GPS Radio Occultation Inversion Analysis of Neutral Atmospheric Detection Technology Based on Dual-Frequency Dual-Mode GNSS Occultation Receiver

Abstract

Compared with the traditional radio atmospheric detection and radar detection, GNSS occultation technique provides a powerful tool for atmospheric detection, the GNSS occultation technique which has the characteristics of without calibration, all-weather, high precision, high vertical resolution, and global uniform coverage. The GNSS occultation technique based on the atmosphere GPS/LEO radio occultation, GPS satellite radio signal is obscured by Earth’s atmosphere, GPS satellite radio signal cutting the Earth’s atmosphere and ionosphere sectional, then the radio signal refracted before reach LEO satellites. The received GPS signal contains information of the Earth’s atmosphere and ionosphere. We can get atmospheric and ionosphere electron density profile, the total electron content of the ionosphere and atmospheric bending angle profiles, index of refraction, temperature and barometric pressure through the relevant atmospheric inversion model. This paper introduces GPS radio occultation atmospheric detection technology based on mountain-based experimental verification, test is located at Wuling Mountain Peak of Yanshan Mountains (located in Chengde in Hebei Province, 117.48°E, 40.60°N, ~2118 m), and made a detailed presentation for signal capture, signal track, and data quality. Different from prediction algorithm of spaceborne occultation, the test used the mountain-based occultation prediction based on the fixed position, getting the forecast results of a week about occultation event. Because of mountain conditions and other factors, occultation signal capture is different because of different azimuths, and made a comparison between different azimuths making a analysis against signal to noise ratio (SNR), the consistency between the Carrier phase and the pseudorange, the reason of signal loss of lock. In order to verify the accuracy of GPS radio atmospheric occultation, this article compares the refractive index profile obtained by inversion with meteorological data, test results were better than 5 %.