Weather Radar Gimbal Calibration Using Reference Angle Sensor
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Solution Overview
Problem
The precision of weather-radar systems is limited by the quality of angular sensors, such as resolvers, which are costly and result in calibration inaccuracies when using simple calibration methods like digital protractors.
Innovation Solution
A method involving the use of a higher precision angle sensor, like optical encoders, to characterize and compensate for the errors of lesser precision sensors by generating and storing data on the system, allowing for improved antenna-position detection and correction during the radar system's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-precision angular sensors are used to improve measurement precision, then measurement precision is improved, but device cost increases
Solution Approach 1:
A calibration system is introduced as an intermediary between the low-precision angular sensor and the final measurement output. The calibration system includes a reference angle sensor mounted to the gimbal that provides high-precision reference measurements during calibration operations, allowing the main angular sensor to be compensated without being replaced with a more expensive sensor.
Solution Approach 2:
The calibration process is performed in advance before normal radar operations. During this preliminary phase, the gimbal is rotated through various positions and the reference angle sensor records precise angular positions. These calibration data are stored and later used to correct measurements from the main angular sensor, eliminating the need for expensive high-precision sensors during actual operation.
2Ease of operation
If simple calibration procedures like digital protractors are used to reduce calibration complexity, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The manual mechanical calibration method (digital protractor) is replaced with an automated calibration system. The system uses a motorized gimbal rotation mechanism that automatically rotates the gimbal through a series of positions, and a reference angle sensor that automatically records precise angular measurements at each position. This eliminates the need for manual operation while significantly improving calibration accuracy.
Solution Approach 2:
The calibration system incorporates feedback through the reference angle sensor that continuously monitors the actual angular position of the gimbal during calibration. This feedback allows the system to accurately map the relationship between the main angular sensor readings and the true angular positions, enabling precise calibration corrections to be applied to subsequent measurements.
Data Source
AI summary
A method of calibrating antenna-position detection associated with a radar system, the radar system including a first gimbal and a first angle sensor configured to detect an angular position of the first gimbal, includes mounting a second angle sensor to the first gimbal configured to detect an angular position of the first gimbal. The first gimbal is rotated through each angular position of a set of the angular positions. A first set of data is generated with the first angle sensor that characterizes a detected angular position of the first gimbal. A second set of data is generated with the second angle sensor that characterizes a detected angular position of the first gimbal. A third data set is determined comprising differences, between the first and second data sets, in detected angular position at each first-gimbal angular position. The third data set is stored in a memory device.