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Old 29-05-2016, 05:47   #16
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Re: GPS not updating at anchor

OK, but it should not be too difficult to beg or borrow or even buy another GPS receiver and plug it into your USB port. New generic pucks are about $100, and there are bunches of used ones out there. Then at least you narrow the problem to software versus GPS receiver.

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Old 29-05-2016, 07:00   #17
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Re: GPS not updating at anchor

Originally Posted by jimthom View Post
Thank you for your help. I installed a program called VisualGPS and I think it is a faulty GPS receiver. It locks onto a particular long and lat and when I reset it, the long and lat will change a few thousandths of a minute every second about five times and then will again lock on to a specific long and lat. Yes, it did work with ver. 4.0 some time ago and the fault may have developed in the meantime. The signal strength of the satellite display on VisualGPS is also changing every few seconds and that doesn't lock.

The really odd thing is that it records a track.

I recorded the data stream from VisualGPS

Cheers, Jim

Since your GPS and OpenCPN 4.0 previously worked, but now the position does not change while you are anchored, it is likely that "static navigation" (SN) has been enabled for the GPS by some program. While SN is enabled in the GPS, whenever the GPS is moving very slowly, a constant latitude and longitude is sent in the NMEA stream until the GPS moves by some "update threshold" distance (might be 50 meters). A new position will be reported each time the slowly moving GPS moves by the "update threshold".

I found the following link while looking through the website. The link contains a little more information on "static navigation".

GpsPasSion Forums - SiRFdemo tutorial (static navigation)

I don't know anything about the SiRFdemo program. It could be good, or it could be bad. It could harm your GPS or system.

If you have the original configuration program for your GPS you might be able to use it to disable the "static navigation" in order to restore continuous position updates.


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Old 29-05-2016, 10:53   #18
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Re: GPS not updating at anchor

Hi Jim,
I am using OCPN since a long time and had the same problem. I have an Navman active GPS antenna. The same when I stay at anchor or at very low speed COG and SOG are 0.
I think the GPS just filters or stops giving out any changes. As spare I have a cheep USB GPS Mouse and it changes position even if in harbour. Try it.
It is not a problem of OCPN.
To get the exact anchor position when anchor has dropped I switch off and on GPS.
Anchor watch a problem with this kind of receiver.


KalleKue is offline   Reply With Quote

anchor, gps

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