Altboc modulation double sideband tracking demodulation circuit and its modulation method

Abstract

The invention relates to satellite navigation and provides a double-sideband tracking demodulation circuit of ALTBOC modulation. The double-sideband tracking demodulation circuit comprises a lower frequency conversion module I, an upper sideband processing circuit, a lower sideband processing circuit, a carrier DDS module, a carrier loop filter, a subcarrier DDS module, a subcarrier loop filter and a weighted combination identification module. An ALTBOC intermediate frequency signal input end is connected with the lower frequency conversion module I. The lower frequency conversion module I is connected with the upper sideband processing circuit, the lower sideband processing circuit and the carrier DDS module. The upper sideband processing circuit is connected with the subcarrier DDS module and the weighted combination identification module. The lower sideband processing circuit is connected with the subcarrier DDS module and the weighted combination identification module. The subcarrier DDS module is connected with the subcarrier loop filter. The subcarrier loop filter is connected with the weighted combination identification module. The weighted combination identification module is connected with the carrier loop filter. The carrier loop filter is connected with the carrier DDS module. The double-sideband tracking demodulation circuit is applicable to a Galileo navigation system and a Beidou global (three-stage) navigation system.

Description

technical field [0001] The invention relates to satellite navigation, in particular to a Galileo navigation system and a Beidou global (phase three) navigation system. Background technique [0002] Satellite navigation (Satellite navigation) refers to the technology of using navigation satellites to navigate and position users on the ground, sea, air and space. The world's four major satellite positioning systems are: [0003] GPS system (USA) Beidou system (China) GLONASS system (Russia) Galileo satellite navigation system (EU). [0004] Those skilled in the art use the Galileo satellite navigation system and the Beidou system room to send the following questions: [0005] The E5 frequency point of the Galileo navigation system and the B2 frequency point of the Beidou global (Phase III) navigation system will use ALTBOC modulation, and the upper and lower sidebands will modulate different navigation messages and pseudo-random codes respectively. The receiver can receive ...

AI Technical Summary

Problems solved by technology

In SSB reception, the signal-to-noise ratio is lost by 3dB, and the sub-carrier information is not used, resulting in a decrease in pseudo-code measurement accuracy and anti-multipath capability

During double-sideband reception, the noise of narrow-lane observations combined with upper and lower sideband carrier phase observations increases by 3dB, and is limited by carrier phase tracking accuracy, which does not reflect the advantage of ALTBOC modulation over BPSK modulation in code tracking accuracy

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