Wei-Huang Wu,¹ Yuan Tian,² Jie Luo,^1,a) Cheng-Gang Shao,^3,b) Jia-Hao Xu,¹ and Dian-Hong Wang¹

¹School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, People’s Republic of China

²School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China

³MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China

(Received 30 May 2016; accepted 20 August 2016; published online 1 September 2016)

In the measurement of the gravitational constant G with angular acceleration method, the accu-rate estimation of the amplitude of the useful angular acceleration generated by source masses depends on the effective subtraction of the spurious gravitational signal caused by room fixed background masses. The gravitational background signal is of time-varying frequency, and mainly consists of the prominent fundamental frequency and second harmonic components. We propose an improved correlation method to estimate the amplitudes of the prominent components of the gravitational background signal with high precision. The improved correlation method converts a sinusoidal signal with time-varying frequency into a standard sinusoidal signal by means of the stretch processing of time. Based on Gaussian white noise model, the theoretical result shows the uncertainty of the estimated amplitude is proportional to , where σ and N are the standard

deviation of noise and the number of the useful signal period T, respectively. Published by AIP Publishing. [http://dx.doi.org/10.1063/1.4962022]