User's Manual

Chapter 4 – Principles of Operation

SKY899 Pilot’s Guide

4-6

Preliminary

TA Symbol Duration

A TA symbol remains on the screen for at least 8 seconds, even

if the intruder aircraft no longer meets the

TA criteria, as long

as the

SKY899 continues to track the aircraft.

Ground Intruder Filtering

Ground intruder filtering reduces the clutter of visual symbols

and aural announcements that would otherwise be generated

for intruder aircraft typically present on or near the ground

near airports.

For intruder aircraft determined to be below

380 ft AGL,

ground intruder filtering prevents the issuing of TAs and PAs,

and prevents the display of

OT symbols. (See figure 4-1.)

The

SKY899 uses ground intruder filtering only if your aircraft

has a radio altimeter and you’re below

1,700 ft AGL.

ADS-B

Unlike the current ATC system of ground-based Secondary

Surveillance Radar (SSR) interrogations and aircraft transponder

replies, the

ADS-B-based Free Flight Air Traffic Management

(

ATM) system of the future will depend more on aircraft-to-

aircraft exchange of aircraft state information (figure

4-4).

Ground Intruder Filtering

Figure 4-4. ADS-B

Intruder

aircraft

Own aircraft

GPS satellite

ADS-B

squitter

message

GPS satellite