Signal Processing Device for SART Detection with Reduced Load
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Solution Overview
Problem
Existing radar systems face challenges in accurately detecting Search And Rescue Transponder (SART) distress signals due to masking by other echo signals and high signal processing loads, particularly in correlation calculations.
Innovation Solution
A signal processing device that calculates the instantaneous frequency change rate of complex reception signals and compares it to reference thresholds to determine the presence of SART distress signals, reducing the calculation load and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cross-correlation calculation is used to detect SART distress signal, then detection capability is provided, but signal processing load becomes high
Solution Approach 1:
The patent extracts only the essential characteristic (frequency sweeping speed) from the complete SART distress signal waveform. Instead of performing full waveform cross-correlation, the system extracts instantaneous frequency and compares its change rate to a reference value, thereby reducing processing load while maintaining detection capability.
Solution Approach 2:
The patent creates a simplified reference model of the SART distress signal that contains only the critical frequency sweeping characteristic. This reference copy is used for comparison instead of the complete complex waveform, enabling faster processing while preserving detection accuracy.
2Measurement precision
If full waveform correlation is performed, then accurate detection is achieved, but calculation time increases
Solution Approach 1:
The patent extracts only the frequency sweeping characteristic from the complete SART waveform for comparison purposes. By calculating instantaneous frequency and its change rate, the system achieves accurate detection without processing the entire waveform, thereby reducing calculation time significantly.
3Reliability
If correlation detection method is used, then SART signal can be identified, but detection accuracy degrades when pulses are masked
Solution Approach 1:
The patent creates a reference copy of the frequency sweeping characteristic that can be compared against the received signal even when parts are masked. The instantaneous frequency change rate comparison method is robust to partial masking because it detects the characteristic frequency sweep pattern rather than requiring complete waveform matching.
Data Source
AI summary
A signal processing device and method to accurately detect a distress signal from a search and rescue transponder and reduce a calculation load for the detection. The device may include an instantaneous frequency change rate calculating module configured to calculate a change rate of an instantaneous frequency of a complex reception signal generated from a reception wave received by a wave receiver, a memory configured to store a value obtained based on a reference frequency sweeping speed that is a frequency sweeping speed of the distress signal, and a distress signal determining module configured to determine whether the distress signal is issued from the search and rescue transponder, based on a comparison result between the instantaneous frequency change rate calculated by the instantaneous frequency change rate calculating module and the value obtained based on the reference frequency sweeping speed stored in the memory.