GPS Good and Lost

I had my first really bad Prius day today. I am notorious for getting lost so the Navigation system in my '05 Prius was essential. Today I had to find a conference center that I have never been to. I input the address into the Address Finder (so far so good), found the address and off I went.

Like most people, I know how to get to the highway so at first I ignored the directions and I didn't notice anything awry. My first indication of a problem was when the NAV system (she) told me to make a left in the next .1 mile. I was traveling 65 on the highway with no exit in sight. I glanced over at the map and it said that I was in Windsor, NY. This was strange since I was just passing Stamford, CT. Clearly, the GPS has LOST its position and it seemed to think that I was heading North and not South.

As you might expect, I got good and lost and it took me over 1.5 hours to find a place that should have taken me 10 minutes or less. I had to call the convention center and ask them for directions. Gasp! I thought my days of direction asking embarrassment were over.

I had thought that this was impossible since it should synchronize with the GPS Satellite, but clearly it is not doing it. I tried shutting off and restarting the Prius, no luck. I tried waiting a bit and then restarting, no luck. I looked at the calibration function in the setup screen, but the interface doesn't seem accurate enough. You can set your current position and direction, but I was lost, so that was of no use. I am also wary to set this myself since I it seems unlikely to get it even close without a compass and a good GPS.

This is what happens when you become too dependant on technology.

My car is going in for service on Friday to fix this but I was wondering: Has this has happened to anyone else ??

 

I have verified that I have the correct region set. However, I haven't checked the diagnostics for the GPS. I will try that and get back to you.


THANKS!
DanMan32, as always, you are a wealth of information.

 

OK, I was able to get into the Diagnostics mode and Clicked on the Navigation/GPS menu items. I pressed and held the Display button while pressing the brake pedal and turning on an off my lights repeatedly. I was able to make it work twice, but I am not sure what I did exactly. I hope nobody was watching

I did see that the Satellites #s were changing, but made no difference. There is a reset button that seems like it would help, but it didn't.

Last night I simply did what I spoke about earlier and manually input my location and direction. The interface for manually inputting the location and direction seems to be well thought out because all you have to do is go to a location where you know you are (i.e. in front of my house) and then find it on the map. Simply line up the arrow with the street and direction you are pointed and Voila, you are calibrated. This is by no means perfect since my street is not really as straight as the map indicates and I am sure that I was NOT perfectly parallel with the curb, but it seems good enough.

I would have thought that the GPS would correct my position automatically. Right? I am beginning to wonder if the Prius works differently than hand held Navigaiton systems. Why, for example, does it want to know when you get new tires? The Garmin GPS system doesn't have access to speed and tire information right? Why does the Prius require it? I have heard that there is some limitation to the accuracy of civilian GPS systems for security reasons, but I can't see how that would make a difference.

Do all navigation systems work this way? Do they require a known starting position and then use the satellites in combination with a built in compass to figure out where you are by calculating the change in position?

For now, manually inputting my starting position seems to have solved the problem because the map seems to be tracking my current position fairly accurately. I spoke with the dealer and they suggested cancelling my appointment and take a "wait and see" attitude. I am not letting them off the hook so fast. I will watch it for a day and decide tomorrow if they are going to have to take a look at it.

Any comments or suggestions would be VERY helpful.

 

List list of sattelites seemd to be full, though I am not sure how many there should be in the list. There at least 8 or 10 of them. There wasn't an obvious column for signal strength, but I will check again and write down the numbers.
FYI, I was traveling down I-95 in south eastern Connecticut when I first noticed that it was wrong. It is hilly, but I am not near any mountains and I was pretty close to the coast. So far the only scenario that I can come up with is that there is a problem with it interpretting the satellite data and it is only using the dead reconning. I wonder how I can tell.

I agree. It is strange.

 

Just to be clear. I didn't calibrate the Navigation system until AFTER it placed me about 30 miles from where I actually was. It was working fine, though possibly using dead reconning for the entire time I have owned the car (3 months). If it is using dead reconning, then it is doing it very well. It is also working correctly now (I think), but I really don't know if it is using the satellites or not.

Wait a minute. Is there a "GPS" indicator on the top left of the display? I remember seeing the compass icon, but I am not sure I have seen anything that says GPS. Does anyone have a picture? This will really help me when I go to the dealer tomorrow.

 

One more thing. I realized that I should mention that I have an '05 Prius and if you have a picture of the NAV on a different model/year, please mention it.

If anyone has an '05 which has the "GPS" icon in the corner, please mention that also. I want to make sure that it isn't different on the '05.

I think that we may be onto something. Thanks everyone.

BTW DanMan32, I saw that you mentioned the "GPS" icon in your earlier post but I didn't realize the import of that statement until just now. Again, thanks.

 

DanMan32:
First, I didn't realize that the car doesn't have a compass, so now I am confused. I can;t tell if it is using the GPS or now.

Second, there is definitely no GPS icon in the top left corner. There is the Compass icon, but that is it.

I guess that the car is going in for service tomorrow. I will let you know what happens.

 

I went back and checked the Diagnostics Screen and the LVL and STS columns are '0's and '-'s for all of the satellites.
The Toyota service technician told me that the FM transmitter for my IPOD is interfering with the Navigation system. As a result it isn't able to "lock-in" to the GPS signal.

Does this seem possible to anyone?

 

I have a DLO TransPod All-in-One Car Solution for my ipod. This is a handy device that charges my IPOD, transmits the music over any frequesncy that I dial into it and is a cradle that places it within easy reach for skipping tracks and viewing the song that is playing, and generally navigating the menus. The only drawback is that the FM modulator is not good at all so I use it in combination with a cassette adapter for the best sound quality. Cleary it wasn't worth the price for just a cradle and a charger, but I own it now so....

In any case, I think that I owe the tech a beer and a letter. As it turns out, if I set the Transpod to 87.5 MHz it interferes with the GPS system. I unplugged it, no problem. The ironic thing about this is that I am not using the FM modulator at all and it was randomly set to that frequency.

Also, all I had to do was change the frequency a tiny bit and the GPS started to work. I wonder why it is true. Anyone have an idea?