GNSS Hostile Environment Simulator Frequency Domain Processing
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Solution Overview
Problem
Current GNSS hostile environment simulators face challenges in accurately simulating dynamic and frequency-dependent antenna patterns in real-time, leading to inefficiencies and potential distortion of signals, particularly when testing GNSS receivers in degraded environments.
Innovation Solution
The implementation of a GNSS hostile environment simulator that applies frequency-dependent antenna patterns in the frequency domain, using a combination of single-precision and double-precision floating-point units to generate accurate transmitter signals, and employs signal extension to eliminate ringing, allowing direct injection of RF signals into the GNSS receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If time-domain antenna pattern application is used in GNSS hostile environment simulators, then the system structure is simpler, but signal distortion and ringing occur due to inadequate frequency dependence
Solution Approach 1:
The patent transforms the antenna pattern application from time-domain to frequency-domain processing. This parameter change enables frequency-dependent antenna patterns to be applied accurately, eliminating signal distortion and ringing while maintaining computational efficiency through FFT-based methods.
Solution Approach 2:
The patent replaces traditional time-domain signal processing with frequency-domain processing using FFT (Fast Fourier Transform). This substitution eliminates the need for complex time-domain convolution operations while achieving more accurate frequency-dependent antenna pattern application, thereby reducing both signal distortion and computational complexity.
2Measurement precision
If real-time simulation with flight hardware in the loop is implemented, then testing accuracy improves, but computational load and processing time increase significantly
Solution Approach 1:
The patent replaces computationally intensive time-domain convolution with efficient frequency-domain multiplication using FFT. This substitution maintains real-time simulation capability by reducing the computational complexity from O(N²) to O(N log N), thereby preserving both testing accuracy and processing speed.
Solution Approach 2:
The patent changes the processing domain from time-domain to frequency-domain, enabling real-time computation of antenna pattern effects. This parameter change allows accurate frequency-dependent modeling while meeting real-time processing requirements through efficient FFT-based algorithms.
3Device complexity
If frequency-independent antenna patterns are applied, then computational complexity is reduced, but signal integrity deteriorates due to lack of frequency dependence
Solution Approach 1:
The patent introduces frequency dependence into the antenna pattern application by moving to frequency-domain processing. This parameter change enables accurate representation of antenna characteristics across the signal bandwidth while maintaining computational efficiency through FFT-based methods, thereby preserving signal integrity without excessive complexity.
Data Source
AI summary
A GNSS hostile environment simulator for accurate real-time processor & hardware in the loop (PHIL) simulations of a multiple antenna GNSSR/AJ system models antenna effects over the entire signal bandwidth allowing direct injection of the RF into the GNSSR. Computational efficiency is achieved by applying the antenna patterns in the frequency domain. To preserve the integrity of the antenna signals, the transmitter signals are generated over an extended period to push any residual ringing outside the update window. Efficiency is further enhanced by using a combination of single-precision and double-precision floating-point units to generate the samples of the transmitter signals with single-precision floating-point. All subsequent calculations are then computed in single-precision.