The core principle of rapid phase calibration of radar antennas on towers is to transmit specific signals and receive echoes reflected from the calibration tower. By using phase comparison and digital signal processing techniques, the phase errors of each channel of the antenna can be quickly measured and compensated for, achieving high-precision calibration.
1. Signal transmission and reflection
The radar emits specific waveform signals such as linear frequency modulation to the calibration tower, which reflects off the tower and is received by the radar antenna. This signal has good autocorrelation characteristics, making it easy to perform precise pulse compression and phase extraction at the receiving end.
2. Multi channel parallel processing
Modern phased array radar typically has hundreds or thousands of receiving channels. The fast phase calibration technology adopts a multi-channel parallel processing architecture, which samples, filters, and processes all channel signals simultaneously through dedicated hardware (such as FPGA) or digital signal processor (DSP), greatly reducing calibration time.
3. High precision phase measurement
The core is to use the Fast Fourier Transform (FFT) algorithm to convert the received time-domain signal to the frequency-domain, thereby accurately analyzing the phase information of each channel signal. Usually, optimization algorithms such as least squares are combined to fit the measurement results, further improving the measurement accuracy of phase difference.
4. Error compensation and calibration
The system will provide real-time compensation for errors introduced by transmission line losses, environmental noise, and other factors. By pre storing calibration data or using adaptive filtering algorithms, the amplitude and phase of the received signal are automatically corrected, and calibration coefficients are finally generated and applied to each channel to complete phase calibration.
5. Automated process control
The entire calibration process is fully automated by computer control, including signal transmission, data acquisition, processing, and parameter adjustment, without the need for manual intervention, ensuring high efficiency, high repeatability, and high reliability of calibration.
