Automotive Radar Chirp Timing for Doppler Ambiguity Resolution
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Solution Overview
Problem
Existing advanced driver assist systems (ADAS) require separate sensors for detecting the linear motion of the rack bar due to the absence of mechanical connection between the steering wheel and the rack bar, leading to inefficiencies in object detection and route planning.
Innovation Solution
A radar system with an antenna array that uses alternating pre-chirp and main chirp signals with varying time intervals and frequencies to identify overlapping distances and velocities of multiple objects, combined with Fast Fourier Transform (FFT) processing to provide accurate object data for driver assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pre-chirp signal is used for object detection, then the detection process is simple, but Doppler ambiguity occurs when multiple objects have overlapping distances or velocities
Solution Approach 1:
The patent divides the object detection process into multiple segments by using different pre-chirp signals with different time intervals. Instead of using a single pre-chirp signal that causes Doppler ambiguity, the system segments the detection into multiple measurements with varying time intervals, allowing each segment to resolve ambiguities that the others cannot. This segmentation enables accurate identification of multiple objects with overlapping distances or velocities by comparing results across different time interval segments.
2Measurement precision
If multiple pre-chirp signals with different time intervals are used to resolve Doppler ambiguity, then object detection accuracy improves, but the processing time and system complexity increase
Solution Approach 1:
The patent employs periodic action by using multiple pre-chirp signals with different time intervals in a systematic, repeating sequence. The controller alternates between different pre-chirp signals with varying time intervals, performing measurements periodically with each signal type. This periodic approach allows the system to resolve Doppler ambiguity through multiple measurements while maintaining a structured timing pattern that optimizes processing efficiency and reduces overall time loss compared to non-periodic or random measurement sequences.
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
Enhances the accuracy and efficiency of object detection and route planning by resolving Doppler ambiguity and enabling simultaneous processing of multiple objects, thereby improving the functionality of ADAS systems.
Implementation Method 1
a radar installed on a vehicle, having a sensing area outside the vehicle, and configured to provide object data
Implementation Method 2
identify a distance to an object around the vehicle and a moving velocity of the object based on processing the object data
Data Source
AI summary
Disclosed herein is an apparatus for driver assistance including a radar. The apparatus may include a radar installed on a vehicle, having a sensing area outside the vehicle, and configured to provide object data, and configured to provide object data, and a controller configured to identify a distance to an object around the vehicle and a moving velocity of the object based on processing the object data. The radar includes an antenna array, and a processor configured to provide the antenna array with a first pre-chirp signal corresponding to a plurality of first pre-chirps and a first main chirp signal corresponding to a plurality of first main chirps, and provide the antenna array with a second pre-chirp signal corresponding to a plurality of second pre-chirps and a second main chirp signal corresponding to a plurality of second main chirps based on overlapping distances or velocities of different objects identified by the first pre-chirp signal or the first main chirp signal. A time interval between the plurality of second pre-chirps is different from a time interval between the plurality of first pre-chirps, and a time interval between the plurality of second main chirps is different from a time interval between the plurality of first main chirps.