Signal Detection Threshold Calculation for Navigation Satellite Systems
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Solution Overview
Problem
Existing Navigation Satellite Systems (NSS) face inefficiencies in signal acquisition due to the need for large look-up tables to set optimal signal detection thresholds, which occupy significant memory and lead to inconsistent false positive rates.
Innovation Solution
A method for setting a signal detection threshold in a navigation satellite system by calculating the expected noise and standard deviation for a specific search space, allowing for dynamic adjustment of the threshold based on the number of search bins and integration time, thereby reducing the need for large look-up tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If look-up tables are used to set signal detection thresholds for different search space sizes and integration times, then optimal signal detection can be achieved, but large amounts of memory are occupied and the system becomes inefficient
Solution Approach 1:
The patent extracts the essential parameters (search space size N, integration time t) from the complex look-up table approach and uses them to directly calculate the detection threshold through a mathematical formula. This removes the need to store vast amounts of pre-computed threshold values in memory, while still achieving optimal detection performance by adapting the threshold to the specific search conditions.
Solution Approach 2:
The patent changes the approach from storing fixed threshold values in look-up tables to dynamically calculating thresholds based on varying parameters (search space size N and integration time t). The formula threshold = μ + k·σ allows the threshold to adapt to different search conditions by changing parameters N and t, eliminating the need for large memory storage of pre-computed values.
2Ease of operation
If a fixed signal detection threshold is used, then the system is simple to operate, but false positive rates become inconsistent across different search space sizes
Solution Approach 1:
The patent introduces dynamics into the threshold setting process by making the threshold adaptive to the search space size N and integration time t. Instead of a fixed threshold, the system dynamically calculates the appropriate threshold based on the current search conditions, ensuring consistent false positive rates while maintaining ease of operation through automated calculation.
Solution Approach 2:
The patent implements a feedback mechanism where the detection threshold is calculated based on the actual noise characteristics (mean μ and standard deviation σ) measured in the current search environment. This feedback loop ensures that the threshold automatically adjusts to maintain consistent false positive rates across different search space sizes and integration times.
Data Source
AI summary
A method and apparatus are provided for setting a signal detection threshold. The noise level, the number of search bins and the integration time are used to calculate the mean and standard deviation of the maximum bin value. The signal detection threshold can then be set as a predetermined number of standard deviations from the maximum bin value.