GPS P(Y)码功率增强监测分析

全球定位系统(GPS)的Block IIR-M和Block IIF卫星具备可编程功率输出能力, 可以灵活增强单个信号分量的发射功率。为了系统评估GPS P(Y)码的功率增强能力, 对弹性功率的原理进行了理论分析, 提出了GPS信号功率增强的监测分析方法, 利用国际GNSS监测评估系统(iGMAS)和国际GNSS服务(IGS)监测站数据、高增益天线监测数据、事后精密星历对GPS增强P(Y)码的覆盖性及星座性能、空间信号和用户端性能进行了分析。结果表明:在保持发射总功率和民用信号功率不变的情况下, Block IIF和Block IIR-M卫星的L1 P(Y)码和L2 P(Y)码功率相比正常水平分别增强约6 dB和5 dB；在功率增强信号覆盖区内仅利用19颗增强卫星进行双频单点定位, 位置误差不大于15 m(95%)；当可见增强卫星数为6, 增强后的P(Y)码载噪比为55 dB·Hz时, P(Y)码之间的多址干扰引起的等效载噪比下降量为0.4 dB。 

Monitoring and analysis on GPS P(Y) code power enhancement

With programmable power output capabilities, global positioning system(GPS) Block IIR-M and Block IIF satellites can flexibly enhance transmit power of individual signal components. In order to systematically evaluate the power enhancement capability of GPS P(Y) codes, the theoretical analysis of the flex power principle was conducted, and a monitoring and analysis method of GPS signal power enhancement was proposed. Furthermore, the coverage, constellation performance, signal-in-space and user-side performance of power-enhanced P(Y) codes were analyzed based on the data of the International GNSS monitoring and assessment system (iGMAS) and international GNSS service (IGS) monitoring station, high-gain antenna monitoring data, and precision ephemeris. According to the findings, it is possible to increase the L1 P(Y) code and L2 P(Y) code power of Block IIF and Block IIR-M satellites by about 6 dB and 5 dB, respectively, compared with the normal level, while keeping the total transmit power and civil signal power unchanged. With respect to the dual-frequency single-point positioning test only using 19 enhanced satellites, the positioning accuracy is no more than 15 m (95%) in the power-enhanced signal coverage area. While the equivalent carrier-to-noise ratio reduction caused by multi-access interference between P(Y) codes is 0.4 dB, when there are 6 visible enhanced satellites and the enhanced P(Y) code carrier-to-noise ratio is 55 dB·Hz.