Weather Radar Signal Path Calibration via Frequency Offset Segmentation
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Solution Overview
Problem
Existing weather radar systems face challenges in calibrating signal paths without interrupting data acquisition or blocking range cells, leading to incomplete or non-comparable measurement data due to thermal drifts and frequency-dependent calibration parameter changes.
Innovation Solution
A weather radar system that allows for permanent calibration of signal paths during operation by using a splitting device or switching device to separate test and radar signals, enabling continuous determination of calibration parameters for any antenna position and range gate, with the option to select a test signal frequency with a frequency offset to the radar signal, and employing various mathematical models to establish frequency dependency relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test signal with the same frequency as the radar signal is coupled into the signal path for calibration, then the calibration parameters can be determined, but data acquisition must be interrupted or range cells must be blocked
Solution Approach 1:
The patent segments the signal processing by separating the radar signal and test signal into different processing channels. The radar signal is processed through the complete signal path including antenna, while the test signal is processed through a separate evaluation unit that directly receives the test signal without requiring antenna blocking. This segmentation allows simultaneous calibration and data acquisition.
Solution Approach 2:
The patent introduces an intermediary evaluation unit that directly receives the test signal from the signal generator and determines calibration parameters without requiring the test signal to pass through the antenna and complete signal path. This intermediary processing path enables calibration without interrupting radar data acquisition.
2Ease of manufacture
If calibration is performed once with a continuous-wave test signal, then the calibration process is simple, but the antenna signal must be blocked for the duration of calibration
Solution Approach 1:
The evaluation unit serves as an intermediary that directly processes the continuous-wave test signal without requiring antenna blocking. This allows the simple continuous-wave calibration method to be used without the time penalty of blocking the antenna, as the test signal is evaluated through a direct path bypassing the antenna system.
3Ease of operation
If a frequency offset is used between the test signal and radar signal, then the signals can be separated more easily, but additional frequency modeling is required
Solution Approach 1:
The patent changes the frequency parameter of the test signal by introducing a frequency offset relative to the radar signal frequency. This frequency parameter change enables easier signal separation in the frequency domain. The evaluation unit then applies frequency modeling to account for the frequency-dependent characteristics of the signal path, transferring calibration parameters from the offset frequency to the radar frequency.
Data Source
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AI summary
Weather radar for measuring radar signals in the GHz range with a receiver (2) comprising at least one signal path (1), comprising a receiving device for an incoming radar signal (3), to which a test signal (5) generated by a test signal generator (26) can be superimposed in a coupler (4), and a processing device (6) for amplifying, filtering, and converting both signals to lower frequencies, and with an evaluation device (7) in which calibration parameters of the signal path (1) for the frequency of the test signal can be derived from the test signal (5) for determining the signal strength of the received radar signal (3), wherein the test signal (5) can be superimposed with at least one frequency different from the radar signal (3), so that the radar signal (3) and the test signal (5) can be processed separately by the evaluation device (7).and the calibration parameters of the signal path (1) for the frequency of the radar signal (3) can be determined from the test signal (5) by modeling the frequency dependence of the calibration parameters for frequencies around those of the radar signal (3).