Radar Device Speed Detection Using Stationary Object Correlation
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Solution Overview
Problem
Existing radar devices installed in moving objects, such as vehicles, face measurement errors in traveling speed and relative speed detection due to high-speed travel and acceleration, leading to reduced detection precision of targets.
Innovation Solution
A radar device that transmits radio-frequency signals and uses correlation processing, electric power profile generation, and Doppler frequency analysis to improve the detection precision of relative speed by distinguishing between stationary and moving objects, reducing measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If output values of a vehicular speed sensor are used to calculate corrected target speed, then the calculation process is simple, but measurement error increases at high speeds and during acceleration
Solution Approach 1:
The patent introduces stationary objects (trees, poles, buildings) as intermediary references to measure the vehicle's own motion. By detecting the apparent motion of these known stationary objects through radar, the system creates an intermediate measurement (vehicle motion profile) that is then used to correct target speed measurements, bypassing the inaccurate speed sensor while maintaining calculation simplicity.
Solution Approach 2:
The radar device performs self-calibration by using stationary objects in the environment to automatically determine the vehicle's motion state. The system serves itself by measuring its own velocity and acceleration through the Doppler shifts of reflected signals from stationary objects, eliminating dependence on external speed sensors.
2Device complexity
If vehicular speed sensor is used for speed detection, then the detection system is simple, but detection precision deteriorates at high speeds and during acceleration
Solution Approach 1:
The patent segments the detection process into two independent parts: (1) using the simple speed sensor for basic velocity information, and (2) using radar-based stationary object analysis for precision correction. This segmentation allows the system to maintain simplicity while achieving high precision by combining multiple measurement approaches.
Solution Approach 2:
The system changes the measurement parameter from direct speed sensor output to Doppler frequency shift of radar signals reflected from stationary objects. This parameter transformation enables accurate speed measurement during acceleration and high-speed conditions where traditional sensors fail, while the overall system remains relatively simple.
3Ease of operation
If traditional radar speed correction method is used, then the processing is straightforward, but measurement error becomes larger during vehicle acceleration
Solution Approach 1:
The patent performs preliminary measurement of vehicle motion characteristics by analyzing stationary objects before using this information to correct target speed measurements. By pre-establishing the vehicle's velocity and acceleration profile through radar analysis of the environment, the system prepares correction data in advance, maintaining both simplicity and accuracy during dynamic conditions.
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 effectively suppresses measurement errors in traveling speed and enhances the detection precision of relative speed, even at high speeds and during acceleration, by accurately differentiating between stationary and moving targets.
Implementation Method 1
a radar transmitter that transmits a radio-frequency radar transmission signal from a transmission antenna
Implementation Method 2
measure the phase difference of the reception signals received by reception antenna elements, thereby estimating a direction of arrival
Implementation Method 3
generates electric power profiles for each arrival direction of the received returning signals and Doppler frequency component
Data Source
AI summary
A radar device mounted in a moving object includes a radar transmitter and a radar receiver. The radar receiver includes a plurality of antenna brunch processors that perform correlation processing of the received returning signals and the radar transmission signal, and generate respective correlation signals each including arrival delay information of each of the received returning signals, an electric power profile generator that generates an electric power profiles for each arrival direction of the received returning signals and Doppler frequency component, using the generated correlation signals, and a stationary object group distribution generator that, based on the generated electric power profiles, obtains a first distribution of a Doppler frequency components of a stationary object group including a plurality of stationary objects as the plurality of targets in the perimeter of the moving object, for each azimuth angle.