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Iguidance 100 feet off w/ BU-353?

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  • Iguidance 100 feet off w/ BU-353?

    Anyone see Iguidance that far off before? If i'm approaching an intersection (regardless of speed) by the time i get to the other side of the intersection Iguidance just then displaying me entering. I have the puck mounted on the rear deck of my car, but don't think that would make that much difference.

  • #2
    Originally posted by wolf2989 View Post
    I have the puck mounted on the rear deck of my car, but don't think that would make that much difference.

    It might

    Comment


    • #3
      Yeah, that limo is about 100 ft long!

      It does that with me too, they say GPS lags about 1 second behind you so you do pass the intersection before the GPS can catch-up.

      If you use it for what it's designed for *Guidance* instead of following you around, you probably won't miss a turn tho'
      ****************************************
      OLD SYSTEM (DEAD)
      Intel D945GCLF2 Dual Core ATOM
      Lilliput 7" 629GL 2008 LED Backlight
      BU-353 USB GPS Receiver / iGuidance / IGO8
      M2-ATX Power Supply
      RideRunner Front End / Various Skins
      Windows XP SP3

      Comment


      • #4
        Originally posted by Marvin Hlavac View Post
        It might

        That happened here in San Francisco.. I saw the news article and I can tell based on the hills/houses.

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        • #5
          I got mine mounted in the front above the rear view mirror and it always seems pretty bang on. I get the beep right before I meet the intersection. It does tell me I'm offroad when I'm parking in my garage though

          Comment


          • #6
            Re: Iguidance 100 feet off w/ BU-353?

            I believe that when commerical GPS first became available, a purposeful discrepancy was engineered into them as it comes to distances. The reason was that they could not be converted into a "weapons grade" gps by the various number of bad guys.

            I do not know if any of the current GPS systems still have that discrepancies build into them.

            This "might" be for the reason you are seeing distances not being reported correctly.

            Originally posted by wolf2989 View Post
            Anyone see Iguidance that far off before? If i'm approaching an intersection (regardless of speed) by the time i get to the other side of the intersection Iguidance just then displaying me entering. I have the puck mounted on the rear deck of my car, but don't think that would make that much difference.

            Comment


            • #7
              Try this.... Put a piece of metal under the GPS, allowing the GPS's magnet to stick to it. I had the same problem and I NEVER had a problem after this.

              My 2000 Accord Project

              Comment


              • #8
                The point of the metal under the GPS receiver is to provide it a ground plane to help amplify the signal. It's better if the metal is connected to the car's chassis to ground it.

                I just got my BU-353 with SiRF III today to replace my GM-210 with SiRF II. And, yep, on iGuidance, it's completely off! I drive past an intersection, 3 seconds later my little arrow finally cruise by the same intersection. I even put it on my roof (so it has the ground plane) and it has 7-10 out of 12 sat's. My old GM-210 can barely get 5 sats on the roof, but it's dead on. I haven't found a solution as I just got home from work, but just thought I'd chime in.
                Gen 1: Pentium 3 1GHz - ATX - 2005
                Gen 2: Pentium M 1.6GHz - ITX - 2006
                Gen 3: Pentium M 2.0GHz - 5.25" SBC - 2007
                Gen 4: (coming soon: Core2 Duo - 3.5" SBC - 2009)
                ...it never ends

                Comment


                • #9
                  Just to add another point, comparing the GM-210 with the BU-353, the reported elevation is different by 30-100 feet (i.e. BU-353 said I was at ~140 feet, GM-210 said I was at 40 feet. I was right on the beach, and I can see the water, and it could NOT have been 140 feet below me. Even with tide and whatnot, the difference is remarkable. I'll do a drive this weekend with my laptop and the carpc to run both GPS receivers at the same time. I hope to put up some pictures to examine the difference in reported position and elevations.
                  Gen 1: Pentium 3 1GHz - ATX - 2005
                  Gen 2: Pentium M 1.6GHz - ITX - 2006
                  Gen 3: Pentium M 2.0GHz - 5.25" SBC - 2007
                  Gen 4: (coming soon: Core2 Duo - 3.5" SBC - 2009)
                  ...it never ends

