GPS speedo?

[TeamBandS]

I tend to use the speed function on the satnav for accuracy and especially when abroad when I can set it to kph. However, the reading is somewhat small and I was wandering if anyone has found something that just give the speed in mph or kph using sat nav tech? This would also negate the somewhat difficult to read Ducato cluster (kph and light issues)

Ideas/info appreciated.

 

[Al n Val]

by an OBD port heads up display from Amazon and set to kph

I think it has about 11 different settings but i only use it on kph, it literally takes 2 mins to fit in Fiat Ducato

I never drive anywhere without it



Al

 

[Stewart J]

Bought a gps Speedo but to be honest was very disappointed with its performance in Spain and France it often struggled for a signal in built up areas where it was very important the French take no prisoners for a tiny margin over the limit. It’s a small unit so I suspect the built in gps antenna wasnt the best, it frequently lost signal in forested areas and mountainous regions. Binned it and went for one that plugs into the obd port, very pleased with it. Here is is similar one
<Broken link removed>

 

[The Dotties]

I use an app on my Android phone. Samsung s20 so a decent size..options include speed only, full screen or various other settings to include distance, average speed etc. Switchable between proper speeds or the vastly inferior foreign sort. Mine was free.

 

[BigDean]

Do the ODB ones use the MPH / KPH from the vehicle speedo or GPS? If it is the same as Fiat speedo, not a lot of good to me as it is vastly out.

Thanks.

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[Guigsy]

Bought a gps Speedo but to be honest was very disappointed with its performance in Spain and France it often struggled for a signal in built up areas where it was very important the French take no prisoners for a tiny margin over the limit. It’s a small unit so I suspect the built in gps antenna wasnt the best, it frequently lost signal in forested areas and mountainous regions. Binned it and went for one that plugs into the obd port, very pleased with it. Here is is similar one
<Broken link removed>View attachment 534922

A mobile will give better GPS performance than a cheap GPS device for three reasons.

A phone can download the GPS almanac (the position of all the satellites) whereas a standalone receiver has to wait for the almanac to be broadcast, which loops once every few minutes. "Assisted-GPS" means a phone can get a fix much quicker.

A phone will probably have a much more recent chipset that can track more satellites and use more than just the US GPS satellites (Glonass, Galileo, etc.)

A phone probably has a better aerial.

 

[Lenny HB]

Do the ODB ones use the MPH / KPH from the vehicle speedo or GPS? If it is the same as Fiat speedo, not a lot of good to me as it is vastly out.

Thanks.

I think you will find they use the pulses from the gearbox sensor so no reason for them to out.

I use a cheap GPS one it works well.

 

[Mark McG]

Using one of these. Very effective and accurate. We can both keep an eye on the speed AUTOOL X95 GPS Speedometer Amazon product ASIN B08GPDTV9T

 

[Stewart J]

A mobile will give better GPS performance than a cheap GPS device for three reasons.

A phone can download the GPS almanac (the position of all the satellites) whereas a standalone receiver has to wait for the almanac to be broadcast, which loops once every few minutes. "Assisted-GPS" means a phone can get a fix much quicker.

A phone will probably have a much more recent chipset that can track more satellites and use more than just the US GPS satellites (Glonass, Galileo, etc.)

A phone probably has a better aerial.

Tried several phone apps on a iPhone again they suffered from signal dropout in built up areas forestry etc, that’s when I bought the disappointing gps one. As with a sat nav I much prefer a stand alone device others will differ it’s what works for me.

 

[Stewart J]

Do the ODB ones use the MPH / KPH from the vehicle speedo or GPS? If it is the same as Fiat speedo, not a lot of good to me as it is vastly out.

Thanks.

What Lenny just said, often compare it to the roadside radar illuminated signs and it is spot on.

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[IanRJ]

What Lenny just said, often compare it to the roadside radar illuminated signs and it is spot on.

