GreenHybrid Interactive Hybrid Car Resource
Home Discuss Articles Compare Share Shop
GreenHybrid.com   Hybrid Car Forums   Tech Information   Mileage & Specs   Photo Gallery   Buying Guide  
GreenHybrid Mileage Database - Click here to track your MPG! Join Hybrid car discussions today - Create a FREE GreenHybrid Account

Go Back   GreenHybrid - Hybrid Cars > Hybrid Cars > Toyota Motor Corporation > Toyota Camry Hybrid
Sign in using an external account
Register Forgot Password?
Register Photos FAQ Members Search Today's Posts Mark Forums Read Vendor DirectoryGarageUsed Cars Add a Tank

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 06-24-2007, 03:10 PM
acco20's Avatar
Active Enthusiast
 
Posts: 142
Default accuracy of GPS mph compared to speedometer

Am waiting patiently for my new 50th anniversary edition camry hybrid. I have read somewhere that the speedometer is off, I think it was 1 or 2 miles per hour fast. Do any of you folks with the gps find this to be true, and is the gps mph reading accurate.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #2  
Old 06-24-2007, 04:07 PM
Pretty Darn Active Enthusiast
 
Real Name: Tom
Hybrids: 2007 TCH, Blue
Posts: 350
Default Re: accuracy of GPS mph compared to speedometer

I have yet to check the speedo against GPS BUT, just yesterday I went past one of those automated radar trailers that various PD's set out on the side of the road, you know the ones that say "Your Speed" along with a placard of the posted speed.

I found my speedo to be about 2.5 to 3 mph under the radar calculation. This is entirely consistent with what others have reported on this board.

Anyone with a 9th grade education in geometry and algebra could design an accurate speedometer. I have to believe Toyota did this on purpose. But why?
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #3  
Old 06-24-2007, 04:19 PM
David Price's Avatar
Happy 07 TCH Owner
 
Real Name: David H Price
Location: Dunbar, WV
Hybrids: 07 Desert Sand Mica W Nav, Sunroof, & Leather
Posts: 186
Default Re: accuracy of GPS mph compared to speedometer

acco20: I checked my wife's TCH against a Magellan 315 GPS last fall and found that the GPS read 67 mph and the speedometer on the car read 70 mph.
Not sure how accurate the GPS is.

.



Junie's TCH
Desert Sand Mica


Last edited by David Price; 06-24-2007 at 04:25 PM.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #4  
Old 06-24-2007, 04:28 PM
Pretty Darn Active Enthusiast
 
Real Name: Tom
Hybrids: 2007 TCH, Blue
Posts: 350
Default Re: accuracy of GPS mph compared to speedometer

Quote:
Originally Posted by David Price View Post
acco20: I checked my wife's TCH against a Magellan 315 GPS last fall and found that the GPS read 67 mph and the speedometer on the car read 70 mph.
Not sure how accurate the GPS is.
With SA (selective availability) turned off back in 1998, if you've got a minimum 3 bird lock, your GPS will be scary-accurate with speed. Position might be another story.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #5  
Old 06-24-2007, 04:49 PM
Sallyspal's Avatar
Too Smug
 
Real Name: Andy
Location: Princeton, NJ
Hybrids: TCH - Titanium
Posts: 89
Default Re: accuracy of GPS mph compared to speedometer

Quote:
Originally Posted by acco20 View Post
Am waiting patiently for my new 50th anniversary edition camry hybrid. I have read somewhere that the speedometer is off, I think it was 1 or 2 miles per hour fast. Do any of you folks with the gps find this to be true, and is the gps mph reading accurate.

This is a frequently discussed topic, going back to last spring when the first TCH's arrived. The general consensus is that the speedos are about 2-3 mph "fast." Whether Toyota did this on purpose is a matter of conjecture. Others have reported that various other models, by other manufacturers have speedos of varying accuracy.

You learn to adjust. I now know that I have a few mph's of leeway when I become concerned about the speed limit on a particular road.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #6  
Old 06-24-2007, 06:22 PM
David Price's Avatar
Happy 07 TCH Owner
 
Real Name: David H Price
Location: Dunbar, WV
Hybrids: 07 Desert Sand Mica W Nav, Sunroof, & Leather
Posts: 186
Default Re: accuracy of GPS mph compared to speedometer

By the way; the odometer read 61 miles and the GPS read 61.9 miles.

.



Junie's TCH
Desert Sand Mica

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #7  
Old 06-24-2007, 07:36 PM
flopshot's Avatar
Ridiculously Active Enthusiast
 
Location: California
Hybrids: 2007 Camry Hybrid
Posts: 567
Default Re: accuracy of GPS mph compared to speedometer

Check out this post from last year:
http://www.greenhybrid.com/discuss/s...ad.php?t=10105

Basically, the speedometer was found to be about 3mph off at 60mph, which caused a 1.5% mileage error when compared to a GPS system.

