Composite Radar Waveform Velocity Ambiguity Resolution
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Solution Overview
Problem
Automotive radar systems face velocity ambiguity issues, particularly in multiple target environments, where targets with different speeds are indistinguishable due to velocity aliasing, leading to challenges in accurately determining true target velocity.
Innovation Solution
The system employs a composite linear frequency modulated continuous waveform formed by alternating or interleaving component waveforms with different velocity ambiguity ranges, allowing for ambiguity resolution by combining Doppler bins from each component waveform to determine true velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single waveform is used for radar detection, then the device complexity is reduced, but velocity ambiguity cannot be resolved in multiple target environments
Solution Approach 1:
The patent combines multiple component waveforms (first and second waveforms with different ambiguity ranges) into a composite waveform. This merging allows the radar system to resolve velocity ambiguity for multiple targets by analyzing Doppler shifts from each component waveform, achieving accurate velocity measurement without requiring separate radar systems.
Solution Approach 2:
The composite waveform is segmented into distinct component waveforms, each with specific characteristics (different ambiguity ranges). By processing reflections from each segment separately and then combining the results, the system resolves velocity ambiguity while maintaining manageable complexity through modular processing.
2Measurement precision
If composite waveforms with different ambiguity ranges are used, then velocity ambiguity is resolved, but the device complexity increases
Solution Approach 1:
The composite waveform structure serves multiple functions: it provides different ambiguity ranges for resolving velocity ambiguity, maintains compatibility with existing radar hardware, and enables processing of multiple targets simultaneously. This multi-functionality reduces the need for additional specialized equipment despite the increased signal processing requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively resolves velocity ambiguity, enabling accurate determination of target velocity even in scenarios where multiple targets with different speeds are present, improving the system's ability to distinguish between targets and clutter.
Implementation Method 1
uses the Doppler effect of the returned signal to determine the target object's velocity
Implementation Method 2
the range to a target can be calculated based on elapsed time multiplied by the speed of light divided by two
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
System and methods are provided which involve a radar system that includes one or more signal generators configured for generating a composite radar waveform formed by combining different component waveforms; and a detector for detecting reflected signals from the composite waveform and determining velocity and distance measurements of a target relative to a host vehicle. Advantageously, the first and second component waveforms are selected such that the composite waveform is able to meet two different sets of resolution requirements with respect to at least one of: (i) the velocity measurement of the target vehicle relative to the host vehicle and (ii) the distance measurement of a target vehicle relative to the host vehicle. Notably, each of the different sets of resolution requirements is pre-selected based on a different type of detection scenario.