Error analysis of same-beam differential VLBI technique using two SELENE satellites

Liu, Q.; Kikuchi, Fuyuhiko; Matsumoto, Koji; Asari, Kazuyoshi; Tsuruta, Seiitsu; Ping, Jinsong; Hanada, Hideo; Kawano, Naoki

doi:10.1016/j.asr.2007.02.044

Cited by 19 publications

(23 citation statements)

References 18 publications

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“…We solve this problem by applying the same beam VLBI method for differential phase delay estimation by the MFV method (Liu et al, 2007). When elongation between two nearby spacecraft becomes smaller than the beam width of the ground antenna, their signals can be simultaneously received.…”

Section: Application Of Same Beam Vlbi Methods For Mfvmentioning

confidence: 99%

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

et al. 2008

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The same beam VLBI method (SBV) is newly applied to the multi-frequency VLBI method in the VRAD mission of SELENE (KAGUYA). By simultaneously observing two nearby spacecraft with one antenna, the error sources of VLBI measurement common in two propagation paths can be almost canceled out. In this paper, error estimation and simulation analysis are carried out for a feasibility study to apply the SBV method to the VRAD mission. Differential phase delay can be estimated without cycle ambiguity even if tropospheric fluctuation is large and/or traveling ionospheric disturbance occurs. The sensitivity of the differential phase delay with respect to the average elevation angle and the elongation of two spacecraft is also investigated. Moreover, a method is developed for estimating differential phase delay in switching VLBI observations using the cycle ambiguity derived from SBV observations. This method can be performed in more than 90% of the VRAD mission's total paths. Precise positioning with SBV contributes to accurate estimation of the low degree coefficients of lunar gravity fields by more than one order of magnitude than previous results.

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Section: Application Of Same Beam Vlbi Methods For Mfvmentioning

confidence: 99%

“…All considerable error sources are evaluated by referring to the error estimation results in Liu et al (2007). Based on those results, simulation analysis is carried out under the predicted conditions of the VRAD mission.…”

Section: Application Of Same Beam Vlbi Methods For Mfvmentioning

confidence: 99%

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

et al. 2008

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“…Equation (4) is generally summed from 1 to N , which can also improve the accuracy to several tens of ps if both frequencies in the S-band and X-band are selected. A higher accuracy can be achieved using same-beam differential VLBI when the effects of the atmosphere, ionosphere, and receivers are almost canceled from the difference in correlation phase, and when channel 0 can be added (Liu et al, 2007;.…”

Section: Main Conceptmentioning

confidence: 99%

“…Traveling time is proportional to the elongation between Rstar and Vstar. The differential frequency-dependent ionospheric delay was less than 5 ps in the S-band and less than 0.3 ps in the X-band (Liu et al, 2007), which can be disregarded. The simulation signal used as a received signal was produced by adding random noise generated by random numbers in a computer and the observed tropospheric phase variations.…”

Section: Simulation Analysismentioning

confidence: 99%

“…In the work of Kono et al (2003), these sources help address cycle ambiguity using the multifrequency VLBI (MFV) method (Kono et al, 2003), especially using the same-beam MFV method, when the elongation between two nearby spacecrafts is smaller than the beam width of the ground antenna (Liu et al, 2007;Kikuchi et al, 2009). In their methods, cycle ambiguity was deCopyright c The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.…”

Section: Introductionmentioning

confidence: 99%

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New method to resolve 2π ambiguity in NBV

et al. 2012

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The Narrow Bandwidth VLBI (NBV) technique is utilized to track spacecrafts in Japanese lunar exploration. However, the problem of 2π ambiguity affects the phase delay of the carrier waves transmitted by satellites. A probabilistic algorithm called coarse search and fine delay search, in combination with a simple ambiguity judgment procedure, is presented in the current paper to resolve the 2π ambiguity. This method is employed to estimate both the delay and the delay rate from the residual phases obtained using NBV. Compared with previous analytic methods, it does not require strict constraint conditions. The ambiguity can be resolved even when the phase variations in the residual phase are 0.2 rad (approximately 11.6 degrees) compared with the less than 4.3 degree phase variations in the analytic method. The method also has the advantage of giving short time variations in the orbital motion of a satellite without ambiguity using NBV.

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Chang'E‐3 spacecraft surface reflection causes turbulence on VLBI delay

Liu

Zheng

2017

Radio Science

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The third Chinese lunar spacecraft Chang'E‐3 (CE3) was launched in 2013, and very long baseline interferometry (VLBI) observations were performed to improve accuracy of its orbit determination. During all the observation time, VLBI group delay experienced very large turbulence, which was up to hundreds of picoseconds, and with variation period of a few tens of seconds. However, VLBI group delay of another lunar spacecraft Chang'E‐5‐T1 (CE5T1), which was launched in 2014, did not show such turbulence. Influences from the troposphere, ionosphere, ground instruments, and phase characteristics of the on board antennas were considered at first, but none of these were the main cause of this large turbulence. Further investigations were made on differential phase delay turbulence, signal‐to‐noise ratio, and layout of spacecraft. The investigation results indicated that the large turbulence on group delay was caused by an interference of reflected signals from the CE3 spacecraft surface. Simulations proved that the delay error caused by signal reflection varied with frequency and therefore caused large turbulence on group delay. To minimize the multipath effect caused by signal reflection, some possible solutions are presented.

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Error analysis of same-beam differential VLBI technique using two SELENE satellites

Cited by 19 publications

References 18 publications

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

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

New method to resolve 2π ambiguity in NBV

Chang'E‐3 spacecraft surface reflection causes turbulence on VLBI delay

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