Guang Je Tsai

GPS/MEMS INS Data Fusion and Map Matching in Urban Areas

This paper presents an evaluation of the map-matching scheme of an integrated GPS/INS system in urban areas. Data fusion using a Kalman filter and map matching are effective approaches to improve the performance of navigation system applications based on GPS/MEMS IMUs. The study considers the curve-to-curve matching algorithm after Kalman filtering to correct mismatch and eliminate redundancy. By applying data fusion and map matching, the study easily accomplished mapping of a GPS/INS trajectory onto the road network. The results demonstrate the effectiveness of the algorithms in controlling the INS drift error and indicate the potential of low-cost MEMS IMUs in navigation applications.

The performance analysis of the map-aided fuzzy decision tree based on the pedestrian dead reckoning algorithm in an indoor environment

Hardware sensors embedded in a smartphone allow the device to become an excellent mobile navigator. A smartphone is ideal for this task because its great international popularity has led to increased phone power and since most of the necessary infrastructure is already in place. However, using a smartphone for indoor pedestrian navigation can be problematic due to the low accuracy of sensors, imprecise predictability of pedestrian motion, and inaccessibility of the Global Navigation Satellite System (GNSS) in some indoor environments. Pedestrian Dead Reckoning (PDR) is one of the most common technologies used for pedestrian navigation, but in its present form, various errors tend to accumulate. This study introduces a fuzzy decision tree (FDT) aided by map information to improve the accuracy and stability of PDR with less dependency on infrastructure. First, the map is quickly surveyed by the Indoor Mobile Mapping System (IMMS). Next, Bluetooth beacons are implemented to enable the initializing of any position. Finally, map-aided FDT can estimate navigation solutions in real time. The experiments were conducted in different fields using a variety of smartphones and users in order to verify stability. The contrast PDR system demonstrates low stability for each case without pre-calibration and post-processing, but the proposed low-complexity FDT algorithm shows good stability and accuracy under the same conditions.

A low complexity map-aided Fuzzy Decision Tree for pedestrian indoor/outdoor navigation using smartphone

With the great international popularity and various sensors embedded, smartphone becomes an excellent mobile and indoor navigator. Pedestrian Dead Reckoning (PDR) is one of the most common technologies for pedestrian and indoor navigation which is based upon pedometer and orientation sensor. But various errors tend to accumulated step by step in its present form. Therefore, this study proposes a novel map aided Fuzzy Decision Tree (FDT) without complex algorithm and individually tuning process to reduce the accumulated error, improve the generation ability and minimize the use of infrastructure. The rule-based FDT algorithm estimates the location based upon the map, sensors and expert knowledge after training once then for other new experiments. Various scenarios consisted of different test sites, smartphones and users are implemented in order to verify the performance of proposed algorithm. The results verify that once the proposed algorithm is well trained, it is able to maintain good position performance regardless of the users, fields and smartphones. In addition, the positioning solution can output the global coordinate because of the use of self-produced map for seamless navigation in both indoor and outdoor environments.