Radar Object Sensing via Doppler Spread Analysis
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Solution Overview
Problem
Existing radar technologies face challenges in detecting objects with small reflected power, especially when they are located near objects with large reflected power, making it difficult to individually sense multiple objects in close proximity.
Innovation Solution
The radar apparatus calculates the width of the Doppler frequency spread at each range bin and determines the boundary between objects using normalized direction correlation values, allowing for the separation of objects with different Doppler spreads, such as pedestrians and vehicles, by analyzing the Doppler frequency components and their correlation values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radar reception waves are sampled for each range bin and Doppler components are determined using power value comparison with threshold, then ground clutter can be suppressed and objects with larger reflected power can be detected, but objects with small reflected power located near objects with large reflected power cannot be individually detected
Solution Approach 1:
The invention changes the detection parameter from power value comparison to Doppler frequency spread width comparison. By calculating the width of Doppler frequency spread for each detected object and comparing it with threshold values, the system can distinguish between objects of different sizes (e.g., pedestrians vs. vehicles) even when they are close together, thereby improving both detection reliability and separation precision
Solution Approach 2:
The invention segments the detection process into multiple stages: first detecting objects using power values, then calculating Doppler frequency spread for each detected object, and finally separating objects based on their Doppler spread characteristics. This segmentation allows the system to handle objects with different reflected powers individually, improving measurement precision
2Measurement precision
If phase difference between peak frequencies of beat signals from multiple receiving antennas is calculated to determine object direction, then objects in different directions can be sensed, but objects with small reflected power near objects with large reflected power still cannot be individually detected
Solution Approach 1:
The invention adds a new dimension to object characterization by incorporating Doppler frequency spread width alongside direction information. Instead of relying solely on phase difference for direction measurement, the system uses Doppler spread width to differentiate object types and improve detection reliability, creating a multi-dimensional object profile
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 enables the distinct detection of objects with large and small Doppler spreads, improving the reliability of sensing multiple objects even when they are closely located, by accurately separating their ranges and positions based on Doppler frequency characteristics.
Implementation Method 1
Doppler components of the reception signals are determined for each range bin... the magnitude of changes in the power value (a Doppler component) of the reception signals in a Doppler frequency domain is compared with a predetermined threshold
Implementation Method 2
radar apparatus and object sensing method... sensing an object (target) by using a radar apparatus
Data Source
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AI summary
A radar apparatus (200) includes an antenna (511) that receives echo signals, each of the echo signals being a radar signal reflected by one or more objects (111,112); a Doppler-frequency acquirer (520) that acquires Doppler frequencies at each range bin from the received echo signals; a direction correlation power-value calculator (541) that calculates direction correlation power values for respective combinations of the Doppler frequencies and of at least one of a distance to the one or more objects and an arrival direction of the echo signals, each direction correlation power value indicating a strength of a corresponding echo signal; and a normalized direction correlation-value calculator (542) that calculates, for the respective combinations, normalized direction correlation values, each normalized direction correlation value indicating a probability of the arrival direction of the corresponding echo signal.