多系统单频紧组合GNSS-R测高方法

GNSS-R Altimetry Method with Multi-system Single-Frequency Tight Integration

全球卫星导航系统反射测量(global navigation satellite system-reflectometry,GNSS-R)技术可以同时接收导航卫星直射信号和来自水面的反射信号,进而利用伪距、载波相位和信噪比信息实现高时空分辨率的水面高度反演。由于岸基设备特别是单频设备在部分受限环境中观测量不足,导致基于载波相位处理的GNSS-R实时测高性能降低,因此提出了一种利用GNSS重叠频率B1C/L1/E1信号的紧组合模型以提升单频GNSS-R的测高性能。首先,从天线极化方式的角度对差分系统间偏差(differential inter-system bias,DISB)进行评估和分析。结果表明,对于左圆极化天线和右圆极化天线组成的短基线,在使用同型号接收机时可以忽略DISB的影响。然后,基于实测北斗三号卫星导航系统/全球定位系统(global positioning system,GPS)/伽利略(Galileo)系统数据评估了多系统紧组合模型下的GNSS-R测高性能。实验结果表明,相比于松组合模型,多系统紧组合模型能够显著减少安装环境对设备的限制,特别是在单系统反射信号观测量不足4个的条件下,紧组合模型GNSS-R水面高度反演在保证厘米级精度的条件下成功率仍高达约94%,从而有效提升恶劣观测条件下GNSS-R测高性能。

Objectives:Global navigation satellite system-reflectometry(GNSS-R)technology can receive direct navigation satellite signals and reflected signals from the water surface at the same time.The code,carrier-phase and signal-to-noise ratio information are used to retrieve water surface height.Due to the observations of shore-based devices,especially single-frequency devices,are insufficient in the partially confined environment,the performance of GNSS-R technology based on carrier-phase processing is degraded.Therefore,we propose a tight integration model of overlapping frequency B1C/L1/E1 signals in global navigation satellite system to improve the performance of GNSS-R.Methods:Differential inter-system bias(DISB)is evaluated from the point of view of the antenna polarization mode,and the altimetry performance of GNSS-R based on tight integration model is assessed.Results:The results show that:(1)There is no obvious relationship between the polarization mode of the antenna and DISB,and GNSS-R using the homogeneous receivers can ignore the effect of DISB.(2)Both the loose and tight integration model can achieve the fixed rate of 99.75%and the standard deviation is less than 1 cm in the good satellite visual environment.When the number of visible satellites in a single navigation satellite system is less than 4,the tight integration model can still achieve the fixed rate of 94%,and the standard deviation is less than 1 cm.Con⁃clusions:The tight integration model can significantly reduce the limitations of the installation environment on GNSS-R device.