scholarly journals Simulation analysis of differential phase delay estimation by same beam VLBI method

2008 ◽  
Vol 60 (4) ◽  
pp. 391-406 ◽  
Author(s):  
Fuyuhiko Kikuchi ◽  
Qinghui Liu ◽  
Koji Matsumoto ◽  
Hideo Hanada ◽  
Nobuyuki Kawano
Keyword(s):  
Simulation Analysis ◽  
Phase Delay ◽  
Delay Estimation ◽  
Differential Phase ◽  
Differential Phase Delay

scholarly journals Differential Phase Delay Estimation in VRAD Mission of SELENE (KAGUYA)

2009 ◽  
Vol 7 (ists26) ◽  
pp. Pk_7-Pk_10
Author(s):  
Fuyuhiko KIKUCHI ◽  
Qinghui LIU ◽  
Natalia PETROVA ◽  
Yuji HARADA ◽  
Hideo HANADA ◽  
...  
Keyword(s):  
Phase Delay ◽  
Delay Estimation ◽  
Differential Phase ◽  
Differential Phase Delay

Method for differential phase delay resolution of phase referencing VLBI technique and its experimental verification

2021 ◽  
Vol 21 (11) ◽  
pp. 296
Author(s):  
Huan Zhou ◽  
Jian-Guo Yan ◽  
De-Zhen Xu ◽  
Yong Huang ◽  
Hai-Tao Li
Keyword(s):  
Orbit Determination ◽  
Angular Position ◽  
Measurement Data ◽  
Angular Separation ◽  
Phase Delay ◽  
Phase Ambiguity ◽  
Deep Space ◽  
Differential Delay ◽  
Differential Phase ◽  
Differential Phase Delay

Abstract The phase referencing Very Long Baseline Interferometry (VLBI) technique is a newly developed tool to measure the angular position of a deep space exploration probe in the plane-of-the-sky. Through alternating observations between the probe and a nearby reference radio source, their accurate relative angular separation can be obtained from the radio images generated by this technique. To meet the requirements of the current orbit determination software, differential delay should be firstly derived from those radio images. A method to resolve the differential phase delay from the phase referencing VLBI technique is proposed in this paper, and as well the mathematical model for differential phase ambiguity resolution is established. This method is verified with practical measurement data from the Chang’E-3 mission. The differential phase delay between the Chang’E-3 lander and rover was derived from the phase referencing VLBI measurements, and was then imported into the Shanghai astronomical observatory Orbit Determination Program (SODP) to calculate the position of the rover relative to the lander on the lunar surface. The results are consistent with those acquired directly from radio images, indicating that the differential phase ambiguity has been correctly resolved. The proposed method can be used to promote applications of the phase referencing VLBI technique in future lunar or deep space explorations, and more accurate orbit determination becomes promising.

scholarly journals The Potential for Discriminating Microphysical Processes in Numerical Weather Forecasts Using Airborne Polarimetric Radio Occultations

2019 ◽  
Vol 11 (19) ◽  
pp. 2268 ◽  
Author(s):  
Michael Murphy ◽  
Jennifer Haase ◽  
Ramon Padullés ◽  
Shu-Hua Chen ◽  
Margaret Morris
Keyword(s):  
Numerical Experiments ◽  
Climate Models ◽  
Mesoscale Model ◽  
Spatial Scales ◽  
Phase Delay ◽  
Weather Forecasts ◽  
Differential Phase ◽  
Numerical Weather ◽  
Differential Phase Delay ◽  
Microphysical Processes

Accurate representation of cloud microphysical processes in numerical weather and climate models has proven challenging, in part because of the highly specialized instrumentation required for diagnosing errors in simulated distributions of hydrometeors. Global Navigation Satellite System (GNSS) polarimetric radio occultation (PRO) is a promising new technique that is sensitive to hydrometeors and has the potential to help address these challenges by providing microphysical observations that are relevant to larger spatial scales, especially if this type of observing system can be implemented on aircraft that can target heavy precipitation events. Two numerical experiments were run using a mesoscale model configured with two different microphysical parameterization schemes for a very intense atmospheric river (AR) event that was sampled by aircraft deploying dropsondes just before it made landfall in California, during the CalWater 2015 field campaign. The numerical experiments were used to simulate profiles of airborne polarimetric differential phase delay observations. The differential phase delay due to liquid water hydrometeors below the freezing level differed significantly in the two experiments, as well as the height of the maximum differential phase delay due to all hydrometeors combined. These results suggest that PRO observations from aircraft have the potential to contribute to validating and improving the representation of microphysical processes in numerical weather forecasts once these observations become available.

Investigation on unexpected variations of differential phase delay of Chang’E-3

2021 ◽  
Author(s):  
Qingbao He ◽  
Kaijun Liu ◽  
Shengyi Ye ◽  
Qinghui Liu ◽  
Tao Deng
Keyword(s):  
Phase Delay ◽  
Differential Phase ◽  
Differential Phase Delay

scholarly journals Multi-wavelength VLBI phase-delay astrometry of a complete sample of radio sources

2007 ◽  
Vol 3 (S248) ◽  
pp. 352-355
Author(s):  
I. Martí-Vidal ◽  
J. M. Marcaide ◽  
J. C. Guirado
Keyword(s):  
Large Fraction ◽  
Interaction Model ◽  
Phase Delay ◽  
Radio Sources ◽  
Polar Cap ◽  
Bl Lac Objects ◽  
Differential Phase ◽  
Multi Wavelength ◽  
Differential Phase Delay ◽  
The Impact

AbstractWe report on the first global high-precision (differential phase-delay) astrometric analyses performed on a complete set of radio sources. We have observed the S5 polar cap sample, consisting of 13 quasars and BL Lac objects, with the VLBA at 8.4, 15, and 43 GHz. We have developed new algorithms to enable the use of the differential phase-delay observable in global astrometric observations. From our global analyses, we determine the relative positions between all pairs of sources with typical precisions ranging from 10 to 200 μas, depending on observing frequency and source separation. In this paper, we discuss the impact of this observable in the enhancement of the astrometric precision. Since a large fraction of the S5 polar cap sources are ICRF defining sources, this may result in a test of the ICRF stability. Our multi-epoch/multi-frequency approach will also provide both absolute kinematics and spectral information of all sources in the sample. In turn, this will provide an important check on key predictions of the standard jet interaction model.

Speed Measurement and Motion Analysis of Chang’E-3 Rover Based on Differential Phase Delay

2016 ◽  
Vol 40 (2) ◽  
pp. 236-246 ◽  
Author(s):  
Pan Chao ◽  
Liu Qing-hui ◽  
Zheng Xin ◽  
He Qing-bao ◽  
Wu Ya-jun
Keyword(s):  
Motion Analysis ◽  
Phase Delay ◽  
Differential Phase ◽  
Speed Measurement ◽  
Differential Phase Delay
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