Navigation peeves

3910 Views 17 Replies 13 Participants Last post by oceanMDX, May 4, 2002

cyclone

Discussion Starter · Feb 26, 2002

While the navigation system undoubtedly has a nice UI and some great features, I have to say I'm not at all impressed with its routing choices. I'm fairly familiar with the methodology of trip routing, and frequently use online (Yahoo, Mapblast, etc.) and PC-based (TopoUSA) routing applications. The MDX navigation system frequently makes very odd suggestions, which are difficult to justify on any basis, including distance, highway versus local streets, or stoplights. The database seems very accurate, so I don' t think it's a matter of having incorrect road data, it just makes poor choices much of the time.

Does anyone know whether the routing logic is updateable, perhaps when the new year's version becomes available?

My other beef is with poor categorization of businesses. If you look up, say, Home Depot, for example, you'll find three or four Home Depot entries (Home Depot, Home Depot Stores, Home Depot Inc.), etc., and within each entry you'll find listings for many different categories (Hardware, Doors, ATM's, etc.). If you want to find the closest Home Depot you have to check every possible entry and category, as it seems that a given store is generally listed only in a single category. There is little excuse for this issue - NavTech (or whomever provides the listings) simply needs to do a much better job of editing the data to consolidate stores under a common name and properly categorize them.

Bill

1 - 18 of 18 Posts

ifeldman

· #2 · Feb 26, 2002

I have to agree with you. In fact, I was just looking up Home Depot yesterday, but it tried to send me into another state. I gave up after several minutes (I knew where it was, I was just killing some time while I was waiting in the car).

My biggest problem with the Nav is that while driving freeways, it keeps thinking Im driving off the side of the freeway on a side street, or in the wrong direction, and tries to get me back on. Once, it said "U turn is possible ahead", while I was on the freeway. I dont know if the GPS needs to be adjusted, or if the problem is related to the freeways having been modified for car pool lanes, and that is confusing the system.

Also, sometimes I try to avoid a freeway by selecting "avoid a street", and the Nav keeps trying to get me back on some other way or some obscure directions instead of the obvious route.

I still love the Nav and would not part with it, it just would be nice if it did not have the above problems.

dakster

· #3 · Feb 26, 2002

I agree with the odd routing and categories that do not make sense. It takes alittle getting used to figure it out.

However, as I too notice that it puts you on the side streets, that is going to be hard to fix because the GPS is can be off by as much as 100 feet. This is by US Gov't design so that you can;t launch a missle to the white house using the GPS sat's.

I do not know what you could do to fix this problem... The other one, well NAVTECH needs to get a yellow pages and better routing logic.

ifeldman

· #4 · Feb 26, 2002

My company is working on the Wide Area Augmentation System (WAAS) which adds super accuracy to the non military GPS. I started to notice this capability added to lower cost consumer GPS systems. Maybe some day it can be retrofitted to the MDX.

rlm32

· #5 · Feb 26, 2002

ifeldman said:
My company is working on the Wide Area Augmentation System (WAAS) which adds super accuracy to the non military GPS. I started to notice this capability added to lower cost consumer GPS systems. Maybe some day it can be retrofitted to the MDX.

Yep, there are some systems already starting to use WAAS (I think Garmin) with claims of improved accuracy to 20-30 feet.

mdxpecting

· #6 · Feb 26, 2002

Does anyone know the position accuracy of the Acura Nav (+_25, 50, 100) I thought that the government had discontinued SA (Selective Availability) so that non-military users could have better GPS resolution.

cyclone

Discussion Starter · #7 · Feb 26, 2002

GPS accuracy

Daxter wrote:

However, as I too notice that it puts you on the side streets, that is going to be hard to fix because the GPS is can be off by as much as 100 feet. This is by US Gov't design so that you can;t launch a missle to the white house using the GPS sat's.

SA (selective availability) got turned off a couple of years ago. Even my $200 handheld GPS can get to within 20 feet if it can see five or six satellites, which the Alpine system should typically be able to when on the open road. WAAS improves on this even more.

acbrown

· #8 · Feb 27, 2002

GPS Accuracy vs. Map Accuracy

It's my understanding that when the nav shows you off the road, it may be more due to an inaccurate map than an inaccurate position from GPS. If you drive the same road and it sometimes shows you off the road, it may be GPS accuracy, but if it always shows you off the road, it may be the map accuracy.

It's my understanding that WAAS uses the same frequency as the normal GPS signals, only that it requires more processing. When WAAS was implemented, some existing GPS receivers could be upgraded just through a firmware change. I would assume that the same is possible for the MDX nav.

cyclone

Discussion Starter · #9 · Feb 27, 2002

acbrown, I agree, the roads are often mischarted. For instance, if driving up either 101 or 280 in the Bay Area, while proceeding on a route, there is one spot on each highway where the Alpine thinks you're off the road and attempts to recalculate. By the time it has recalculated it thinks you're back on the road.

ghost

· #10 · Feb 27, 2002

It's a snap

Keep in mind the navi uses a 'snap' algorithm to put car icon on the road when the GPS is within a certain tolerance distance. If you want to check your GPS accuracy, drive down an 'off-road' road several times so your GPS drops breadcrumbs - the horizontal 'scatter' in your breadcrumbs is an estimate of GPS accuracy. It's hard to read off the map scale, but mine seems to be about 20-30 feet - not bad, although it's enough to confuse the navi sometimes when you're on frontage roads.

