Precise kinematic positioning experiments with a low-cost RTK GPS engine

Canadian Marconi Company has recently developed a low-cost RTK GPS engine called the RT Star and has presented the system architecture and design along with preliminary test results at the ION GPS´97 Conference. Since then, extensive experiments have been conducted using a dual GPS signal simulator configuration and a vehicle equipped with a RT Star following various routes. These experiments permit an assessment of the absolute accuracy of the system in various dynamic scenarios as well as its operational functionality in real-life situations. Laboratory experiments utilize a dual configuration of Nortel(R) STR2760 GPS signal simulators. Outdoor testing was realized by installing an antenna and a RT Star on a vehicle, along with a RT-Star base station located on a surveyed rooftop control point. Communication between both was performed with a modem transmitting the messages encoded in the RTCM-104 format at 9600 bauds. The vehicle followed a route with a surveyed geodetic marker situated along it. Stop-and-go operations were performed at the marker. This paper will describe the test scenarios, the setup of the test platforms and the results obtained for the series of experiments. It will show that a 20-centimeter-level accuracy can be obtained in real-time under many kinematic scenarios with a low-cost L1 GPS sensor. In the authors´ view, the results represent a possibility for a significant decrease in cost for applications requiring a high level of accuracy