Prius NAV vs. Tom Tom 910

My fiance has a Garmin GPS (tom-tom sized) and I have the built in GPS. We both prefer the built-in as it simply looks better, is a lot easier to read and is "there" when you need it. Her GPS we need to keep hiding in the car so that no one will steal it. I'm also a sticlker for that built-in look and to mee it feels a little silly to have a 7" screen in the car and not use it for something useful. Also driving through Boston's tunnels it's nive to have dead reconing, the Garmin has an annoying features in tunnels where is removes the "Take Exit #33" and says "No Signal" instead. This means I can't even remember what exit I was supposed to take when I'm in the big dig tunnel in my fiance's car.

That said it's a lot of money for the unit. As I was looking at a Volvo before the Prius the "top-of-the-line" model didn't seem that expensive (compared). If I was more thinking along the lines of a base camry or a corrolla then I would probably skip all but the air-bags and VSC and buy myself a handhelp GPS.



I don't think you can go wrong either way.

 

<div class='quotetop'>QUOTE(Zzyzx @ May 15 2006, 08:18 AM) [snapback]255622[/snapback]</div>

You don't have a cell phone, do you? Many cell phones have a hybrid GPS system to pinpoint your position for... whatever reasons whomever has access to the system may want to pinpoint you. I'm not sure what kind of warrant that takes, but I understand that given newer cell networks, you can be pinpointed down to what part of a building you're in (sans GPS).

I don't think the Prius has anything of the sort with its GPS receiver. That's a pretty specific thing to OnStar, as it's built with a cell phone transciever (to my knowledge) that lets you communicate with OnStar people and, along with that, for them to ascertain your position if necessary.

Sounded reasonable enough to me! Now, the cell phone bit is scary. It makes a good argument for 1) a pager and 2) keeping your cell phone off unless you need to make a call! If you're paranoid enough, anyway

 

<div class='quotetop'>QUOTE(divide @ May 31 2006, 03:20 PM) [snapback]263651[/snapback]</div>

The reason that cell phones are now including GPS recievers in them is primarily for enhanced 911 service. I.e so the police/fire/ambulance can find you when you call 911 from your cell-phone, especially if you don't know where you are. Sprint/Nextel has for a while been using the GPS technology in the phones to provided additional services (directions from your phone, tracking empoyees/family-members/friends, etc).

You are correct that OnStar does include a GPS receiver as part of the system. And I believe you are correct that is integrated into the built-in cell phone that the system uses, and not as part of a navigation package that the car may or may not have. There certainly are OnStar equipped vehicles that have no navigation system in them.

There is a good technical reason why GPS receivers don't transmit: because they are just receivers. Otherwise they would be called GPS transceivers.

 

I like the built-in system, just for the fact that it is built in - no cradle, no wires, big screen, integrated with the audio. I own four GPS systems: two Garmin marine systems for boat navigation, a Garmin wrist mounted unit for hiking, and the built-in system on the Prius. The Garmin units are top drawer, but the Prius built-in unit does a good job. I'd get it again.

Tom

 

<div class='quotetop'>QUOTE(qbee42 @ May 31 2006, 07:52 PM) [snapback]263756[/snapback]</div>

That is exactly why we're going with the nav system in our Prius. I've had a few GPS receivers in my life - DeLorme TravelMate (years ago) that plugged into my laptop and mapped with StreetAtlas, a few older handhelds (mostly horrible), a Garmin Vista (great handheld), and a Garmin wrist mounted(?) GPS for jogging.

There are certainly a lot of decent GPS units these days. However, the ease of having it built into the car -- larger screen, larger buttons, connected to the audio system, dead reckoning, voice commands... These are certainly things you *could* live without, but they make the whole experience nicer... like a navigation system is supposed to

For the extra money, it seems worthwhile to me!

 

I have a Garmin iQue 3600 that we use in my wife's Highlander and a Lowrance 500C in the motorhome. We got the NAV system in the Prius and I have been please with it in terms of accuracy, routing, etc. The real issue with any of these systems is setting the default parameters so that the resulting routing will mirror your own choices. One aspect of the Prius NAV system is the default speeds for highways, arterials and local roads. The relatively low default speed for highways (55 mpt) can have you routed off the highway for a slightly shorter route over an arterial on a regular basis. Likewise, if you don't include toll roads, or some of the other alternatives in your setup you may well not like the result of the unit's routing.

