GPS Speed indication...

[Bassfiend]

Anyone using a Road Angel here?

I have noticed that my speedo varies quite greatly by how much it is out depending on whether I've been accelerating or decelerating previously so I was thinking of getting a Road Angel Compact to simply use as a GPS Speedo - anyone using one and have any comments on how accurate / responsive they find it? Any other comments?

Cheers

Phil

[mouseymousey]

I have a Road Angel Compact, it's pretty accurate although not staggeringly responsive. Under a good signal it takes a couple of seconds to respond to large changes in speed.

Under a poor signal (very poor!) it has a bit of a habit of displaying crazy speeds, 600mph or so is my current record. Not bad for a 4 litre Chimaera! Usually sorts itself out within 10 seconds or so.

It has never missed a camera which is handy and overall I like it. I've tried various other sat nav and GPS camera locators and having started with a Road Angel years ago I went back to Road Angel with the compact about 3 years ago and I'm very happy with it.

[Bassfiend]

OK, thanks - just ordered one for £50 off eBay (Item number 190338423143 ) - there's a guy selling some new at that price...

Phil

[mouseymousey]

Bassfiend said:

OK, thanks - just ordered one for £50 off eBay (Item number 190338423143 ) - there's a guy selling some new at that price...

Phil

Don't forget you'll need a subscription to the Road Angel database if you want to use it as a camera detector. Won't be needed if you're just using it as a speedo although you'll get a warning message about the database being out of date every time you turn it on.

[nelly1]

[madbadger]

At a steady speed the TVR speedo always reads 1mph faster than Tomtom GPS. I have found while accelerating the GPS is the one that takes a while to catch up while the speedo is bang on. As clearly the RA above also does.

Not sure of the logic in relying on a GPS rather than the speedo.

[dvs_dave]

Speedo v's GPS when at a steady speed, the speedo reads a consistent 10% fast. Most car speedo's are set-up this way.

[itiejim]

My Cerbera speedo is spot on at 100 lepton when measured against my sat nav.

[RFC1]

my griffs speedowas also spot on compared to my road angel,

sandy

[Bassfiend]

dvs_dave said:

Speedo v's GPS when at a steady speed, the speedo reads a consistent 10% fast. Most car speedo's are set-up this way.

Cheers - yes - I know they're set up to overread by a small margin (10% is the usual accepted figure) and if it was consistently out then I wouldn't mind but mine varies depending on whether you were acelerating up to the indicated speed or decelerating down to it - for example acelerating up to 70mph on the speedo might result in a TomTom indicated 60mph but decelerating to 70mph on the speedo might give a TomTom indicated 50mph - just adding a pair of braces to go with the belt...

Phil

[Byker28i]

nelly1 said:

LOL - they do sometimes go a little funny when under tress for a while and it loses signal.
I stopped using mine as all I kept getting false alarms or being told about scameras I already knew. Mk1 eyeball worked better for the vans on bridges over the M4

[Bluebottle]

Bassfiend said:

dvs_dave said:

Speedo v's GPS when at a steady speed, the speedo reads a consistent 10% fast. Most car speedo's are set-up this way.

Cheers - yes - I know they're set up to overread by a small margin (10% is the usual accepted figure) and if it was consistently out then I wouldn't mind but mine varies depending on whether you were acelerating up to the indicated speed or decelerating down to it - for example acelerating up to 70mph on the speedo might result in a TomTom indicated 60mph but decelerating to 70mph on the speedo might give a TomTom indicated 50mph - just adding a pair of braces to go with the belt...

Phil

Your road angel has to recieve a signal fromn a satelite, Do you really expect that to happen at the same speed a tvr can accelerate or decelerate?

I would expend a 1-2 delay between true readings...I was driving Spa a couple of years back with the Road Angel still attached (much to the amusement of the track stewards) and as is was half way throught the new "Bus Stop" chicane looking across the to the left at my exit point whilst in second gear, I remember seeing 148mph displayed on the RA.

[Bassfiend]

Bluebottle said:

Your road angel has to recieve a signal fromn a satelite, Do you really expect that to happen at the same speed a tvr can accelerate or decelerate?

/Pedant mode - I would expect it to happen much faster, after all the GPS signal is received from the satellite at aproximately the speed of light whereas the Tiv takes somewhat longer to accelerate.

Of course any fully digital system can only give you feedback of what your speed *WAS* over a period of time so given that GPS only provides the ability to locate you in a 3D environment then to get a speed you need two locations and a time between them to calculate the average speed that you were doing over that period. A fully analogue system (old fashioned flexible drive directly driven from the gearbox output) will give you (pretty much) a true instantaneous reading of speed. There are obviously other ways of calculating speed in between those two extremes - the pulse counter from the rear axle being one - but that again relies on counting pulses over a period of time.

/Sensible mode - No - but I would expect it to happen quickly enough for what I would need when I'm driving in a situation when I need a reasonably accurate speed reading, not "hooning" ... if I'm hooning then what speed I'm hooning at would be immaterial as it'd be north of whatever the posted speed limit was at that location anyway...

