Top 10 In-Car GPS Need to Know Facts | Auto Expert John Cadogan | Australia

The truth about GPS in cars. I get a lot of questions about this. But first: Should you make GPS a mission-critical criterion in the selection of a new car? I’d suggest not.

Can I add GPS to the car later?

Sure: If you’re buying a car without GPS, there are several options. In the aftermarket industry you can get them to perform day surgery and install a GPS head unit, so you won’t have to futz with suction cups and cables.

But why not just use Google Maps or download an app from a GPS nav specialist like Tom Tom for your smartphone?

How good are GPS units in cars?

They’re all as accurate as each other from a navigational perspective. The location and speed computations are all done off the back of of the US Military’s Navstar Satellite (GPS) system, so accuracy doesn’t vary between units.

And the map data generally all comes from a government entity – so it’s all the same for particular places. What does vary is the user interface and the software routines driving the navigation. So they look different and use different logic.

In my view car companies are generally shit at this – really counter-intuitive and clunky. The best in-car executions are in fact licensed direct from (say) Tom Tom.

Map upgrades are a disaster for in-car GPS, and the older the car the more epic the disaster. Some older cars are no longer supported, so upgrades are just unavailable. And if they are, and they are only available from a dealer, they are likely to cost a bomb, leaving you in a situation where you could by half a dozen standalone Tom Toms for the price of one in-car update.

GPS for dummies: There’s a Navstar Satellite Constellation in medium earth orbit, 20,200km overhead. It’s been there nearly 40 years. The system only needs 24 satellites to function brilliantly – but there are 31 currently in orbit. So it’s all stocked up on satellites.

Your GPS receiver only needs to see four satellites to resolve the four big questions: Latitude, longitude and altitude, plus precise time. Once you know that, speed and navigation are all computations done based on firmware on the device in your car or in your hand.

Satellite signals do have a problem punching through dense foliage. So big, thick tree canopies are bad, and if you’re deep in a canyon with only a narrow slit of sky overhead, that can compromise satellite visibility.

You might not be driving in the Amazon any time soon, and you might think you don’t drive in canyons very often, but I’d suggest you are wrong (about the canyons, at least). Canyon driving is a very ‘first world’ scenario indeed.

The most common place to encounter canyon-type satellite compromises are when you are driving in cities.

It is one of the most outstanding developments of the 20th Century. Of course in the boonies it’s always nice to know how to move with a map and compass, because batteries go flat, but the earth’s magnetic field is somewhat more dependable.

Any claim by a carmaker that the underlying dodginess of their GPS unit in your car is because satellites are dropping out is almost certainly uninformed nonsense. A lame-arsed, technically incognizant attempt to brush you off.

GPS dysfunctionality is far more likely to be the result of their hardware or the firmware just being shit and not working properly.

Time for some mad science. Dr Who meets Einstein and makes GPS work.

The Navstar satellites are further than we are from the earth’s gravitational mass. Therefore (brain-bending time) time on the satellites runs at a faster rate than it does for us. The effect is only minor – but without correcting for it we’d never get a decent answer to where we are on the planet.

I just use the Tom Tom app on my phone. It’s free. You get free lifetime map upgrades (dear car dealers, stick that where the Pope fears to wash) and that freeness comes with 75 kilometres of free nav per month.

After that, if you go with the paid version of the app, which is under $100, the nav is unlimited. This has the added advantage of coming with you after you park the car – which is quite useful if there’s an on-foot component to your destination, or if you fly into an unfamiliar place and rent a car.

And, finally, data: Doesn’t mobile phone GPS app-based nav use data? Won’t it rack up a big data bill if you thrash it your GPS app on your phone?

Ahhh – no. It doesn’t and it won’t. It works like this: The maps and the navigational software live on the phone – there’s no cloud connectivity or mobile data component to running the maps and navigating.


MountKeverest says:

The intro was hilarious

Frank Salman says:

What’s up with the obsession with President Trump. Great Videos, but explains why only about 110K subscribed as to date. Besides, it must be very embarrassing to still wish for a Hillary office. It’s wrong that she lost but she still forces her thoughts on us; an example why many should also keep their obsessions to themselves.

