: Navigation Calibration



evaccaro
05-10-07, 12:59 AM
Has anyone heard of this problem:

I have a 2007 STS V6 Luxury performance with navigation. The car came factory equipped with 18" wheels. The navigation system always get the street address wrong - it's off by about +250 feet. I have tried running the calibration routines but nothing changes. The odd thing is that the vehicle is properly positioned on the map and the offset error is constant regardless of the address. Is there some kind of offset parameter that gets set to make up for variations in GPS accuracy? I have yet to take the vehicle back to the dealer - just haven't had the time to take it in.

Onalaska
05-10-07, 07:25 AM
Your kidding, it that a problem 250 feet? Maybe it the car drives itself.

evaccaro
05-10-07, 09:22 PM
Your kidding, it that a problem 250 feet? Maybe it the car drives itself.

I don't want the car to drive itself. I am perfectly capable of doing that, thank you. However, I expect that when the car is sitting in front of address 1400 Main Street that the navigation system would agree with that. Instead, it reads something like 1458 Main Street (the address that is about 250 feet further down the street). After all, I paid $2500 for this thing. I have a Magellan 760 that costs less that $1000. It knows exactly where 1400 Main Street is. It doesn't have an external antenna. It isn't hooked up to te speedometer. It can be programmed whlie in motion. It has turn by turn voice assistance. So, for two and half times the price I don't think that my expectations are out of line.

bigdog9586
05-10-07, 09:54 PM
I don't think any of the nav units from any car company can compete with the cheaper nav. units that you can pick up for less than $700. They are all a big joke for what we paid for them.
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I don't want the car to drive itself. I am perfectly capable of doing that, thank you. However, I expect that when the car is sitting in front of address 1400 Main Street that the navigation system would agree with that. Instead, it reads something like 1458 Main Street (the address that is about 250 feet further down the street). After all, I paid $2500 for this thing. I have a Magellan 760 that costs less that $1000. It knows exactly where 1400 Main Street is. It doesn't have an external antenna. It isn't hooked up to te speedometer. It can be programmed whlie in motion. It has turn by turn voice assistance. So, for two and half times the price I don't think that my expectations are out of line.

evaccaro
05-10-07, 10:33 PM
I don't think any of the nav units from any car company can compete with the cheaper nav. units that you can pick up for less than $700. They are all a big joke for what we paid for them.
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I don't know, I bought my wife a 2007 Lexus RX350 in February. Its navigation unit is considerably more accurate than my STS. Funny thing is that it is a Denso unit as well. Does Lexus get better product than Cadillac from the same supplier?

LStasy003
05-11-07, 01:43 AM
I have the same problem with my nav. Points of interests are really off too. Ill be at Burger King and the Burger king on my map is a block or two down. Very annoying and embarressing with a very expensive car.

dkozloski
05-11-07, 02:41 PM
I have the same problem with my nav. Points of interests are really off too. Ill be at Burger King and the Burger king on my map is a block or two down. Very annoying and embarressing with a very expensive car.
There's your problem. They don't want you sitting in a place as crappy as Burger King with a Cadillac.

northlites
05-13-07, 01:01 PM
:caddy: evaccaro, does your GPS navigation
system have WAAS capability?

I don't know where you live and that could have a impact on your
system's accuracy, but if the system can use WAAS than try that. In
a lot of cases that will really improve accuracy.

There's always a joker around, isn't there dkozloski? That was a
good line though! Hee-Haw.

evaccaro
05-14-07, 06:14 PM
:caddy: evaccaro, does your GPS navigation
system have WAAS capability?

I don't know where you live and that could have a impact on your
system's accuracy, but if the system can use WAAS than try that. In
a lot of cases that will really improve accuracy.

There's always a joker around, isn't there dkozloski? That was a
good line though! Hee-Haw.