+1

 

[Guigsy]

The Ducato comes with a large range of tyre sizes. I think the smallest is 215/70R15 which is 2141mm circumference and the biggest is 225/75R16 which is 2336mm, so roughly 9% bigger. I don't think the ECU can tell the difference, so the speedo (and any OBD device) just assumes you've got the biggest wheels. So it could be quite a long way off.

 

[Roger20]

Tried a £30 Amazon HUD recommended on the forum but couldn't get it to work on GPS so returned it. Also needed a fairly intrusive polarizing filter in mid line of sight to be 100% clear.

Now using Ulysse app on the phone and it seems perfect. Will probably try and install on an old smartphone just in case burn in is an issue. Not tried yet but you can choose to install using a much earlier version of the app which is compatible with an older Android operating system. No need to install a sim to make it work apparently.

 

[DelMar]

I have used a HUD for a few years now and find it very accurate. About £30 on Amazon mph and kph. I reckon it has saved me speeding fines abroad.

 

[Two on Tour]

I use an old Andriod smartphone, and use one of the dozens of speedo apps on the Google play store for free. They are GPS so if your driving in a long tunnel you will loose the GPS signal, so between the speedo cluster to see your speed on either the phone or dash without having to look away. The apps are easy to change over between MPH and KPH when you cross over the water.

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[Fragle]

Big Dean
Do the ODB ones use the MPH / KPH from the vehicle speedo or GPS? If it is the same as Fiat speedo, not a lot of good to me as it is vastly out.

That’s right Dean. But then you can adjust it up or down
Mine is set when showing 80 kph for instance you are doing 77/78 on sat nav
Works great

 

[two]

I tend to use the speed function on the satnav for accuracy and especially when abroad when I can set it to kph...

Speedos are deliberately calibrated to display a speed higher than you are actually travelling, by a small percentage, to avoid misleading you into going faster than you should. I'm not normally in that much of a hurry to need to know my exact speed, but do like to confirm that I'm within the limit (which can often be a challenge to determine as it changes so often and my memory is not as good as it should be).
I think that GPS devices calculate your speed based on assumptions about the surface of the earth and that you are travelling in a straight line. If you are not moving along their assumed path I believe your actual speed would be more than that calculated because you have travelled indirectly (vertically and around) between the measured positions. The very best devices should do better but I don't think the cheap ones are particularly accurate in determining position. Their primary aim is to identify where you are in the world.

 

[Lenny HB]

Speedos are deliberately calibrated to display a speed higher than you are actually travelling, by a small percentage, to avoid misleading you into going faster than you should.

Under construction & use regulations a speedo must not under read and must not over read by more than 10% + 10kph (6.2mph) for the life of the vehicle.
So at 50mph it can legally read 61.2mph.

 

[two]

It will also enable them to fit different diameter wheels.

 

[the1andonly]

I used to use a gps speed ap with a smartphone. Now when i remember i use an OBD Dongle and torque on a smartphone. Using torque you can display SPEED in a number of different ways, GPS, OBD , difference between GPS and OBD. You have the choice

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[rod_vw]

I use a Mio dash cam which displays vehicle speed, this is invariably the same as roadside displays so I can but assume that it is accurate.

Any display that used OBD data can only use pulses from the vehicle transmission just the same as that used by the dash display.

 

[kevenh]

Speedos are deliberately calibrated to display a speed higher than you are actually travelling, by a small percentage, to avoid misleading you into going faster than you should. I'm not normally in that much of a hurry to need to know my exact speed, but do like to confirm that I'm within the limit (which can often be a challenge to determine as it changes so often and my memory is not as good as it should be).
I think that GPS devices calculate your speed based on assumptions about the surface of the earth and that you are travelling in a straight line. If you are not moving along their assumed path I believe your actual speed would be more than that calculated because you have travelled indirectly (vertically and around) between the measured positions. The very best devices should do better but I don't think the cheap ones are particularly accurate in determining position. Their primary aim is to identify where you are in the world.

