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Forum Index : Microcontroller and PC projects : GPS position averaging

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vk4tec

Senior Member

Joined: 24/03/2012
Location: Australia
Posts: 239

Posted: 03:12am 25 Apr 2012

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Hello

I would like to average my GPS location.

The numbers are like -27 and 153

Am I likely to strike a limit ?

Should I stop it averaging at a particular point ?

The averaging process as I know it is to add up samples and divide by the numeber of samples.

- Andrew -

Andrew Rich VK4TEC
www.tech-software.net

JohnS
Guru

Joined: 18/11/2011
Location: United Kingdom
Posts: 4020

Posted: 07:25am 25 Apr 2012

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I don't think you've given remotely enough info.

But... if you get successive numbers (in any data gathering/measuring) that are so wildly different then averaging would normally be a really bad idea. You'd want a way to reject those that are clearly garbage and then do (whatever) with what's left.

John

vk4tec

Senior Member

Joined: 24/03/2012
Location: Australia
Posts: 239

Posted: 07:42am 25 Apr 2012

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1 Hz GPS

LAT is 27 deg

1 hour = 3600 samples

3600 X 27 = 97200

The PIC must be able to count up to 97200 to average in one hour

27 * 3600 = 97200 ( avg ) / 2600 = 27

To do 24 hours averaging.

27 * 3600 * 24 = 2,332,800 / 3600 * 24 = 27 deg

The worst number encountered in GPS is 180 degrees

180 deg * 3600 * 24 = 15,552,000 / 86400 = 180

So to average 24 hours of GPS data, the PIC has to be able to add up to

15,552,000 ( worst case )

Andrew Rich VK4TEC
www.tech-software.net

JohnS
Guru

Joined: 18/11/2011
Location: United Kingdom
Posts: 4020

Posted: 04:22pm 25 Apr 2012

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You want an integer with that range (to 15,552,000)? Yes, they are - comfortably.

John

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