Member Since: 09 Oct 2006
Location: Germany
Posts: 4
draughtsman wrote:
I'm sure i read somewhere that the altitude reading on sat nav systems is deliberatley inaccurate due to possible terrorist use.
i.e two signals in use.
a) US military scrambled is accurate.
b) General purpose signal for Say Nav systems with altitude set inaccuratley.
I can't remember where this came from though
Hi There, Just to let you all know, the US error function has been switched off for a few years now. For a 3D lock and accurate height you will need a min of 4 sattelites tracked, dont know how many the LR D3 system tracks at any one time. Have you tried calibrating the system at a known point.
24th Dec 2006 6:24 pm
Barry C-All
Member Since: 13 Nov 2008
Location: Essex
Posts: 169
Hi, I am pretty convinced that my MY08 with the latest Sat Nav disc fitted, doen't show altitude.
1st Apr 2009 1:07 pm
opodden
Member Since: 29 Jun 2006
Location: Elverum
Posts: 100
Geometry related altitude error
Due to the geometry between the receiver and the 4 satelites, the altitude will always be less accurate than your coordinates in latitude and longitude. It's a bit hard to explain, but as a gross approximation you could imagine that the receiver on the earth surface and the satelites are almost in the same plane, whereas the direction and distance to each satelite in that plane will vary much more. Thus the receiver will be able to calculate the 2D position more accurately than the altitude. Typically position will be accurate to within 3-7 meters, while altitude may be more than 3 times as much off.
My altitude read out on my TT910 is very accurate even checked it with Google Earth.
Flack
18th Apr 2009 3:17 pm
Roel
Member Since: 16 Aug 2008
Location: home
Posts: 1215
I have an old Garmin II plus in my Camel and that is accurate it reads about 2 meters high also on mountain peak when the reception is OK. It reads 2 m high as the external antenna is placed on the Camels roofrack.
So if an old Garmin can get good elevation measurements why not the LR system. That gives me 40m were about 0 or less should be the right number.Roel
1997 Camel Trophy Disco ex-P101JWK (traded it for a Britains 42101)
1984 90 TD5
2005 G4 Disco 3 BN55WPT
Also member of club MTR
and Club Faultmate
Interested in my 4x4 history see my website: www.mudmachine.webklik.nl
Sorry it's in Dutch and with google translator it gets funny.
18th Apr 2009 4:51 pm
wvlenthe
Member Since: 07 Jan 2009
Location: Arnhem
Posts: 1967
Lelystad... definately less.
WiljoD3 V8 HSE Auto in Zermatt silver - driveway version gone but not forgotten, only the living room cupboard version remains
20th Apr 2009 7:17 pm
Roel
Member Since: 16 Aug 2008
Location: home
Posts: 1215
I know you are way above sea level but you should be more afraid because off the big rivers Roel
1997 Camel Trophy Disco ex-P101JWK (traded it for a Britains 42101)
1984 90 TD5
2005 G4 Disco 3 BN55WPT
Also member of club MTR
and Club Faultmate
Interested in my 4x4 history see my website: www.mudmachine.webklik.nl
Sorry it's in Dutch and with google translator it gets funny.
21st Apr 2009 10:03 am
wvlenthe
Member Since: 07 Jan 2009
Location: Arnhem
Posts: 1967
Ehm. I've been looking.
Where's the altimeter readout on offroad nav? I only see latitude/longitude, no height.
Anyone have a piccie?
WiljoD3 V8 HSE Auto in Zermatt silver - driveway version gone but not forgotten, only the living room cupboard version remains
21st Apr 2009 6:42 pm
wiggs
Member Since: 03 Sep 2006
Location: Manchester
Posts: 14372
G4 Gone ...but not forgotten
21st Apr 2009 6:55 pm
wvlenthe
Member Since: 07 Jan 2009
Location: Arnhem
Posts: 1967
Wiggs,
who else would have the pic
Thanks a bunch
note to self:
must check if really that stupid not to notice numbers just next to other numbers.
WiljoD3 V8 HSE Auto in Zermatt silver - driveway version gone but not forgotten, only the living room cupboard version remains
To be fair to you wvlenthe, when you're in the Netherlands you aren't going to notice many of those numbers for height in feet above sea level.... The older I get, the more I realise that people confuse wrinkles for wisdom
Founder member of Club FFRRV
Club Orange, Mint or Fruit
Club Walnut Sniffers
21st Apr 2009 8:15 pm
wvlenthe
Member Since: 07 Jan 2009
Location: Arnhem
Posts: 1967
Hi JMC,
Quote:
you aren't going to notice many of those numbers for height in feet above sea level
Correct, for more than one reason:
- we measure in meters not in ft
- not going to look at it much anyway
- and if I would, I could measure how high the local bridge or dike is relative to its surroundings
It seams to me displaying height *in a car* is quite pointless. I can imagine lots of uses where you want to know how high you are, but can anybody please tell me where else to find my car at a certain lat/lon position other than on ground level?
BUT
If it's on there, I want to (be able to) see it and know that it works (correctly). Boys and their toys... Well so far the D3 is telling me my driveway is 60m above sea level which is about 50 m overstated. So it does not work correctly and therewith I confirmed the fault in this topic.
regards,
WiljoD3 V8 HSE Auto in Zermatt silver - driveway version gone but not forgotten, only the living room cupboard version remains
22nd Apr 2009 6:18 am
Roel
Member Since: 16 Aug 2008
Location: home
Posts: 1215
I am now on a Drilling Rig in Southern Germany. The wellsite elevation should be 715 m. The D3 is maybe standing 2 m Higher.
Click image to enlarge
The GPS antenna is mounted in the roof so ad another 2 m. The screen should read now 719 m.
It reads a little more:
Click image to enlarge
So here it reads about 41 m high.
At home it reads about 40 m. The garmin in my Camel with the antenna at the roofrack reads between -2 and 0. So it looks like that I have a contant difference of about 40 m High.
I will continue checking that.
Do you guys have a constant error?Roel
1997 Camel Trophy Disco ex-P101JWK (traded it for a Britains 42101)
1984 90 TD5
2005 G4 Disco 3 BN55WPT
Also member of club MTR
and Club Faultmate
Interested in my 4x4 history see my website: www.mudmachine.webklik.nl
Sorry it's in Dutch and with google translator it gets funny.
The overstatement of height in the D3 nav system is a built-in feature specifically to make purchasers in the Dutch market feel good about leaving their car parked at Schiphol Airport for any length of time. The older I get, the more I realise that people confuse wrinkles for wisdom
Founder member of Club FFRRV
Club Orange, Mint or Fruit
Club Walnut Sniffers
22nd Apr 2009 9:44 am
stapldm
Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
Could this constant height error be related to the reason the 'background' features in the road maps such as rivers and railway lines are always shown 100m North and 100m West of where they really are? You certainly can't rely on a "take the next left after the bridge" as the turn may well be before the river.Dr. Ian Malcolm:
"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
Transgenic tomato anyone?
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