FINAL REPORT - Stakeholders - Ofcom

• achievement of required data rates and latency times for ATS were expected to
require the use of relatively expensive ground based electronically scanning
antennae;
• alternative data links in the VHF and L-Band appeared to be becoming available.
Whereas these reasons are still valid, the study team feel that it may be worth revisiting
the possible use of Mode S:
• Mode S provides a very secure data link compared with other modes;
• the spectrum is available and expected to be capable of supporting the data
load;
• the system is well standardised and has been demonstrated;
• a mandate for Mode S enhanced surveillance would provide a level of equipage
that could be upgraded to support data communication on 1030/1090 MHz
channels.
Implementation of data services on 1030/1090 MHz channels would alleviate the load on
the VHF spectrum.
5.8 Replacement Technologies (radio, other or none)
5.8.1 Introduction
There are a number of replacement technologies for which there are emerging
development plans but for which standardisation and demonstration is immature.
Implementation dates and, in some cases, frequency assignments, are very uncertain
and probably only possible from 2012 onwards. The identified technologies are:
• New satellite services including:
• Next Generation Satellite Service (NGSS);
• Satellite Data Link Service (SDLS);
• Broadband technology;
NGSS is used to refer to the LEO/MEO systems such as Iridium and Globalstar whose
primary purpose was mass communications market but which initially offered aviation
service. ICAO is currently considering none of these systems.
SDLS is a long term ESA research programme aim at demonstrating improvements to the
current AMSS. During the course of this study EUROCONTROL have commenced work on
NexSat which is a proposed L-band satcom solution which includes elements of the
SDLS programme.
Other companies have shown interest in providing new aeronautical mobile satellite
communications systems both in the existing L-band allocation and at other frequencies
such as Ka- and Ku-band which do not have an aeronautical allocation. Given the
embryonic nature of these systems they have not been discussed in detail.
5.8.2 Establishment of new satellite services
This section considers two possible future satellite systems which could carry
aeronautical traffic:
• the next generation satellite system;
• SDLS.
Page 166