First Acquisition and tracking, in Vietnam, of the first four Galileo IOV Satellites
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Galileo signal decoding team, from left to right: Eng. Truong Minh Duc, Mr. Tran Thanh Trung, Eng. Nguyen Dinh Thuan, Dr. La The Vinh

From 15h25 to 19h25, December 17th, 2012, the first four satellites of the Galileo system were visible at the same time in the sky of Hanoi, Vietnam for about one hour. It was the first time in which the satellites were visible together from Hanoi after all of them started transmitting their E1 signals.

The researchers of the NAVIS Centre in the Hanoi University of Science and Technology could, for the first time, receive the signals of all the four satellites and track them with the Software Receiver that was recently developed in the NAVIS Centre.

The signals were received at the NAVIS Centre (105.8372oE, 21.0341oN). At the time of successful acquisition and tracking the four satellites (PFM, FM2, FM3, FM4) were broadcasting a Galileo Open Service signal on E1 band. In particular satellite PFM was using Code Number 11 of the Galileo Interface Control Document (ICD) while satellites FM2, FM3, and FM4 were using Code Number 12, 19, and 20.

Figure 1. Skyplot of Galileo satellites at the time of the experiment (4 satellites in Hanoi's sky)


Figure 2. Ground traces of Galileo satellites

In Figure 1 and 2 (that have been obtained with the free software tool, Orbitron, © by Sebastian Stoff) the orbits of the four Galileo satellites are reported at the time of signal acquisition.

First acquisition and tracking results for the signals of all the four satellites are reported in the following figures.

Figure 3. Acquisition results of the 4 satellites

Figure 4. Outputs of DLL tracking loop

The demodulation of the E1b data channel of the four satellites has also been performed checking the content of the navigation message. It has been found that, while satellite FM2 had a valid navigation message, satellites PFM, FM3, and FM4, on the contrary, have a dummy one, so that it has not been possible to perform the first fully Galileo fix point.


Figure 5. Power of received signals