Adaptive coding modulation method for data transmission of inter-satellite links of satellite navigation system

Abstract

The invention provides an adaptive coding modulation method for data transmission of inter-satellite links of a satellite navigation system. The distance between any two satellites in a constellation is measured by an inter-satellite distance measuring device, the signal-to-noise ratio of a received signal of a receiving terminal is estimated, a coding modulation scheme selector selects a corresponding LDPC-CPM scheme on the basis of a target error rate algorithm and a handling capacity-to-bandwidth ratio algorithm and sends the LDPC-CPM scheme to a receiver through pilots, a data signal is processed by an LDPC code coder, a random interweaver and a CPM modulator to generate a modulated signal, the modulated signal is sent to an additive white Gaussian noise channel, a pilot signal is analyzed by a coding modulation scheme estimator and then superposed with the data signal of noise of the additive white Gaussian noise channel to be subjected to iterative detection by a CPM demodulator, a de-interweaver, an LDPC decoder and a random interweaver, and the LDPC decoder makes a hard decision and then outputs data. According to the adaptive coding modulation method, the reliability and effectiveness of an inter-satellite adaptive coding modulation system can be effectively improved.

Description

technical field [0001] The present invention relates to a satellite navigation system inter-satellite link (Inter-satellite Link, ISL) data transmission (referred to as "digital transmission") method, especially a continuous phase modulation (Continuous Phase Modulation, CPM) based automatic Adaptive coding modulation (Adaptive Coding Modulation, ACM) data transmission method. Background technique [0002] With the intensification of competition between Global Navigation Satellite System (GNSS) and the escalation of navigation warfare, higher requirements are placed on positioning accuracy, integrity, reliability and anti-destruction capabilities. Inter-satellite links ( ISL) is one of the main ways to solve this problem. The mutual ranging and communication between satellites through the inter-satellite link can shorten the update cycle of the ephemeris, realize the satellite-ground joint orbit determination of the navigation constellation, thereby improving the positionin...

AI Technical Summary

Problems solved by technology

Although QPSK modulation is a constant envelope modulation, its phase is discontinuous, which will cause spectrum expansion and high-voltage transient phenomena of the transmitter; QAM modulation is not only phase discontinuous, but also the envelope of the modulated signal is not constant. A linear power amplifier will produce nonlinear distortion

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