TM 1-1510-223-10 3-76           Change 3 (2)    GPS Initialization mode. Successive depres- sions of R1 will cause the GPS mode to toggle from NAV to INIT, with the active mode boxed. Normally, on power- up, a BIT runs for approximately 30 seconds, followed by the nav legend automatically being boxed and the legend QUICK, NORMAL or COLD (indicating start-up mode) being displayed to the right of the text at L5. Valid year data is 1 or two digits in the range 0 through 99. If GPS data displayed is not correct, depress R1 to select INIT and correct data as follows: (a)   GPS position data insertion.   1.   If position is not correct, enter position data into the scratchpad. Valid position  data is X.DD.MM.SS.T. Y.DDD.MM.SS.T, where: X = Latitude Hemisphere.(N or S) DD = Degrees of Latitude (0 - 90) MM = Minutes of Latitude or Longitude SS = Seconds (0 - 59) T = Tenths of Seconds (0 - 59) Y = Longitude Hemisphere (E or W) DDD = Degrees of Longitude NOTE Zero is assumed for minutes and seconds if not entered. If INS is in NAV, its position and altitude will be sent to the GPS in INIT and displayed next to L1. 2.   L1 line selection switch - Depress. With valid data in the scratchpad and GPS in the INIT mode, depressing L1 will cause the scratchpad data to be displayed to the right of the text at L1. (b)   GPS altitude data insertion.   1.   If altitude data is in error, enter valid altitude data into scratchpad. 2.   L2  line  selection  switch  -  Depress. With valid data in the scratchpad and GPS in the INIT mode, depressing L2 will cause the scratchpadded data to be displayed to the right of the text at L2. Valid altitude data is 1 thru 5 digits with a range of 0 - 99999. NOTE The units of altitude for GPS are feet MSL. (c)   GPS time data insertion.   1.   If time data in in error, enter valid UTC time data into scratchpad. 2.   L3 line selection switch - Depress. With a valid time entered in the scratchpad and GPS in the INIT mode, depressing L3 will cause the scratch- padded data to be displayed to the right of the text at L3. Valid time is HH MM SS, where: HH = Hour of the day (0 - 23) MM = Minutes after the hour (0 - 59 SS = Seconds after the minute (0 - 59) NOTE Zero is assumed for minutes and seconds if not entered. 3.   Day of year (DOY) data insertion. 4.   Enter valid day of year (DOY) data into scratchpad. 5.   L4 line selection switch - Depress. With a day of the year (DOY) entered in the scratch- pad and GPS in the INIT mode, depressing L4 will cause the scratchpadded data to be displayed to the right of the text at L4. Valid day of the year data is 1 through 3 digits in the range of 1 through 365. (d)   Year data insertion. 1.   If year is wrong, enter valid year data into scratchpad. 2.   L5  line  selection  switch  -  Depress. With a year entered in the scratchpad and GPS in the INIT mode, depressing L5 will cause the scratchpadded to be displayed to the right of the text at L5. Valid year data is 1 or 2 digits in the range 0 through 99. (3)    GPS quick start-up mode. The QUICK start-up mode is the mode which is normally automatically se- lected by the ASE/ACS. When the QUICK start-up mode is complete, the QUICK legend below the NAV INIT text is removed to cue the crew that the GPS is ready for normal navigation. The transition from QUICK start to navigate mode occurs when 3 or more satellites are be- ing tracked and the figure of merit is less than 9. Figure of merit (FOM) is a single digit from 1 to 9. It represent estimated position error (EPE) in feet as fol- lows: FOM = 1, then EPE < 82 FOM = 2, then EPE < 164 FOM = 3, then EPE < 246 FOM = 4, then EPE < 328 FOM = 5, then EPE < 642