In an aircraft, the VOR receiver is commonly called ‘the VOR’. (VOR = Very high frequency Omnidirectional Range.)
The navigation system in my car is seen on the ‘multifunctional display’ that has the map, audio controls, environmental controls, energy management/information, and other things. I call it ‘the nav unit’.
If it’s a Garmin, you can choose to give her an Australian accent which doesn’t sound as bitchy when you miss a turn. You can also turn the voice off completely; anyone riding shotgun can keep an eye on it and relay the instructions more pleasantly.
Oh, and we call ours “The Garmin”.
You would think that but i’ve seen it mean nav more often (not that what I’ve seen should be considered fact). It can often be confusing what SAT refers to.
One of my sisters calls hers “Garmin Electra.”
Tris
Oh, god…I wish mine was a Garmin now. I’d download an outrageously flamboyant voice and call it “Garmin Ghia”.
“Gary Garmin” here, as opposed to our other navigator, Gary aka Dad.
I tried naming ours Garmina Burana, but it didn’t stick. I mean, it was perfect! The most well “traveled” book of poetry from all over Europe! Sadly, my family members are not the enormous nerds that I am.
My friend’s GPS has the voice of R. Lee Ermey. It will make disparaging remarks about her intelligence if she makes a wrong turn. It will also randomly insult her during long, boring stretches. She dubbed it “SGT Garmin”.
Yeah, people call it “the GPS”, though GPS is only one of three major components that make it work: GPS for getting the position, map data for knowing where the roads are and how they connect to each other, and software for putting it all together and being able to calculate routes.
I thought I was clear that navi is the colliquial term here in Germany (Southwest Germany specifically). 
For the USA calling it a GPS (the technology) seems consistent with referring to a cellular telephone handset as a cell. “Can I use your cell to call home?” It took me a bit to catch on that a cell phone here is a handi.
Another odd usage is when people call their cellular telephone headset a “Bluetooth.”
When I saw the thread title, I at first assumed that “satnav” must be a foreign word, probably Hebrew, and my brain didn’t make any effort to parse it further. I was wondering why anyone would expect Americans to typically use a Hebrew word for anything.
See, that I’d pay for.
my mother has a navigation radio in her car, with the “standard” female voice. On a couple of occasions she’s said “I hate that broad, why can’t I have Sean Connery’s voice instead?”
I imagine it’s really mostly imitators, but you can find third-party voices, including Connery.
I might go for William Daniels, the voice of KITT from Knight Rider.
Systems with built in cell connectivity also triangulate position using cell towers. Which is why the free Google Navigation app on my phone is much more accurate than the Garmin receiver in my mother’s car.
I know some offer that, but this is a factory piece.
That’s true. Which is why the term “GPS” for the complete system may be a total misnomer. It may not be using GPS at all.
In fact, some very early car navigation systems were made before GPS was even around. They relied on a compass and sensors from the speedometer and odometer of the car, among other things. I work with a guy who made some of those early systems; he’s got some interesting stories.
I was thinking maybe it was one of those cases where a brand name becomes synonymous with the product. My understanding is that Britons call a vacuum cleaner a hoover for this reason. And when I was a boy, ski-doo was a generic name for snowmobiles (although it appears Bombardier has successfully fought out the generification of the name and nobody currently would refer to an Arctic Cat ski-doo.)