Users Manual

ALL

EFFECTIVITY

Page 5-8

22 Apr 2019

23-15-49

SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL

ASPIRE-400

(2) The ACD ADGW uses the ICAO address for AAP addressing.

(3) When the SDU receives an AAP test message, the ACD:

(a) Sends a test Acknowledgment if the message was valid.

(b) Responds with a Message NACK if the message was invalid.

F. Air to Ground

(1) AAP messages sent to the ground are time-stamped with UTC time synchronized over

the SBB air/ground link.

(2) The ACD ADGW populates all Air-to-Ground AAP messages with the current spot beam

ID.

(3) When the ORTenables SBB safety location reporting, the ACD populates current

location information in every Air-to-Ground AAP message including the following as

available:

(a) Current latitude and longitude

(b) Altitude

(d) Ground speed

(e) Source of the position data

(f) Location timestamp indicating time of location data retrieval

(g) Vertical rate.

G. Ground to Air

(1) The ACD discards AAP variable parameters received from the GDGW that are unknown

or not applicable to the supported services and treats the remainder of the message as

valid.

(2) When the SDU receives a message from the GDGW containing:

(a) Invalid indication (e.g. incorrect ICAO)

(b) Out of bounds parameter.

(3) The ACD:

(a) Discards the message

(b) NAK the message indicating invalid message.

H. Security Gateway Functions (SecGW)

(1) The air security gateway parameters (timers, counters) are downloaded through the VPN

using HTTP GET and persist in the AES for use with next VPN setup.

I. PKI Certificate Check

(1) The ACD ASGW obtains the Safety channel authentication information from the safety

USIM.

(2) The ACD ASGW verifies:

DRAFT

3rd rvw Draft as of:

29 January, 2020