two small questions: 1) is there ANYBODY who has a freerunner with a "normal" functioning GPS? 2) We must presume openmoko tested the GPS before starting the mass production. The GPS of those devices must have worked, no?
On Mon, Jul 14, 2008 at 3:05 PM, thomasg <[EMAIL PROTECTED]> wrote: > On Mon, Jul 14, 2008 at 10:45 AM, Kalle Kärkkäinen > <[EMAIL PROTECTED]> wrote: >> >> In my past life I developed a fleet management device that had GPS and >> GSM in it, able to send the fix data to server in intervals. we even >> implemented some location alerts (around the vicinity of, or near >> customer..). >> >> Based on that experience, we used on of falcoms devices for it, it most >> probably did not have much of a cache for gps data (black box, tough to >> tell), but it needed a strong antenna for gps. For a GSM antenna you >> could use a hairpin, anything that had 10-15 cm of length was totally >> enough for good quality gsm connection. GPS required much more, in our >> case we supplied all the devices with external antennas. >> >> My knowledge is based solely on this work experience, I'm no radio-geek >> so I cant really tell much about antennas and signal catching. What kind >> of GPS-antenna is there in FR? Embedded for sure, but could that be the >> problem? >> >> I guess your TomTom comes with an external windshield antenna? >> >> -- >> Kalle. > > No, it has no external antenna, only a window-mount with antenna connector > but without one connected. > That GSM works better is sure, because mobile GSM devices can receive at > -110 dBm (usually ~ -70 to -90) while GPS chips receive at up to -160 dBm > (usually between -130 and -150 at the antenna). > I think the antenna in the freerunner is not that bad, it even has a preamp. > Ublox can receive at -158 dBm (according to the datasheet), what is pretty > good (and definitely not worse than every good navigation device), and > should get at least -130 dB (good enough for a cold boot fix) _after_ the > antenna (preamplified) I guess. It even has it's own additional amp on chip. > So the problem is imho only bad build quality (QA) at least in some of the > devices (might be a defect connector by 3rd party, don't know). > Short version: antenna good (I bet it's better than the antennas in most > other smartphones with GPS), chip very good -> bug. > > And btw. - SIRF Star III are damn good chips and used in many navigation > devices and bluetooth gps devices, but the antaris is almost at the same > level. > > It surely is no software issue, theoretically it could be a firmware issue > of the u-blox, but I don't think it is. > > _______________________________________________ > Openmoko community mailing list > community@lists.openmoko.org > http://lists.openmoko.org/mailman/listinfo/community > > _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community