| In this paper, a new algorithm of phase smoothing pseudo range GNSS PPP/INS tight coupled is proposed to solve the problem that the calculation accuracy of the low cost MEMS is limited by the traditional tight coupling method in navigation practice. Experimental shows that using phase smoothing pseudo range GNSS PPP/INS tight coupled method, the position accuracy of low cost MEMS and GPS receiver can reach decimeter level. The speed accuracy is centimeter per second or even millimeters per second level. This coupling method has higher accuracy, and a better convergence than the traditional C/A code. Secondly, when the number of epochs is increased, the accuracy also increased. When GPS signal is interrupted, the method can speed up the convergence of the filter after the interruption, and improve the navigation accuracy in middle or high level. This method can save the cost of navigation equipment, and has some practical significance.This paper is divided into two modules: the traditional GPS/INS loose combination, tight combination system; based on the phase smoothing pseudo range of GNSS PPP/INS tight combination system. Firstly the system sub module layers on the basic principle, mathematical modeling and algorithm equation were introduced one by one, followed by the introduction of the Kalman filtering technique and the improvement methods of the specific application. Finally, it puts forward the whole based on phase smoothing pseudorange GNSS PPP / INS tight coupling technology detailed way to improve the navigation accuracy of low cost MEMS Research.Technology of tight coupling navigation technology of GNSS PPP/INS with phase smoothing pseudo range,when processing low precision MEMS the position precision can reach decimeter level even cm level, speed and accuracy for cm per second or millimeters per second grade, higher than the traditional C / a code pseudo range accuracy of tightly coupled mode, has faster convergence speed; with the increase in the number of smoothing epochs, smooth pseudo distance of observation accuracy improve reached high accuracy inertial navigation equipment requirements; when GPS outages, the algorithm GNNS PPP/INS greatly shorten the rear to filter convergence time, reduce the influence of GPS data interrupt and control the accuracy in the range needed for the project, greatly improve and enhance the application value of low cost MEMS in navigation. In conclusion, this study saves cost of equipment for high precision navigation operation, and has certain practical significance. |