Bluebottle said:

I would expend a 1-2 delay between true readings...I was driving Spa a couple of years back with the Road Angel still attached (much to the amusement of the track stewards) and as is was half way throught the new "Bus Stop" chicane looking across the to the left at my exit point whilst in second gear, I remember seeing 148mph displayed on the RA.

See that's the difference between driving a lap at Spa and just trying to make sure that I'm confident I'm holding an appropriate speed through the 2 miles of Specs cameras on the M3 at Hook. If I was looking to know how I was doing on a circuit I'd be trying to blag the installation of an old datalogger from my mate who races Skylines.

My TomTom has a speed reading option but it's simply too small to see when driving but other than that for the times that I do want to check my speed reasonably accurately its update speed is quick enough and the R.A.C. would just be a bit more visible...

Phil

Edited by Bassfiend on Tuesday 6th October 07:32

[Byker28i]

I have an old Garmin GPS12. It's remarkably accurate and records a new point every change of direction. Quite interesting to have it enabled and running on track days, then analyse the data afterwards.

[Bassfiend]

I have a Garmin 405CX here which is a sports watch with GPS and heart rate monitor - could be interesting to try to confuse the workout software by interspersing the data it captures from the usual running sessions with that from a track day or two...

Phil

[grahamw48]

My Garmin gives accurate speed no matter what the conditions - just slightly slow to catch up sometimes.

It is much easier to read...sort of head-up display...than taking eyes off the road longer to check tiny numbers on the speedo.

[Bluebottle]

Bassfiend said:

Bluebottle said:

Your road angel has to recieve a signal fromn a satelite, Do you really expect that to happen at the same speed a tvr can accelerate or decelerate?

/Pedant mode - I would expect it to happen much faster, after all the GPS signal is received from the satellite at aproximately the speed of light whereas the Tiv takes somewhat longer to accelerate.

Of course any fully digital system can only give you feedback of what your speed *WAS* over a period of time so given that GPS only provides the ability to locate you in a 3D environment then to get a speed you need two locations and a time between them to calculate the average speed that you were doing over that period. A fully analogue system (old fashioned flexible drive directly driven from the gearbox output) will give you (pretty much) a true instantaneous reading of speed. There are obviously other ways of calculating speed in between those two extremes - the pulse counter from the rear axle being one - but that again relies on counting pulses over a period of time.

/Sensible mode - No - but I would expect it to happen quickly enough for what I would need when I'm driving in a situation when I need a reasonably accurate speed reading, not "hooning" ... if I'm hooning then what speed I'm hooning at would be immaterial as it'd be north of whatever the posted speed limit was at that location anyway...

Bluebottle said:

I would expend a 1-2 delay between true readings...I was driving Spa a couple of years back with the Road Angel still attached (much to the amusement of the track stewards) and as is was half way throught the new "Bus Stop" chicane looking across the to the left at my exit point whilst in second gear, I remember seeing 148mph displayed on the RA.

See that's the difference between driving a lap at Spa and just trying to make sure that I'm confident I'm holding an appropriate speed through the 2 miles of Specs cameras on the M3 at Hook. If I was looking to know how I was doing on a circuit I'd be trying to blag the installation of an old datalogger from my mate who races Skylines.

My TomTom has a speed reading option but it's simply too small to see when driving but other than that for the times that I do want to check my speed reasonably accurately its update speed is quick enough and the R.A.C. would just be a bit more visible...

Phil

/Pedant mode - Speed of light to a geostationary orbit is 0.12 seconds or, the difference between pole and 2nd or 3rd row of the grid in a moden GP these days
But more importantly your gps speedo has a built in display dampner otherwise you would not be able to read the digital display read-out continually changing in real time. In the case of the Road Angel it is set to update the display once every 1 seconds. - So not much use for measuring acceleration

Edited by Bluebottle on Tuesday 6th October 12:46

[Byker28i]

You need something like a gtech pro to read acceleration

[Bassfiend]

Bluebottle said:

/Pedant mode - Speed of light to a geostationary orbit is 0.12 seconds or, the difference between pole and 2nd or 3rd row of the grid in a moden GP these days

If I were in the position to be that concerned as to whether I'm on the first, second or third rows of the grid I'm sure I'd have access to somewhat more sophisticated monitoring equipment than a simple GPS camera warning system...

Bluebottle said:

But more importantly your gps speedo has a built in display dampner otherwise you would not be able to read the digital display read-out continually changing in real time.

This applies to all speedos - whether they are analogue or digital ... anyway, we do seem to be veering off the original original question which had absolutely no mention of circuits or tracks where the actual speed that you are doing is irrelevant however your lap time is. Perhaps it was my fault for not specifically stating that I was just looking for an aid to give me a sanity check on a somewhat charismatic speedo rather than something to time my next entry at LeMans...

Bluebottle said:

In the case of the Road Angel it is set to update the display once every 1 seconds. - So not much use for measuring acceleration

Again ... nothing to do with the original question but I appreciate the contribution...



Phil

[Bluebottle]

my mistake Phil, I missread your OP as asking how accurate and responsive the RA was at tracking your Acceleration/deceleration, as opposed to your constant speed.

__note to self; must read threads properly before responding __