FINAL REPORT - Stakeholders - Ofcom

the cost to an already saturated channel. The studies should also assess the timescales
over which the applications will remain effective given that increased traffic will further
saturate the channel. Crucially, it should be ensured that the introduction of new
applications does not impact on existing safety of life applications such as SSR and
ACAS.
Recommendation 3.19: Ofcom should work with the CAA to evaluate other technologies
for ADS-B and ensure that spectrum efficient solutions are developed and implemented.
Socio-economic factors
The introduction of ADS-B via 1090 extended squitter is possible at the same time as
airborne equipment is upgraded to support Mode S enhanced surveillance. Hence, from
the point of view of commercial aircraft users, there is marginal cost argument that
favours implementation of 1090 ES rather than some other ADS-B system such as UAT
or VDL Mode 4. A EUROCONTROL study analysed costs for the three ADS-B systems
and concluded that a new installation of VDL Mode 4 or UAT would cost between £30k
and £40k per aircraft compared with an upgrade of equipment already installed as part of
a Mode S enhanced surveillance equipage. Pricing mechanisms could therefore work to
alleviate congestion of the 1090 MHz band. However, because of the international nature
of aviation, there is a need first for the aeronautical community to determine a strategy for
the long term use of ADS-B in order to ascertain detailed requirements. At that point, use
of incentive pricing might be appropriate to encourage the most spectrum efficient
solution.
The final recommendation applies to extension of the use of the 1030 MHz frequency.
Recommendation 3.20: The possibility of further utilising 1030MHz (for example, for TIS-
B) should be encouraged and studied.
3.4 Aeronautical Radio-Navigation Services (ARNS)
3.4.1 Introduction
The primary purpose of navigation is to enable an aircraft to “plan, direct, or plot its path”
[from Collins English Dictionary] from departure to destination.
In the early days of aviation, this would be the remit of a specialist member of the flight
crew (navigator), whose task it was to plot the routing on a map, using visual observation
marks. This method of navigation, known by some as ‘pilotage’, is still used in today’s
VFR (Visual Flight Rules) flights mainly undertaken by GA aircraft. Allied to this method is
dead reckoning: a mathematical calculation of time, distance and direction, by which a
pilot can chart the course of his flight. Dead reckoning is still used in many forms of
aviation as an error check.
In today’s environment, navigation is a mix of ground-based radio navigation aids, inertial
systems and satellite navigation systems. These provide pilots with a means to navigate
accurately, even when in instrument meteorological conditions (i.e. IFR – Instrument
Flight Rules). Together, these aids form the radionavigation service, the definition of
which is: “a radiodetermination service used for the purposes of navigation, including
obstruction warning (radiodetermination is the determination of the position, velocity
and/or other characteristics of an object of information relating to these parameters, by
means of the propagation properties of radio waves)”- source: ITU-R website.
The primary purpose is still to allow aircraft to direct themselves from A to B. However, in
today’s crowded airspace, aircraft must do this whilst respecting ATC system constraints.
These are put in place for two main reasons:
• To maintain or improve the safety of the flight (and overall traffic situation);
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