Radar Apparatus Vertical Bearing Estimation via Virtual Array
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Solution Overview
Problem
Existing radar systems for automotive use face challenges in accurately estimating the vertical bearing of elevated objects due to multi-path fading from the road surface, leading to potential false automatic braking interventions.
Innovation Solution
A radar apparatus is designed with a transmitting portion and a receiving portion that generates a virtual receiving array of virtual receiver elements, allowing for the separation and resolution of direct and multipath reflection signals through covariance matrix data averaging and spatial smoothing, enabling improved estimation of vertical bearings without increasing the size or complexity of the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If receiver elements at other vertical positions were added to detect vertical bearing, then measurement precision of vertical bearing is improved, but device complexity and size increase
Solution Approach 1:
The patent creates a virtual copy of the receiver elements by using the transmitting elements as additional receiving elements. The transmitting elements are capable of receiving radar signals and are connected to the signal processing portion, effectively creating a virtual receiving array that mirrors the physical receiving array. This copying approach enables vertical bearing estimation without adding physical receiver elements, thus avoiding increased device complexity and size while maintaining measurement precision.
2Measurement precision
If multiple receiver elements at different vertical positions are used to resolve direct and multipath signals, then measurement precision is improved, but the receiving antenna size increases
Solution Approach 1:
The patent makes the transmitting elements multi-functional by enabling them to serve both as transmitters and as receivers. The transmitting elements are connected to the signal processing portion and can receive radar signals, allowing them to perform dual functions. This universality eliminates the need for additional dedicated receiving elements, thereby resolving direct and multipath signals without increasing receiving antenna volume.
3Measurement precision
If receiver elements are densely arranged to improve vertical bearing estimation, then measurement precision is improved, but ease of manufacture decreases due to overlapping elements
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of receiver elements to a three-dimensional virtual array configuration by utilizing the transmitting elements at different vertical positions. This dimensional change allows the system to achieve fine vertical bearing resolution without densely packing physical receiver elements in the same plane, thereby avoiding manufacturing difficulties associated with element overlapping while maintaining high measurement precision.
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 allows for accurate estimation of the vertical bearing of elevated objects, reducing false interventions in automatic emergency braking systems by effectively decorrelating direct and multipath signals, thereby enhancing the resolution of object detection.
Implementation Method 1
a transmitting portion (16) including a plurality of transmitter elements (30) for emitting a transmitting signal as a radar wave toward an object (3)
Implementation Method 2
a receiving portion (20) including a plurality of receiver elements (34) for receiving a reflection signal that is a reflection of the transmitting signal by the object (3)
Data Source
AI summary
A radar apparatus includes: a transmitting portion including transmitter elements that emits a transmitting signal as a radar wave toward an object; a receiving portion including receiver elements receiving a reflection signal; and an estimation portion. The estimation portion generates a virtual receiving array including virtual receiver elements. The estimation portion divides the virtual receiving array into identical sub-arrays. The estimation portion generates covariance matrix data for each of the sub-arrays. The estimation portion averages the covariance matrix data for each of the sub-arrays to decorrelate a direct reflection signal from the object and multipath reflection signal among the reflection signal and spatially smooths the reflection signal. The estimation portion resolves the direct reflection signal from the object and the multipath reflection signal. The estimation portion determines the direction of the object.