Thursday, January 13, 2011

GPS visualizations

Using the Pharos GPS-500 we can get a latitude and longitude coordinate pair. If this pair is then converted to a coordinate system in python, you can observe the visual drift of the signal. This first image is a screen shot of the GPS signal drift while the connected laptop is stationary.

The scale on the image can be compared to the theoretical width of the ball, which is 2 meters. The average drift during the test was 3.3 meters, and the maximum was 7.25 meters. This is pretty accurate, but when the laptop moves its a completely different story.
The following image represents a u shaped walking path. It very nearly resembles the actual path I took, but it has jagged locations where it deviates from the real path.

The final image is a graphical representation of the drift in the x and y coordinates while the laptop is stationary. As you can see there is considerable drift in both coordinate plains, and this poses a problem for precise robot navigation. It is my intention to look into the WaaS system to augment this signal.

In the above image the red line represents X axis drift, and the green line represents y axis drift.

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