| Virtual playback testing technology has gradually become the mainstream testing method for receivers because of its high efficiency,low cost and repeatability.However,this technology can only test the performance of the receiver in single-point positioning mode,and the maturity of network RTK technology increases the positioning mode of the receiver.Therefore,the realization of virtual playback testing technology that can support RTK positioning mode becomes an urgent problem in navigation field.A set of navigation signal record and playback instrument is designed In this paper,which downconverts and digitizes the RF signal within the specified bandwidth,and stores it as IF data on appropriate media.In playback section,IF data are converted into analog signals by up-conversion and output at the original RF frequency.In the differential data record mode,the host computer can synchronously record the data stream transmitted by the base station.On the basis of realizing RTK mode playback test,the influence of quantization digit and sampling bandwidth of record and playback instrument on signal playback accuracy is analyzed.A software receiver platform for navigation signal analysis is built to realize single-point positioning,pseudo-range differential positioning,carrier phase differential positioning,and the error introduced in positioning algorithm by configuration of parameters of record and playback instrument is analyzed.The performance index and test and evaluation scheme which can present the performance of the record and playback devices are designed based on the result of terminal positioning.The effects of receiver positioning mode,quantization number and sampling bandwidth of record and playback device on the consistency of record and playback were compared and analyzed through experiments,and the feasibility of the record and playback device and its test and evaluation scheme designed in this paper is verified. |
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