Garmin sat nav

Hans, I'm just guessing here - so may be totally wrong - but possibly by knowing it's position, the satnav could selectively download (or receive over the air) information relevant to where it is. In other words, the information is being broadcast for all areas, but the unit only grabs what it needs.

Actually, the more I think about that, the less likely it seems

Maybe someone else knows for sure?

Rob

Hi Hans, I guess they must transmit your position, otherwise how would it be able to tell when you reach junctions etc? and give you the next instruction and tell you when you have reached your destination, and it will recalculate when you go wrong or get a diversion or you decide to take a short cut that you know of.

Regards Nick.

Edited By Nicholas Farr on 19/07/2021 16:16:33

The basic unit is just a doppler receiver, it can't transmit

No, GPS is not a doppler receiver, but let's not go into how it actually works, Wikipedia no doubt has a great explanation.

Traffic data is transmitted on a number of channels using RDS on FM and similar facilities on DAB. Certainly the TomTom that I had could use this data coming from the car radio to show live traffic though it needed an extra dongle. Both my recent VAG group cars showed live traffic data on the built-in Satnav - one Skoda and one Audi - coming from this source. Neither asked my permission to share my position since no data needed to leave the car - I suspect Garmin asking for your consent is just Americans going over the legal top to avoid being charged under GDPR regs.

[quote]

Personal data that is processed when you use your Garmin auto navigation device or app:

If you use a Garmin auto navigation device or app and provide your consent, then Garmin will collect and upload from your device data such as location, speed, direction, and time and date of recording. If you provide your consent when asked, then Garmin may also share this aggregated data with third parties to enhance the quality of the traffic, parking, and other features enabled by content providers.

PURPOSE AND LEGAL GROUND:

This data is aggregated with data from other consenting users and is used to enhance the quality of our products, services, and apps and the traffic, parking, and other features enabled by Garmin or third parties. The legal ground for processing this data for this purpose is your consent, which you may withdraw at any time within the settings of your Garmin device or app.

[/quote]
.

Ref. **LINK**

https://www.garmin.com/en-GB/privacy/global/policy/

MichaelG.

I dont think so. The GPS system knows where it is on the digital map. It then calculates where you are and distances to the next nav point. My Garmin receives traffic data as an FM signal (Traffic Message Channel) through the special cigarette lighter charging lead. A two way system would probably involve mobile telephony and a sim card, which would involve an annual charge like on most modern cards.

Rod

+1

Frances is correct. The phenomenon is called convergence, where computing, communications and real-world devices integrate in new ways, usually with plummeting costs. It's not like the good old days when a typewriter, telephone, radio and TV set were all separate devices built from incompatible technologies. Now, because they are pretty all much made the same way, it's feasible to merge almost anything even slightly electronic.

As old technology was single function it was necessary to buy several different boxes whenever several functions were needed. People rightly expected complex systems to cost much more than basic ones but this is no longer true: it's not expensive to make a smart phone that communicates world-wide, knows where it is with 2 metres,can be a spirit level, compass, and altimeter, navigate a car, stream Radio and TV, browse the internet, print, take photographs and HD videos, link to anything Bluetooth, and connect to a multitude of services the owner knows nowt about.

The advantage of putting a mobile phone chip in a Satnav is it keeps itself up-to-date without bothering the owner with complicated USB cables and horrid software! The disadvantage is loss of privacy. There's no particular reason why a car Satnav shouldn't communicate with the engine management unit, or the dealer, or the Disney Channel, or be hacked by organised crime.

Whether or not a Satnav phones home or not depends on the model. Many do. Older models probably don't because mobile phone calls used to be expensive; not now! As far as I can see there is no end to convergence.

Dave

Access to private data and what data is accessed will depend on the type of operating platform and their business model options. What private data are we talking about? Once you register a legit copy they have a tag of the software serial purchase linked to you - this is the trick manufacturers use to get you to register a warranty. As you drive about their software can sample routes you take and where you go to and at what times. Aggregated this information can be sold for traffic management purposes. To reduce the amount of data they have to keep stored on you, this may be no more than date,start point, end point grid references and journey time.

If you have old Garmin or TomTom using a memory card, maps are stored on it according to what you pay and there is no magic 'back channel' for data to get back - Unless you do an upgrade when the software licence is verified and there could be an opportunity to upload data to them. If you use F.M traffic data, intelligence sits in the application and again there is no back channel to send back data. As you drive the GPS receiver continuously updates you position (receive only, no back channel) which is overlaid on the map stored locally.

If your satnav device has a wi-fi connection' always on' or can connect to the internet using a cable to your PC, supposedly for updates, then you have agreed and opened up a back channel for data other than licence details to be sent back. I always disable automatic software updating and choose to do these things when I want and not have my devices crash or freeze doing huge updates.

A new business model approach is to put Maps needing a large amount of storage and most of the processing that would have been done locally on a Cloud server. This takes care of authenticating licenses, they only have to update their server maps and devices need less memory and processing power. In addition the user can get a high resolution location map and route faster from a cloud server rather than doing heavy calculations on a local device. But they do need a back channel which may be mobile internet SIM through your phone account. This would be how you use Google maps on a phone whilst driving. Once you allow this model, you are open to all kinds of data extraction about you and your journeys which can be in realtime as you drive.

Someone has finally pointed out that there is a big gorilla in the corner of the room

What happens to British ships when satellites don't work?

My answer would be a laser sextant for use at night

Point it at the star, self levelling bubble horizon, self contained clock, push a button, tell it which star you just read, get a position line in 10 seconds.

Edited By Ady1 on 28/07/2021 10:12:17

Download Camsextant from app store. Don't even need to know which star. Why would you need a laser? Ships took sights at night for centuries without one?

okay

Just to add to my reply, inertial navigation systems are used already for marine navigation and give a continuous real-time estimate of position with no external reference. Semi-automatic sextants exist that can take a sight on a star, and you can get a reasonable fix from a single star sight if you have the right almanac data, it's bearing, and accurate time (which can come from a low cost atomic clock). Though GNSS signals can be jammed and spoofed there are countermeasures, and given there are 4 global systems in operation, put up by the USA, EU, Russia and China, it's unlikely that all 4 would be unavailable at the same time - and multi-standard receivers are common. I think marine navigation would find it inconvenient if GNSS disappeared but it could be survived. The loss of time synchronisation on land-based cellular networks and financial transaction systems would be much more of a worry I think.

And that BBC report is awful, confuses GPS positioning with satellite communications, confuses Loran-C that uses low HF bands with cellular phones that use uhf and microwave bands.

If you think it's just foreign states that jam GPS this makes interesting reading.

Edited By John Haine on 28/07/2021 16:59:24