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Force navigation sync?

Discussion in 'Gen 2 Prius Audio and Electronics' started by dlskier, Apr 3, 2006.

  1. dlskier

    dlskier Junior Member

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    Hello,

    I tried some searching, so I hope this isn't something that is covered over and over again. But, is it possible to force the nav to try and find your actual location?

    A couple times a week I'll be driving along and it will be off by miles. After a while it will find itself but it doesn't always happen when the car is turned off and it doesn't always happen quickly. I've made a trip from southern california to northern california and had it be off the whole time. Unless I was somehow in the Pacific Ocean :)

    The only thing I could find was the calibration but it's not like it's off by a block, it has been off by 60 miles after long enough time.

    Thanks a ton
     
    #1 dlskier, Apr 3, 2006
  2. aaf709

    aaf709 Ravenpaw of ThunderClan

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    That's never happened to me. If I have moved the map from where I am, I press the MAP button and that snaps it back to my location.
     
    #2 aaf709, Apr 3, 2006
  3. eagle33199

    eagle33199 Platinum Member

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    Very odd problem... luckily something i haven't had to deal with. I don't know if there is a way to force it to update your position. However, i can propose a few ideas as to why this might be happening:
    1. Your actual location is correct, there's something wrong with your map CD (unlikely)
    2. The nav system takes as input your speed, direction (forward/reverse), and compas direction. One of these could be off. for example, if your compas is off by a little bit, you would gradually shift off the street (although the nav would try to match you to the nearest street).

    It might be easier to document the problem (for example, photographs of the nav showing you in the middle of the ocean when, infact, you are not) and take it to your dealer... that is something that should be covered under warenty as defective.
     
    #3 eagle33199, Apr 3, 2006
  4. mikepaul

    mikepaul Senior Member

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    I haven't noticed it since the 4.2 upgrade, but there was a stretch of Route 74/76 in NC where I'd be show driving off the road by about 100 yards. The same thing happened in the mountains of PA and WV at least twice. In all cases, eventually I'd be 'correct' again.

    However, 60 miles is far beyond that issue. It's like your GPS antenna is turned off, and the 'dead reckoning' that's a fallback isn't very supportive.

    One of the service menus includes a list of 'visible' GPS satellites. I don't have directions handy, but if you can get them, next time you seem 'off' check to see if you have any GPS assistance...
     
    #4 mikepaul, Apr 3, 2006
  5. auricchio

    auricchio Member

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    You didn't say what year you have. The nav systems may differ.

    Check if you see the "GPS" letters up near the upper left corner of the map view. This means the nav is properly receiving satellite signals. If they're not there, then it uses dead-reckoning to try to determine your position. (Dead reckoning uses time/distance. It counts tire revolutions.)
     
    #5 auricchio, Apr 3, 2006
  6. hdrygas

    hdrygas New Member

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    Boy I have to say you can not force a GPS to "sync" you are either getting a signal or you are not! I have waded out hip deep in the woods to get a signal to end a dispute over position. The dead recoining in the Prius uses the speed tire rotation and inertia and turning monitors to supplement the GPS. Trust me if you are driving through a forest with tall Douglas Fir on other side or the "canyons" of NY city your may not be the greatest. There dead recoining cuts in and it is a god send. Get it?
     
    #6 hdrygas, Apr 3, 2006
  7. dlskier

    dlskier Junior Member

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    I have an '05 with the original nav, I think 4.1?

    I'll keep an eye out to see if the GPS logo is up when the problem is happening. I've noticed the problem when I was travelling through tall trees in the Northern Sierras, but I've also had it happen driving through the forest known as "the 405" in Los Angeles, no interference around.

    The car will continue moving and trying to stick to roads but it's no roads near me so it hops from road to road or sometime just goes through a large empty space. Meanwhile I'm heading straight up the 405,5,99.

    The nav saves me, but some times it lets me get into trouble because I rely on it too heavily and once it goes down I'm hosed :)
     
    #7 dlskier, Apr 4, 2006
  8. KTPhil

    KTPhil Active Member

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    What region is it set for?
     
    #8 KTPhil, Apr 4, 2006
  9. IFixEm

    IFixEm New Member

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    <div class='quotetop'>QUOTE(KTPhil @ Apr 4 2006, 11:57 AM) [snapback]234817[/snapback]</div>
    I think KTPhil has pegged your issue. If it is set for the wrong zone, it defaults to the dead reconing mode. The easy way to tell is if the GPS icon is displayed under the compass needle. To delve a bit deeper, you can power up the veh, hold the info button down, and cycle the light on/off three times and it takes you to the Nav and Avec/Lan codes. Select nav and then I think it says GPS data.....you have 8 "slots" off satelites displayed. You will see "-", "T", or "P". - is no signal, T is a time hac only from the satalites to allow dead reconing, and a P is positive lock for GPS. You need 3 P's for accurate triangulation. You have to shut the car off to exit this mode. Also take a look at the "vehicle sensor" srteen and make sure your gyro voltage is stable, and the pulse per mile seems to increase with veh speeds. But I suspect you are in the wrong zone.
    There are 2 navs and this info is for the more popular, so if nothing is as I said, ping us back.
    Regards, Mike
     
    #9 IFixEm, Apr 4, 2006
  10. narf

    narf Active Member

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    Do you have something blocking the GPS antenna? The antenna is just forward of the center speaker in the dash. If you place a radar detector or something similar in that area you may be blocking antenna reception.
     
    #10 narf, Apr 4, 2006
  11. dlskier

    dlskier Junior Member

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    Luckily this hasn't happened since I asked. The only modification to my car so far is the addition of the XM but not the good Prius XM, it's the XM Commander and the unit is inside the sunglasses holder.

    I think I am in the correct region but will double check. I usually have the GPS icon under the compass but have not had this happen recently to check if it's there when the error occurs.

    I really appreciate all of your responses and will give you an update the next time the problem occurs. Hopefully that's no time soon :)

    Thank you!
     
    #11 dlskier, Apr 10, 2006
  12. dlskier

    dlskier Junior Member

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    Looks like I need to take the car into the dealer and get it fixed. It doesn't have a satellite connection most of the time now. Sometimes it comes on and I have signals for all but 3 or 4 of the sattelites, most of the time, there is nothing for any of them.
     
    #12 dlskier, Apr 21, 2006
  13. dlskier

    dlskier Junior Member

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    Took the car into the dealer. I am going back in next week with an appointment and a different service rep this time.

    The last rep told me:
    -It's like a cellphone, sometimes you're just out of reach, nothing we can do.
    -All the satellite information is working.
    -The tech that looked at it is a certified Prius tech, he knows what he's doing.

    Meanwhile, the GPS icon hasn't been seen in the past 2 weeks. Limited to dead reconing atm, however since the dead reconing showed me where I was supposed to be they didn't see a problem.

    Nevermind the fact that dead reconing seems to stay accurate on a freeway about as well as Bill Clinton can stay faithful on secretaries day.

    I have my fingers crossed, this is really annoying.
     
    #13 dlskier, May 2, 2006
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