Development and Test of 'Tightly Coupled' Military GPS / INS Systems

摘要

Diehl BGT Defence (DBD) develops and tests different kind of integrated GPS/INS navigation systems. The paper is focused on integrated GPS/INS navigation systems for missile applications. In this case a tactical grade IMU has to be combined with a military SAASM based PPS GPS receiver. These high dynamic missile applications call for special requirements on the IMU, on the GPS receiver and on the method to couple both systems. Beneath the navigation function the IMU (inertial measurement unit) will be used for guidance and control. Thus the required performance of the inertia! sensors is determined by the required navigation accuracy, but also by the required autopilot functionality and performance. E.g. sensor bandwidth requirements are often derived from the autopilot requirements. In addition the GPS receiver has to be able to acquire directly on the P(Y) code. To achieve a maximum performance within a GPS/INS system, in addition to the selected sensors, an optimized hardware and software mechanization has to be used. This system concept of a tightly coupled GPS/INS system will be presented. A main focus within coupled high dynamic applications, such as missile applications is on the time synchronization between IMU and GPS data. Finally a general procedure how DBD tests integrated GPS/INS systems will be descript. To be able to perform an optimized test strategy special test features have to be part of the system design.