I set mine up the way I make decisions, and the routings it provides are essentially the same as I get with the other two units - just on a larger, more easily readable screen. One very nice feature of the voice directions on the Prius unit is the fact that when it gives you a turn direction it also advises of what the next turn direction will be. For example, "...turn right in 400 feet followed by left turn..." This alerts you that you may want to move immediately to the left lane after making the right turn. Neither the Garmin or Lowrance units have this feature.

I do like the Lowrance's oblique angle view, which is nice for identifying upcoming crossroads and the fact that it will provide a continuous elevation display. My one complaint is that the Prius NAV unit does not display elevation, at least I haven't been able to find a way to get it to do so. Otherwise I am quite pleased with the unit in the Prius - it does the job.

 

<div class='quotetop'>QUOTE(SomervillePrius @ May 15 2006, 11:38 AM) [snapback]255685[/snapback]</div>

I have three Toyota products with built-in GPS including my '06 Prius and I recently bought my Brother-in-Law the top of the line Tom-Tom for his 50th B-Day. There is no doubt in my mind the built in option is much better than the plug in option. I would also recommend the Bluetooth option which I think is the winner - I find I use Bluetooth much more than I use or need the GPS system but at this point I could not live without either.

 

<div class='quotetop'>QUOTE(divide @ Jun 1 2006, 12:20 AM) [snapback]263651[/snapback]</div>

Cell phones (at least for GSM) commicate with the network of relay stations. They have to, because they need to authenticate themselves to the relays while roaming. As soon as your phone is switched on, they can follow your track through the different cells. You don't need to talk to someone for this to happen! This feature has saved a few lives, and has sent quite a few criminals to jail...

On the other hand, normal GPS devices definetely don't transmit anything.

 

GPS is a *receiver*. Onstar and such are much more than that, and
must include a transmitter of some sort to re-send the position data
back out to the snoops.
.
_H*

 

<div class='quotetop'>QUOTE(hobbit @ Jun 1 2006, 08:16 AM) [snapback]264016[/snapback]</div>

Cell phones are "trackable" (either via cell-tower triangulation or via imbedded GPS receivers) so that 911 type emergency folk can locate you when you call up, say "Help me!" and pass out (at least, that's the justification they used). It's similar to tracking a land-line to a specific house for 911.

GPS systems are receivers, and don't transmit anything. They simply receive satellite transmissions of the current time (very exact) and use triangulation to locate you on the earth. Two satellites in range gives you longitude and latitude on the earth, and 3 can give you altitude.

It's been a while since I've researched it, but I believe On-Star is still cellular based (because it's available everywhere). You're essentially buying a dedicated cell phone built into your car. Again, it uses triangulation via cell towers to locate you (that's my understanding).

 

<div class='quotetop'>QUOTE(davidf @ Jun 1 2006, 11:31 AM) [snapback]264025[/snapback]</div>

Actually, there's *no* way to triangulate a position between cell towers. To do that, your phone would have to be actively communicating with more than one, and that's not how the system works.

Onstar locates you by sending your GPS information via it's cellular connection.

More info here: How OnStar works..

 

<div class='quotetop'>QUOTE(davidf @ Jun 1 2006, 08:31 AM) [snapback]264025[/snapback]</div>

2 things:

A GPS receiver needs to see at least 3 satellites before it can provide a lat/long fix for you. 4 or more satellites are required for an altitude reading. And the position of the satellites in the sky can affect the accuracy of the 2-D (lat/long) or 3-D (lat/long/altitude) fix. A good website that explains how GPS works is: http://electronics.howstuffworks.com/gps1.htm

On-Star does include a cell-phone for communication between your car and their center, but it doesn't rely on triangulation between cell towers to fix your posistion, but rather an embedded GPS receiver in the cell-phone to provide a more accurate location fix. Cell phone tower triangulation can give an approximate fix, if there are other towers in the area, but it won't be nearly as accurate as the GPS fix.

