Radar Ambiguity Resolution via Waveform Segmentation and MHT
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Solution Overview
Problem
Existing radar systems face inefficiencies in resolving range and Doppler ambiguities due to intensive processing and resource allocation issues, particularly with medium- and high-Pulse Repetition Frequency (PRF) waveforms, which can lead to reduced signal-to-noise ratio and complex logic requirements, exacerbated by spurious measurements from Jet Engine Modulation (JEM) and Enemy Countermeasures (ECM).
Innovation Solution
The method employs multiple hypothesis tracking (MHT) by choosing a single waveform per scan, generating position predictions for true and false targets, and comparing them until a preselected condition is met, ensuring that only one track represents the true target, thereby resolving ambiguities over time and avoiding combinatorial problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple radar waveforms (multiple PRF) are transmitted during a given dwell to resolve signal processing ambiguities, then range and Doppler ambiguities are resolved, but radar processing complexity and resource allocation inefficiency increase
Solution Approach 1:
The patent segments the ambiguity resolution process by assigning different waveform types to different dwells within a scan sequence. Specifically, it uses low-PRF waveforms for first dwells (good for range measurement) and high-PRF waveforms for second dwells (good for Doppler measurement), thereby resolving ambiguities through temporal segmentation rather than simultaneous multi-waveform transmission. This reduces processing complexity while maintaining measurement precision.
Solution Approach 2:
The patent implements periodic action by alternating between different waveform types in a systematic sequence across multiple dwells. The scan sequence periodically switches between low-PRF and high-PRF waveforms, allowing the system to accumulate range data during low-PRF dwells and Doppler data during high-PRF dwells. This periodic waveform alternation resolves ambiguities over time without requiring intensive simultaneous processing of multiple waveforms.
2Measurement precision
If multiple radar waveforms are transmitted during a given dwell to resolve ambiguities, then signal processing ambiguities are resolved, but time-on-target per PRF per dwell is reduced
Solution Approach 1:
The patent segments the dwell time allocation by dedicating specific dwells to specific waveform types. Instead of dividing a single dwell into multiple PRF transmissions, the system allocates entire dwells to low-PRF or high-PRF waveforms sequentially. This segmentation allows maximum time-on-target for each waveform type during its designated dwell, improving signal-to-noise ratio while still resolving ambiguities through the combined information from multiple dwells.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that during each dwell, the radar transmits a single waveform type continuously without interruption or switching. This continuous transmission of a single waveform type during its designated dwell maximizes the time-on-target for that specific PRF, improving measurement quality while the alternating sequence across dwells provides the necessary diversity for ambiguity resolution.
3Measurement precision
If conventional techniques (Chinese Remainder Theorem, Hovanessian algorithm, clustering algorithms) are used to resolve ambiguities of a single target, then range and Doppler ambiguities are resolved, but intensive radar processing per dwell is required
Solution Approach 1:
The patent applies preliminary action by collecting and organizing measurement data from multiple dwells with different waveform types before performing ambiguity resolution. Instead of applying complex algorithms like Chinese Remainder Theorem or Hovanessian algorithm to resolve ambiguities immediately for each target, the system first accumulates range data from low-PRF dwells and Doppler data from high-PRF dwells, then performs a simplified resolution process that leverages the pre-organized data structure, thereby reducing processing intensity.
Solution Approach 2:
The patent uses periodic action to systematically alternate between data collection phases (different waveform types in different dwells) and resolution phases. The periodic structure of the scan sequence, with alternating low-PRF and high-PRF dwells, creates a natural rhythm of data accumulation followed by ambiguity resolution. This periodic approach simplifies the resolution process compared to conventional methods by providing regularly spaced, structured data that requires less intensive real-time processing.
Data Source
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AI summary
Methods for resolving radar ambiguities using multiple hypothesis tracking are described. One such method includes (a) choosing a single waveform for each of a plurality of dwells of a first scan, wherein the single waveforms of consecutive scans are different, (b) generating the first scan using the single waveform for each of the dwells of the first scan, (c) receiving observation data as a result of the first scan, the observation data comprising measured positions of true targets and false targets, (d) generating, using multiple hypothesis tracking, position predictions for true targets and false targets, (e) comparing the predicted positions and measured positions, repeating (a)-(e) until a preselected process condition is met, and determining the true targets based on the results of the comparisons.