Radar Signal Processing Phase Rotation Pattern Matching
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Solution Overview
Problem
Traditional radar techniques using the Doppler effect struggle to accurately detect the moving speed of targets when the reflection position changes, especially when the radar is located near the target, due to the assumption of a constant reflection position.
Innovation Solution
A radar signal processing apparatus and method that generates time-series phase data, calculates phase rotation, and performs pattern matching between the phase rotation data and templates defined by distance and target speed to accurately detect the moving speed, even with changes in the reflection position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the radar emits radio waves in the orthogonal direction to detect target speed, then the detection can be performed when the target moves laterally, but the reflection position changes causing inaccurate speed detection
Solution Approach 1:
The patent segments the continuous phase data into discrete phase difference values between consecutive time points. By calculating phase differences Δφ(n) = φ(n) - φ(n-1), the system breaks down the complex reflection position changes into manageable incremental changes that can be processed through template matching to extract accurate speed information.
Solution Approach 2:
The patent pre-calculates and stores template data representing expected phase difference patterns for various target speeds and distances before actual detection. These templates are computed based on the geometric relationship between radar, target path, and speed, allowing the system to directly compare measured phase differences against known patterns without real-time complex calculations.
2Measurement precision
If the radar is located near the target to improve detection detail, then more reflection position changes occur, but this increases the error in speed detection
Solution Approach 1:
The patent creates a virtual model (template) of the expected phase difference pattern based on geometric parameters (distance d, speed V, wavelength λ) before comparison. By copying the theoretical phase evolution pattern into a template that accounts for reflection position changes, the system can match against actual measurements even when the radar is near the target causing significant reflection position variation.
3Device complexity
If the related art assumes constant reflection position to simplify calculation, then the processing is simpler, but the speed detection becomes inaccurate when the target moves
Solution Approach 1:
The patent changes the fundamental parameter being analyzed from absolute phase φ(n) to phase difference Δφ(n) = φ(n) - φ(n-1). This parameter transformation eliminates the need to assume constant reflection position because the difference operation naturally compensates for systematic phase shifts caused by reflection position changes, while preserving the speed-related phase evolution information.
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
Enables robust detection of target speed with changes in the reflection position, reducing waveform similarity loss and improving accuracy in determining the moving speed of targets.
Implementation Method 1
A traditional radar technique to detect the moving speed of a target is utilization of the Doppler effect. This technique detects the moving speed of a target on the basis of the difference (hereinafter referred to as 'Doppler frequency shift') between the frequency of a radio wave transmitted (emitted) to the moving target and the frequency of a radio wave reflected off the target
Implementation Method 2
The reflected wave from target 23 positioned at distance R and angle θ1 at time t=t1 is received by each antenna element. At the time of reception, a radio wave channel path difference of dlm sin θ1 occurs between two given antenna elements, e.g., Akl and Akm. Consequently, reflected waves having a phase difference corresponding to the channel path difference are detected between the two antenna elements
Data Source
AI summary
A radar signal processing apparatus is disclosed which includes: time-series phase data generating section 3 generating time-series phase data in a range bin of interest based on a range profile indicating, for each range bin, a phase of a reflected wave of a radio wave from a target; phase-rotation-amount time-series data generating section 4 that divides the time-series phase data into segments of a predetermined time length, calculates an amount of phase rotation that occurs in the segments, and generates time-series data on the amount of phase rotation; pattern matching section 6 that performs pattern matching between the generated time-series data on the amount of phase rotation and a template of time-series data on the amount of phase rotation that is defined by a distance and a moving speed; and speed detection section 7 that detects the moving speed of the target based on a result of the pattern matching.