Mixed Modulation Satellite Navigation Signal System
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Solution Overview
Problem
Traditional satellite navigation signal systems have limited anti-interference ability due to their reliance on direct sequence spread spectrum modulation, which restricts their performance in complex and interference-rich environments.
Innovation Solution
A design method for a satellite navigation signal system that incorporates mixed modulation of direct spread spectrum and frequency hopping, including baseband code sequence generation, signal separation and recombination, frequency hopping modulation, and direct spread spectrum signal generation, to enhance anti-interference capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct sequence spread spectrum modulation is used in satellite navigation signal systems, then signal gain is improved, but anti-interference ability is limited due to open frequency points
Solution Approach 1:
The patent combines direct sequence spread spectrum modulation and frequency hopping modulation into a mixed modulation system. The signal undergoes both DS-SS spreading and frequency hopping, merging the advantages of high signal gain from DS-SS with the frequency diversity and anti-interference capabilities of frequency hopping, thereby resolving the contradiction between signal gain and anti-interference ability.
Solution Approach 2:
The patent creates a composite modulation signal that integrates two different modulation techniques (direct sequence spread spectrum and frequency hopping). This composite signal structure combines the properties of both modulation methods, achieving both high signal gain and enhanced anti-interference performance through the synergistic effect of the two techniques.
2Reliability
If frequency hopping technology is used to improve anti-interference ability, then anti-interference capability increases, but signal gain decreases compared to direct sequence spread spectrum
Solution Approach 1:
The patent merges frequency hopping modulation with direct sequence spread spectrum modulation in a mixed modulation framework. The frequency hopping component provides anti-interference capability by rapidly changing frequency points, while the direct sequence spread spectrum component maintains high signal gain through spreading. The combination allows the system to achieve both high anti-interference ability and sufficient signal gain simultaneously.
3Power
If traditional direct sequence spread spectrum modulation is used, then signal gain is achieved, but adaptability in complex interference environments is limited
Solution Approach 1:
The patent introduces dynamic frequency hopping into the traditionally static direct sequence spread spectrum system. The frequency hopping component dynamically changes the operating frequency points according to a predetermined pattern, making the system adaptable to complex interference environments. This dynamic behavior allows the signal to avoid interference by switching frequencies, thereby improving adaptability while maintaining the signal gain benefits of spread spectrum.
Solution Approach 2:
The patent merges the static, high-gain direct sequence spread spectrum modulation with the dynamic, adaptive frequency hopping modulation. This combination creates a mixed modulation system that inherits the high signal gain from DS-SS and the environmental adaptability from frequency hopping, resolving the contradiction between signal gain and adaptability in interference-rich environments.
Data Source
AI summary
A design method for a satellite navigation signal system with mixed modulation of direct spread spectrum and frequency hopping includes: modulating the spread spectrum code sequence of multipath signal components; mixing and multiplexing with the signal components corresponding to the same frequency point; forming a baseband code sequence; separating signal components corresponding to the baseband code sequence to obtain separated radio frequency signals; recombining and modulating separated radio frequency signals; controlling the frequency hopping pattern by the frequency hopping code sequence if the separated radio frequency signals are authorized signals, and performing mixed frequency synthesis modulation; performing direct combined radio frequency modulation if the separated radio frequency signals are unauthorized signals, and obtaining the recombined signal component; amplifying the signal power to obtain the direct spread spectrum navigation signal.