Radar Antenna Spacing for Angular Resolution
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Solution Overview
Problem
Current radar apparatuses face challenges in achieving enhanced target detection accuracy, particularly in wide-angle detection scenarios, due to limitations in antenna array configurations and processing methods, which result in reduced angular resolution and increased ambiguity in direction-of-arrival estimation.
Innovation Solution
The radar apparatus employs a configuration where LR and SR antennas are shared across modes, optimizing antenna spacings to reduce grating lobes and ambiguity, and uses code multiplexing with orthogonal codes to enhance array gain and angular resolution, allowing for improved target detection performance in both Long Range (LR) and Short Range (SR) modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If antenna spacing is increased to improve detection coverage, then wide-angle detection range is improved, but grating lobes and ambiguity increase reducing angular resolution
Solution Approach 1:
The transmit antenna array is segmented into multiple sub-arrays with different spacing configurations. Each sub-array has optimized element spacing to reduce grating lobes in specific angular sectors, allowing the system to maintain high angular resolution across the entire wide detection coverage by selectively activating appropriate sub-arrays based on target direction
Solution Approach 2:
The patent transitions from a single uniform antenna spacing to a multi-dimensional spacing structure where different transmit antennas have different spacings relative to receive antennas. This creates a virtual array with enhanced aperture in multiple dimensions, simultaneously achieving wide coverage and high angular resolution without the grating lobe problems of uniform large-spacing arrays
2Measurement precision
If antenna elements are increased to improve angular resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges transmit and receive antenna functions into a unified MIMO array structure where transmit and receive elements are co-located or closely integrated. This combining approach achieves high angular resolution through virtual array synthesis without requiring separate large-scale transmit and receive arrays, thereby reducing overall system complexity while maintaining measurement precision
Solution Approach 2:
Each antenna element is designed to serve multiple functions: transmission, reception, and participation in multiple virtual array configurations. The antenna elements can be dynamically assigned to different sub-arrays and spacing configurations based on detection requirements, reducing the total number of physical elements needed while achieving high angular resolution across wide coverage angles
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 configuration enhances target detection accuracy and angular resolution, reducing ambiguity and increasing array gain, thereby improving the overall performance of the radar system in both LR and SR modes, enabling more effective detection of vehicles and pedestrians.
Implementation Method 1
a radar apparatus includes a radar transmitter... which transmits a transmission signal; and a radar receiver... which receives a reflected wave signal, which is the transmission signal reflected by a target object
Data Source
AI summary
The target detection accuracy of a radar apparatus is improved. The radar apparatus includes transmission circuitry, which, in operation, transmits a transmission signal using a plurality of transmit antennas, and reception circuitry, which, in operation, receives using a plurality of receive antennas a reflected wave signal that is the transmission signal reflected by an object, in which the plurality of transmit antennas include at least one first transmit antenna and a plurality of second transmit antennas, and, in a first direction, an absolute value of a difference between, on one hand, a spacing between the at least one first transmit antenna and a phase center of those of the plurality of second transmit antennas which are used for beam synthesis, and, on another hand, a spacing between adjacent receive antennas of the plurality of receive antennas is a defined value based on a wavelength of the plurality of transmission signals.