GPS GeoLocation Navigation Information

Traditionally positions are given using degrees, minutes, and seconds of angles in two measurements:
  1. latitude, the angle north or south of the equator
  2. longitude, the angle east or west of the Prime Meridian aka  International Date Line
  
A Minute of angle is one sixtieth of one Degree and equals about 1.86 km or 1.15 miles
A Second of angle is one sixtieth of one Minute and equals about 30 meters or 100 feet
When Selective Availability is turned off accuracy is within 150 feet
Differential GPS is accurate to within 2 metres.
Which makes me think we need to record locations to within 2/30th of a second.
The Android can report position in three different formats:
  
FORMAT_DEGREES Constant used to specify formatting of a latitude or longitude in the form "[+-]DDD.DDDDD where D indicates degrees. However the references I see are to 6dp.
  
FORMAT_MINUTES Constant used to specify formatting of a latitude or longitude in the form "[+-]DDD:MM.MMMMM" where D indicates degrees and M indicates minutes of arc (1 minute = 1/60th of a degree).
  
FORMAT_SECONDS Constant used to specify formatting of a latitude or longitude in the form "DDD:MM:SS.SSSSS" where D indicates degrees, M indicates minutes of arc, and S indicates seconds of arc (1 minute = 1/60th of a degree, 1 second = 1/3600th of a degree).
  
  
1 degree = 1.000000
1 minute  = 0.016667
1 second = 0.000278
2/30th second = 0.000019