I’ve done that and sometimes thats a fix.
Other times I did it over and over and over and it never worked. THEN, when I look close, I see that the GPS has the date and time wrong. Fix that and then its up and running.
Yeah, it could be software glitch or confimation bias, but I doubt it. Because I notice the problem and do my best to fix it when other folks GPS units are working fine and they have plenty of satellites and I am sitting here wondering why mine aint picking up anything.
That just means it already has information about the satellite and does not have to re-download that info if you are reconnecting within a certain time frame. Therefor it connects faster.
It does not look at certain portions of the sky for the satellite. It’s just a receiver. To be able to look at certain areas, it would have to know what it’s own position already is.
It does not need to know precisely where a satellite is, but it does need to know whether it’s above the horizon or not so that it can decide whether to try tuning in to it. Depending on where my GPS unit (a Garmin 276C) is and what time/date/year it is, it has an idea of what satellites should be in view. Under these circumstances it locks onto those signals fairly quickly, and within a couple of minutes it’s got the latest ephemeris data and can start telling me exactly where I am.
If I power-down the GPS and move it a couple thousand miles (say, on a cross-country plane flight), then when I power up I have two options:
manually tell the GPS approximately where it is, or
wait for the GPS to tell me it has no idea what’s going on, and that it wants to go into its minutes-long satellite search routine.
If I choose #1, startup proceeds as described in the previous paragraph. If I choose #2, it’s a good five or ten minutes before the GPS unit has determined what satellites are in view, and then it can lock on and figure out where it really is.
Along a similar vein, several months ago my GPS unit’s internal battery stopped holding a charge. This is not the removable main power pack, it’s the little coin battery inside the case that lets the internal clock keep time even when you’ve powered down. With that battery dead, the GPS forgot the current date/time every time I shut it down. Each time I started it up, it didn’t know which satellites to look for, and after several minutes of trying, it would ask if it had been stored without batteries; I had to say yes, and then it would do something like #2 above (manually setting time/date was not an option). This was a major pain in the ass, so I’ve since replaced that dead battery.
My Garmin GPSmaps 60 seems to have lock on times of about the same regardless if I move or not. Usually about 60 seconds. I have no option on either GPS to tell it where it is.
In any case, I’m just trying to say that while it may know which sats should be available based on a previous search, it does not look South South West at 20 degrees elevation for such and such satellite.
San Diego = Navy = Military Base = Secret Stuff = Blocking = Conspiracy
I’m not sure what all this means. As soon as it has a signal, it knows what time it is.
Highly unlikely. Sensitivity is not typically an issue for a plane GPSes as it has a much less cluttered environment than a car to deal with. If anything a car would probably need a more sensitive GPS antenna system than a plane. No GPS, matter how expensive, will be picking a up useful satellite fix signal through pavement or concrete or where the signal is constantly blocked and interrupted by tall buildings…
Folks might find more useful info about how GPS works here:
http://www.gpsinformation.net/#faq
Scroll down to the “Tutorial: How Does GPS Work” for a bunch of relevant links.
Found good info from this link. Last revision was 2001, but the basic GPS operation is still the same.
:::sigh::: the aircraft unit has a better antenna so yes, it will be better. Mu 60CSx is better & faster with an external antenna in a better place than the unit. the raw computing power will be better, faster, stronger, with an aircraft unit. Think your hand held can keep up with 300+ speeds and also handle the altitude computations fast enough for a instrument approach? That it has a better antenna? Not so much.
Hand held units are amazing things but to think that they have more sensitivity than an aircraft unit just ain’t so.
YMMV
Why must the peons bother you?
This really surprises me. five to ten minutes? I have a Garmin GPSMAP 60Cx, and it rarely takes more than 30 seconds to get a lock on. And as I said, I don’t have the ability to tell it where it is first. I also have a BlackBerry with Garmin software in it. Again, maybe a minute to aquire satellites. Is anyone elses GPS as slow as Joes? (not being snarky, just curious)
Just so we’re clear, the 5-10 minute “where the hell am I” startup is only if the GPS unit has been moved a few thousand miles with the power off. If I power it up within a few miles of the last place it was turned off, it only takes a few seconds to find satellites. If its stored ephemeris data is still fresh, it’ll start reporting location within ten seconds; if the data is old, it may take a minute to download fresh ephemeris data.
Ok, so a minute, not 5 or 10. That seems a little more reasonable. About once or twice a year I travel 1100 or so miles to Pittsburgh. When I power on, it takes no longer to aquire sats than if I use it just hiking around my house. Usually < a minute. I sometimes don’t use the unit for months at a time. I don’t see any extra delay when I power it up.
We’re talking at cross purposes. I’m not arguing a plane unit has a more computing horsepower for tracking location, I’m saying (1) that, contrary to your expectation, a plane unit has no more chance of getting a decent GPS signal through pavement or concrete than a car unit does regardless of the size of the antenna and (2) I would guess (and it’s just a guess) that the RF circuit sensitivity for a decent quality car GPS would have a much more challenging environment with respect to signal strength vs a plane’s GPS environment, and I’d be surprised if a plane GPS actually performed better on the ground re sensitivity and accuracy against a good quality car GPS optimized for that environment.
Just because a plane GPS is more expensive does not mean it is more sensitive, if anything given how fast GPS tech for cars advances I would not be surprised to find aviation and marine GPS tech lagging a generation or two behind car units.
Item #1 yeah, aircraft seldom have to work under ground or at street level in NYC.
Item #2
I can and have taxied totally blind and stayed within 1 foot either side of the center line on a taxi-way. Your GPS can do that? As to actual sensitivity, I have no hard numbers for that. But no matter the sensitivity, without the computer horse power, you do not have as good a unit. And yes, in GPS just as in airplanes, bigger, faster, more powerful is a direct function of $$$$$ for all practical purposes.
Having done airborne aerial triangulation using GPS for control of aerial photography in mapping projects and having used GPS survey equipment to tolerances many times more stringent than First Order work I can assure you that your hand held is wonderful. They amaze me. But it is no where as good as airborne units nor survey units.
Maybe the sensitivity to be able to hear and reach the satellite is as good in that circuit but that in no way translates into equal precision of position.
A unit with less sensitivity but better processing can give more accurate positions if it can get to the same number of satellites side by side with the other unit. Garmin seems to be the leader for the most part in all areas. At least IMO.
I do not believe that my Garmin 60CSx is better or more sensitive than the aircraft units of the same manufacture year of certification. Small improvements will get to un-certified units (car & handhelds) faster than IFR certified aviation units just because of the red tape.
I do not have the $$$$ to do so but I would bet a lot on taking an aviation unit and the handheld of your choice and putting them side by side anywhere and that the aviation unit would get a better and faster fix than the handheld.
Until that comparison is done, I will go with what I have experienced and what the Garmin folks tell the avionics folks and what the operating manuals I have read say and all that stuff…
I have a 60CSx and a nuvi 760. Think they are amazing.
I also have many hours using the airborne stuff… ::: shrug ::::
I’m through. Have a good one.