Wideband Radar Sub-pulse Segmentation for Ambiguity Resolution
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Solution Overview
Problem
Conventional narrow-band radar systems face inefficiencies due to extended timelines required for coherent and non-coherent integration modes, leading to blind-ranges, blind-speeds, range ambiguity, and Doppler ambiguity, which necessitate additional radar resources and prolonged processing times.
Innovation Solution
A wideband radar system that generates radar signals with multiple sub-pulses in each pulse repetition interval (PRI) to enable both coherent and non-coherent integration within a single radar dwell, using a wideband antenna and signal processor to perform these integrations simultaneously, thereby reducing the overall processing time and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pulse integration at constant carrier frequency is used for coherent processing, then clutter mitigation is improved, but blind-ranges, blind-speeds, range ambiguity, and Doppler ambiguity occur
Solution Approach 1:
The patent segments the radar waveform into multiple sub-pulses within each PRI, with different sub-pulses assigned to different carrier frequencies. This segmentation allows the radar to perform coherent processing on each frequency segment separately, avoiding the blind ranges and blind speeds that affect the entire bandwidth, thereby maintaining target detection information while achieving clutter mitigation.
Solution Approach 2:
The patent introduces frequency diversity as an additional dimension by transmitting sub-pulses at different carrier frequencies within the same PRI. This frequency dimension allows the radar to resolve ambiguities in range and Doppler that cannot be resolved in the time domain alone, eliminating blind ranges and blind speeds while maintaining coherent clutter mitigation.
2Loss of information
If multiple bursts with PRF diversity are used to resolve ambiguities, then target visibility is improved, but extended timeline and additional radar resources are required
Solution Approach 1:
The patent merges multiple PRF diversity bursts into a single dwell by transmitting sub-pulses at different carrier frequencies within each PRI. This combines the ambiguity resolution capability of PRF diversity with the time efficiency of a single dwell, improving target visibility without requiring extended timelines or additional radar resources.
Solution Approach 2:
The patent maintains continuous radar operation within a single dwell by performing both coherent and non-coherent integration simultaneously on different sub-pulse sets. This continuous action eliminates the need for sequential bursts, reducing the radar timeline while maintaining unambiguous target detection.
3Adaptability or versatility
If narrowband radar resources are allocated for coherent and non-coherent integration streams, then both integration modes can be supported, but additional radar timeline and resource allocation are required
Solution Approach 1:
The patent makes the wideband radar resources universal by using the same antenna, waveform generator, and receiver for both coherent and non-coherent integration modes. The waveform generator generates sub-pulses that are simultaneously processed by both integration streams, eliminating the need for separate narrowband radar resources and reducing device complexity.
Solution Approach 2:
The patent changes the bandwidth parameter from narrowband to wideband, allowing a single radar resource to handle both coherent and non-coherent integration modes. The wideband antenna and receiver can process multiple carrier frequencies simultaneously, enabling dual integration mode support without additional radar resources or increased complexity.
4Measurement precision
If extended timeline with multiple dwells is used for PRF and RF diversity, then unambiguous visibility over desired range/Doppler extents is achieved, but processing time and resource expenditure increase
Solution Approach 1:
The patent segments the bandwidth into multiple carrier frequencies, with each frequency providing unambiguous visibility over a specific range/Doppler extent. This segmentation allows the radar to achieve comprehensive coverage by combining results from different frequency segments within a single dwell, maintaining measurement precision while improving productivity through parallel processing.
Data Source
AI summary
Radar signals are generated to have signal characteristics that define multiple sub-pulses in each of a plurality of pulse repetition intervals (PRIs) of a single radar dwell. Electromagnetic radiation is emitted according to the radar signals and the emitted electromagnetic radiation is sensed as radar return signals over a receive interval in each PRI. Coherent integration is performed on a set of the radar return signals and non-coherent integration is performed on another set of the radar return signals.