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i compared the specs for the tyco A1029 and ublox TIM-LR dead reckoning gps modules and found a few differences:
the tyco A1029 does not come with internal SRAM that can be backed up with a backup battery. from my understanding, the backup battery on the A1029 only maintains the RTC and i believe that the position information is not stored for next use if the power is cut off from the module. however, if a command is sent before power is cut off, the position data will be stored in the on-board flash memory and will be available when power is restored. this may be a little difficult to manage since the com port may be tied up by other programs before a carpc goes into hibernate mode. i'm going by the assumption that power to the gps module will be lost when the car is shut off. if power is maintained, this will be a no issue.
the ublox contains internal SRAM that is backed up with a battery when power is lost. there is no need to send any commands to the module in regard to position data.
an alternative is to go with tyco's A1030 module which is programmable and contains the SRAM memory that is battery-backed. this seems to be a more comparable module to the ublox. i'm not sure what pricing info is for this module.
another difference is that the ublox tracks up to 16 satellites whereas the tyco tracks up to only 12. this isn't a big factor since 4 satellites are sufficient for gps positioning.
price is also another big difference... after contacting a retailer for the tyco A1029B, they changed their pricing as follows: 1-15 units @ $132/unit, 16-127 units @ $47.87/unit, and the price break continues for higher quantities (no more minimums). ublox is still sitting at $199.
i'm leaning towards a ublox at this point...
can anyone shed any more light on my findings?
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