The System Design Of GPS Singal Receiving And Processing Based On DSP

Global Positioning System (GPS) is first developed by the US Defence Department to navigate the satellites of army, navy, and air-forces. It is capable of precisely navigating and positioning in three dimensions all-weather, around-the-clock, and globally, thus is potential of significant application and development which has been witnessed over the last decade, whereof the vantage point positioning (both stationary and dynamic) is highlighted in research and application.Although the US government cancelled the Selection Availability Jamming in 2000 and the GPS precision is improved accordingly, there still exist many random errors in dynamic positioning, such as satellite clock error, calendar error, delay error by ionosphere, delay error by troposphere, multi-path error, and the noise of receiver, which deteriorate the precisions of positioning.In order to eliminate errors and improve precisions, this thesis proposes an approach of optimal estimation, i.e., the Kalman Filtering. Specifically, based on system modeling and observation modeling, the true position of target can be pin-pointed regardless of various random errors by means of the Self-adaptation. The outcome of simulation of this technique accords with the expectation: the precision is improved indeed.The dynamic filtering of GPS is superior to difference positioning. It costs less since no base station nor data communicating equipment is needed. Moreover, there is no limit to the coverage of its signals. By this means, the precision of positioning can be improved even though the data have been undergone the difference treatment.The paper puts forward a GPS signal receiving and processing system based on the Digital Signal Processing chip (DSP) as DSP's computation capacity is suitable for all the real-time filtering and processing of digital signals. The system can facilitate at large the soft- and hard-ware designing of serial communication between DSP and GPS, the DSP power designing, the soft- and hard-ware designing of LCD monitoring module, the Self-adaptive Kalman filtering and computing, the expansion of DSPmemory, and the designing of other independent systems. DSP's computation capacity ensures the high precision of GPS and experiments show that this system is of great importance in both civil and military application of high precision positioning.