VLBI observations to the APOD satellite
Journal article, 2018

The APOD (Atmospheric density detection and Precise Orbit Determination) is the first LEO (Low Earth Orbit) satellite in orbit co-located with a dual-frequency GNSS (GPS/BD) receiver, an SLR reflector, and a VLBI X/S dual band beacon. From the overlap statistics between consecutive solution arcs and the independent validation by SLR measurements, the orbit position deviation was below 10 cm before the on-board GNSS receiver got partially operational. In this paper, the focus is on the VLBI observations to the LEO satellite from multiple geodetic VLBI radio telescopes, since this is the first implementation of a dedicated VLBI transmitter in low Earth orbit. The practical problems of tracking a fast moving spacecraft with current VLBI ground infrastructure were solved and strong interferometric fringes were obtained by cross-correlation of APOD carrier and DOR (Differential One-way Ranging) signals. The precision in X-band time delay derived from 0.1 s integration time of the correlator output is on the level of 0.1 ns. The APOD observations demonstrate encouraging prospects of co-location of multiple space geodetic techniques in space, as a first prototype.




Space ties



Jing Sun

Geshi Tang

Fengchun Shu

Shanghai Astronomical Observatory

Xie Li

Shushi Liu

Jianfeng Cao

Andreas Hellerschmied

Vienna University of Technology

Johannes Böhm

Vienna University of Technology

Lucia McCallum

University of Tasmania

Jamie McCallum

University of Tasmania

Jim Lovell

University of Tasmania

Rüdiger Haas

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Alexander Neidhardt

Technical University of Munich

Weitao Lu

SongTao Han

Tianpeng Ren

Lue Chen

Mei Wang

Jinsong Ping

Advances in Space Research

0273-1177 (ISSN)

Vol. 61 3 823-829

Driving Forces

Sustainable development

Subject Categories

Physical Sciences

Earth and Related Environmental Sciences


Basic sciences


Onsala Space Observatory



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