TM 55-1510-220-10 NOTE Prior   to   next   step,   ensure   all   required initialization data has been entered correctly,  as  they  cannot  be  changed  after selection of NAV mode. 6. Mode selector switch NAV. GPS will begin to search for satellite signals. NOTE If COLD alternates with the figure of merit display, the GPS is performing a cold start. 7. Data selector switch STAT. NOTE The    number    of    satellites    (SAT)    being acquired   and   tracked   can   be   observed. Estimated  position  error  (EPE)  and  figure of merit (FM) can be monitored.  The GPS will   be   ready   for   use   for   INS   updating when  SAT  4  is  displayed  on  STAT  page  1 and FM (figure of merit) is PM3 or below. 8. Select page 2 of STAT. Check almanac age (ALM). If greater than 5000 hours, force a cold start. 9. While the GPS is acquiring satellites, periodically check STAT page I for SAT 4 message.  Figure  of merit (FM) is another indication of a converging position fix and can be directly monitored from page 1 of any data selection, where FM alternates with the system map datum and other alerts. 10.   SAT 4 should be displayed within five minutes.  If not, check that position, time, track, and groundspeed have been entered correctly.  Also check  that   satellites  are available.  If all information is correct and satellites are available, force a cold start. (b)  GPS quick start. 1. Mode selector switch Set to NAV directly from OFF.  After power-on test has been completed, the  GPS uses   velocity estimates from the aircraft's   sensors (if available). If velocity is not available  from the aircraft, zero velocity is assumed.    If  position  and time are not available from the aircraft, the position estimate from GPS memory is used, and the internal low power time source (LPTS) is used to    initialize time. 2. As the GPS is acquiring satellites, position, time, and velocity estimates can be    checked to ensure that they are within startup error limits.  If so, monitor STAT page 1.  If not, a normal start is required. 3. After SAT 4 is achieved with good EPE (estimated position error), and FM (figure of merit) of FM3 or below, check position, velocity, and time. 4. GPS is now ready for normal navigation. (c) GPS cold start. 1. Mode selector switch INIT. 2. Data delector switch OPT. 3. Slew key Select page 4. 4. Enter 04 on line 1. 5. Line select key 2 Press next to COLD START to initiate. 6. Line select key 3 Press next to COLD START to clear cold start message and resume normal display. 7. Mode selector switch NAV. Change 5        3-76E/(3-76F blank)