In order to meet the requirements of Location-based Service (LBS), there are many proposed positioning solutions that
may be able to provide LBS support, such as GPS, Mobile Phone Location, RFID, and so on. With the most widely
recognized system being the Global Positioning System (GPS) and Windows Mobile 5.0 system characteristics, this
paper first provides three kinds method, i.e. invoking Win32 API, using Ports namespace and calling GPS Intermediate
Driver, to receive GPS raw data on Windows Mobile devices.
Since internet-based GPS VRS RTK workstation can provide real-time streaming of differential GPS corrections. The
following text introduces a high precision Net-based RTK (NRTK) mobile positioning solution which is mainly
equipped with a Windows Mobile 5.0 device and an Ashtech Z-Xtreme receiver. With it a rover-side (NtripClient)
firstly connects to an NtripCaster which is a part of a VRS workstation, via GPRS /CDMA, using the IP and specified listening Port of the Tongji VRS workstation. Then the rover-side transmits NMEA GGA strings after the HTTP request to the NtripCaster. With that the Windows Mobile device continuously receives RTCM data back from the NtripCaster and instantly sends them out into the Ashtech Z-Xtreme receiver. Finally, the Ashtech Z-Xtreme receiver will work out vector solution information of the rover-side.
Thus, this paper provides a multimode mobile LBS positioning solution based on NRTK and Windows Mobile 5.0.