mygps66iaccuracy[] takes two arguments. The first argument is a single list containing measurements with each measurement being of the form:
{{YYYY,m,d,h,m,s},{±DD.DDD,±DD.DDDDD}}. The second argument is the accuracy in feet.
An example containing 10 measurements:
samptrack={{{2022,6,10,17,52,43.},{38.9374,-771929}},{{2022,6,10,17,52,44.},{38.9374,-771929}},{{2022,6,10,17,53,10.},{38.9374,-771929}},{{2022,6,10,17,53,18.},{38.9374,-771929}},{{2022,6,10,17,53,36.},{38.9374,-771929}},{{2022,6,10,17,54,53.},{38.9374,-771929}},{{2022,6,10,17,58,52.},{38.9375,-77193}},{{2022,6,10,18,1,48.},{38.9375,-77193}},{{2022,6,10,18,4,31.},{38.9374,-771929}},{{2022,6,10,18,4,54.},{38.9374,-771929}}}a
Here is an example of those 10 measurements, 7 of which are within 10 feet horizontally of the average location: