Pilot's Guide

190-00498-08 Rev. A
Garmin G1000 Pilot’s Guide for Cessna Nav III
SYSTEM
OVERVIEW
FLIGHT
INSTRUMENTS
EIS
AUDIO PANEL
& CNS
FLIGHT
MANAGEMENT
HAZARD
AVOIDANCE
AFCS
ADDITIONAL
FEATURES
APPENDICES INDEX
627
APPENDIX D
FREQUENTLY ASKED QUESTIONS
If a particular aspect of G1000 operational capability is not addressed by these commonly asked questions or in
the index, contact Garmin (see the copyright page or back cover for contact information) or a Garmin-authorized
dealer. Garmin is dedicated to supporting its products and customers.
What is sBas?
The Satellite Based Augmentation System (SBAS) uses a system of ground stations to correct any GPS signal
errors. These ground stations correct for errors caused by ionospheric disturbances, timing, and satellite
orbit errors. It also provides vital integrity information regarding the health of each GPS satellite. The signal
correction is then broadcast through geostationary satellites. This correction information can then be received
by any SBAS-enabled GPS receiver.
SBAS is designed to provide the additional accuracy, availability, and integrity necessary to enable users to rely
on GPS for all phases of flight.
There are several SBAS systems serving different parts of the world. The Wide Area Augmentation System
(WAAS) is currently available in the United States, including Alaska and Hawaii. The European Geostationary
Navigation Overlay Service (EGNOS) offers coverage of Europe, parts of the middle east and northern Africa. The
Multi-functional Satellite Augmentation System (MSAS) covers mainly Japan and parts of northern Australia.
hOW DOes sBas aFFect appROach OpeRatiOns?
LP and LPV approaches use the accuracy of SBAS to provide additional precision for lateral (LP, LPV) and
vertical (LPV) guidance capability. LPV approaches also allow lower approach minimums. When SBAS is not
available, LP and LPV approaches cannot be added to the active flight plan. An LP or LPV approach already
loaded will be downgraded to an LNAV or LNAV/VNAV approach, using LNAV or LNAV/VNAV minima.
What is Raim anD hOW DOes it aFFect appROach OpeRatiOns?
When SBAS is unavailable, the GPS receivers use Receiver Autonomous Integrity Monitoring (RAIM) to
perform the following functions:
• Monitor and verify integrity and geometry of tracked GPS satellites
• Notify pilot when satellite conditions do not provide necessary coverage to support a certain phase of
flight
• Predict satellite coverage of a destination area to determine whether the number of available satellites is
sufficient to satisfy requirements (refer to the System Overview Section for instructions on RAIM prediction)
• Detect and exclude bad satellites from the navigation solution (Fault Detection and Exclusion, FDE)
RAIM ensures that satellite geometry allows for a navigation solution calculation within a specified protection
limit (4.0 nm for oceanic, 2.0 nm for enroute, 1.0 nm for terminal, and 0.3 nm for non-precision approaches).
Without SBAS or RAIM, GPS position accuracy integrity cannot be monitored.
NOTE : If RAIM is not predicted to be available for the final approach course, the approach does not become
active, as indicated by the “RAIM not available from FAF to MAP” message and the LOI annunciation
flagging on the HSI.