Retrieving Doppler Frequency via Local Correlation Method of Segmented Modeling

Abstract

The high accuracy radio Doppler frequency is critical for navigating a deep space probe and for planetary radio science experiments. In this paper, we propose a novel method based on the local correlation of segmented modeling to retrieve Doppler frequency by processing an open-loop radio link signal from one single ground station. Simulations are implemented, which prove the validity of this method. Mars Express (MEX) and Tianwen-1 observation experiments were carried out by Chinese Deep Space Stations (CDSS). X-band Doppler frequency observables were retrieved by the proposed method to participate in orbit determination. The results show that the accuracy of velocity residuals of orbit determination in open-loop mode is from 0.043 mm/s to 0.061 mm/s in 1 s integration; the average accuracy of Doppler frequency is about 3.3 mHz in 1 s integration and about 0.73 mHz in 60 s integration. The Doppler accuracy here is better than that of the digital baseband receiver at CDSS. The algorithm is efficient and flexible when the deep space probe is in a high dynamic mode and in low signal to noise ratio (SNR). This will benefit Chinese deep space exploration missions and planetary radio science experiments.

A High-Accuracy, High Anti-Noise, Unbiased Frequency Estimator Based on Three CZT Coefficients for Deep Space Exploration Mission

“…In this section, the raw data obtained from the Mars Express and Tianwen-1 orbiter observation experiment were utilized to evaluate the frequency estimation performance when the two probes were both orbiting Mars. The observation experiments were simultaneously implemented by CDSN, which consists of three Chinese deep space stations, the Jiamusi (JM) station, the Kashi (KS) station, and the Argentina (AG) station [ 8 ].…”

“…The Doppler measurement results of the MEX obtained by the proposed method in this paper were compared with that of the MEX obtained by the Very Long Baseline Array (VLBA), European VLBI Network (EVN), and the Chinese VLBI network (CVN) as well as CDSN [ 3 , 6 , 8 ], respectively, as shown in Table 1 . For quantitative comparison, the Doppler frequency results of MEX by the proposed method were obtained within 1-s integration.…”

“…All of the above results of the MEX Doppler accuracy are displayed in Table 1 ; here, we can see that the accuracy of the proposed method in this paper is approximately consistent with EVN and VLBA, as well as with the previous work at CDSN, while is about two times better than CVN. Since the raw data processed in references [ 3 , 6 , 8 ] and in this paper were sampled and recorded by different ground station assemblies, the comparison results have proven to be feasible and effective for the frequency estimation of the proposed method.…”

“…Currently, the existing open-loop algorithms have the disadvantages of complicated algorithms or large computation [ 4 , 5 ] or special hardware platforms [ 6 , 7 ]. Chen et al (2021) presented a Doppler frequency retrieving method via local correlation and segmented model, which was successfully applied to Chinese deep space exploration [ 8 ]. At the same time, there is a little complexity in setting the segment parameters for various dynamics.…”

“…Proakis (2021) [ 17 ] described the theory of CZT in detail. Furthermore, Granados-Lieberman (2009) [ 18 ], Chen (2010, 2021) [ 8 , 19 ], and Zhang (2019) [ 6 ] have already introduced the CZT to improve the frequency estimation performance. The current methods estimate the frequency, and they are still mostly dependent on searching the peak line position of the CZT spectrum, meanwhile, making the estimation accuracy directly constrained by the CZT spectrum resolution.…”