Three-frequency GNSS (Global Navigation Satellite System) real-time cycle slip fixation technology based on ionized layer-free combination

Abstract

The invention belongs to the field of satellite navigation positioning technology research, and particularly relates to a three-frequency GNSS (Global Navigation Satellite System) real-time cycle slipfixation technology based on an ionized layer-free combination. The method comprises the following steps that: receiving and analyzing a broadcast ephemeris telegraph text, a real-time precise satellite correction telegraph text and a navigation telegraph text; according to a real-time precise satellite orbit and clock difference correction amount and the modeling correction of a main error, improving the distance measurement accuracy of a pseudo-range and carrier wave phase observation amount; between the (k-1)th epoch and the kth epoch, carrying out original observation amount differentiation; constructing an ionized layer-free EWL (Extra-wide Lane) combination; on the basis of a fixed EXL cycle slip, constructing an ionized layer-free WL (Wide Lane) combination; and on the basis of thefixed EXL and WL cycle slip, constructing an ionized layer-free NL (Narrow Lane) combination. By use of the technology, the steps of traditional multi-frequency combination cycle slip detection and repairing can be simplified, calculation efficiency is improved, and the fixation success rate of the cycle slip under an ionospheric disturbance situation can be improved.

Description

technical field [0001] The invention belongs to the field of satellite navigation and positioning technology research, in particular to a triple-frequency GNSS real-time cycle slip fixing technology based on ionosphere-free combination. Background technique [0002] With the modernization of the Global Navigation Satellite System (GNSS), providing real-time high-precision positioning services is the main direction of the future development of GNSS. Carrier phase observation is crucial for high-precision GNSS positioning, such as Real-time Kinematic (RTK) differential positioning technology and Precise Point Positioning (PPP) technology, because its measurement accuracy can reach mm class. In practical applications, the phenomenon of discontinuous ambiguity (that is, cycle slip) in the carrier phase observation due to signal loss of lock and other reasons can cause the increase of PPP positioning accuracy and fixed convergence time of RTK ambiguity , thereby reducing the pe...

AI Technical Summary

Problems solved by technology

At present, ionospheric suppression methods in cycle slip detection and repair methods include: (1) introducing external correction information, but limited by the accuracy of the ionospheric model, resulting in a decrease in the reliability of cycle slip detection and repair, and the introduction of communication burden

(2) The ionospheric delay is used as a parameter to be estimated, but this method usually takes a few minutes to obtain a relatively accurate ionospheric delay error, which is difficult to meet the real-time requirements

(3) Introduce differential technology, but ionospheric scintillation will lead to weak correlation of ionospheric delay items, making the residual error after ionospheric correction larger

(4) With the development of GNSS modernization, the broadcast of three-frequency and above signals provides convenience for the ionospheric suppression cycle-slip detection and repair method of multi-frequency observation combination, but the existing multi-frequency observation combination method usually assumes that The ionospheric delay between epochs is negligible at high sampling rates, and as the epoch interval increases, the reliability of cycle slip detection and repair is bound to be reduced

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