A Real-Time Internal Calibration Method for Radar Systems Using Digital Phase Array Antennas

This paper proposed a real-time internal calibration method for receiving channels of radar systems using phased array antennas with real-time digital beam-forming. In most calibration methods, the frequency of the calibration signal (CalSig) is different from that of the echo signal, leading to some disadvantages in the calibration procedure. This paper analyzed and proposed a novel solution to solve those disadvantages. In the solution, we use the CalSig with the same frequency as the echo signal. The CalSig is a binary phase-shift keying (BPSK) signal and amplitude-modulated by an on-off keying (OOK) code sequence. The proposed CalSig has peak power equivalent to noise power but its average power is much lower than noise power by using OOK modulation with a small duty cycle D such that it does not affect the echo signal significantly. Measurement of receiving parameters is based on correlation properties of the signal. The performance of the proposed method is analyzed using the statistical theory and verified by Matlab simulation. Results show the effectiveness of the method with high accuracy, satisfying the real-time requirement while affecting receiving quality insignificantly. Phase and amplitude errors can be achieved values below 0.5° and 0.2 dB, respectively. © 2021, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.