Radar Signal Processing Device Speed Measurement Ambiguity
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Solution Overview
Problem
Radar systems using chirp signals face ambiguity in speed measurement due to spectrum folding, particularly when the repetition period of chirp signals is constrained, leading to increased measurement time and the need for additional frequency compensation circuits.
Innovation Solution
A radar signal processing device that uses two sets of voltage data corresponding to different modulation center frequencies, performing frequency analysis and calculating speed by comparing speed candidates with a reference speed based on the difference between these frequencies, thereby eliminating ambiguity without increasing measurement time or requiring additional circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the repetition period of chirp signals is reduced to increase the folding frequency and eliminate ambiguity, then the range of measurable speed increases, but the transmission system constraints (particularly high-frequency circuit characteristics) prevent further reduction of the repetition period
Solution Approach 1:
The patent changes the parameter of modulation center frequency, dividing the frequency band into multiple bands with different center frequencies. By performing frequency analysis on voltage data corresponding to different modulation center frequencies and comparing speed candidates with reference speeds, the system eliminates ambiguity without reducing the repetition period, thus resolving the contradiction between measurement accuracy and transmission system constraints
Solution Approach 2:
The patent segments the frequency analysis process into multiple independent analyses, each operating on voltage data from different modulation center frequency bands. This segmentation allows parallel processing of multiple frequency bands, eliminating the need to reduce repetition period while maintaining speed measurement accuracy
2Measurement precision
If two types of chirp signals with slightly different frequency ranges are used to eliminate ambiguity, then speed measurement ambiguity is resolved, but a frequency compensation circuit for high frequencies must be added
Solution Approach 1:
Instead of using two types of chirp signals with different frequency ranges that would require frequency compensation circuits, the patent changes the modulation center frequency parameter and processes voltage data from different frequency bands through digital signal processing, eliminating the need for additional analog compensation circuits
Solution Approach 2:
The patent replaces the mechanical/electrical frequency compensation circuit with a digital signal processing approach. By performing frequency analysis on voltage data from multiple modulation center frequencies and using reference speed comparison, the system achieves ambiguity elimination through software/algorithms rather than additional hardware circuits
3Measurement precision
If two different types of methods are used to measure speed (one with high accuracy but ambiguity, another with low accuracy but no ambiguity), then ambiguity is eliminated, but the time required to obtain final measurement results increases
Solution Approach 1:
The patent merges the frequency analysis processes for multiple modulation center frequencies into a unified processing framework. By simultaneously performing frequency analysis on voltage data from different frequency bands and comparing results with reference speeds, the system eliminates ambiguity in a single integrated process rather than sequentially applying multiple methods, thus reducing measurement time
Solution Approach 2:
The patent maintains continuous useful action by processing voltage data from multiple modulation center frequencies in parallel through frequency analysis. The reference speed comparison method allows continuous determination of unambiguous speed values without interrupting the measurement flow, eliminating the time loss associated with sequential method application
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 eliminates ambiguity in speed measurement while avoiding the need for additional circuits and reducing measurement time, improving the accuracy and efficiency of speed measurement in radar systems.
Implementation Method 1
measures a moving speed of an object using voltage data obtained by mixing transmitted signals with received signals
Implementation Method 2
a first frequency analyzing unit for performing frequency analysis on first voltage data among the voltage data; a second frequency analyzing unit for performing frequency analysis on second voltage data among the voltage data
Implementation Method 3
the speed calculating unit calculates the moving speed of the object by calculating a reference speed and comparing a plurality of speed candidates with the reference speed, the reference speed being based on a difference value between the modulation center frequency of the range corresponding to the first voltage data and the modulation center frequency of the range corresponding to the second voltage data
Data Source
AI summary
First voltage data (V11 to V1n) and second voltage data (V21 to V2n) each correspond to ranges of the same transmitted signals (T1 to Tn) that have different modulation center frequencies. A speed calculating unit (50) calculates a moving speed of a radio-wave-reflecting object by calculating a reference speed (Sref) which is based on a difference value between the modulation center frequency (Fc_1) of the range of the transmitted signals (T1 to Tn) corresponding to the first voltage data (V11 to V1n) and the modulation center frequency (Fc_2) of the range of the transmitted signals (T1 to Tn) corresponding to the second voltage data (V21 to V2n), and comparing a plurality of speed candidates (Scand[m]) with the reference speed (Sref).