MDXLuvr

· #11 · Mar 13, 2002

hey cyclone, i don't have much to add. just hoping the next version will have less kinks.

btw, nice vizsla. I have a 2 yr. old male.

cyclone

Discussion Starter · #12 · Mar 19, 2002

Woof!

Thanks! As near as we can tell, he's actually a Vizsla / Weimeraner mix, based on looking like he could be a littermate of a co-workers certified (breeder's mistake) Visla / Weimeraner. He's a great dog; fifteen months old, a bit rambunctious, but incredibly sweet. The jury's still out on his smarts; we thought he was not too bright, based on the usual putting a treat under a blanket and that sort of thing, but he's shown a real knack for trying to sleep on the couch without us knowing about it!

msu79gt82

· #13 · Mar 21, 2002

Hope This Helps

Routing problems are often the result of road naming inconsistencies. I'll share an aggravating real life example. We live outside of Houston, TX. Both our folks live in Memphis, TN. The best route to get there is take US-59 North to Texarkana and then IH-30 to Little Rock and then take IH-40 into Memphis. There is no way I can make Navi program that simple route.

The reason: Hwy 59 has too many names on the DVD. As we are traveling on it we can watch the names change.
Hwy-59, US-59, US 59N, Hwy 59N, etc, etc. To the computer these are all DIFFERENT roads. Hence to the computer it is not the Direct Route, nor is it the Easy Route, etc.

There is nothing wrong with the software, it is the road name inconsistencies on the DVD ROM that is causing most of the problems that we encounter. Of course the DVD ROM is simply a digitized version of an existing database. Either the names in the database need to be corrected, or somehow a logic operator included to suggest that US 59 is the same road as US 59N.

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cyclone

Discussion Starter · #14 · Mar 21, 2002

Naming inconsistencies

What do you get when you use Yahoo to chart that course? Yahoo uses a NavTech database, which I believe is what our nav system uses, but I find Yahoo generally has much more sensible routing. Curiously, Yahoo has a much less up-to-date database, though - my office campus was built about a year ago, Yahoo has no concept of it, the Acura nav system is fully up-to-date.

mogur

· #15 · Mar 23, 2002

Actually, SA (Selective Availability) has been turned off since the Clinton days so that is no longer a consideration. Accuracy of 10-15 feet is now the norm for GPS without WAAS. WAAS will knock that down to about 5 feet but is poorly suited for use in an automotive environment because the satellites are close to the horizon and thus easily blocked. It was designed for aviation use where this is not a consideration. Standard GPS should be plenty accurate enough for automotive uses these days.

Tom

dakster said:
However, as I too notice that it puts you on the side streets, that is going to be hard to fix because the GPS is can be off by as much as 100 feet. This is by US Gov't design so that you can;t launch a missle to the white house using the GPS sat's.

vicpai

· #16 · Mar 24, 2002

another angle on this ever changing technology!

I was shocked and dismayed to know that Acura, Alpine, Lexus, Kenwood etc. (most automotive companies) are using the older (now obsolete) 8-channel GPS receivers in their navigation systems which can supposedly have an error of as much as 105 feet (varies between 35 to 105 feet) - EVEN WITH SELECTIVE AVAILABILITY NOW BEING TURNED OFF

The newer 12-channel GPS receivers used by much cheaper handhelds such as GARMIN typically have a maximum error of about 30 feet (varies between 10 to 30 feet) - This is because the receiver selects the FOUR BEST satellites and with 12 channels versus 8 there are simply more choices

That is what was quoted for Garmin's older 8-channel and 12-channel receivers......and Garmin's WAAS enabled 12-channel GPS V achieves an accuracy of 3 to 15 feet!! (in conditions where WAAS can be made use of - otherwise the 10 to 30 foot accuracy applies) - The Garmin site also stated that the 2 satellites that send the "WAAS-corrected" signals are "fixed" or "stationary" above the equator, in certain circumstances they may be hard for the GPS receiver to acquire

Another possibility would be to use DGPS (Differential GPS) which uses "land-based transmitters/radio beacons" to correct the error - but its my understanding that there are simply not enough of these to make this a viable alternative at this time - Most transmitters have a 100-mile (not sure, maybe less) or so radius and are mostly around coastal areas and rivers only (U.S. Coast Guard has installed these transmitters for Marine navigation purposes)

Makes me wonder why auto manufacturers and Aftermarket Nav system manufacturers who charge THOUSANDS OF DOLLARS for Navi systems cannot do something as simple as using the newer 12-channel receivers.........while some 12-channel handhelds from Garmin are sold for as little as 200 odd dollars

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Pauls MDX

· #17 · Apr 14, 2002

still better than other systems

it still blows away the other stock systems and aftermarket systems!

oceanMDX

· #18 · May 4, 2002

Very good Vicpai...

that's an excellent summary on GPS nav systems. Since my MDX is a Canadian version, I wasn't able to buy Acura's nav system, so I opted for Garmin's StreetPilot III (a 12-channel unit). Typical accuracy is 17 ft. with this unit around the southwest. I too am shocked that Acura's nav unit is only an 8-channel unit (obsolescent technology) - that was something I didn't know until you posted! Owners have complained that Acura's nav unit often thinks they are on some side street when they are actually on the freeway. No doubt that one of the reasons why this occurs is because they only have an 8-channel receiver. The StreetPilot III has only done this once to me so far, and that was because the map was rendered inaccurate after the roads in one area had been moved and reconstructed .

1 - 18 of 18 Posts

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