Satellite radio navigation service channel zero-value calibration system

Abstract

A satellite radio navigation service channel zero-value calibration system comprises a dual-channel digital oscilloscope, a control and process computer, an attenuator and a vector network analyzer. The vector network analyzer is used for calibrating time delay of a test cable and the attenuator. The dual-channel digital oscilloscope is used for synchronously sampling second pulsed signals of a navigation satellite and output of an RNSS signal channel to be test. The control and process computer is used for completing initialization of the oscilloscope, data acquisition of the oscilloscope channels, zero-value start point determination, channel initialization, local parameter data generation, capture of RNSS signals and zero-value calculation so as to acquire absolute time delay of an RNSS signal transmission channel. The satellite radio navigation service channel zero-value calibration system adopting a digital domain processing mode is applicable to zero-value calibration of the RNSS signal channel in a navigation satellite signal system according to different modulation methods. The calibration precision is determined only by thermal noise of the system, calibration precision of the test cable and the A / D (analog / digital) sampling resolution ratio.

Description

technical field [0001] The invention relates to a satellite radio navigation service channel zero value calibration system, which can be used for precise calibration of the zero value of the navigation satellite RNSS (Radio Navigation Satellite Service) signal transmission channel. Background technique [0002] The satellite navigation system can send high-precision, all-day and all-weather navigation, positioning and timing information, and is an indispensable and important space infrastructure for today's national economy and national defense construction. The value of the global seamless service provided by the satellite navigation and positioning system is immeasurable, and its application has formed a huge satellite navigation industry. The navigation satellite system uses the radio wave transmission time to calculate the pseudo-range. The measurement of the downlink navigation signal transmission delay is the time from the generation of the baseband signal of the navig...

AI Technical Summary

Problems solved by technology

[0003] Traditional delay measurement systems are based on vector network analyzers and carrier-based modulation methods. These methods are only suitable for frequency conversion systems and amplification systems. The input and output signal spectrum characteristics of the system to be tested are basically the same, mainly because of the carrier center frequency and signal amplitude. changes; while the navigation signal transmission channel includes the baseband processing and radio frequency generation and amplification of the navigation signal, such signals cannot be tested with high-precision time delay using the test method of the vector network analyzer

Literature "Absolute Calibration of a Geodetic Time Transfer System" (John Plumb, Kristine M.Larson, Joe White, and Ed Powers [J] IEEE transactions on ultrasonics, ferroelectrics, and frequency control, vol.52, no.11, November 2005pp1904 -1911) proposed to use a high-speed oscilloscope to observe the starting point of the second pulse of the navigation satellite and the notch point of the BPSK waveform modulated by the RNSS signal carrier to obtain the zero value of the channel. At present, the zero value of the navigation satellite RNSS transmission channel generally adopts this oscilloscope observation method , but there are three problems in the oscilloscope observation method: (1) The absolute time delay of the channel of the DUT cannot exceed one chip time delay, otherwise there will be ambiguity of the whole baseband chip time delay, which will cause a large measurement error; ( 2) The error of the notch point observed by the oscilloscope is large, and the error is on the order of several ns; (3) It can only be applied to the RNSS signal channel that modulates a navigation signal on one frequency point

In order to improve the performance of satellite navigation systems, in the current navigation signal system of major navigation satellite systems, navigation signals of various modulation modes are jointly modulated at one frequency point, and the method of observing the notch point of RNSS carrier modulation with an oscilloscope is no longer applicable

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