Research And Implementation Of Onboard GPS Attitude Measurement System

This paper introduces the research and implementation of onboard GPS measurement system.According to the requirements of course,roll,pitch,speed and others during the vehicle movement,three GPS antennas and OEM boards were used to synchronously receive GPS data.Besides,differential positioning technology was applied to achieve attitude measurement in order to calculate the information of posture,speed and position of the carrier quickly and to achieve the ultimate goal of providing real-time navigation for vehicles.According to the practical application and environmental requirements of the onboard GPS measurement system,we selected the corresponding hardware,designed circuit and mechanical structure to meet the requirements of the onboard navigation equipment.In the development of software application systems,we fully demonstrated the principles of GPS positioning,attitude measurement,carrier phase difference,satellite position and so on according to the software life cycle to work on the data reception and processing,ambiguity search,GPS pseudo-code and loss of lock processing and to analyze practical application of baseline length,installation position and error calibration.In the application,in order to determine the north-center angle,the roll angle and the pitch angle of the vehicle body,as well as the vehicle speed and position quickly in the northeastern sky coordinate system,we used least squares method to calculate the center distance vector length of two GPS antennas.Finally,the experimental verification indicated that the attitude precision is within 0.5 mil and the positioning precision is within 1 meter.In conclusion,we found onboard GPS measurement systems enjoys the reputation of high measurement precision,lacking accumulative errors,low cost and high reliability,which is suitable for the position determination and navigation of huge vehicles and boats.