Many Scenes Of Gps Signal Simulator Design

Global position system is wide-used in military and civil areas. That is, it providesseparate services. These are called the Standard Positioning Service (SPS) for civilusers and the Precise Positioning Service (PPS) for military users.According to receiver’s dynamic environment, multi-scene GPS signal canprecisely generate GPS signal, and provide realistic simulation signals for the GPSreceiver. Multi-scene GPS receivers generally are applied to aircrafts, missiles,vehicles, ships and other carriers. Overseas research on high dynamic GPS simulator isearlier than domestic research. There are few open literatures. So developing our ownmulti-scene GPS simulators is very important.Firstly, the structure of GPS simulators is introduced. The generation andcharacteristic of the C/A code is designed. The principle of NCO is analyzed. Theparameters in navigation message are produced. Based on the flow chart of GPSsimulators, MATLAB can generate GPS signal. In addition, GPS receivers areintroduced in the basic concepts.Secondly, the coordinate systems used by GPS signal simulator are introducedand the conversion formulas between them are given. The user’s dynamic models aredivided into the basic carrier scene and the complex carrier scene. The basic scenecontains a linear motion, circular motion and spiral movement. The complex scene hasthe movement of satellites, missiles, aircrafts, vehicles and ships.Thirdly, GPS satellite signal status is given in detail. According to the parametersof navigation message, the effects of carrier attitude variation and the receiver’santenna pattern, we can select the visible satellites. The position of the visible satellitescan be calculated by the parameters of navigation message. Because of the relativemotion between carrier and satellite, we can get signal power, the delay and carrierDoppler frequency calculation.Finally, on the GPS signal simulator platform, MATLAB program is ported to theCCS software in order to complete algorithm implementation. According to the resultsof GPS receivers, the trajectory of carrier can be calculated.