3 ms·
Doesn't this imply that all measured distances (GPS or otherwise) are overestimated, to the extent that the measurements have any uncorrelated variance?
by lvs 11y ago
Doesn't this imply that all measured distances (GPS or otherwise) are overestimated, to the extent that the measurements have any uncorrelated variance?
- caf 11y agoOnly distances that are calculated by taking two (noisy) position measurements and calculating the displacement between the positions. If you're summing up directly measured ranges, there shouldn't be a statistical bias.
- zardo 11y agoAll measurements have noise, you should still see this effect if you use a steel ruler, just scaled down to the noise of temperature fluctions changing the length of the ruler.
- caf 11y agoIf you use the ruler to directly measure the distance between subsequent points, the random temperature fluctuations will be as likely to increase as decrease the measured distance (of course for a real steel ruler, this would be dominated by the systematic error in the ruler's markings, which will accumulate over summed measurements). If instead you used the ruler to measure (X, Y) co-ordinates of each point, then calculated the displacement between the points from those co-ordinates, the random errors would have a bias towards lengthening the path as in the article.