I have used my model 205 Garmin GPS without problems in Indianapolis, Cincinnati, Kansas City, Denver, St. Louis as well as smaller cities. I never had problems.
However in San Diego when I turn it on, I usually get 1 bar and it takes 5 minutes in order to get a satellite signal.
Does anyone know why? My brother gets the same problem with his (more advanced) garmin GPS, it takes forever to get a satellite signal. I’ve never had this problem in any other large city.
Is it something about the military base, the atmosphere, or something else?
Are there other cities where it is hard to get a signal?
It could be the taller buildings blocking the satellite signal. I know that if I am in Boston or way out in the sticks where tall trees line both sides of the road it can be very tough getting a signal. X2 if it’s a cloudy day.
A GPS needs to know WHERE it is and WHEN it is to quickly lock onto a satellite signal. It doesnt just look for a signal. Its looking for it in a particular “place”.
My el cheapo hand held unit freaks out when if forgets what day/time it is, or its a good distance from the last place it was turned on. Sometimes its so bad it NEVER works until I reset the date/time.
Building and moutains may be an issue, but I wouldnt be surprised it aint a time/location problem as well.
I had issues with my garmin in Chicago. Oddly, I only had problems in Pedestrian mode, while using it in my hand. While in the car, it worked pretty flawlessly. The signal did drop a few times, but that was it.
I was in Chicago last week and getting GPS shot at a satellite is generally going to be easier driving in the middle of the road between buildings than on the sidewalk alongside one of the tall buildings.
GPS satellites are not geostationary (and with good reason).
Unless the place you describe is ‘up,’ I can’t imagine how a GPS would decide which way it was facing and where it expected to find its next satellite signal.
It does need/help to know when its going to get a signal from a particular satellite. It all about timing and locking in on a faint signal, which is a hell of alot easier when you know about where/when to look.
Because the satellites MOVE because they are NOT in geostationary orbit, it helps for the GPS to have a “good idea” of when and where it is.
You have a better explaination of why if my GPS doesnt have the right time or day it takes mucho time to lock on, and sometimes its so bad it won’t even work until I fix the date and time? And then when I do, its presto, bango, no problemo.
I’ve had the same problem in Manhattan. It seems to maintain the signal OK as you drive into the city on a surface road, but go down into a parking garage in midtown and come out again, and you’re not picking it up until you’re halfway to Harlem or out along one of the rivers.
A GPS clock is accurate to an incredible degree. Your setting the time isn’t going to do anything. Satellites tell your GPS what time they have with every sentence they send. Your GPS then compares the time it has with what it heard from the satellite to figure out how far away it is, reasoning that the signal from the satellite came at the speed of light. The reason I point this out is that I don’t think you’re setting your clock accurately enough to distinguish if a GPS signal is 35 millionths or 36 millionths of a second old.
A GPS will use the last place it had as a starting guess, of course. And the more open sky it has, the better. But it really has no idea where to look for a particular satellite until it gets a signal.
Under ground, down among tall buildings, trying to lock while moving, not having a good starting point. Well DUH BRT… Don’t want much from a $200 unit do ya?
Go buy a $5000 aircraft unit, bet it will be better. ::: sheesh :::::
Now driving in NYC, ( why on earth would anyone want to even be there – I tigress… ) and not having a good view out and trying to lock on the move… well, I would be slow also.
If you really need the GPS to be able to travel, mark the place where you are going under ground before it loses the lock and then stop and let it find itself at that same place when you come up for air… Will be much faster…
There have been three or four occasions where my Garmin would take forever to lock on to the satellites. I once let it go 10 min and it still was still looking – and this was in front of my house less than 50 feet from where it was shut off.
Shutting the unit off and restarting seemed to fix the issue. I assume it’s a software glitch.
It actually kinda does know where a particular satellite is. The satellite identifies itself, when it was launched, what time it’s sending this message, and a few other things.
If you told me you’re 346.3 miles from me, but I didn’t know where you were, it wouldn’t help me figure out where I am.
GPS math is cool. It’s understandable by a layperson, but it’s very complicated.
In fact, to go further into how much it knows about where the satellite is and what time it sent the signal, you have to involve that jerk Einstein. Since he invented relativity, the fact that the satellites are going faster than we are on the ground means they’ve experienced less time than we have. It’s a small amount of time, because they’re not going fast in terms of the speed of light, but it’s enough to screw with the necessarily uber-precise calculations your little unit is doing to figure out where you are. That’s why the satellite broadcasts when it was launched - so your unit can figure out how much time dilation it’s experienced.
The GPS does not need to know where the sat is to connect to it just like the radio in your car does not need to know where the radio station is. Once it’s connected, then it knows where it is.
There is the data download and then there is the timing signal. Once its connected it can get the data. Getting a precise fix on the timing signal a harder thing to do.