On-Orbit Reprogrammable Digital Waveform Generator for Anti-Jam GPS
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Solution Overview
Problem
Existing GPS systems are vulnerable to jamming in anti-access/area denial environments, as they rely on single-band signals that can be easily disrupted by jammers, lacking robustness and complexity to counteract interference.
Innovation Solution
An on-orbit reprogrammable digital waveform generator (ORDWG) generates a resilient frequency-hopping Global Positioning System (GPS) signal that combines frequency-hopping spread spectrum and direct-sequence spread spectrum techniques, allowing the signal to quickly hop between multiple GPS bands, making it difficult for jammers to interfere with the signal, while maintaining backward compatibility with existing GPS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-band GPS signal is used, then the system is simple and compatible with existing GPS receivers, but the system becomes vulnerable to jamming in anti-access/area denial environments
Solution Approach 1:
The GPS signal dynamically switches between multiple frequency bands according to a hopping pattern, making it difficult for jammers to track and disrupt the signal. The system transitions from static single-band operation to dynamic multi-band frequency hopping, enhancing anti-jam robustness while maintaining compatibility through structured signal design
Solution Approach 2:
The GPS signal is segmented across multiple frequency bands (L1, L2, L5) with each band carrying portions of the navigation data. This segmentation allows the receiver to reconstruct the complete signal by combining information from multiple bands, providing redundancy against jamming while maintaining overall system compatibility
2Reliability
If frequency hopping between multiple GPS bands is implemented, then the anti-jam robustness is improved, but the signal structure becomes more complex
Solution Approach 1:
The GPS signal is designed to serve multiple functions simultaneously: it maintains compatibility with legacy direct-sequence spread spectrum receivers while incorporating frequency-hopping spread spectrum capabilities for enhanced anti-jam performance. The same signal structure supports both traditional and advanced receiver types across multiple frequency bands
Solution Approach 2:
The patent combines direct-sequence spread spectrum (DSSS) and frequency-hopping spread spectrum (FHSS) techniques into a unified signal structure. The DSSS component ensures compatibility with existing GPS infrastructure, while the FHSS component provides dynamic frequency switching for anti-jam robustness, creating a hybrid signal that achieves both goals
3Reliability
If a frequency-hopping spread spectrum signal is used, then the signal becomes resistant to jamming, but existing GPS receivers cannot decode the signal
Solution Approach 1:
The frequency-hopping component is applied partially to specific portions of the GPS signal while maintaining the traditional DSSS structure in other portions. This partial application allows advanced receivers to exploit the FHSS anti-jam capabilities when available, while legacy receivers can still process the DSSS components using existing algorithms, ensuring backward compatibility
Data Source
AI summary
A frequency hopping Global Positioning System (GPS) system comprises an on-orbit reprogrammable digital waveform generator configured to generate a GPS signal comprising a resilient frequency-hopping spread spectrum GPS signal that hops at a hop rate between two or more GPS channels. The GPS signal further comprises a legacy direct-sequence spread spectrum signal for at least two of the two or more GPS channels. Further, a receiver is configured to receive the GPS signal, wherein the receiver is further configured to decode the GPS signal.