In the CWEX11 S directory at EOL is a file of Splus code, latlonalt.q, for computing averages of the GPS values of latitude, longitude and altitude.

I ran it on 6 days of data from Jul 9 11:15 to Jul 15 16:00 (arbitrary period), and it returned the following:

stn

Lat(deg)

Lat stddev(deg)

Lon(deg)

Lon stddev(deg)

Alt(m)

Alt stdev(m)

1

42.06605

1.101896e-05

-93.28521

9.501855e-06

339.0

1.8

2

42.06977

1.317406e-05

-93.28515

1.091214e-05

340.4

1.8

3

42.07344

1.417124e-05

-93.28522

1.358779e-05

340.0

2.0

4

42.07679

1.39572e-05

-93.28523

1.211881e-05

341.6

2.0

Note that the GPS does not provide a highly accurate estimate for altitude, the std deviations are about 2 meters.

Here's a kml file viewable in GoogleEarth, cwex_ncar.kml, with the above positions.