GPS is sometimes not used properly

I don't know where in New York you are but here's a link to start:

https://www.tracking-system.com/news/3-tracking-system-infor...

Welcome to The Factory. Stick around, there's a lot to learn and gather here.

Cities with skyscrapers and high rise buildings cause a phenomenon known as "urban canyons" where the GPS signal can't penetrate the buildings. I know when I was in Manhattan a few years ago I was trying to use my GPS to navigate as a pedestrian and it would sometimes show me on the wrong block, or would jump a whole block all at once.

I have a stretch of rail trail nearby that seems to be a GPS anomaly area. Although I will be on the trail, and appear properly located on the map, the GPS elevation will indicate -100 to -75 ft. This happens almost every time and happens on different devices. And note that I explicitly said GPS elevation, not barometric elevation.

Here's the thing. You'll never know that your GPS isn't navigating correctly or correctly for that matter. Testing your GPS in your home town or where you drive every day is a bad idea. Of all the Gps's I've had through out the years not one has ever chosen the quickest route. I've moved since i retired to a different city and its the same story. Sometimes its 10 minutes more. That sounds like a lot but in reality its nothing. These things have come a long way since my first one 10 years ago. I think people expect more of these things than i do. Street lights, construction, accidents, rush hour and other stuff all play a role. Many people are asking these things to compensate for all of these factors.
Simply....they can't. Here's how i look at it, and i've said it before. I set my units so they do not take me into some farmers field, believe me it can tell you to do so. Settings are really important. When i really need these things is when i'm traveling in foreign territory. Do i care that its taking me 10-20 minutes longer to get there? I really don't. I'm sure there is a quicker way, but i don't know that way because i don't know where i'm going so i'm relying on my gps to get me there, and it does...safely too boot.

My Garmin loses signal every now and then while driving around downtown San Francisco. Skyscrapers are the cause of the problem.

Accuracy is associated with how close is the GPS saying it is to where it really is.

Navigation is totally different. If there are multiple options as far as routing goes, there really is no one right, or accurate, route. They will certainly be different distances, but the time to travel will be highly dependent on traffic and much more.

User discretion is advised.

Try comparing your GPS to Google Maps on your phone, or the WAZE app.

Even two different Garmins with the identical maps and settings may route you differently.
Now try to use 2-3 different GPS makes in the mix and see what happens.

trying to get two different Garmins to take you a specific route to the end destination..lol
I have such a route and no matter how i program and or change the route along the way it refuses to take me there

Not area 51 is it??

That would explain it. But no sadly this isn't my first rodeo with GPS's, it just makes no sense. I can see the exit on the Map...it's there...it shows i can take it, you would think i could force it to take it...nope, and it should have learned by now, nope to that also....lol. Btw its 10 minutes quicker if i take this route and its straight..lol
But like i said, its all ok because i really don't need it at home In foreign territory i wouldn't know anyways and all i want is to get there and it will do that.

Signal could be the problem.

Many government buildings are designed to block GPS signals in surrounding areas.

The old conspiracy issue rears its ugly head again!
Would you care to substantiate your claim with irrefutable proof!

Check your google map from cell, may be good idea

This site explain GPS errors in cities:

https://www.gps.gov/systems/gps/performance/accuracy/

I put aluminum foil over my GPS when I don't want it to know where it is.

Can you give us the location of the troublesome exit. Maybe an example of the route you are trying to make.

Except I put it over my head so THEY don't know where I am...

he-he-he

How are these buildings going to block GPS signals in the surrounding areas?

I had something similar happen a long time ago. An old road that I traveled all the time was not routable at all with my GPS. It was routable from either direction towards this troublesome point. Turns out there was a missing piece of data, road or whatever, in the mapping that made the GPS think there was a gap, no road, and the GPS would then route around this "missing" slice of road that was really there. It was very frustrating indeed.

Report this as a map error.

In all the years I used Delorme maps, AAA, Street Atlas, and Topo, it took quite a few years to get all the gaps fixed in the maps. Most of them are the cartographers error, as the developing maps contained a lot of hand drawn stuff. While there were a couple of major mapping companies selling these maps to Delorme, Tom Tom, Magellan, Rand McNally, and even Streets and Trips, the finally shook out Here, Google, and Bing.

I thought that with all the reporting and maps corrections and consolidation that most of those type errors would have been corrected. Especially on long existing roads, i.e. Interstates. But I guess there are still a few errors still out there.

