Recent FAA data shows their high quality, single frequency GPS receivers attaining horizontal accuracy of . m . ft. , of the time..D Operating Mode A two dimensional GPS position fix that includes only horizontal coordinates no GPS elevation . It requires a minimum of three .USCG Navigation Center Plane Slot SVN PRN Block Type Clock Outage Date Nanu Type Nanu Subject A IIF.M code or M Code may refer to. Machine Code MATLAB programming language Military GPS signal or GPS_signals Military_.M code. , or half of the G M Code .