Garmin GNC 420W Pilots Guide - Page 16

SECTION 1 INTRODUCTION Satellite Status Page The Satellite Status Page (Figure 1-10) appears as the GNC 420 attempts to collect satellite information. An 'Acquiring' status is displayed on the Satellite Status Page, and the signal strengths of any satellites received appear as 'bar graph' readings. This is a good indication that the unit is receiving signals and a position fix is being determined. Following the first-time use of the GNC 420, the time required for a position fix varies, usually from one to two minutes. Viewing a system message: Press the MSG Key (Figure 1-11). The Message Page appears and displays the status or warning information applicable to the receiver's current operating condition. Figure 1-11 Message Page Figure 1-10 Satellite Status Page If the unit can only obtain enough satellites for 2D navigation (no altitude), the unit uses the altitude provided by the altitude encoder (if one is connected). The 'INTEG' annunciator (bottom left corner of the screen) indicates that satellite coverage is insufficient to pass built-in integrity monitoring tests. In the example above, not enough satellites are being received to determine a position. The Satellite Status Page shows the ID numbers for the satellites and the relative signal strength of each satellite received (as a bar graph reading). 'Searching Sky' indicates that satellite almanac data is not available or has expired (if the unit hasn't been used for six months or more). This means the unit is acquiring satellite data to establish almanac and satellite orbit information, which can take five to ten minutes. The data is recollected from the first available satellite. The Satellite Status Page displays a 'Search Sky' status, and the message annunciator (MSG), above the MSG Key also flashes to alert the pilot of a system message, 'Searching the Sky'. Returning to the previous page after viewing a message: Press the MSG Key again. NOTE: The GNC 420 utilizes certain software algorithms to ensure reliable GPS receiver operation. Receiver Autonomous Integrity Monitoring (RAIM) and Fault Detection and Exclusion (FDE) are two examples. These features allow navigation during Oceanic/Remote legs of a flight using the GNC 420. For further details, please refer to Sections 10.3 and 12. 1-8 GNC 420(A) Pilot's Guide and Reference 190-00140-20 Rev. K