Garmin Cirrus Perspective SR20 Pilot's Manual page 48

SYSTEM OVERVIEW
Satellite Constellation
Diagram
The GPS Status Page provides the following information:
• Satellite constellation diagram
Satellites currently in view are shown at their respective positions on a sky view diagram. The sky view is
always in a north-up orientation, with the outer circle representing the horizon, the inner circle representing
45° above the horizon, and the center point showing the position directly overhead.
Each satellite is represented by an oval containing the Pseudo-random noise (PRN) number (i.e., satellite
identification number). Satellites whose signals are currently being used are represented by solid ovals.
• Satellite signal information status
The accuracy of the aircraft' s GPS fix is calculated using Estimated Position Uncertainty (EPU), Dilution
of Precision (DOP), and horizontal and vertical figures of merit (HFOM and VFOM). EPU is the radius of a
circle centered on an estimated horizontal position in which actual position has 95% probability of laying.
EPU is a statistical error indication and not an actual error measurement.
Cirrus Perspective
34
Satellite Signal
Information
Figure 1-24 GPS Status Page
by Garmin – Pilot's Guide for the SR20/SR22/SR22T
™
GPS Receiver
Status
RAIM
Availability
Prediction
Satellite
Signal
Strength
Bars
190-00820-08 Rev. A