Vanity-GPS Navigation Devices Question

11.29.07 | trumandogz

[pabianice]

Here

[Squawk 8888]

What lattitude are you at? I found that the closer to the equator you are the stronger the signal. My unit gets a signal capture in Georgia in half the time it takes when I’m in Toronto, so if you’re in one of the northern states (WA, MN, WI, ND are all north of here) it could make a difference.

[CPOSharky]

...I was driving at 400MPG and eventually lose signal.

You get 400MPG? ;-)

[iMacMan]

>I have placed it on all parts of the windshield within sight excluding those that
> would cause me to not see the road.

The 350 has a flip-up antenna, and although I’ve never had any problem with the antenna in any of the “up” positions, maybe the 200 is different. Not sure how the built-in antenna is connected — maybe a bad connection somewhere.

As others have suggested, the folks at Garmin should be able to help you — this is definitely NOT right.

[pbear8]

TomTom has been really good and has rarely lost satellite contact. When it has, it has been brief. We've taken TomTom across the desert and into big cities and have had good results.

Hope yours works out!

[Squawk 8888]

the unit needs to “see” 3 satellites to find its location — 4 or more (of the 27 in the constellation) is better.

Three satellites are needed to establish a position on the surface while a minimum of four are required to calculate altitude.

[Squawk 8888]

You need to upgrade to a laser ring.

[Tennessee_Bob]

Used a INS, but the gyroscope took up the entire trunk!

Oh - you went old school. Need to try one of the laser-ring gyros then. Spin up time is minimal, and the high pitched whine only bothers the dog for a minute or two.

[SGCOS]

here's your problem

&^)

[cinives]

I can’t look up the tables and drive at the same time :)

My Garmin works great FWIW, thru the windshields of both a LS and a Land Rover.

It sounds to me like an antenna/antenna connection problem.

[fireforeffect]

Satellite are in high orbit, around the equator (not quite but close). The further north you go the closer the signal gets to the southern horizon. Trees, buildings, and children on tricycles can affect your signal if you are far enough north.

Power lines, the roof of your car, and the local air force base (or just the navigation aids at the local air port) can also affect your signal. Power lines too. Also cell towers that are real close. Something to do with that 0.4 mW signal from 200 miles up.

ALWAYS remember, GPS lets you get lost with a high degree of confidence.

[AmericaUnited]

Some units do have a newer GPS receiver chip that is much better. I’ll go to a online estore like www.tigerdirect.com and look at the various customer reviews of the different units. Quite revealing...

[RainMan]

There are several things that can mess things up ... many of which have been mentioned. I had a Jag S-Type with a built in GPS. The Antenna was mounted behind the rear view mirror, and if you looked carefully, the film on the glass was not on the area directly around the antenna.

If you dont have an antenna, get one if you can.

Position in relationship to other electronics can also be an issue. Do you have a CB, Police Radar detector or other strong signal generator in your vehicle ... that could explain why sometimes it does not work outside the vehicle. If so, target your research around RF interference.

Do you have a Graphic Equalizer/Booster, pre-Amp, Amp, oversized Bass, or other strong entertainment system ... if so, look into EM interference. Do you get a hum in your speakers?

Then there is plain old/sloppy wiring ... did someone inadvertantly turn your entire chassis into an antenna by fishing a wire someplace and abrading the conduit so that the wire touches your chassis.

Do a little research along these lines and then call tech support ... they should be able to get things resolved once you have narrowed down the problem.

[Liaison]

Your Magellan must have the updated positioning/ outage information of the satellites and must be able to see 4 satellites at a time from constellation in order to give you proper 4 dimensional location for your unit. Being able to see 4 satellites gives you X-Y-Z axis coordinates and time so your GPS Receiver can update and give you proper positioning, navigation, and timing. Also having updated map data is critical in a format that the unit can read properly.

Other issues: GPS signal bounce can put you in the wrong location. If your GPS has been off for a long period of time, 24-48 plus hours, it can take 10-30 minutes for your GPS to rebuild the GPS constellation almanac (where the each satellite is in its orbit )before it can give you a proper location and be able to guide you on your way:

FIX: Either keep your unit constantly on with a unobstructed or limited obstruction view of the sky or put it outside 30 minutes before you begin traveling. It needs time to acquire information before the unit can help you get where you are going. Physical obstructions and terrain masking will always play havoc with signals not much you can do except do your best to understand the effects and don't get to upset with the GPS. Its only as good as the system limitations.

[SGCOS]

I don't use a GPS system, but that's a lot of information.

Thank You.

[Yo-Yo]

Satellite are in high orbit, around the equator (not quite but close)

You're thinking of the Geosyncronous orbit satellites for communications, not GPS satellites.

GPS satellites are in a lower earth orbit and cover the entire globe equally.

[comet13]

I have a Nuvi 200 and don’t experience any of the issues you are reporting. In fact once i get lock, i have rarely lost it, not counting parking garages, of course.

[Attention Surplus Disorder]

” If your GPS has been off for a long period of time, 24-48 plus hours, it can take 10-30 minutes for your GPS to rebuild the GPS constellation almanac..”

Had no idea, thanks for posting that.

[IllumiNaughtyByNature]

I use my Verizon Wireless phone with the VZ Navigator option for $9.99 cents a month. It updates maps etc. every 30 days. Works great for a sales guy on the road all the time. Since I have verizon wireless service anyway it was a natural fit. And it can be turned on and off without affecting the contract.

Hope that helps.

[untrained skeptic]

Don’t know.