GNSS baseband signal processing method for ionospheric total electron content monitoring

Abstract

The invention provides a GNSS base band signal processing method for monitoring the total electron content of the ionized layer. The method for monitoring the TEC of the ionized layer through GNSS double-frequency carrier signals is based on the application characteristics of the GNSS in the field of monitoring the TEC of the ionized layer, addition and subtraction are performed on carrier tracking loop phase discriminators of the GNSS double-frequency signals, and tracking loops of the double-frequency carrier signals are coupled, so that mutual assistance between the double-frequency signal carrier tracking loops is achieved; moreover, code loops are smoothed through differential loop output conversion values of the tracking loops to output the calculated TEC of the ionized layer, and thus the high-precision and high-accuracy value of the TEC of the ionized layer can be obtained. With the GNSS base band signal processing method for monitoring the total electron content of the ionized layer, the precision for monitoring the TECA of the ionized layer can be effectively improved, and effects of cycle slip on the monitored value of the TEC of the ionized layer can be avoided due to the mutual assistance between the double-frequency signals; due to the mutual assistance between the double-frequency signal carrier tracking loops, the double-frequency carrier tracking loops can be assisted mutually by loop tracking information of each other, and thus the tracking sensitivity of the double-frequency signals can be improved.

Description

technical field [0001] The invention belongs to the technical field of space weather monitoring, and in particular relates to a GNSS baseband signal processing method for monitoring the total ionospheric electron content. Background technique [0002] Ionospheric TEC is an important parameter to characterize the characteristics of the ionosphere, and it has attracted attention in space weather monitoring and forecasting. Due to the relatively stable strength and phase of satellite navigation signals, it has the advantages of abundant signal resources, low cost, easy popularization, and convenient multi-point simultaneous detection when used to monitor the ionosphere. The modern GNSS system presents the characteristics of multiple systems and multiple frequency points. For example, after the modernization of GPS, L2C civilian signals are added on the basis of L1CA signals. GLONASS system broadcasts civilian signals on G1 and G2 frequencies. B2 and B3 frequencies broadcast ci...

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Problems solved by technology

[0007] 3. The tracking of the dual-frequency carrier signal has obvious defects: L1 / L2 is tracked separately, the bandwidth of the tracking loop is large, and the error of the obtained tracking dual-frequency carrier is relatively large; L1 assists L2 tracking, and the tracking of the L2 signal depends on the L1 signal Tracking, there is a situation where L1 loses lock and L2 inevitably loses lock, and the back-end ionospheric TEC solution will also introduce tracking errors between the L1 loop and the L2 loop

[0008] 4. Due to the wide loop filter of the traditional signal tracking method, there is a cycle slip in the carrier phase obtained by tracking, so the ionospheric carrier TEC obtained by it has an error caused by a cycle slip

[0009] 5. Dual-frequency signal tracking sensitivity is not high

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