Inaccurate waypoint - is my Nuvi broken?

[snorkle]

I went around the neighborhood to add wapoints on my Nuvi 260w. Most of the waypoints are placed correctly. However, there are few that are placed a block away from where it it supposed to be. I'm a GPS newbie.

It was raining when I'm placing my waypoints. It was also cloudy. Did that played a role?

How long do I have to stand and wait in that new waypoint spot before I can hit "where am I now?" and "save location"? Baka gumagalaw pa ang GPS when I hit "save location" kaya mali ang mark.

[The Judge]

Hi there!

There are certain variables/factors that may affect GPS accuracy but rain and clouds are not one of them.

As you recorded Wps that are in the correct location and there are some which are not in the correct location, the accuracy of the gps signal may have dipped when you recorded the WPs that were in the wrong location.

Are you inside a vehicle while recording the WPs? If so, are the vehicle windows heavily tinted (metal impregnated tints significantly decreases radio signals)? Are there foliage or tall/large buildings around?

If you're using your Nuvi with the built in antenna, you can expect the accuracy to fluctuate especially when moving. That is why I would recommend an external active antenna for the serious hobbyist.

HTH

[snorkle]

How long do I have to stand in one spot before I can save my location? Don't I have to stand still for a while for the GPS to adjust where I'm at?

[The Judge]

Actually, the time it takes for you to save the WP and pressing the buttons is enough. Your gps updates your position continuously in split second intervals.

[snorkle]

Actually, the time it takes for you to save the WP and pressing the buttons is enough. Your gps updates your position continuously in split second intervals.

I don't have to wait for the little icon to stop moving around the map to save it?

[The Judge]

I don't have to wait for the little icon to stop moving around the map to save it?

Huh!?

I'm really lost. Will someone be kind enough to answer this. I'm 'outta here!

[John Ryan]

How long do I have to stand in one spot before I can save my location? Don't I have to stand still for a while for the GPS to adjust where I'm at?

no. you don't have to wait for it to stop moving. just mark that WayPoint.

[Tofu]

I don't have to wait for the little icon to stop moving around the map to save it?

No, you don't have to wait, just press the icon and it will be saved.

Actually, the accuracy of a gps device depends on the quality of fix you have on the satellites. The more satellites you see in the gps info is generally better as long as the signal strength is good and the satellites are nicely spaced around the circle. If you see them bunched in the center of the circle, it is not very good. If you see them mostly on one side of the circle, it's not good either.

One more thing, nuvi's are designed for car navigation, you don't expect them to be as accurate as dedicated hand held gps trackers or more sophisticated DGPS systems. Normal ideal conditions for nuvi's would give an accuracy of 15 meters.

[Borgie]

How long do I have to stand in one spot before I can save my location? Don't I have to stand still for a while for the GPS to adjust where I'm at?

Using my 60CSx, i can mark waypoints even on the run. Just remember that the instance you press the mark button, the coordinates for that location is recorded. So when you press "mark", it has to be in front of the POI or where you want the POI icon to be (i.e. a hotel's or malls entrance, a school's gate & etc.). After pressing "mark", you can take your time pressing "ok" as the coordinates are already marked. The 60CSx also has a feature wherein you can average the coordinate readings for a particular waypoint for a more accurate mark. So after pressing "mark" you press "avg" and you see a countup of the number of times the location is recorded, which would be averaged when you press "ok". But imo, it's not necessary to "avg" a waypoint... HTH

[The Judge]

Ok, I think I understand it now.

The fact is, if you're on a standstill (not moving at all), the GPS sats finds it harder to establish your exact location. Accuracy is best when you are moving at least 3-5km/hr especially when establishing your heading. You will notice this when you are recording a track. The locations recorded when you are moving are smooth but at the point where you stopped, the gps points are all over the place and becomes smooth again when you move.

[Borgie]

Ok, I think I understand it now.

The fact is, if you're on a standstill (not moving at all), the GPS sats finds it harder to establish your exact location. Accuracy is best when you are moving at least 3-5km/hr. You will notice this when you are recording a track. The locations recorded when you are moving are smooth but at the point where you stopped, the gps points are all over the place and becomes smooth again when you move.

Hmmm... i've a different experience with my 60CSx. Although the tracks are all over the place when at a standstill, i can still get an accurate waypoint mark, moreso if i avg it. Methinks the wandering tracks are not an indication that the gps is having a hard time fixing your location, but maybe it's erratic bec. you're not moving and it's just one of those cons with the newer sirf chips ? But you're right, when you start to move, even if at a very slow pace, the tracks do smoothen out. In older GPS handhelds like the etrex, tracks don't move as much when you're standing still, but you do lose the sats quick when under tree cover or inside the car and even on a cloudy day...

[The Judge]

It happens more with Nuvis. As the 60csx have the averaging function which I assume averages the positions that are all over the place and comes up with a more accurate position.

I think when you're at a standstill or moving very slowly, the heading/bearing suffers more than the accuracy of the location.

Again it will all depend on the gps antenna as such phenomenon never happens when I'm using an external one.