                  Comment


                  • #10
                    Great! Please do report your findings..subscribing.
                    ****************************************
                    OLD SYSTEM (DEAD)
                    Intel D945GCLF2 Dual Core ATOM
                    Lilliput 7" 629GL 2008 LED Backlight
                    BU-353 USB GPS Receiver / iGuidance / IGO8
                    M2-ATX Power Supply
                    RideRunner Front End / Various Skins
                    Windows XP SP3

                    Comment


                    • #11
                      never had this problem with my microsoft puck. (pharos)

                      but it is the older model so no SiRF III. And here I was thinking of buying the 353.... now I dont know. Are more people having this problem?
                      Car : 00' Chrysler 300M
                      Speakers : Rainbow Audio SLC 265 | Subs : Diamond Audio D6 12" Subs X2
                      Amp's : Hifonics ZXi 6006 AB | Hifonics BXi 1606 D
                      CarPC: HP Laptop AMD Sempron 3000+ | 1.5GB RAM | DVD+RW | 80GB 5400RPM HD | ATI R200 Video

                      Comment


                      • #12
                        don't have this problem with my POS USB mouse, nor did I have it with my gr231 bluetooth, it sounds like a problem with the receiver, not the software

                        Comment


                        • #13
                          Okay, I had my brother drive my car while I play with the GPS. What I'm testing:

                          iGuidance 2.1.3 on GM-210 (SiRF II) on my carpc
                          iGuidance 2.1.3 on BU-353 (SiRF III) on my laptop
                          Garmin iQue 3600 (I think the map data is maybe 5 years old, definitely not SiRF III).

                          Preconceived notions before this test:
                          I always thought the GM-210 was great and that it never let me down. I've had it route me to wrong places, but it was the address that was bad, and not my position based on GPS. My brother's iQue never let him down either and we regard it as fairly accurate.

                          Testing:
                          The iGuidance used the same map data, with only the GPS receiver different. The iQue was brought along for fun. We tested while in motion (local and highway roads), checking differences in reported altitude, speed, and position. All the antennas were placed near each other (check the pictures). We also tested sitting in an intersection. The road is old and established, so shouldn't have changed with map data.

                          Pictures:
                          Sitting right at the intersection:
                          Click image for larger version

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                          Antenna array:
                          Click image for larger version

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                          iGuidance w/ BU-353 (note how far we're from the intersection):
                          Click image for larger version

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                          iGuidance w/ GM-210 (also note how far):
                          Click image for larger version

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                          iQue:
                          Click image for larger version

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                          Conclusion:
                          In some intersections the reported positions were exact, in other intersections the reported positions were off by up to 100 feet. However, all positions were the same in all three devices. The only thing I can conclude is that the GPS receivers are precise, but the maps are inaccurate.

                          I guess I have mentally adapted to the inaccuracies that I didn't notice until I swapped GPS receivers and actually looked at the map. Same with my brother and his iQue - after using it all these years, he's adapted his driving to the map (when it says to turn in 100 feet, he knows it as basically 'turn right now' and ascribes the difference to when the map actually hits the point and when the sound clip says it)

                          Basically, nothing wrong with the BU-353.
                          Gen 1: Pentium 3 1GHz - ATX - 2005
                          Gen 2: Pentium M 1.6GHz - ITX - 2006
                          Gen 3: Pentium M 2.0GHz - 5.25" SBC - 2007
                          Gen 4: (coming soon: Core2 Duo - 3.5" SBC - 2009)
                          ...it never ends

                          Comment


                          • #14
                            i wonder if iguidance 3.0 is any better?? or anymore accurate.

                            Comment


                            • #15
                              Fantastic! Great report! Thanks.

                              Let me go mess with my bluetooth GPS receiver, i believe it's more accurate than that..
                              ****************************************
                              OLD SYSTEM (DEAD)
                              Intel D945GCLF2 Dual Core ATOM
                              Lilliput 7" 629GL 2008 LED Backlight
                              BU-353 USB GPS Receiver / iGuidance / IGO8
                              M2-ATX Power Supply
                              RideRunner Front End / Various Skins
                              Windows XP SP3

                              Comment

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