Strapdown Seeker Sight Angular Rate Estimation Method Study

The line of sight (LOS) rate is one of the important parameters in guidance and control system. The precise estimation of LOS rate has a close impact on the overall performance of system. Strapdown seeker can only measure the body LOS angle. The LOS rate in inertial coordinate system can not be measured directly by Strapdown seeker. So we have to add the derivative of body LOS angle with measurement noise and data of rate gyro to obtain LOS rate. In most cases, the differential method can be used to obtain the derivative of a signal approximately, but there is noise in almost all signals, so this method can not estimate the derivative of signals accurately. Through the establishment of an appropriate object model, Kalman filter can suppress noise and obtain the derivative of the signal.In this thesis, a Kalman filter based on FPGA has been designed, which includes hardware and software systems, in order to obtain the derivative of body LOS angle, thus obtain the precise estimation of LOS rate. In software design, the system is divided into A/D control module, Kalman filtering algorithm module and D/A control module. Kalman filtering algorithm module is also divided into several functional modules. Time division multiplexing method has been used to minimize the complexity of the algorithm; in addition, floating-point arithmetic operations have been used to ensure operational accuracy. Through the simulation tests of modules and entire system, the design has good performance in target tracking and derivative estimation, and meets the design requirement. Hardware system includes least system of FPGA, AD circuit and DA circuit. At last, we test the hardware circuits, download and debug the software in hardware system.This study explores the application of FPGA in LOS rate estimation, which has good prospects.