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learner71 Occasional Visitor
Joined: Jul 29, 2013 Posts: 8
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Posted: Fri Oct 18, 2013 5:17 am Post subject: calculation of speed in GPS |
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Hi,
In GPS module, i are getting information about
1. latitude and longitude
2. Time
3. Horizontal Estimated Positional Error
4. Heading
5. vertical speed
6. horizonatl speed
7. Altitude
8. Location uncertainty angle
9. Standard deviation of axis along
10. Standard deviation of axis perpendicular to
How can we calculate the velocity of GPS device based above information?
Can any one explain it? if possible with example.
Best Regards
Learner |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Fri Oct 18, 2013 9:11 am Post subject: |
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The horizontal speed gives you the horizontal velocity probably in M/sec. If you are gaining or loosing height at the same time, you can use Pythagoras to calculate your velocity and angle to the horizontal/vertical and the heading reading gives your horizontal direction.
Bear in mind that the vertical accuracy of a GPS device is not as good as the horizontal.
It would have been good had you asked this question along with your others here
The use of the word 'heading', although in general use meaning direction of travel, it is not strictly true as that. The heading of an aeroplane (say) is the direction in which the pilot is pointing the aircraft. Its 'track' is the direction it is actually travelling in over the surface of the earth. The two may differ (considerably, in the case of a boat) due to cross winds or cross currents causing the aircraft/boat to drift off course and not track in the direction of their heading. You have to steer (head) into the wind/current enough to cancel the drift in order to maintain the wanted track. |
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Lariliss Occasional Visitor
Joined: Nov 05, 2021 Posts: 10 Location: UK
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Posted: Fri Nov 05, 2021 5:24 pm Post subject: |
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1. You should choose the sampling rate, according to precision needed and calculate using latitude and longitude (this is fair enough) to calculate the path length.
2. In case you need to calculate distance from point A to point B - use lat/lon(A) and lat/lon(B) with the same calculation.
And divide time, could be referred to number of samples.
Here is formula:
https://www.movable-type.co.uk/scripts/latlong.html
Here is calculator example:
https://www.nhc.noaa.gov/gccalc.shtml
Of course mind the coordinates system, map datum. |
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