GPS STATUS PAGE

Satellite Status Page

•Satellite constellation displaying the following for each satellite being tracked:

Azimuth Elevation PRN number Tracking status

•A receiver tracking status display that displays the following GPS sub-system status situations:

‘2D NAV’, when only 2-dimensional position is available

‘3D NAV’, when 3-dimensional position is available

•Estimated position error

•Dilution of precision

•Horizontal uncertainty level

•GPS calculated position

•GPS calculated time of day

•GPS calculated altitude

•Ground Speed

•Track

MULTI FUNCTION DISPLAY

The sky view display at the top left corner of the page shows the satellites currently in view as well as their respective positions. The outer circle of the sky view represents the horizon (with north at the top of the circle); the inner circle represents 45° above the horizon and the center point shows the position directly overhead. Each satellite has a 30-second data transmission that must be collected (hollow signal strength bar) before the satellite may be used for navigation (solid signal strength bar). Once the GPS receiver has determined your position, the G1000 indicates your position, altitude, track and ground speed. The GPS receiver status field also displays the following messages under the appropriate conditions:

•Acquiring Sat - The GPS receiver is acquiring satellites for navigation. In this mode, the receiver uses satellite orbital data (collected continuously from the satellites) and last known position to determine the satellites that should be in view.

•2D Navigation - The GPS receiver is in 2D navigation mode.

•3D Navigation - The GPS receiver is in 3D navigation mode and computes altitude using satellite data.

MULTI FUNCTION DISPLAY

The Satellite Status Page also indicates the accuracy of the position fix, using Estimated Position Error (EPE) and Dilution of Precision (DOP) figures. DOP measures satellite geometry quality (i.e., number of satellites received and where they are relative to each other) on a range from 0.0 to 9.9. The lowest numbers are the best accuracy and the highest numbers are the worst. EPE uses DOP and other factors to calculate a horizontal position error, in feet or meters.

RAIM Prediction

“RAIM” is an acronym for Receiver Autonomous IntegrityMonitoring,aGPSreceiverfunctionthatperforms a consistency check on all tracked satellites. RAIM ensures that the available satellite geometry will allow the receiver to calculate a position within a specified protection limit (2.0 nautical miles for oceanic and en route, 1.0 NM for terminal and 0.3 NM for non-precision approaches). During oceanic, en-route, and terminal phases of flight, RAIM is available nearly 100% of the time.

Because of the tighter protection limit on approaches, there may be times when RAIM is not available. The G1000 automatically monitors RAIM and warns you with an alert message when it is not available. If RAIM is not available when crossing the FAF, the pilot must fly the missed approach procedure.

The RAIM prediction function also indicates whether RAIM will be available for a specified date and time. If RAIM is not predicted to be available for the final approach course, the approach does not become active

— as indicated by an “Approach is not active” message, and a “RAIM not available from FAF to MAP” message.

To predict RAIM availability:

1.Select the GPS Status Page.

2.Press the FMS knob. Turn the small and large

FMS knobs to select the ‘WAYPOINT’ field.

3.Turn the small FMS knob to display the Waypoint Information Page.

4.Turn the small and large FMS knobs to enter the desired waypoint. Press the ENT key to accept.

5.Turn the small and large FMS knobs to enter an arrival time and press the ENT key.

6.Turn the small and large FMS knob to enter an arrival date.

7.The cursor highlights the ‘COMPUTE RAIM’ field. Press the ENT key to compute RAIM.The following options are displayed:

•‘COMPUTE RAIM?’ if RAIM has not been computed for the current waypoint, time, and date combination

•‘COMPUTING AVAILABILITY’ if the RAIM calculation is in progress

•‘RAIM AVAILABLE’ if RAIM is predicted to be available for the given combination of waypoint, time, and date

•‘RAIM NOT AVAILABLE’ if RAIM is predicted to be unavailable for the given combination of waypoint, time, and date

NOTE: RAIM computations predict satellite coverage within +/- 15 minutes of the specified arrival date and time.

Figure 7-79 RAIM

GPS Signal Strength

The Satellite Status Page can be helpful in troubleshootingweak(ormissing)signallevelsduetopoor satellite coverage or installation problems. Refer to this page occasionally to monitor GPS receiver performance and establish a normal pattern for system operation. Should problems occur at a later date, it may be helpful to have an established baseline from which to compare.

MULTI FUNCTION DISPLAY

As the GPS receiver locks onto satellites, a signal strength bar is displayed for each satellite in view, with the appropriate satellite number (01-32) underneath each bar. The progress of satellite acquisition is shown in three stages:

•No signal strength bars - the receiver is looking for the satellites indicated.

•Hollow signal strength bars - the receiver has found the satellites and is collecting data.

•Solid signal strength bars - the receiver has collected the necessary data and the satellites are ready for use.

•Checkered signal strength bars - the receiver has excluded the satellite (FDE).