Antenna Array Self-Calibration via Dual-Frequency Phase Difference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radar systems face challenges in accurately determining relative distances between antenna elements due to manufacturing errors and structural changes, requiring complex and costly end-of-line calibration, and have limited resolution, especially for advanced autonomous driving applications.
Innovation Solution
A method involving transmitting and receiving radar signals of different frequencies by antenna elements within the array to determine relative distances and phase imbalances, allowing for online or offline calibration without external devices, using techniques such as mixed-integer programming, frequency modulated signals, and high-resolution methods like MUSIC and BPDN to achieve precise positional error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If end-of-line calibration techniques are applied to determine true values of relative distances, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The antenna array performs self-calibration by using its own antenna elements as both transmitters and receivers. The system determines relative distances between antenna elements through mutual signal transmission and reception, eliminating the need for external calibration devices or complex end-of-line calibration processes.
Solution Approach 2:
The patent introduces an intermediate signal processing approach where received signals are demodulated to extract phase information. This intermediate phase data serves as a mediator to calculate relative distances, simplifying the overall calibration process while maintaining high measurement precision.
2Measurement precision
If external devices are used to obtain distance errors, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The antenna array determines its own positional errors by having antenna elements transmit and receive signals mutually. This self-diagnostic capability eliminates the need for external calibration devices, reducing system complexity while maintaining the ability to accurately determine position errors.
3Measurement precision
If non-uniform antenna arrays are used to improve resolution, then measurement precision is improved, but calibration difficulty increases
Solution Approach 1:
The calibration method works universally for both uniform and non-uniform antenna arrays. Each antenna element serves as both transmitter and receiver, allowing the system to automatically determine relative distances and phase imbalances regardless of the array's geometric configuration, thus simplifying calibration for non-uniform arrays.
Solution Approach 2:
The patent determines both relative distances and phase imbalances as separate parameters. By treating phase imbalance as an independent parameter that can be calculated from the intermediate signals, the method adapts to different array configurations including non-uniform arrangements, reducing calibration difficulty while maintaining high resolution.
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
Enables precise determination of large positional errors and calibration of antenna arrays, reducing the need for external components and complex end-of-line calibration, while improving spatial resolution for 3D imaging in automotive applications.
Implementation Method 1
transmitting a first radar signal, with a first frequency f1, by the first antenna element and receiving a first receive signal, related to the first radar signal, by the second antenna element
Implementation Method 2
transmitting a second radar signal, with a second frequency f2, by the first antenna element and receiving a second receive signal, related to the second radar signal, by the second antenna element
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An embodiment of a method 100 for determining a relative distance r between a first antenna element and a second antenna element each being part of an antenna array, comprises transmitting 101 a first radar signal, with a first frequency f1, by the first antenna element and receiving 102 a first receive signal, related to the first radar signal, by the second antenna element. The method 100 further comprises demodulating 103 the first receive signal based on the first radar signal to obtain a first intermediate signal s1 having a first phase ϕ1. Further, the method 100 comprises transmitting 104 a second radar signal, with a second frequency f2, by the first antenna element and receiving 105 a second receive signal, related to the second radar signal, by the second antenna element. The method 100 further comprises demodulating 106 the second receive signal based on the second radar signal to obtain a second intermediate signal s2 having a second phase ϕ2. Further, the method 100 comprises determining 107 the relative distance r based on the first phase ϕ1 and the second phase ϕ2.