 

<div class='quotetop'>QUOTE(Jonnycat26 @ Jun 1 2006, 08:50 AM) [snapback]264029[/snapback]</div>

Thanks for the link to onstar. It cleared up some holes I had.

I could be wrong (certainly not my area of expertise), but -- at one point -- there was a push to have cell companies use tower triangulation to locate people (ala 911 emergencies). While it's true that only one tower "owns" your call at any given time, your cell phone is a radio. Multiple towers recieve your signal are aware of your presence at any given time. For example, they need to coordinate "handoffs" from one tower to the next as you drive, and need to have a sense of which tower should be next. It's a matter of where you tie into the system. If you tie into the tower's system at the "all the cell signals I'm receiving" point, you could triangulate. My understanding was that this wasn't as accurate as GPS, so cell companies didn't want triangulation to be the long term strategy for pinpointing people.

Perhaps someone in the industry knows more about this than I do (which isn't hard )

 

<div class='quotetop'>QUOTE(davidf @ Jun 1 2006, 01:34 PM) [snapback]264101[/snapback]</div>

The E911 system uses a GPS receiver in the phone (at least for Spring/Verizon), the same way OnStar works. GSM carriers use the timing difference between you and the tower (ie, how long it takes for your signal to hit a tower) to determine difference.

If you want to see how hard it is to actually track someone using a cell tower, without any sort of enhancements, look into zonetagging. It's a lot of fun and it's pretty wild to see how off it can be.

 

I have tom tom's in all my vehicles.. think they are great.. and I do a lot of deliveries so need addresses quickly.. they do adjust volume relative to vehicle noise.. and it's set to the left of the mfd.. I use sticky tape. I do notice washout when the sun is directly overhead but still see and hear well enough...

 

Some of these GPSs come with bluetooth.
Does anybody know if they can be made to work with the bluetooth built in the prius.
Basically if both have BT they can we make them talk to each other and use MFD screen for all the GPS functions (like we do for telephone) and so the audio system for all the audio functions of GPS.
Has somebody tried this.
Basically registering GPS unit as additioal (phone) and hacking it that way.

 

<div class='quotetop'>QUOTE(MBPR @ Jul 20 2006, 03:54 PM) [snapback]289656[/snapback]</div>

I don't think it would work. For one thing (and I'm no expert on BT) it sounds like you're trying to get two headsets to link up, not a phone with a headset. Besides, the BT in the Prius is a half-duplex, it probably wouldn't be able to carry the information you want.

 

<div class='quotetop'>QUOTE(benbethel @ May 13 2006, 08:27 PM) [snapback]254956[/snapback]</div>

 

I have the Navigation on my 2006. The only disappointment with this car! I have a Garmon streetpilot 2610, and a iquem4 and just received a Garmin nuvi 360.
The Prius Nav is, by far, the most expensive. Yes it is a bigger display and comes on with the push of a button. It also has a voice recognition that is laughable. If you want to spend a lot of time trying to make it hear and know what your are saying then this is the system for you.
First of all the Prius Nav does not know where I live in a town of 40,000. Many areas it can not give guidance! Big areas. Also it does not recalculate the route. Say it gives you a route and you know a shorter route. So you turn on a different road and would hope the Nav on the Prius would re-route you. No it does not do this. It keeps trying to give you U turns to get back to the original route instead of guiding you a corrected way. One time it had me going 90 miles out of the way to get me back to the route that it thought best.
Many will tell you that it is the settings. Believe me when I tell you that the settings do have to be correct but that still does not matter.
In my humble opinion this Nav needs major help.
Good luck on your decision.

 

I love the NAV system in the 2006 Prius. The downside is that I spend 99.999% of my driving on the same route. That makes is useless. I will be pretty happy when I get to drive somewhere and say "home" and I actually do not know the best route. I would highly recommend getting it.

The nice thing about a portable unit is that you could use it in any car and take it with you when you travel. If that is important to you, that may be the best option.



ps- I live in a town of ~ 4 million people. :blink: