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Objectives: The emerging global navigation satellite system (GNSS) interferometric reflectometry (GNSS-IR) technique can obtain the information of reflector using geodetic GNSS receiver, and has been extensively applied to the research on snow depth, tide level, soil moisture, sea surface wind and so on. However, multipath suppression technique is often adopted in geodetic GNSS receiver and the reflected signal will be weakened or even eliminated, which will undoubtedly reduce the performance of GNSS-IR. Therefore, the influence of multi-receiver and multi-frequency on GNSS-IR should be carefully investigated. Methods: By learning from the method of zero baseline, we design an experiment of snow depth retrievals using GNSS-IR at Chinese Arctiv Yellow River Station in Svalbard, and quantitatively illustrate the influence of receiver performance on the accuracy of snow depth retrievals. In the experiment, two different GNSS receivers are connected to the same antenna with a power divider. It brings a special benefit that the observations of two receivers at three frequencies are derived from absolutely the same reflector. After collecting enough data, the daily average retrievals of the two receivers in the three frequencies are compared in order to verify the effectiveness of the retrieval strategy. Then the differences in the retrieval of different receivers are compared and analyzed to check the influence of receivers. Results: The results show that the observations of each receiver and each frequency can be used to retrieve snow depth and the bias is in 3 cm. However, in spite of the same reflector, the differences between the snow depth retrievals from two receivers and three frequencies remain, especially when the snow depth changes rapidly. Conclusions: Different receivers have different methods to suppress multipath effect, which will affect the retrieval effect of GNSS-IR. Therefore, when using geodetic GNSS receivers for GNSS-IR retrievals, the difference brought by receivers cannot be ignored. If the method of multipath suppression can be properly considered in GNSS data processing, it should be helpful to improve the accuracy of GNSS-IR retrievals. [ABSTRACT FROM AUTHOR]

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Aiming at the acquisition problem brought by NH code in the signal of BD2 which leads to sensitivity reduction problem by traditional acquisition methods, this paper presents a weak BD2 signal acquisition method based on adaptive stochastic resonance algorithm. By combining the DBZP method with adaptive stochastic resonance algorithm, the method can eliminate the data hopping and NH hopping, and significantly improve the signal-to-noise ratio. The method can be adopted to achieve the fast signal acquisition with high sensitivity characteristic. The simulation and test results verify that, this method provides stronger capacity of acquainting BD2 signal, has more advantages in real-time, high sensitivity and has a higher application value. [ABSTRACT FROM AUTHOR]

Copyright of Geomatics & Information Science of Wuhan University is the property of Geomatics & Information Science of Wuhan University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We study PPP-AR rapid ambiguity re-convergence in the case of short-term loss or disruption of observation data, offer a reasonable extrapolation time threshold for using augmentation information, demonstrate the reliability improvement of existing URTK services when using this method, and design a corresponding real-time testing scheme to verify its availability. The results show that, augmentation information can be extrapolated for at least 30s, and that the PPP-AR rapid ambiguity re-convergence method can improve the reliability of URTK service for control center and rovers even in poor observation conditions. Rovers can independently realize ambiguity rapid re-convergence without the support of regional URTK augmentation service, which will reduce the real-time data communication burden between rovers and control center significantly. [ABSTRACT FROM AUTHOR]