Research and Implementation on BDS/GNSS Real-Time Positioning for Urban High-Precision Location-Based Services

With the deepening development of mobile Internet technology and Global Navigation Satellite System (GNSS), realizing high-precision positioning and navigation on mobile intelligent terminals is not only an important way to achieve the urban high-precision location-based services (LBS) in the future, but is also one of the development trends and major application fields of the satellite navigation industry. Although those mobile intelligent terminals such as smart phones basically have integrated a GNSS module, their positioning accuracies are generally low which cannot meet the requirements of high-precision location-based services. In this work, a system design scheme for realizing high-precision location-based services was studied and proposed, and a set of BDS/GNSS real-time high-precision positioning software for mobile intelligent terminals is developed based on Android platform. By collecting the observation data stream from an external GNSS module through the built-in Bluetooth module on those intelligent devices and receiving the differential correction data from a nearby reference station via 3G/4G or Wi-Fi wireless network, respectively, users' high-precision position then can be calculated in real-time by the software, and the positioning result will be displayed on Google maps simultaneously. At present, this software supports real-time single point positioning and real-time pseudorange differential positioning for BDS/GPS/GLONASS standalone and combined system. The experimental results of combined BDS/GPS/GLONASS real-time positioning show that the accuracies of single point positioning in horizontal and vertical are better than 2.5 and 3.5 m, respectively, and the accuracies of real-time differential positioning in horizontal and vertical are better than 0.5 and 1.0 m, respectively. As a consequence, this contribution can provide some technical references for the realization of urban high-precision location-based services.