地球静止轨道卫星数对广域增强系统性能的影响

为了评估广域增强系统(wide area augmentation system,WAAS)中地球静止轨道(geostationary earth orbit,GEO)卫星数对WAAS性能的影响,正确解码WAAS报文,对比分析GEO卫星和全球定位系统(global positioning system,GPS)卫星的伪距改正值和用户差分距离误差指数;将GEO卫星纳入导航定位解算,并基于WAAS监测站实测数据,解算分析GEO卫星数对WAAS报文延迟、中断和导航性能的影响.结果表明:当现有GPS卫星均正常工作时,GEO卫星数的增加可有效降低报文的延迟和中断,但对WAAS定位精度和完好性的提升并不明显.星基增强系统(satellite-based augmentation system,SBAS)中有两颗正常工作的GEO卫星是比较理想的状况.

Influence of GEO satellite number on WAAS performance

In order to evaluate the influence of the number of Geostationary Earth Orbit (GEO) satellites in the Wide Area Augmentation System (WAAS) on the performance of the WAAS, the WAAS messages are correct decoded, the Pseudo Range Correction and User Differential Range Error Indicator of the GEO satellites and the Global Positioning System (GPS) satellites are compared and analyzed. The influence of the number of GEO satellites on the WAAS message delay, interruption and navigation performance are calculated and analyzed by introducing the GEO satellites into the navigation and positioning solution and by the use of the measured data of the WAAS monitoring station. The results show that the message delay and interruption can be reduced effectively by the increase of the number of GEO satellites when the existing GPS satellites is in normal operation, but the accuracy and integrity of the WAAS are not improved significantly.