Development of a GPS/INS Integrated System on the Field Programmable Gate Array Platform

The integration of GPS and INS can overcome the defects of INS or GPS standalone systems, and benefits from the complementary characteristics of the two systems. This paper describes progress on the development of a GPS/INS integrated system based on a field programmable gate array (FPGA) platform. Compared with the application-specific integrated circuit (ASIC) approach, the FPGA approach can shorten the research and development period. Its reprogrammable hardware configuration represents a system design methodology of lower risk. It also allows maximum flexibility, being able to integrate a wide range of GPS and INS sensor packages. The research is conducted under the Australian Cooperative Research Centre for Spatial Information (CRC-SI) project 1.3 “Integrated Positioning and Georeferencing Platform”. This project aims to develop a generic hardware/software platform for positioning and imaging sensor integration. The current work focuses on development of software and algorithms, and a FPGAbased GPS/INS data logging device. Software packages for both tight and loose integration have been completed. The tight integration system is implemented to fuse the INS solution with the GPS pseudorange and Doppler measurements based on the extended Kalman filtering and sigma-point Kalman filtering algorithms. The loose integration system extends the functionality of the tight integration system to support a broader range of GPS receivers that provide only position output. A FPGA-based data logging device has been implemented. The system records the GPS and INS data onto a compact flash card. The data can then be subsequently processed by the tight/loose integration software for estimation of the INS errors. Many laboratory and field tests have been conducted to verify the software, hardware, as well as the system design. Some experimental results are presented and future plans are outlined.