LEO Satellite Navigation Jamming Immunity
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Solution Overview
Problem
Current satellite navigation systems, such as GPS, are vulnerable to jamming and interference, which limits their reliability and accuracy, especially in critical applications like aviation and military operations, due to their weak signal strength and susceptibility to jamming from low-power sources, leading to significant disruptions and safety risks.
Innovation Solution
A navigation system that employs a network of ground reference stations and Low Earth Orbiting (LEO) satellites to provide real-time aiding signals to user receivers, allowing them to lock onto carrier phase measurements and extend coherent integration of GPS signals, thereby overcoming jamming effects and improving jamming immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signal power is increased to improve jamming resistance, then jamming immunity is improved, but satellite payload and launch costs increase significantly
Solution Approach 1:
The patent applies preliminary action by having ground reference stations pre-calculate and transmit aiding navigation information to LEO satellites before the satellites reach the user. This allows the LEO satellites to relay enhanced navigation signals without requiring increased power output from GPS satellites, thus improving jamming immunity while avoiding higher payload costs
Solution Approach 2:
The patent introduces LEO satellites as intermediary vehicles between ground reference stations and user receivers. These LEO satellites receive aiding information from ground stations and relay it to users, enabling enhanced navigation signals without requiring the original GPS satellites to increase their power output, thereby avoiding the cost increase associated with higher payload power
2Reliability
If GPS broadcast bandwidth is increased to improve jamming resistance, then jamming immunity is improved, but spectrum coordination complexity increases
Solution Approach 1:
The patent segments the navigation signal transmission by separating the function of spectrum allocation (handled by ground reference stations with authorized GPS spectrum access) from the function of signal relay (handled by LEO satellites using their allocated spectrum). This allows GPS signals to be transmitted at higher effective power without requiring GPS satellites to change their broadcast bandwidth, avoiding complex spectrum coordination changes
Solution Approach 2:
LEO satellites serve as intermediaries that receive navigation information within authorized GPS spectrum from ground stations and relay it to users. This intermediary approach allows enhanced signal delivery without requiring GPS satellites to modify their broadcast spectrum allocation, thereby avoiding the complexity of global spectrum coordination changes
3Reliability
If traditional navigation aids are used instead of GPS to avoid jamming vulnerability, then jamming resistance is improved, but navigation performance and cost efficiency decrease
Solution Approach 1:
The patent creates a universal navigation system where LEO satellites can serve multiple functions: they relay GPS signals for high-precision navigation when available, and provide autonomous navigation capabilities when GPS is jammed. This multi-functional approach maintains high navigation performance while providing jamming resistance, surpassing the capabilities of traditional single-function navigation aids
Solution Approach 2:
The patent changes the operational parameters by having LEO satellites transmit aiding navigation information at high power levels (comparable to traditional navigation aids) while maintaining the precision benefits of satellite-based navigation. This allows the system to achieve both high accuracy and jamming resistance simultaneously, overcoming the trade-off present in traditional navigation aids
4Use of energy by moving object
If GPS receiver power consumption is reduced to improve portability, then device power efficiency is improved, but signal processing capability for jamming resistance decreases
Solution Approach 1:
The patent applies preliminary action by having ground reference stations perform complex signal processing and calculate aiding navigation information in advance. This reduces the processing burden on the user receiver, allowing portable devices with lower power consumption to achieve enhanced jamming resistance without requiring sophisticated real-time signal processing capabilities
Solution Approach 2:
LEO satellites act as intermediaries that receive complex navigation data from ground stations and relay simplified aiding information to users. This intermediary approach allows portable receivers to obtain enhanced jamming protection through simpler signal processing, maintaining low power consumption while improving reliability against jamming
Data Source
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AI summary
A navigation system provides a significant level of protection against all forms of interference or jamming to GPS in a cost-effective way. The system employs a network of ground reference stations and Low Earth Orbiting (LEO) satellites in conjunction with GPS. A common-view ranging geometry to a GPS satellite is established that links a reference station and a user. A second common-view geometry to a LEO satellite between the same reference station and user pair is also established. The ground stations synthesize real-time aiding signals by making carrier phase measurements of GPS the LEO satellite signals. This aiding information is transmitted via the LEO satellites to the user receiver at high power to penetrate ambient jamming. The user receiver locks onto the carrier phase of the LEO satellite, demodulates the aiding information, then applies the carrier phase measurements and the aiding information to enable extended coherent measurements of the GPS signals. The system thereby recovers the GPS signals that would otherwise be lost to the jamming.