.

CAMRHEE Hybrid - SOLD!!! Oct2008
Completed Mods: RK-Sport body kit, 18" LexusGS430 wheels 235/50ZR18 tires, TRD/SE springs, Rear Lip Spoiler, Terk XM-Direct, Smoked tail lights, Sliding Armrest, Rear Bumper Applique, Front License Bracket, Lower Grill chrome inserts, K&N, Blaupunkt THB200A sub, moved rear HSD emblem
Future Mods: fog lights, black chrome my wheels

http://www.greenhybrid.com/share/fil...fterFront4.JPG
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #8  
Old 06-25-2007, 09:42 AM
Active Enthusiast
 
Real Name: Chris
Location: Fair Oaks, CA
Hybrids: 2007 toyota camry
Posts: 173
Default Re: accuracy of GPS mph compared to speedometer

The 3 mpg high reading on the speedometer matches my experience also. It is my understanding that this is pretty common. Motorcycles typically have an even higher overshoot, often as high as 10%
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #9  
Old 06-25-2007, 04:04 PM
spiff72's Avatar
Ridiculously Active Enthusiast
 
Real Name: Jeff
Location: West Michigan
Hybrids: '07 Camry Hybrid - Mag. Gray
Posts: 620
Default Re: accuracy of GPS mph compared to speedometer

I am resurrecting a post from another thread regarding the diagnostics screen's speed indicator (and its variance from the speedo reading):

Quote:
Actually my theory that this is the wheel sensor is that it is labeled "SPD". I thought that this was a sensor in the wheel that could be used for "dead reckoning" when the GPS signal is lost. This way it estimates your location on the map by using your speed/distance traveled, coupled with the gyro sensor that gives a relative bearing.

That brings up another question. That same diagnostic screen shows the relative bearing from the gyro sensor, but this never seems to match your compass heading. I am curious what this value is actually relative to. Is it relative to the direction you were going when you entered diagnostic mode, or is it relative to the direction you were going when you started out in (when you started the car)? I think it is the former, since the latter would be tricky if you started out in reverse...

I think that the speedo probably uses the input from this SPD sensor, but for some reason it is calibrated strangely to cause the low readings.

I recall reading somewhere about speedo error, and that European cars had their speedo calibrated in such a way that they NEVER read low, even if someone puts a huge set of wheels/tires on the vehicle. This is due to some European regulations that stipulate this "NEVER low" requirement. Perhaps Japan has a similar mandate? (I think this was from a Car and Driver editorial column a few years ago).
Well, I found the article from C&D that I referred to (five years ago - I have a mind like a steel trap -- or a steel sieve if you ask my wife):

Linky: http://www.caranddriver.com/features...r-scandal.html

.

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
  #10  
Old 06-25-2007, 04:55 PM
Ridiculously Active Enthusiast
 
Real Name: Peter
Hybrids: Camry
Posts: 512
Default Re: accuracy of GPS mph compared to speedometer

To answer your questions about GPS heading:
1. you have to be moving for GPS to show any direction, if the car is parked there is no way for GPS to know where the car is facing.
2. There are actually 2 types of North: magnetic and true North. As the name would suggest Magnetic North would be North as shown on magnetic compass and point to somewhere in North Canada at the moment (it slowly changes) and it's different for different parts of US. The difference between true North (pointing straight to the North Pole) and magnetic North is called declination and for continental US can be between -20 to +20 degrees depending on location.
As you probably already guessed, Compass will always show magnetic North.
With GPS it is preferable to use true North, however magnetic North could be calculated using correction tables as long as you know your location. I would imagine your discrepancy is due to one showing magnetic North and the other showing true North unless your electronic compass is not calibrated and adjusted especially inside all metal car. I hope this helps.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 06-25-2007, 04:55 PM
 
 
 
Reply

Tags
2005, accuracy, accurate, calibration, camry, gps, hour, mileage, miles, mph, show, speed, speedometer, system, total, toyota

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Topic Starter Forum Replies Last Post
Speedometer 4-5 mph under actual speed wallpad Toyota Camry Hybrid 22 11-17-2006 03:52 PM
Speedometer accuracy Mtn Dog Ford Escape Hybrid 14 08-03-2006 07:20 AM
What Can A 15 MPH Difference Do To Affect FE? bar10dah Fuel Economy & Emissions 22 07-10-2006 08:19 PM
My commute mpg and elevation ericbecky Honda Insight 2 06-15-2005 09:19 PM



All times are GMT -7. The time now is 04:23 PM.

Home | Hybrid Discussion Forums | Hybrid Articles Archive | Mileage Database | Hybrid Photo Galleries | Compare Vehicles
Terms of Service - Privacy Statement - - Advertising
GreenHybrid.com, Copyright 2008
InternetBrands.com Automotive Network

GreenHybrid.com founded by Jason Siegel.
Emails Backup

SEO by vBSEO 3.5.2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73