Beidou No.3 global short message sending method in high-speed dynamic environment

Abstract

The invention discloses a Beidou No.3 global short message sending method in a high-speed dynamic environment. The method comprises the steps of capturing all current MEO satellites, and carrying out the tracking and demodulation despreading processing, and obtaining a current accessible satellite; selecting a satellite with the highest elevation angle as an inbound response satellite; calculating Doppler observed quantity of the inbound response satellite, transmitted inbound carrier Doppler data and inbound pseudo code Doppler data, and compensating a carrier nominal value and a pseudo code nominal value; and carrying out real-time monitoring and processing in the data transmission process to complete data transmission. The method can be quickly realized based on conventional outbound and inbound processing, is suitable for any navigation equipment capable of using Beidou No.3 global short message frequency points, and is easy to understand and realize, high in reliability and good in stability.

Description

technical field [0001] The invention belongs to the field of navigation signal processing, and in particular relates to a method for sending Beidou-3 global short messages in a high-speed dynamic environment. Background technique [0002] At present, my country's Beidou-3 system has been officially put into operation. The global short message communication function is a characteristic function of my country's Beidou satellite navigation system. It relies on MEO satellites to serve global regions, and the length of a single message is 40 Chinese characters. The global short message is composed of the space segment, the ground segment and the user segment. The user sends the short message inbound signal through the L frequency band. After receiving the inbound signal, the spaceborne receiver forwards it to the ground station through the inter-satellite link. [0003] In practical applications, not every MEO satellite has the access capability of the satellite-borne in-station...

AI Technical Summary

Problems solved by technology

At the same time, for a certain MEO satellite, the receiving capacity of its global short message users is limited. If many users in a certain area enter the station at the same time, it will cause the blockage of the large system; therefore, in the list of accessible satellites, adaptive selection stars are more important

In addition, since the inbound receiver is a space-borne receiver, the lock-in frequency range needs to be limited within the range of plus or minus 1kHz to ensure successful lock-in and demodulation of the inbound receiver; while MEO satellites are medium-orbit satellites, The radial velocity is large, and the generated Doppler is also large, and the communication rate has only one gear, and it takes 2s to send 40 Chinese characters. At this time, if the carrier is in a medium-high dynamic motion scene, the message will The uplink frequency jitter and frequency deviation are too large, so that the uplink frequency exceeds the frequency range of the inbound receiver's acquisition and stable tracking; in this case, even if the inbound receiver can capture the inbound signal, it will still be due to Cause information demodulation error or even loss of lock

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