Robust Estimation of Allan Variance Based on Uncorrelated Difference
Hang Gong, Xiangwei Zhu, Jingyuan Li, Zengjun Liu, Jing Peng, Guangfu, Sun, College of Electronic Science, National University of Defense Technology, China
Location: Regency B
The estimation of atomic clock’s frequency stability will significantly deviate from its true value if anomalies occur. This paper proposes an robust estimation method based on uncorrelated difference and Huber weight function. Firstly, difference estimation model of Allan variance is established, and computation complexity of noise identification and whiten introduced by correlative difference is analyzed based on statistical property of difference clock sequence. In order to solve this problem, a construction model of uncorrelated difference sequence is established to avoid complex noise identification and whiten computation effectively. Based on this, correlative difference robust estimation method of Allan variance is derived, followed by a counteracted technique of error accumulation introduced by robust estimation. Finally, the integrated robust estimation solution is given, and its effectiveness is verified by experiment. The results show that the method has significance robust ability for phase outliers and phase jumps, and the relative deviation introduced by anomalies can be reduced from almost 200% to less than 5%.