scope:

FOREWORD

The purpose of this manual is to specify technical provisions for the formats and associated protocols used in Mode S services and extended squitter. These detailed technical provisions supplement requirements contained in Annex 10 -Aeronautical Telecommunications, Volume III (Part I -Digital Data Communication Systems), and Volume IV -Surveillance Radar and Collision Avoidance Systems, and are necessary to ensure global interoperability.

The provision of Mode S services, specified in this document, include the following:

a) data formats for transponder registers;

b) formats for Mode S specific protocols:

traffic information broadcast; and

dataflash;

c) Mode S broadcast protocols, including:

1) uplink broadcast; and

2) downlink broadcast.

Formats and protocols for extended squitter automatic dependent surveillance - broadcast (ADS-B) messages are also included since registers are defined for each of these messages. Those registers are assigned so that the extended squitter messages can be readout on demand by a ground interrogator, in addition to being delivered via an ADS-B message.

The second edition of this manual introduces a new version of extended squitter formats and protocols (Version 2). The first edition of this manual specified earlier versions of extended squitter messages (versions 0 and 1). Version 2 formats and protocols were developed to enhance integrity and accuracy reporting. To support identified operational needs for the use of ADS-B not covered by Version 1, a number of additional parameters were included in Version 2. Additionally, several parameters were modified, and a number of parameters no longer required to support ADS-B applications were removed.

The manual also includes implementation guidelines as well as information on future Mode S services that are under development.

This manual has been developed by the Aeronautical Surveillance Panel (ASP). Comments on this manual from States and other parties outside ICAO would be appreciated. Comments should be addressed to:

The Secretary General International Civil Aviation Organization 999 University Street Montreal, Quebec Canada H3C 5H7