Design And Implementation Of Multi-source Fusion Positioning For High-speed Trains Based On Dual-mode Satellites

The high-speed train is one of the most important transportation of trips and goods transport in China.It is essential to precisely locate the high-speed trains in real time for train scheduling.At present,China’s high-speed train positioning is realized by combining track circuit and transponder.However,This approach comsumes much material clmsumption.More seriously,the transponder is vulnerable to bad whether,posing the risk of severe accidents.Global navigation satellite system(GNSS),which provides location services on a global scale all time,is not affected by bad weather.However,the precision of GNSS is low,and the location service will be unavailable when GNSS signal is blocked.To tackle the above problem,this paper proposes a multi-source fusion locating system based on the dual mode of satellites.On the one hand,we introduce the inertial measurement unit(IMU)to increase the location accuracy by fusing the sensors.On the other hand,we introduce the chirp spread spectrum(CSS)signals to compensate for the absence of GNSS signals when GNSS fails to locate the trains.The system can effectively provide the accurate and reliable estimation of the location under the condition of high speed motion and variable environments.The proposed system can be divided into two parts: the front end and the back end.The front end processes the sensor data,solves the dual differential position of GNSS to improve the accuracy,solves the time difference of arrival(TDo A)of CSS to obtain the ranging information,and pre-integtates the IMU to obtain the optimal condition attitude estimation.The back end estimates the train states and uses the sliding window method and nonlinear optimization method to obtain the optimal condition.Based on the above scheme,extensive experiment are counducted in various scenarios.Experimental results show that when GNSS is partially blocked out,the average errors are2.23 meters and 0.79 meters without and with CSS,respectively.