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.
Conclusions The tight integration model can significantly reduce the limitations of the installation environment on GNSS-R device.
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