Erik Neland says:

I have an Android based headunit in my car and use TomTom Go!. Thanks to Tomtom my drive synchronization, I can use my cell phone to select a destination while sitting in my living room, and when I get in my car, the destination is already set and I’m ready to go instantly.

Barry Maskell says:

For Navigation – Google maps still isn’t as good as my 2006 Garmin StreetPilot 7200

Dave Insert Lastname says:

I use Mapfactor navigator free for android and the only time I need to go on line is to update the maps, once per month, if I feel like it. Other than that, the navigator works off-line for navigation so it will work almost anywhere, the available maps cover almost the entire planet, without a data connection other than for update.

oztuber2 says:

All gays hate god, he’s just another

steve morrill says:

I use GPS in boats, which is quite different from cars. There, the GPS is just one tool among many. The boat GPS will cheerfully direct you right across islands or mud flats. The image also differs from the (old, not updated for forty years) paper chart you’re looking at. Mental gymnastics required here. I recall once finding myself supposedly sailing down the main street (if “street” is the word) of Hopetown, Abacos, Bahamas. The GPS showed my accurate position but the chart was wrong.

mrthomasfritz says:

The American FBI and other spy organizations use those OnStar other crap like that to spy on people and track their movements. If you like smoking stuff, and don’t want your local spy organization (coppers) to find your dealer, to listen to your private conversations in your car, you might want to have all that crap removed from your car. Not just the display unit, but the unit behind the dash. So you get “wood” from TomTom but they were reporting people speeding europe and taking reward money for it. This makes your favorite GPS maker an Uncle TomTom

stuart Haynes says:

I can imagine the price of an app update on a vehicle by the dealer every couple of years ..Google apps are mostly free on your phone ..I know my choice

wabby67 says:

Another excellent video!!

Christopher Gibbs says:

You are one of the funniest people on youtube today. And I live roughly half the world away from ‘straya. Just as an addendum, I think both Waze and Google Maps work better than TomTom (no real evidence, only my empirical impressions), and for a free complete offline system, Here Maps (ex Nokia/Microsoft maps which were the best in their class at the time) do an impressive job with navigation in the car, foot, and even public transport.

Max Waterman says:

not all maps are available for download on google maps

Shanilla Abdul says:

Gravity is the minor part of the time dilation (-7μs), the speeds effect of the satellites is a bit larger (45μs). Still need both for them to work though.

Brian Waller says:

Anyone who has a smart phone doesn’t need gps. Google maps or Apple always have updates and doesn’t require spending 3k on a tech package for gps.

Veronica Manning says:

I am thinking of buying this gps I heard its one of the best at the moment.

esa4aus says:

Hi john… I believe the time dilation is a factor of the speed of the satellites as compared the the surface of the earth. They are travelling faster so time runs very slightly slower. This speed is required to prevent the satellite from “falling” into the earths gravity well per Mr Einstein’s theory about space time being a Four Dimensional Housdorf differential manifold upon which a metric tensor is imposed giving rise to a geodesic that describes the satellites path based on the forces experienced.

Otto Wor says:

With some statements I / we agree, but some have a shitty response time and this has nothing to do with cloud cover or positioning! The small Garmin / 5 inch worked well until the map upgrade stopped working after three years. We bought another Garmin and took two of the 7 inch version back as they were bad. After 12 min driving they found finally the satellites, very bad in showing the correct speed / variations of 18 Km / h up and down even while driving a constant speed on cruise control. While stopping at the lights it still did show we were driving 8 Km / h after 40 seconds and the spoken announcements came on when we were already several 100 meters past those spots. We swapped to a Navman, same size – oh boy this one is crap in finding satellites as well and the display options are far poorer. Navigon on our Samsung mobile worked so prompt and suburb, but the cops are chasing everybody when spotting a mobile and they try to proof that we used the phone while driving – we are sick of that arguing with the cops shit and this why we bought a GPS. The two Din in dash sound units are preferred over the one Din units as their LCD screen push out mechanism is slow and they wear fast out, but now we do not have the room to put one in in this car. Both systems are a bit fiddly to install and the connections to the steering wheel buttons are not always possible (DVD, TV, GPS, reverse camera and fitting all antennas for a good signal is paramount) were we can get maps on an SD-card ( I Go 8 or Go Primo) are never the latest in maps but work so much better than the GPS units when once installed correctly and they are almost equal pricewise. There is only Tomtom left and the unit tester are not impressed with that one, recommending Navman so why should we? So what is out there that is easy affordable and does the job as good as Navigon on our Samsung mobile?

