Phased Array Radar Calibration via Pilot Injection During Quiet Periods
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Solution Overview
Problem
Existing on-vehicle radar systems face challenges in accurately calibrating phase, gain, frequency, and related parameters due to temperature differentials and the need for intrusive calibration methods, which affect radar performance over time.
Innovation Solution
A dynamic in situ calibration system for radar systems, comprising a phased array antenna, a transmitter array, a receiver array, a calibration circuit, and a controller, which injects a pilot signal during quiet periods to determine phase offsets and gain imbalances, enabling continuous calibration without disconnecting antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used requiring disconnection of antennas to inject calibration signals, then calibration accuracy can be achieved, but the calibration process becomes intrusive and cannot be performed during normal operation
Solution Approach 1:
The patent introduces a calibration signal injection circuit that couples calibration signals into the receiver array through communication leads without requiring physical disconnection of antennas. This intermediary coupling mechanism allows calibration signals to be injected during normal radar operation, resolving the contradiction between maintaining calibration accuracy and avoiding intrusive calibration procedures
Solution Approach 2:
The system performs calibration during quiet periods between radar signal transmissions by injecting calibration signals through the communication leads. This preliminary action ensures calibration is completed before the next radar measurement cycle, maintaining calibration accuracy without interrupting normal radar operation
2Device complexity
If radar systems are calibrated only once during vehicle production, then manufacturing complexity is reduced, but temperature-induced phase differences during operation degrade radar performance
Solution Approach 1:
The patent implements periodic calibration by injecting calibration signals during quiet periods between radar transmissions. The controller periodically determines phase offsets and gain imbalances for each receiver channel, updating calibration parameters continuously during operation to compensate for temperature-induced phase differences and maintain radar performance stability
Solution Approach 2:
The system continuously monitors receiver channel characteristics by analyzing calibration signal responses and uses this feedback to dynamically adjust phase and gain calibration parameters. This feedback mechanism ensures radar performance remains stable despite temperature variations during vehicle operation
3Reliability
If dynamic calibration is implemented during operation, then temperature-induced phase differences are compensated, but system complexity increases due to additional calibration circuits and processing
Solution Approach 1:
The patent utilizes existing radar communication leads and receiver channels for dual purposes: normal radar signal reception and calibration signal injection. The same communication leads that carry radar return signals are also used to inject calibration signals during quiet periods, eliminating the need for separate dedicated calibration hardware and reducing overall system complexity
Solution Approach 2:
The radar system performs its own calibration using its existing hardware resources. The controller utilizes the transmitter array to generate calibration signals, the communication leads to distribute them, and the receiver array to measure them, making the calibration system self-sufficient without requiring external calibration equipment or additional dedicated calibration hardware
Data Source
AI summary
A system and associated method for calibrating a radar system is described, wherein the radar system includes a phased array antenna including a first antenna array and a second antenna array, a transmitter array, and a receiver array, communication leads, a calibration circuit, and a controller. The calibration circuit includes a power divider and directional couplers. A pilot signal is injected, via the power divider and the directional couplers, to the receivers during a quiet period. Phase offsets and gain imbalances for the receivers are determined in relation to a reference channel based upon the pilot signal, and phase calibrations and gain calibrations for the receivers are determined based upon the phase offsets and the gain imbalances, and a radar-related parameter is based upon the phase calibrations and the gain calibrations for the receivers.