Method for generating satellite navigation signals in minimum shift keying (MSK) or Gaussian filtered minimum shift keying (GMSK) modulation mode

Abstract

The invention discloses a system and a method for generating satellite navigation signals based on a minimum shift keying (MSK) or a Gaussian filtered minimum shift keying (GMSK) modulation mode. The system comprises a first pseudorandom sequence navigation data adding unit, a second pseudorandom sequence navigation data adding unit, a first subcarrier input unit, a second subcarrier input unit, a plurality of modulo two addition units and an MSK or GMSK modulator. The method comprises the steps of enabling a pseudorandom sequence I and navigation data I to form a sequence through modulo two addition and then to obtain a signal CI through the modulo two addition with a subcarrier I, enabling a pseudorandom sequence Q and navigation data Q to form a sequence through the modulo two addition and then to obtain a signal CQ through the modulo two addition with a subcarrier Q, and carrying out the modulo two addition on the signal CI and the signal CQ to obtain a signal CIQ for MSK or GMSK modulation. According to the system and the method for generating the satellite navigation signals based on the MSK or the GMSK modulation mode, the advantages that MSK or GMSK is rapid in power attenuation and constant in enveloping are remained, meanwhile a common binary phase shift keying (BPSK) mode receiver can be used for receiving, the method and the system are particularly suitable for navigation frequency ranges with limited bandwidth and facilitate utilization of a high-power amplifier by a satellite, and complexity of the receiver can not be greatly increased.

Description

technical field [0001] The invention relates to the technical field of satellite navigation, relates to a method for generating satellite navigation signals using MSK or GMSK modulation, and relates to the application of MSK or GMSK technology in the generation of satellite navigation signals. Background technique [0002] At present, BPSK (Binary Phase Shift Keying, binary phase shift keying), QPSK (Quadrature Phase Shift Keying, quadrature phase shift keying) and BOC (Binary Offset Carrier, binary offset carrier) technologies are generally used in the field of satellite navigation to realize data For modulation and reception, these technologies all use square wave signals as baseband signal waveforms. In actual transmission, the steep rising edge makes the spectrum wider and the power more dispersed. [0003] In the case of abundant electromagnetic spectrum, these technologies fully meet the requirements, but with the increase of satellite navigation and other space microw...

AI Technical Summary

Problems solved by technology

However, the shortcoming of its direct application to satellite navigation is that at the last level, since the information carried by the baseband digital signal does not have the autocorrelation characteristics of the pseudo-random sequence, it is impossible to use the pseudo-random sequence when the satellite navigation signal is extremely weak when it reaches the ground. Sequential correlation detection and tracking signals, which makes MSK and GMSK not directly applicable to such systems

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