Thanx for all that good information. GPS Receivers a fairly cheep and they output rs232 which means a microcontrol would be able to handle all the processing needed. And for the task at hand it could give you that and more.
I wish someone would do a tutorial on this site about GPS and their outputs. I beleive the format they output is know as NMEA often pronounce (knee-ma). NMEA is an orginization the provides standards to marine equipment. Hince the name National Marine Electronics Association
The GPS Protocol provides:
$GPGGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh
GGA = Global Positioning System Fix Data
1 = UTC of Position
2 = Latitude
3 = N or S
4 = Longitude
5 = E or W
6 = GPS quality indicator (0=invalid; 1=GPS fix; 2=Diff. GPS fix)
7 = Number of satellites in use [not those in view]
8 = Horizontal dilution of position
9 = Antenna altitude above/below mean sea level (geoid)
10 = Meters (Antenna height unit)
11 = Geoidal separation (Diff. between WGS-84 earth ellipsoid and
mean sea level. -=geoid is below WGS-84 ellipsoid)
12 = Meters (Units of geoidal separation)
13 = Age in seconds since last update from diff. reference station
14 = Diff. reference station ID#
15 = Checksum
**broken link removed**