But for speed a GPSr receiver is measuring changes in where you are so that is accurate.
If you have a weak satellite signal for you location the change due to moving along a road will be accurate.
I.e.if the GPSr location at a set of traffic lights but with +/-2.34m accuracy, when you got across the junction 12m away in 5s you’re 12m with the same accuracy on location. The speed can be calculated accurately with the details on what changed.
But there is an algorithm used,
The GPSr knows your height and location but I’m not sure if that detail is all used for speed.

I have used GPSr speed readings as a reliable guide for about 20 years and not being let down. YMMV

 

[two]

I have a Garmin GPS for walking. It uses several satellite systems to work out location and claims to be pretty accurate. When I plot my route after a trip I appear to be meandering around the place that I stopped for lunch, rather than remaining stationary, as it keeps recalculating my location.
If I want to get a more accurate location, I need to wait a while and let it average out several fixes. I'm not sure that the calculations for speed do similar.
My post was to point out that they may not be particularly accurate, although they will be more so than a vehicle's speedo because of the built-in overstatement that is applied to speedos.

 

[kevenh]

I have a Garmin GPS for walking. It uses several satellite systems to work out location and claims to be pretty accurate. When I plot my route after a trip I appear to be meandering around the place that I stopped for lunch, rather than remaining stationary, as it keeps recalculating my location.
If I want to get a more accurate location, I need to wait a while and let it average out several fixes. I'm not sure that the calculations for speed do similar.
My post was to point out that they may not be particularly accurate, although they will be more so than a vehicle's speedo because of the built-in overstatement that is applied to speedos.

Not my area of expertise but my understanding is speed needs the timings of your plot samples.
That time accuracy is what GPS excel at.
Related, a Satnav is inevitably setup for “lock to road” too.

 

[Guigsy]

I have a Garmin GPS for walking. It uses several satellite systems to work out location and claims to be pretty accurate. When I plot my route after a trip I appear to be meandering around the place that I stopped for lunch, rather than remaining stationary, as it keeps recalculating my location.
If I want to get a more accurate location, I need to wait a while and let it average out several fixes. I'm not sure that the calculations for speed do similar.
My post was to point out that they may not be particularly accurate, although they will be more so than a vehicle's speedo because of the built-in overstatement that is applied to speedos.

It might wonder about at 0.5mph here or there when you're stationary as it moves your location a metre this way or that. But when you're doing 50mph, the location inaccuracy stays about the same. But when you've traveled 30 metres in the last second, that metre of inaccuracy becomes less relevent. GPS becomes more accurate the faster you go.

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[two]

I have no doubt that GPS will be more accurate than a vehicle's speedo but gained the impression that the OP wanted to 'sail' closer to the limit, believing a GPS readout. My post was to caution a notion that you'd be OK if you stuck to what the GPS displayed because I think you might get caught out.

Is the Fiat display still as unreadable as earlier (2016) versions? It seems incredible that they don't see fit to correct that.
I've not been overseas for a couple of years, now, but seem to recall being able to set my speed limiter to kph when I did (even if I couldn't always read it).

 

[WoldsSunlight]

from me for the <£30 OBD HUD display which arrived this morning from Amazon. Fitted in minutes, not too obtrusive, and - despite the figures being slightly blurred (a film is provided to stick to the inside of your windscreen to sort this, but I'm happy enough that I can read the figures without it,) - it does exactly what I want it to do.

(Y

es, I took a photo whilst driving...naughty me...) The photo actually looks worse than it is due to some camera shake.

 

[Two on Tour]

I wonder if a MOT tester will issue a fail for an obstruction in the arch of the wiper blades if the film was in place ?

 

[WoldsSunlight]

I wonder if a MOT tester will issue a fail for an obstruction in the arch of the wiper blades if the film was in place ?

That thought also occurred to me - as I said, I'm happy I can read the figures clearly without the film.

 

[Vipar]

Don’t like it blocking part of the road

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