When I have queried co-workers they thought both handi and navi were American. They were a bit surprised when I told them we don’t use those terms.
I am not familiar with any brand by the name Navi and didn’t find anything googling it. Are you perhaps thinking of the Garmin model name, nuvi?
Don’t you mean Mr. Feeny? 
“I said turn right you jackwagon!”
I use the one in my droid, I named him Diogenes.
I call it the GPS or the GPS thingy.
No love for Garmin Miranda?
The voice is fruity.
WOPR here.
Is it Cynical? 
Anyone else see that car commercial where somebody bought a new car but not the latest nav system, but he says his “older model” is almost as good? And his “older model” nav system is a literal old guy in the back seat with a map?
THAT’s my current nav system - or rather, it’s my husband’s current nav system. It’s me, riding shotgun with a paper map.
I feel both old and out of touch >sniff!<
HEY, GET OFF MY LAWN!
Well, I do talk back at him =)
I love the commercial for the insurance company with the guy as the GPS
Nah. John Adams.
I call mine my navigatrix.
Why, yes, I did steal that from Stephen Fry.
Virginian here.
It’s a GPS. “GPS device” or “GPS navigator” is probably also acceptable and understandable, but saying something like “Don’t worry about finding directions, I have a GPS” would be perfectly acceptable and normal.
I also had never heard of the brand Navi and assumed you meant the Nuvi line by Garmin.
I travel almost every weekend with three kids playing travel sports and we use these devices constantly. Most commonly they are called “GPS” (by far number 1). I also hear many people refer to it as “the Garmin.” And another very common name is “the Navi” as in “I’ll plug it into the Navi.” I seem to hear this more with women (no idea why) so you can’t flatly rule it out as a generic term used for them here in the US.
I tend to use “the Garmin” even though over half the time I’m using the system on my Droid instead of my Garmin Nuvi.
Which is kind of ironic, because the GPS was originally a military system that the govt. let civilians use.
Are the European ones GPS or GLONASS or GALILEO?
GLONASS got off to a rocky commercial start and is barely being used. Galileo isn’t operational yet but will be better than both GLONASS and GPS so it’s likely to be pretty popular. Ideally, devices may be able to use all three in the future.
I’m surprised at the responses. In Ireland and the UK, it’s always been satnav. We know that it works by GPS, but that term is not used to describe the object in your car. Satnav seems self-explanatory - satellite navigation.
In the same way, cell phone has never been used here to any extent, and many people would be puzzled by the word “cell”. Why would you have a phone in a cell? It’s always been a mobile phone, or mobile.
It seems surprising that complex terms have become popular, ones which are not intuitive. i wonder if it’s because of the way early versions were marketed. Is this a branding issue in the USA?
However, I note that we call cash machines ATMs. Indeed, the term has become so usual that people say ATM machine, ignoring what the M stands for. So, it may be linked to what we learn at first introduction of any new technology.
You’re surprised that there are minor differences in colloquial usage?