Radar Velocity Aliasing Resolution via Dynamic Hypothesis Selection
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Solution Overview
Problem
Existing radar devices face challenges in accurately detecting the velocity of objects moving at relative velocities beyond the observable range, leading to velocity aliasing and decreased detection accuracy.
Innovation Solution
The radar device employs a transmitter that sends radar waves with changing frequencies, a repetition period setter that adjusts the repetition period, and a hypothesis selector that chooses between three hypotheses based on velocity-accuracy posterior distributions to accurately determine the object's velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a preset repetition period is used for radar wave transmission, then the radar device can operate with simple timing control, but velocity aliasing occurs when detecting objects moving beyond the observable velocity range
Solution Approach 1:
The patent applies dynamics by making the repetition period variable rather than fixed. The repetition period changing unit dynamically adjusts the repetition period based on detected velocity information from multiple cycles, allowing the system to adapt to different velocity ranges and eliminate velocity aliasing while maintaining operational simplicity through automated adjustment.
2Measurement precision
If the repetition period is changed each cycle, then the observable velocity range can be adjusted to detect higher velocities, but the device complexity increases due to the need for multiple hypothesis testing and tracking
Solution Approach 1:
The patent implements feedback by using detected velocity information from previous cycles to guide repetition period adjustments in subsequent cycles. The repetition period changing unit receives velocity detection results and automatically adjusts the repetition period accordingly, creating a closed-loop system that reduces processing complexity compared to exhaustive hypothesis testing while maintaining accurate velocity detection.
3Measurement precision
If multiple hypotheses are tested to resolve velocity aliasing, then the detection accuracy can be maintained, but the processing time and loss of time increase
Solution Approach 1:
The patent applies preliminary action by performing velocity detection over multiple cycles before final hypothesis selection. The system accumulates velocity detection results across cycles and uses this preliminary information to intelligently adjust the repetition period and select the most likely hypothesis, reducing the need for extensive post-processing and hypothesis testing while maintaining detection accuracy.
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 configuration enables the radar device to select the hypothesis with the highest velocity accuracy, thereby improving the detection accuracy of the object's velocity and preventing ambiguity due to velocity aliasing.
Implementation Method 1
a radar device that detects an object by transmitting radar waves and receiving their reflected waves from the object
Implementation Method 2
calculates a relative velocity (hereinafter, a target velocity) of an object by receiving reflected waves of radar waves transmitted repeatedly
Data Source
AI summary
In a radar device, a hypothesis selector selects one of first to third hypotheses based on velocity-accuracy posterior distributions after a preset number of distribution calculations. The first hypothesis assumes that an observed velocity of an object is an aliased relative velocity when the relative velocity is higher than an upper limit of an observable velocity range. The second hypothesis assumes that the observed velocity is an unaliased relative velocity. The third hypothesis assumes that the observed velocity is an aliased relative velocity in a case where the relative velocity is below a lower limit of the observable velocity range. The velocity-accuracy posterior distributions are respectively calculated for the first to third hypotheses from velocity-accuracy prior distributions and a detection result of observed velocities for the preset number of distribution calculations.