Radar Calibration via Optical Alignment and Phase Error Correction
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Solution Overview
Problem
Conventional radar object detection systems face challenges in accurate calibration due to high costs and inability to correct antenna radiation patterns related phase errors, especially when antenna element spacing introduces significant phase changes, limiting detection resolution.
Innovation Solution
The system employs a calibration unit that aligns object detection units using RF and optical data, with an antenna array for transmitting and receiving signals, and an optical sensor to capture images, allowing for error correction in processing units and improving detection accuracy by comparing reference patterns with actual patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional calibration techniques using pre-calculated phase signals are employed, then calibration can be performed, but expensive additional hardware switches are required and antenna radiation patterns related phase errors cannot be corrected
Solution Approach 1:
The radar system performs self-calibration by using its own transmitted signal and comparing the received signal phase with the transmitted signal phase. The calibration unit utilizes the system's inherent signals rather than requiring external calibration equipment, making the system self-sufficient and eliminating complex external hardware
Solution Approach 2:
A calibration unit is introduced as an intermediary component that processes the transmitted and received signals to extract phase information. This unit acts as a mediator between the signal processing components and the calibration function, enabling accurate calibration without requiring expensive external hardware switches
2Area of stationary object
If antenna elements are spaced to cover wider area, then detection coverage is improved, but phase changes between channels increase making calibration more difficult
Solution Approach 1:
The calibration unit continuously monitors the phase relationship between transmitted and received signals and uses this feedback to dynamically adjust calibration parameters. This feedback mechanism compensates for phase variations caused by antenna spacing, maintaining measurement precision across wide detection coverage areas
Solution Approach 2:
The system dynamically adjusts calibration parameters based on the actual phase measurements from each antenna channel. By changing the calibration parameters adaptively rather than using fixed values, the system can accommodate varying phase changes caused by different antenna spacings while maintaining accurate detection
3Reliability
If BIST signal phase estimate is used for calibration, then calibration can be performed, but errors in BIST signal phase estimate between RF channels cannot be corrected when antenna spacing introduces 180 to 130 degree phase change
Solution Approach 1:
The patent replaces the mechanical/BIST-based phase estimation method with a signal-processing-based approach. The calibration unit uses digital signal processing to compare transmitted and received signals directly, eliminating the need for physical BIST signal routing and associated phase estimation errors
Solution Approach 2:
The calibration approach transitions from one-dimensional BIST signal phase estimation to a multi-dimensional comparison of transmitted and received signal characteristics. By analyzing signals in the time-domain and frequency-domain simultaneously, the system can accurately determine phase relationships even with large antenna spacing-induced phase changes
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 enhances the accuracy and resolution of object detection by correcting phase errors and improving calibration, enabling more precise navigation and object identification.
Implementation Method 1
an antenna array for transmitting a second RF signal over the first region and an antenna array for receiving a reflected RF signal that is reflection of the second RF signal from the first object
Implementation Method 2
an optical sensor capturing a first image frame of the first region
Implementation Method 3
the second object detection unit and the first object detection unit are aligned to detect the object in a first region
Data Source
AI summary
An object detection system comprises a first object detection unit detecting an object from a first radio frequency (RF) signal data comprising first set of characteristics representing a first object, a second object detection unit detecting the object from an optical image data and a calibration unit calibrating the first RF signal data from the optical image data, in that, the second object detection unit and the first object detection unit are aligned to detect the object in a first region.