A similar question was asked in this thread: http://e2e.ti.com/support/low_power_rf/f/869/p/266896/933125.aspx#933125
It seems that there is not a way to get centimeter resolution accuracy:
[quote user="LeonardEllis"]
Accuracy is going to depend on 1PPS accuracy and jitter. Here is an App Note that adresses this issue: http://processors.wiki.ti.com/images/f/f1/TI_GPS_PPS_Timing_AppNote.pdf .
Also, GNS uses the CC4000 in their highly accurate GPS modules, and the TC6000GTIM shows a 2m TYP accuracy, 3m MAX, so I'm guessing that you are not going to achieve <3m with GPS; here is the GNS datasheet: http://www.tc6000.gns-gmbh.com/files/tc6000gtim_datasheet_v002.pdf . As well, the gov't GPS page states an accuracy of 7.8m for GPS: http://www.gps.gov/systems/gps/performance/accuracy/ .
Finally, check out the GPS wiki, you may find some techniques for improving the accuracy, as there is software available there: http://processors.wiki.ti.com/index.php/CC4000_GPS_for_MCU .
Other than the LOC Location Engine technique of the CC2431, I don't believe you are going to get much better location accuracy with GPS.
-Leonard
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