"I think when all the satellites are operational the accuracy is in the cm's (<10cm)" Do you have a source on that accuracy figure? Is that using what is called 'P code' - Precision code, using a 10.23 MHz chip rate and available -so far- only to the US Military versus 'C/A code' - (Course/Acquisition code - available for civil apps) which uses a 1.023 MHz chip rate? There are ways right now to gain increased accuracy - such as DGPS - differential GPS - simplified explanation: a technique wherein *the position error* in the GPS sugnal from the satellites in a given geographical area is noted and transmitted for use as a correction factor by user-segment GPS equipment. One could *also* implement one's own localized "GPS" system (as was done when test of the system was done at Yuma Az) during development testing. One could use the principles of the GPS system and implement a localized position determining system using unlicensed gear in the 900 MHz ISM-band ... perfect app for a PIC ... Jim (a veteran of GPS/HDUE (High Dynamic User Equipment) development at TI in the late seventies ...) ----- Original Message ----- From: "Kathy Quinlan" To: Sent: Friday, August 31, 2001 9:10 AM Subject: Re: [EE]: - Botboard > Start another war involving America, all the military satellites come online > and use GPS I think when all the satellites are operational the accuracy is > in the cm's (<10cm) > > Regards, > > Kat. > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics