported through these applications, and the potential for these applications to be useful in certain conditions where monitoring and recording vehicle or pedestrian movement is needed. To analyze the reliability of the applications, three of the more popular and widely used tracking programs were downloaded to three different smart phones to represent a good spectrum of operating platforms. Several tests were conducted to evaluate the applications ability to measure speed, elevation change, and positioning on aerial imagery. The data reported by the applications in each test was compared to a Race Logic VBOX VB20SL3 Data Acquisition Unit that was also used in the same tests. The VBOX unit was used as a standard against which to measure the applications efficacy since this unit is specifically designed to monitor and record vehicle movement1. The results show that under certain conditions, speed, positioning on aerial imagery, and elevation change as recorded by applications were relatively accurate for conditions where the recorded period occurred over a long duration of time. The results from this testing shows that recording the motion of a vehicle or pedestrian over a long duration of time, greater than 10 seconds, with minimal changes in velocity can be properly documented by the use of a smart phone running a commonly available applications.

Mid-Range Data Acquisition Units UsingGPS and Accelerometers

“…Global Position System (GPS) -During previous testing, it was found that the GPS sample rate for any smart phone tested was a maximum of 1 Hz [9]. For some phone applications, the sample rate was even lower, 1/3 Hz to 1/5 Hz.…”

“…The mid-level applications can potentially acquire better speed, acceleration, and positional data than basic applications because they differ in the way they sample the data and report it. In previous testing, Neale et al showed that conventional health fitness applications such as Map My Fitness allows sampling of GPS data every one to two seconds [5]. A reason for this longer interval in fitness applications is that sampling at shorter intervals requires more data storage as well as battery usage and generally is not required for exercise activities that take 20 or 30 minutes.…”

Smartphone‐based crowdsourcing for position estimation of public transport vehicles

“…In the last one decade, smartphone‐based crowdsourcing techniques are often used for collecting public transport‐related data [10]. Owing to recent advances in technology, efficient GPS receivers are provided in smartphones for accurate location tracking [17]. Often, raw positioning GPS data does not match with actual position due to various errors in different mobile modules and the navigation system [1].…”