Interesting enough, Delorme finally added the feature to Draw Routable Roads, and allowed the ability to fix stuff like that, pending maps updates. Unfortunately, Garmin bought out Delorme for the Hand Held and fitness products, and dropped the Mapping Products in favor of their own. Delorme mapping products are still far superior to Basecamp, and the last map product was Street Atlas 2015. Which I still use instead of Basecamp for route planning.

I loved that feature in Street Atlas USA. I always preferred Street Atlas for route planning (over Mapsource/BaseCamp), and the transfer of routes to Garmin was very seamless.

Of course Street Atlas navigation never kept up with Garmin, Google and others with features like lane guidance. And I swear the last several SA map updates never added or fixed anything! Sadly I think its demise was inevitable.

A giant tinfoil hat over the buildings will do the job. Nothing gets in, nothing gets out.

Only Military GPS were pin point accurate, civilian GPS was 10' or more off for security reasons.

I don't think I need a GPS tracking device.
I looked up the data on the Internet and found that someone might have used a GPS jamming device. Because there are no tall buildings nearby.
I tried to search signal jammer and found this site:
https://www.perfectjammer.com/
Is it possible that someone is using a GPS jamming device nearby?

Sure it's possible ... Whether it's likely is another question ...

Are you near a Truck Stop? Or near a major Distribution Center with heavy truck traffic?

GPS jamming is a problem. I doubt a GPS jammer would operate continuously at a stationary location. These devices can be sniffed out, and the penalties for using one are steep. I doubt this is the source of your problem. Can you post the coordinates for this troublesome location?

But your previous description of the problem seemed to be more like a mapping error.

Why did you say that you think you do not need a GPS tracking device?

When I press on the strength icon (top left when no map showing) it states a 3 meter accuracy as well as all the satellites my GPS (2689 ) sees

Think about it... 10 feet is still pretty good for military purposes.

If I can narrow the search area to a 10 foot radius, I think I'll find or hit what I'm looking for.

My GPS devices almost always report less than 10' accuracy.

i've done that in here before, Its a simple icon called home. Coming from the west heading east on the highway it refuses to take the earlier exit, its direct, its 10 minutes faster, the road is straight, it only has two stop and go lights. I cannot force it using detour, slower, faster, more economical nothing works. Once on the ramp it changes the route to the way i want. Coming from the east you can't use this exit. Its not like i can't see the exit on the map. Both units do it. No idea why but it doesn't matter to me, in the end it would get me there. At my last place it couldn't find my house, it would put me 200ft. up the street at the cross street. Just a corner with nothing there but a bust stop...lol. We lived there for 27 years. Like i said before at the end of the day these things will get you there, not always the quickest route but they will get you there. I could get out a map...lol NOT

Sounds like that ramp is not in the mapping.

In the 1990s, the US government used a feature called Selective Availability that intentionally degraded civilian accuracy globally. In 2000, at the direction of President Clinton, the government ended use of Selective Availability, so civilian users receive the same accuracy as military units.

Not the irrefutable proof you are asking for, but something that happened to me one night while driving in Washington, DC. I was stopped at a red light, and I glanced down at my nuvi 760. It was showing I was still moving, at approximately 10mph. After about 20 seconds, I got a "Signal Lost" notification. Turns out I was stopped on a street along side the White House grounds. I would not be at all surprised if they didn't have some sort of GPS jammer in place.

It does as long as i want to go north.

It could be in the database but only one way ...

Couldn't fine 8710 Maple grove crescent either, lived there for 27 years. would always put me 1/2 mile away. It gets you form point A to point B. 10 minutes sooner or later, makes no never mind to me.

All things are possible. About two years ago I was driving on a major North-South highway in California and encountered issues that I am convinced were due to a GPS jammer - probably in a truck on the same road.

Part of the reason I believed that was happening is that I was using two separate devices at the same time, to compare a new GPS with my "old dependable" unit. Both units screwed up in the same way for about 40 miles, and then both behaved correctly after that - which is why I assume that there was a jammer in a moving vehicle heading the same way on the same road.

- Tom -

Yes it's true that without selective availability, military and civilian GPS equipment now use the same signal. However military equipment, as well as that used by surveyors, use the signal differently and is capable of a much higher degree of resolution. Position errors with this equipment is measured in tenths of an inch, not feet.

Be prepared to pay for this accuracy though. Some Trimble surveying GPS equipment runs in the $40,000 range.