SLOW DOWN

[TheBiscuits]

31 minutes ago, furnessvale said:

Indeed.  The last time I used a car based GPS to track a narrowboat down the River Weaver, it studiously placed the boat on the bank.  Somehow, it just could not accept the fact that the boat was out in the river.

 

A lot have them have a "snap to road" setting you can turn on or off buried in the menus.  It's usually on by default for car units, which is quite reasonable!

 

 

[blackrose]

I like to feel my boat move. That's part of why I live on a boat. 

[Alan de Enfield]

4 hours ago, IanD said:

One reason GPS has become ubiquitous is that it works much better then it used to, especially with initial locking speed. People don't realise how much it has changed "under the hood" since the first GPS receivers appeared, both in performance and cost -- technology advances are sometimes sadly unappreciated... 😞

 

In the days before GPS we had "Decca" on the boat, a system by Racal-Decca that use land based triangulation to give you a postion that was +/- about 1 mile in good weather and about +/- 20 miles if it was dark, cloudy or raining.

 

The system was so 'secret' and expensive Decca would not sell it it was only available on lease.

 

 

 

The monopoly on leased, not purchased, receivers by Decca generated great wealth for the company, which was headquartered in Hertfordshire. This monopoly was later broken the early 1980s when receivers could be purchased by users, thereby reducing the cost following the lapse of the patent on the basic system technology.

A Danish company started manufacturing receivers for fishing boats which employed Decca's navigation charts, but users didn't pay rental for using the system.

In the ensuing court battle Decca lost the monopoly, and that signalled the beginning of the end. Income dwindled and eventually, the UK Ministry of Transport stepped in, having the lighthouse authorities take responsibility for operating the system in the early 1990s.

Edited May 10, 2022 by Alan de Enfield

[furnessvale]

2 hours ago, TheBiscuits said:

 

A lot have them have a "snap to road" setting you can turn on or off buried in the menus.  It's usually on by default for car units, which is quite reasonable!

 

 

Thanks for that.  I remember on another occasion with a different satnav, I ventured onto a short new bypass near home.  As I had not updated the poor device was quite confused as it thrashed away in a "field" until I regained the old road system.

[IanD]

12 hours ago, nicknorman said:

You are just paraphrasing what I said but in a way that gives you the last word. You hoped!

If you *really* want to have the last word on the subject, I have a suggestion for you...

 

Instead of carrying on making posts that show you don't really understand how the GPS system or receivers work, why not spend a couple of years actually designing one from the ground up (geddit?) and then testing it?

 

Then you'd be able to make statements about GPS safe in the knowledge that they're correct... 😉

Edited May 11, 2022 by IanD

[Guest]

22 hours ago, nicknorman said:

I know it is very important to you to always be right and to hold the power in any discussion,

 

Perfect summary.

[Mike Todd]

13 hours ago, TheBiscuits said:

 

A lot have them have a "snap to road" setting you can turn on or off buried in the menus.  It's usually on by default for car units, which is quite reasonable!

 

 

That would be in the SatNav rather than the GPS?

[TheBiscuits]

5 hours ago, Mike Todd said:

That would be in the SatNav rather than the GPS?

 

Yes, that's true.  The GPS just knows where it thinks it is, it's the digital map that "snaps to road" on the display.

 

 

[cuthound]

My first SatNav, a TomTom, used to show the car avatar in the fields alongside the motorway when a drove along a section of the M2.

[Guest]

1 hour ago, cuthound said:

My first SatNav, a TomTom, used to show the car avatar in the fields alongside the motorway when a drove along a section of the M2.

 

My old Garmin used to do that on a section of the A66 into Penrith in Cumbria. It used to show me on what was presumably the path of that road section pre it being re aligned. Even when it was updated that particular section never did, we were always driving in the adjacent farmers field. 😀🤣🤣

[Guest]

Its a little known fact that the signal from GPS satellites will even penertrate water and land and work underground.......🤣🤣🤣🤣

 

 

 

[howardang]

58 minutes ago, The Happy Nomad said:

Its a little known fact that the signal from GPS satellites will even penertrate water and land and work underground.......🤣🤣🤣🤣

 

 

 

Or how about Omega, or even Inertial?

 

Howard

 

[Guest]

12 minutes ago, howardang said:

Or how about Omega, or even Inertial?

 

Howard

 

 

My understanding is that they calculate roughly where you are in the tunnel based on the approach speed and elapsed time. Not sure if that is correct.

 

On that occasion we emerged at Folkestone before the sat nav showed we would. Then of course it re aquired a satellite signal.

 

I presume the train sped up part way through.

 

It gave up completely in the Gotthard tunnel though.