Position determination of the Chang’e 3 lander with geodetic VLBI

Abstract

We present results from the analysis of observations of the Chang'e 3 lander using geodetic Very Long Baseline Interferometry. The applied processing strategy as well as the limiting factors to our approach is discussed. We highlight the current precision of such observations and the accuracy of the estimated lunar-based parameters, i.e., the lunar lander's Moon-fixed coordinates. Our result for the position of the lander is 44.12193 • N , − 19.51159 • E and − 2637.3 m, with horizontal position uncertainties on the lunar surface of 8.9 m and 4.5 m in latitude and longitude, respectively. This result is in good agreement with the position derived from images taken by the Narrow Angle Camera of the Lunar Reconnaissance Orbiter. Finally, we discuss potential improvements to our approach, which could be used to apply the presented concept to high-precision lunar positioning and studies of the Moon.

Promoting Earth-Based Radar Astronomical Observations of the Moon

“…The radar transmitter and a complex of radio telescopes spaced by hundreds and thousands of kilometers constitute the basis of the experimental facilities. All antennas are pointed at the ChangE-3 lunar lander (CE3) coordinates at 44.12 • N, 19.51 • W [23] at the Mare Imbrium lunar region, taking into account the signal round-trip travel time. The Chinese radar antenna at station Kashi (Ks) [21] illuminates the moon with a continuous wave (CW) signal at a frequency of 7209.125 MHz in left-hand circular polarization.…”

Precise positioning of Chang’e 3 lander based on Helmert-VCE-aided weighting method using phase delay data from Chinese VLBI Network

“…The lander positions closest to that from the LRO NAC results were calculated by Klopotek et al (2019). Their observations were made under the OCEL program, where geodetic VLBI observations were carried out in 2014, 2015, and 2016 during twelve 24-hour sessions using a global network of VLBI telescopes.…”

“…The accuracy of the Chang'e 3 lander positioning based on only VLBI observations (December 20 to 23, 2013, UTC) was up to the hundred-meter level (He et al, 2017). The accuracy from lander/quasars VLBI joint observations (OCEL program, Haas et al (2016)) was down to ten meters (Klopotek et al, 2019), but observations from multiple antennas in different countries were needed, with all the subsequent organizational complexities.…”

Review of the Precise Orbit Determination for Chinese Lunar Exploration Projects

“…(2014), meanwhile Klopotek et al. (2019) calculated the Chang’e 3 lander position with the help of the news observations as tracked by the geodetic Very Long Baseline Interferometry (VLBI). In addition, Liu, Yan et al.…”

“…Huang et al (2012) and J. Huang et al (2014), meanwhile Klopotek et al (2019) calculated the Chang'e 3 lander position with the help of the news observations as tracked by the geodetic Very Long Baseline Interferometry (VLBI). In addition, used the VLBI delay data from the Chang'e 3 lander and determined its position with a Helmert-VCE-aided weighting method to further improve its positioning accuracy.…”