I live in the Washington DC metro area. I'm not sure what WAAS is. My system is the factory installed satellite navigation system that is optional on all Cadillacs. There aren't a lot of options on how it navigates. From a map reference perspective, the thing is dead on. Longitude and latitude look OK as well. I'm thinking there is simply some software offset error on the translation between map reference coordinates and street adresses. Might even be something goofy loaded off of the DVD. It can't be that complex if the system always gets the streets and intersections correct. I guess I'll have to take it back to the dealer for a trip into the "abyss of frustration".

P.S. I LOVED the Burger King quip as well :thumbsup:

dhemrick
05-24-07, 11:34 PM
You know... it just occurred to me today what might be going on here. It's not the navigation system or software that is off, but the actual maps.

For example, I live in a neighborhood that has large lots (2 acres plus). However, all the houses on the street are numbered sequentially regardless of lot size. I live at address 107 which is the 4th lot on the odd numbered side of the street (101, 103, 105, 107...)

Other neighborhoods have houses much closer together, yet their houses are also sequentially numbered.

If I put my address 107 into the nav system, it wants to take me to about the border between addresses 101 and 103. The reason, I theorize, is because standard addressing assumes a uniform distribution of houses along a route each with a certain amount of road frontage. Because the lots are larger in my neighborhood yet still sequentially numbered, it throws this off.

I further confirmed this by setting my home location to where my house actually is. When I look at the actual address the nav THINKS my house should be, it lists address 138. There is no such address on this street.

So, I'm thinking the whole problem here is that some streets are actually numbered wrong by the developers, city or post office. The navigation system is simply following the rules as they are supposed to be, and when the house numbers don't follow the rules, the nav reports the wrong location for an address.

Maybe someone who knows more about how houses are supposed to be numbered could confirm or deny.

Onalaska
05-25-07, 08:00 AM
Originally our house numbers were assigned by the rural electric company so they could locate the service address. They were not based on a geographic location, just a map in their office. Later we changed our house numbers to facilitate a 911 addressing system that was based upon the distance from a cross street. I am not sure that every state/county does it the same way. The nav system still does not get our street address right, probably due to the changes. Imagine the amount of data having to be managed to get everyone's street addresses right. I think it's unrealistic to expect the nav to get you to the exact location by street address every time, but you are right it is a software problem and in time all of this will probably be resolved. There are a number of companies that provide maps for use with GPS, I imagine some are better at getting it more correct than others. Think about it, GPS navigation in cars hasn't been around that long. I started using a Delorme GPS product with my laptop about 10-12 years ago. Before GPS I used paper maps that were never 100% correct either!

Skibanker
06-24-07, 09:57 PM
Evaccaro, Just had a thought about your problem. Search the threads for "diagnostic mode instructions". Once you're in, find Navigation and then the button for "Position Reset". Maybe that will do the trick.

evaccaro
06-25-07, 11:04 PM
Evaccaro, Just had a thought about your problem. Search the threads for "diagnostic mode instructions". Once you're in, find Navigation and then the button for "Position Reset". Maybe that will do the trick.

Thanks for the tip. I'll check this out and post the results.

ssstealth
06-26-07, 09:57 PM
Just a thought here... The manual that comes in the map dvd case indicates "detailed areas". I have found that addresses outside of these areas are very unreliable, sometimes sending you to the wrong end of the street or defaulting to the center of the street length.

Another thing to consider is that the navigation system is designed to announce your arrival in advance simply to allow you time to turn. If it waited to the EXACT point to announce your arrival, your moving car would have just passed it. Are you finding that your 250 feet is always in advance or does it vary?

evaccaro
06-27-07, 09:52 PM
It is always in advance of the location.

ssstealth
06-27-07, 10:04 PM
I really think that is normal operation just so that you can act before you pass it. I have 3 different cars with navigation systems and they ALL do exactly that.

The CTS is especially telling because at my house, the voice announces that you have arrived when you are within sight of the house but not there yet, but the distance display continues to count down in feet, finally hitting "0" right at my mailbox.

My STS-V and Fleetwood both only display distance resolution down to 1/10 mile but still announce arrival at the same time.