First Galileo-only position fix in Asia at NAVIS
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News on GPSWorld and InsideGNSS magazines:

On March 27, 2013, the four In-Orbit Validation Galileo satellites (PFM, FM2, FM3, FM4) were visible at the same time in the sky of Hanoi, Vietnam for nearly two hours (from 2:15 to 4:00 GMT) while transmitting a valid navigation message.

Figure 1. Positions obtained by only Galileo E1 Open Service
(the antenna is located at the roof of the Ta Quang Buu library building inside HUST campus)

It was then possible for the research team of the NAVIS Centre at Hanoi University of Science and Technology (HUST) to compute successfully the first Galileo-only position fix in the Region.

In Figure 1 the obtained positions are depicted on top of the roof of the NAVIS Centre, were the antenna used to receive the signals is located (latitude = 21°00’16.69” N, Longitude = 105°50’37.90” E, height = 35,2 meters).

Figure 2. Skyplot of the satellites of the GPS and Galileo systems at the time of the campaign

In Figure 2 the position of the four Galileo satellites and of 12 GPS satellites at time of acquisition is depicted, while in Figures 3 the acquisition results of the four Galileo IOV satellites are reported.

Comparison of the position computed using only Galileo, only GPS or both systems together is also presented in Figure 4. It should be noted that during the campaign, the data demodulation process reports that the Galileo system announces the "navigation data valid" status for PFM and FM3, meanwhile the "working without guarantee" for FM2 and FM4.

Figure 4. Position computed when using GPS only, Galileo only, or GPS+Galileo




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