Automotive Radar Array Disambiguation via Dynamic Sub-Array Switching
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Solution Overview
Problem
Automotive radar systems face challenges in precisely locating close-in radar contacts due to the ambiguity caused by side lobes, which are undesirable and difficult to suppress, especially in scenarios where the main lobe is blocked by obstacles or nearby vehicles.
Innovation Solution
A method involving the transmission of two radar energy patterns with different main lobe-to-side lobe power ratios, allowing for the comparison of reflected energies to determine if a contact is within a side lobe or the main lobe, by adjusting the electronic size of the antenna array and using sub-arrays to disambiguate the location of radar contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of radiating/receiving elements is increased to narrow the main beam, then the measurement precision of radar contact location is improved, but the side lobe structure becomes more complex and ambiguous
Solution Approach 1:
The patent applies dynamics by making the antenna array configuration changeable over time. The system transmits radar energy patterns using different subsets of the antenna elements in different time intervals, dynamically switching between full-array mode (narrow beam) and sub-array mode (simplified side lobe structure). This temporal variation allows the system to adapt to different measurement needs and resolve ambiguities by comparing results from different configurations.
Solution Approach 2:
The patent segments the antenna array into multiple sub-arrays that can be independently controlled. By dividing the full array into smaller functional units, the system can transmit radar patterns using only portions of the total elements, thereby simplifying the side lobe structure while maintaining adequate beam directionality for contact location disambiguation.
2Object-generated harmful factors
If the number of radiating/receiving elements is decreased to simplify side lobe structure, then the measurement precision is reduced, but the side lobe ambiguity is decreased
Solution Approach 1:
The system dynamically switches between using the full antenna array and using reduced sub-arrays. During periods when side lobe ambiguity is the primary concern, the system uses fewer elements to simplify the side lobe structure. When main beam directionality is more critical, the full array is engaged. This dynamic adaptation allows the system to optimize for different operational requirements.
Solution Approach 2:
By segmenting the antenna array into controllable sub-arrays, the system can selectively activate only the necessary number of elements for each radar transmission. This segmentation enables flexible control over the effective aperture, allowing the system to reduce element count when side lobe simplification is needed while maintaining the option to use all elements when higher precision is required.
3Measurement precision
If amplitude weighting is adjusted to increase main lobe-to-side lobe power ratio, then the measurement precision is improved, but the main beam width increases
Solution Approach 1:
The system dynamically adjusts the antenna configuration rather than relying solely on amplitude weighting. By switching between full-array and sub-array modes, the system can achieve adequate main lobe-to-side lobe power ratios through geometric configuration rather than amplitude manipulation, thereby avoiding the beam widening that would result from aggressive amplitude weighting adjustments.
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 effectively disambiguates the location of radar contacts by distinguishing between main lobe and side lobe reflections, improving the accuracy of obstacle detection and reducing false indications, even in scenarios where the main lobe is blocked.
Implementation Method 1
Radar beams are formed and directed by shifting the phase of a signal emitted from each element so as to create a constructive and destructive interference pattern
Implementation Method 2
create a constructive and destructive interference pattern that can be 'steered' in the direction of the increasing phase shift among the elements
Implementation Method 3
collecting reflected energy of the first radar energy pattern from the contact
Data Source
AI summary
Methods for disambiguating the location of a radar contact using an N×M dimensioned radar array are provided. In the horizontal plane, the method comprises transmitting a first radar energy pattern in a direction, collecting reflected energy of the first radar energy pattern from the contact, transmitting a second radar energy pattern in the direction and collecting reflected energy of the second radar energy pattern from the contact. The method further comprises comparing the collected energy of the first radar energy pattern and the collected energy of the second radar energy pattern and determining if the contact is located in a side lobe or a main lobe of the first and second radar energy pattern based on the comparison. In the vertical plane, other similar embodiments may be used to determine if the radar antenna(s) are blocked by an obstacle.