Here, we are going to demonstrate the spot-on accuracy of FURUNO's hybrid GPS receiver modules in comparison with the conventional standalone GPS positioning:
Date when the test is conducted: Thursday, 30th of November 2010
Test location: Areas around Umeda, Osaka and Sannomiya, Kobe
Test method: Simultaneous positioning of the aforementioned hybrid GPS receiver modules and conventional GPS receiver to compare the positioning accuracy
Vehicle's plotted position by means of GPS standalone positioning starts to deviate northward as soon as the vehicle enters underneath the elevated railway track. However, with the GV-85 with gyro and speed input, vehicle's positions are plotted in line with the actual movement of the vehicle thanks to dead reckoning positioning utilizing gyro input as well as speed signals. As soon as the vehicle comes out of the elevated railway track, the GPS receiver acquires GPS signals again, hence keeping track of the vehicle's positions while minimizing the effect of multipath propagation.
Having tested the above, we drive the same route once again to obtain the position samples for the second round. Photo samples below show plotted positions of the vehicle by both GPS receivers. While the GV-85 with speed and gyro input obtains the position data that is more or less consistent with the first round, the plotted positions by the standalone GPS receiver deviate southward this time, due, perhaps, to different GPS signal states. This shows the plausibility of dead reckoning navigation by GPS receiver module with speed and gyro input.
While driving urban area where tall buildings are lining up, positions plotted by standalone GPS deviate from the road (see image sample below on the right-hand side). This deviation stems from multipath propagation. However, the positions plotted by the GV-85 with speed and gyro input are in line with the road.
When we drive inside a long tunnel, standalone GPS positioning stops soon after the vehicle enters the tunnel (see image sample below on the right-hand side). This is because GPS signals cannot be received inside the tunnel. The GV-85 with speed and gyro input, on the other hand, continues to plot the vehicle's position even after the vehicle enters the tunnel thanks to dead reckoning navigation (see image sample below on the left-hand side).
In urban canyon, multitude of tall buildings are lining up. This is where GPS receiver is influenced by multipath propagation, and as a result, GPS positioning by standalone GPS deviates from the road on which the vehicle is running (see image sample below on the right-hand side). The GV-85 with speed and gyro input continues to generate position data in line with the roads, less affected by multipath propagation (see image sample below on the left-hand side).
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