Radar Device Cross-Range Velocity Estimation Using DC Component Removal
Solution Overview
Problem
Conventional UWB-based radar devices interfere with other wireless systems and struggle to accurately detect object movement at short distances due to high signal intensity from stationary reflection points, which masks information from nearby reflection points.
Innovation Solution
A radar device using FMCW and multi-frequency CW schemes to calculate and extract reflection points, remove DC components, and compute cross velocities, enabling accurate detection of object movement in both range and cross-range directions without wideband radar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-frequency CW scheme is used for short-distance measurement, then processing load is reduced, but signal intensity from stationary reflection points masks nearby reflection points
Solution Approach 1:
The patent extracts and removes the DC component from the beat signal, which corresponds to the stationary reflection points. By separating and eliminating this dominant signal component, the weaker signals from nearby reflection points become detectable without being masked by the intense stationary reflection signals.
Solution Approach 2:
The patent segments the beat signal into different frequency components, distinguishing between the DC component (stationary reflection points) and the AC components (moving objects and nearby reflection points). This segmentation allows selective processing to enhance detection of nearby reflection points while removing the harmful DC component.
2Measurement precision
If UWB-based technique is used for short-distance measurement, then distance resolution is improved, but interference with other wireless systems occurs
Solution Approach 1:
The patent changes the frequency parameters by using multi-frequency CW schemes instead of UWB. This parameter change maintains the ability to detect short-distance objects while avoiding the broad spectrum interference characteristic of UWB systems, thus resolving the contradiction between measurement precision and wireless interference.
3Measurement precision
If UWB-based technique is used for short-distance measurement, then distance resolution is improved, but hardware complexity increases
Solution Approach 1:
The patent employs a multi-frequency CW scheme that uses simpler, lower-cost hardware compared to UWB systems. By using continuous waves at multiple frequencies rather than ultra-wideband pulses, the hardware complexity is significantly reduced while maintaining adequate measurement precision for short-distance detection.
4Measurement precision
If stationary reflection points are detected, then position information is obtained, but relative velocity is zero preventing movement detection
Solution Approach 1:
The patent transitions from one-dimensional FMCW measurement (range and velocity) to two-dimensional measurement by incorporating multi-frequency CW data. This dimensional expansion enables detection of cross-range velocity components, allowing movement detection even for objects that appear stationary in the FMCW range direction.
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
The radar device accurately detects object movement at short distances by isolating signal components from nearby reflection points, preventing false detection and improving velocity estimation in the cross-range direction.
Implementation Method 1
calculates, from a beat signal obtained by transmitting and receiving frequency-modulated continuous waves (hereinafter referred to as 'FMCW'), positions and relative velocities of points of reflection of FMCW
Implementation Method 2
calculates, from the beat signal from which the DC component has been removed by the removing unit, positions and relative velocities of points of reflection of the multi-frequency CW
Implementation Method 3
The removing unit removes a DC component from a beat signal obtained by transmitting and receiving multi-frequency continuous waves
Data Source
AI summary
A radar device calculates positions and relative velocities of points of reflection from an FMCW beat signal, extracts stationary reflection points each being a point of reflection having a relative velocity of zero, and sets, for each of the stationary reflection points, an object area estimated to contain an object including the stationary reflection point. The radar device calculates positions and relative velocities of points of reflection from a 2CW beat signal from which a DC component has been removed, extracts in-area reflection points each being a point of reflection that belongs to the object area. The radar device then computes, for each of the in-area reflection points, a cross velocity that is a velocity of the in-area reflection point in a cross-range direction, and statistically processes calculated cross velocities for each of the object areas. The radar device calculates an estimated value of a cross velocity of an object.