How many satellites?

from Garmin

What if I'm standing still? The last direction of travel when I was moving?

I was interested in what the red dot was, so looked up what Garmin said.

Maybe someone else can chime in.

Try it and find out. Let us know.

Just did. It appears so. The red dot is at the northeast, and, according to my Navigation screen, my vehicle is pointing NE.

http://www.gpsreview.net/satellite-info-screen/

When you look at the satellite info, you will see how many feet of accuracy. That indicates what the maximum error would be. Of course, it is almost impossible to see 0 foot accuracy because this not military grade equipment.

When you are standing still, and turn on your GPS, there is no last movement direction. Then the accuracy comes into the play, you will see the direction of travel keeps moving around ever few minutes, and you will also see speed of movement. Because the error in GPS thinks your are moving to that direction.

When driving for a certain period of time on a frontage road located parallel to an interstate highway, the consumer GPS won't know which one your driving on even though it states 12 feet accuracy.

Here's an interesting article concerning the snap to road feature.

http://www.gpsreview.net/snap-to-roads/

Thanks for the link.

I used my gps while mowing my sister's yard. I knew that the trip log feature would not give me the track I wanted. So I used the "Raw Logging" feature found on most Garmins. The link to a pic gives a pretty good idea of the accuracy of the unit.
http://i139.photobucket.com/albums/q297/spokybob/nancylawn-1...
I don't know how to share the MapSource file I created.

My '40 does this, if I use the 'Where To' mode.

It recommends that I go on the major road to my route, but sometimes I use the parallel frontage road (about 20 meters away). It thinks I am on the major road, and gives me directions as such.

But, if I use the 'Navigation' mode, it correctly tells me that I am on the frontage road.

Hopefully not taking this thread too much off topic...

Do the Nuvis, specifically the Nuvi 1390, use WAAS data? My old Quest and it's manual talked quite a bit about WAAS improving accuracy, but I find almost nothing recently about WAAS.

If so, can you turn WAAS on and off on the Nuvis? On the satellite screen are any specific satellite numbers actually WAAS data?

Don't worry about that. Where ever y'all want it to go.

I think that most (all?) nuvis now do not use WAAS. Correct me if I'm wrong, folks.

But remember that with City Navigator maps, the nuvi uses "snap to" so that when traveling down a street or highway, rather than seeing your vehicle where the GPS lat/long actually places it, it'll snap your vehicle to the nearest roadway.

My old c340 uses WAAS, very accurate. The other day I was sitting on our porch swing rocking back and forth, watching the map flip at the same time as the GPS adjusted accordingly. I was rather impressed by that.

Look at the user manual and then scroll through the different modes to see if your unit has it. I don't think that any of the newer models have it.

Yes, as an example, look at the user manual for the nüvi350 on page 45
https://buy.garmin.com/shop/shop.do?cID=164&pID=31655

Garmins explanation of WAAS http://www8.garmin.com/aboutGPS/waas.html

Cheers

Yeah, no mention of WAAS in the manual for my model (Nuvi 1390T)

The WAAS birds are geostationery, so over time if you are not moving very far, you can notice them to stay at the same azimuth and elevation from your position, unlike the others.

The "real" GPS birds get numbers from 1 through 32 on the Garmin display, while the WAAS birds get numbers above that range.

As a geeky note, the number displayed by Garmin for WAAS birds is the actual PRN minus 87, which gives the NMEA designation.

I've never seen a WAAS bird on my nuvis (855 and 3790LMT) and don't think it is mentioned in the manuals. On my eTrex Vista HCx, which is WAAS-capable, turning the WAAS function on or off is an option on the system configuration menu.

You are correct. Some of the original Nuvi models used WAAS but it's been a number of years now since a Nuvi used it. My understanding was that even with the models that did use it, finding a WAAS bird was tricky depending on where in the country you were and overall made little difference in the strength of the sat. signal or the units accuracy.

I had an iQUE (Palm with Garmin). It used WAAS. It improved accuracy, my memory is to 10-12 feet. You had to turn the feature off if you were running off the internal battery off batter, and wanted any battery time. The unit didn't really lock on the satellites (in the car) very well. I mounted an external antenna on the roof.

I suspect current GPS units get adequate results without the added expense of including WAAS. Garmin deleted mp3 playback, presumably to save a small licensing fee.