Bob Pfaff says:

I have a Garmin (Navigon) app on my phone. $25 for lifetime updates.

RagingTiger says:

Why use Tom Tom when you have Google maps? Free and unlimited

Just for Fun says:

It’s just a matter of time until all cars have standard gps with base version. It’s cheap to have gps nowadays so more and more car manufacturers offering that at cheap prices.

125pheonix says:

i use a Garmin nuvi-42LM, cost me about £50 when i bought it and has life time free maps. and for outside the car i do have my phone

steve morrill says:

I just use my iPhone mapping (I have two e-mapping versions, don’t recall names right now) and a gizmo that holds the phone and plugs down into a cupholder in the center console:!33602!US!-1

Set me back all of $13 USD and I already owned the phone. When not in use, I put the thing, sans phone, into one of the rear seat cupholders.

John Cahill says:

I would have to disagree on the accuracy of the data. On some GPS units, my house is 2 blocks from where it really is, and on others, it is correct and right on the money. I have many units. 1 is an in car GPS and the other four are TomToms. All five show my house where it physically is, but the ones that use Google Maps are the ones that do not. 2010+ Ford vehicles make upgrades easy (A simple SD Card) but, not really cheap and most of my TomToms have lifetime maps.

J A Z Z M A N says:

VOLVO NAV sucks… it still does!!

partymanau says:

The Stealers rob people blind for map updates on incar GPS systems.

Russell Smith says:

My thoughts exactly. I generally find the in-car navigation systems crap! My must have features in the car are safety related as you suggested, in particular stability control.

Mateusz Wojtkiewicz says:

I don’t really think in-car systems are that bad. I only had experience with the one in my car, so my experience is limited, but the update cost (if you want to do it through the dealer and not just download the maps from the internet for free) aren’t that bad. My grandpa had a TomTom unit he bought for his car (which lacked gps) and map updates cost exactly the same. Moreover he asked me a few months ago to update it again and the TomTom PC app happily announced that this device is no longer supported – so basically fuck you go buy a new one. Considering GPS in my car still works quite well even though it came out before Android was even a thing, I’d say this wasn’t a bad thing. Maybe now, when you have those screens installed anyway and AndroidAuto is available out the box so you’d have to pay extra just for the GPS itself, overpaying for it isn’t advised. Don’t know.

smokeyjayshouse says:

Why would I use a paid TomTom app when I can just use a free Google maps app with no limits and live traffic mitigation and recent satellite picture views. Been using that for years and never paid a dime.

MrDavee1 says:

Using your phone GPS while driving will incur a fine in South Australia.

Mike Jung says:

Wow, gps, totally cool.

Ian Miller says:

The Satnav in my 2016 Tuscon in the U.K is TomTom live and the map updates and speed camera updates are done via my smartphone. The maps are loaded onto an SD card…

Marshall Smith™ says:

The earth is shaped like a flat penis therefore GPS is homosexual… I read this on the USDA fan website so it has to be plausible. I can not say how I know the obvious secret info of what a flat penis is shaped like but that is eyes only top secret and only Alex Jones fans are allowed to view it.

oztuber2 says:

what a boring long winded lot of hogwash.. more like gps BY dummies..  unintelligent wanker.. embarrassing Australia. ironstein? ffs…   get an edumacation moron

François Collins says: is a good cheap alternative that works very well offline, even at 35 000 feet if you are close to a window.

J A Z Z M A N says:

Im an Airline Captain; you explain GPS very well. Well done.

Peter Edin says:

The Smart Car (451 variant) had the worse built in GPS in the world. In fact the whole touch screen infotainment system (Made by Bosch, branded Smart) was diabiolical.

Joshua Stabach says:

John I was waiting for the video on oil catch cans. Did I miss it or is it still on your to do roster?

Daniel Rusch says:

Your videos are simply fantastic. Ahhh and your writing- the commentary- just awesome.

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