Abstract
Global Navigation Satellite System interferometric reflectometry (GNSS-IR) can be used to monitor a series of geophysical parameters in a cost-effective manner with high temporal resolution. The technique makes use of the simultaneous reception of direct and reflected GNSS signals with a single antenna. Based on the low-cost u-blox M8N chips, a GNSS-IR instrument is developed, which could be used to collect and process GNSS signals automatically and save and transmit generated GNSS data. Details about the instrument are described here for the first time. Then, the recorded SNR observation characteristics are analyzed by comparing three in-situ SNR sequences, which are simultaneously collected by the instrument with a low-cost patch antenna and a geodetic antenna and by a geodetic GNSS receiver with a geodetic antenna. Based on the developed function relating the peak power spectral density to peak frequency estimation error of the low-cost instrument, a weighting method is proposed to fuse multiple estimations of the reflector height to improve the estimation accuracy of the GNSS-IR-based reflector height. The performances of the developed low-cost instrument and the proposed reflector height estimation method are evaluated using a data set collected in Xinxiang City, Henan, China, over 6 days. The results show that there exists good agreement between the instrument-based reflector height estimates and the ground-truth estimates, with root-mean-square errors of 1.1 cm and 0.4 cm for the normal average and the proposed weighted average results, respectively, when the antenna height is in the range of 0.65 m to 2.15 m and the reflecting surface is flat, silty loam soil ground.
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Data availability
The GNSS-IR simulator and Trimble GNSS antenna gain data are available at http://www.ngs.noaa.gov/gpstoolbox. The u-blox GNSS antenna gain data are available at https://www.u-blox.com/en/product/ann-mb-series. The GNSS data are available upon request to Prof. Taoyong Jin (tyjin@sgg.whu.edu.cn).
Change history
18 August 2021
A Correction to this paper has been published: https://doi.org/10.1007/s10291-021-01172-5
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Acknowledgements
The authors would like to thank the anonymous reviewers for their careful work and thoughtful suggestions. This work was supported by the National Natural Science Foundation of China under Grant Numbers 41721003 and 41574031, Natural Science Foundation of Hubei Province, China, under Grant Number 2019CFB427, Key Laboratory of Geospatial Environment and Geodesy, Ministry of Education, Wuhan University, under Grant Number 19-02-06, and Key Laboratory of Surveying and Mapping Science and Geospatial Information Technology of the Ministry of Natural Resources under Grant Number 2020-1-3.
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Li, Y., Yu, K., Jin, T. et al. Development of a GNSS-IR instrument based on low-cost positioning chips and its performance evaluation for estimating the reflector height. GPS Solut 25, 127 (2021). https://doi.org/10.1007/s10291-021-01163-6
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DOI: https://doi.org/10.1007/s10291-021-01163-6