GPS Receiver Built-In Test Signal Path Segmentation
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Solution Overview
Problem
Current GPS receivers lack comprehensive built-in test capabilities, particularly for complex systems with SAASM and M-Code technologies, which are essential for ensuring safety in civil aviation by preventing hazardous and misleading information outputs.
Innovation Solution
The implementation of a system and method that provides both loop forward and loop backward built-in test capabilities, using built-in test equipment to generate deterministic RF test signals and sample positioning data, ensuring comprehensive testing of both analog and digital signal paths within the GPS receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If GPS receivers incorporate complex technologies like SAASM and M-Code, then the functionality and security of the receiver are improved, but the difficulty of providing comprehensive built-in testing increases
Solution Approach 1:
The patent divides the signal path into distinct segments (analog portion and digital portion) and implements separate test signal paths for each segment. The analog test signal path tests components from the RF front end through the analog-to-digital converter, while the digital test signal path tests components from the digital signal processor through the output. This segmentation allows comprehensive testing of complex SAASM and M-Code technologies without requiring a single overly complex test system.
Solution Approach 2:
The patent introduces test signal generators as intermediary devices that inject known test signals into both the analog and digital signal paths. These intermediaries provide controlled test inputs that allow the system to verify the functionality of complex components like SAASM and M-Code modules without requiring access to external test equipment or disrupting normal operation.
2Reliability
If comprehensive built-in testing is implemented for both analog and digital signal paths, then the reliability of the GPS receiver is improved, but the device complexity increases
Solution Approach 1:
The patent merges the test signal generation, injection, and verification functions into the existing GPS receiver architecture. The test signal generators are integrated with the signal processing chain, and the verification logic is combined with the normal signal processing functions. This merging approach provides comprehensive testing coverage for both analog and digital portions while avoiding the need for separate external test equipment.
Solution Approach 2:
The patent implements universal test signal paths that can test multiple components and functions through a single integrated system. The analog test signal path can test the RF front end, mixers, amplifiers, and analog-to-digital converter, while the digital test signal path can test the digital signal processor, cryptography modules, and output interfaces. This multi-functional approach achieves comprehensive reliability verification without proportionally increasing system complexity.
3Measurement precision
If deterministic test data is generated and processed through the operational signal path, then the ability to detect malfunctions is improved, but the loss of time for testing increases
Solution Approach 1:
The patent generates deterministic test data in advance and prepares test signals before actual testing begins. The test signal generators are pre-configured with known input patterns, and the test pathways are established before malfunction detection is needed. This preliminary preparation allows for rapid execution of comprehensive tests without significant time loss during actual operation.
Solution Approach 2:
The patent implements continuous testing capabilities where deterministic test signals are continuously injected and monitored through both analog and digital signal paths. Rather than performing discrete periodic tests, the system maintains continuous verification of signal integrity, allowing malfunction detection to occur continuously without interrupting normal GPS operations. This continuous action eliminates idle testing time while maintaining high detection accuracy.
Data Source
AI summary
Built-in test equipment (BITE) incorporated in a GPS receiver for providing a loop forward test. The loop forward test capability may be combined with a loop backward capability to provide a comprehensive built-in test (BIT) capability for the signal path in a GPS receiver. A code generator generates deterministic test code signals such as C/A code, P code and pseudo M code that are used to modulate one or more radio frequency (RF) carriers to produce RF test signals. The RF test signals are injected into the GPS receiver's RF input. The RF test signal signals are then down-converted and demodulated through an operational signal path of the GPS receiver. The processed test signals may then be compared to the initial test data. A loop backward BITE may also be used to sample the positioning data output by the receiver.