Research And Implementation Of An Active Array Calibration Method Based On Uniform Circular Array

Using array signal processing technology to finding the direction and location of electromagnetic wave signals has been a hot topic for researchers, especially the super-resolution DOA Estimation technology using MUSIC algorithm based on eigenvalue decomposition have a lot of attention and application for its super-resolution in ideal array manifold. However, in engineering applications, deviations from the true array manifold, typically resulting from antenna position errors, mutual coupling and array channels mismatch can seriously degrade the algorithms' performance. So, finding an effective array errors calibration method has become the key technology for the super-resolution DOA Estimation technology. This paper mainly analyse the amplitude and phase errors in the receiver of the cloud lightening detection system and design a active array calibration method based on emitting the sources in the array center on considering the system's resources and the circular symmetry of uniform circular arrayThrough verifying the performance of the receiver including channel gain,noise figure and S-parameter, we can see the obvious channel mismatch in the receiver. When receiving the same signal, maxium difference between the channel output powers is up to 4dB. And the array errors have also caused deviation of the DOA results in outfield experiments.Realization can be divided to two parts. One is the hardware designing of the generation of calibration sources, including schematic design and PCB design. At present, the hardware unit has been revised once and can well meet the requirements of the system.The other is selecting the suitable methods of the calibration sources feeding into the system, which is feeding the calibration sources in the center of antenna array.Through verifying from outfield experiments using several detecting systems in multiple emitting points, the array calibration method in this paper can calibrate the array errors efficiently and stablely, and guarantee the DOA performance.