12-10-2012, 01:09 PM
Development of an Airborne Internet Architecture to Support SATS: Trends and Issues
Development of an Airborne.pdf (Size: 125.18 KB / Downloads: 29)
ABSTRACT
NASA is undertaking the development of the Small Aircraft
Transportation System (SATS). SATS could play a major
role in decreasing the doorstop to destination times for
travel and shipping. It is conceived to meet four major
objectives: higher volume at non-towered/non-radar
airports, lower landing minimums at minimally equipped
landing facilities, increased single crew safety and mission
reliability, and integrated procedures and systems for
integrated fleet operations. SATS is to be prototyped in the
2005 timeframe.
A key enabling technology for such a system is the
development of an Airborne Internet to provide aircraft to
the ground, ground to ground and aircraft to aircraft
communications in support of air traffic management, fleet
operations, and passenger support services. A critical first
step in attaining the desirable capabilities of an airborne
Internet is a well-conceived architecture. The architecture
must be robust enough to enable the concept of operations
envisioned for the 2025 timeframe yet flexible enough to
support prototyped using technology and systems available
in the 2005 timeframe.
INTRODUCTION
The hub and spoke system consisting of a handful of major
air carriers servicing only the largest of the country’s
airports is at or near saturation. Travel delays are costing
the US economy hundreds of millions of dollars in lost time
and revenue. To address this problem, NASA has
conceived of the Small Aircraft Transportation System
(SATS). This system is envisioned to use a combination of
technologies in an attempt to create a set of small (4 – 10
passenger) aircraft and associated systems capable of
providing efficient, economical air travel to the nation’s
smaller, under-utilized airports.
SATS: CONCEPTS, OBJECTIVES, PROGRAM
NASA is taking leadership in developing technologies for a
Small Aircraft Transportation System (SATS) that could
play a major role in helping to relieve large airport
congestion and provide reliable, convenient, safe
environmentally compatible air transportation service to
rural and outlining communities, as well as revolutionizing
the national transportation system. The AGATE and GAP
programs have taken a quantum step in this process through
the development of affordable, easy to use, environmentally
friendly aircraft and propulsion systems. This investment is
already benefiting the flying public through much more
affordable, informative and readable avionics systems and
will soon cause a revolution in small aircraft with the
introduction of a whole new class of aircraft; safe,
comfortable, affordable small jet aircraft. To bring the
SATS vision to its full potential of a personal transportation
alternative, however, will require major technology
enhancements to the national air space (NAS) system, and
another order of magnitude advancement in affordability,
performance and environment impact for aircraft systems.
ARCHITECTURE DEVELOPMENT
METHODOLOGY
An architecture defines the structural and collaborative
relationships of system components. Often described using
views (e.g., functional, component, implementation,
temporal, user), the architecture provides information to
guide system and software developers during initial
development and inevitable system improvement activities.
In addition to defining the functional and physical
relationships between system components, an architecture
often provides design guidance in an attempt to achieve
other desirable objectives such as efficient resource
utilization, incremental development, verifiability, use of
COTS products, ease of maintenance, and system
extensibility.
TRENDS AND ISSUES
An important part of any analysis is the identification of
trends and issues that may impact the system development.
This is especially true for SATS, as it must coexist with
other aircraft in the National Airspace System (NAS) for
several years to come.
Trend – Capacity constraints of the current hub/spoke
system are leading to a desire to take advantage of excess
capacity of small/medium sized airports. Issues to be
considered include:
• Most small and medium-sized airports have limited if
any instrument landing equipment. Meeting the SATS
objective of landing during “all weather” conditions
will require that these airports be equipped with
sufficient augmentation and communications support
equipment to provide separation during arrivals and
departures at these airports.
• Overcoming today’s “one-in, one-out” rule at smaller
airports will require improved surveillance systems so
that SATS aircraft cannot only separate from each other
but maintain separation from non-SATS aircraft.
Today’s NAS supports a large variety of aircraft with
an even larger variation in the configuration of onboard
avionics. SATS aircraft will need to co-mingle with
these less well-equipped aircraft. This requires that the
SATS aircraft assume primary responsibility for
separation. SATS aircraft will need to be able to
determine the position of their aircraft relative to non-
SATS equipped aircraft.
ROADMAP OF FUTURE ACTIVITIES
We intend to continue applying the methodology defined
above to develop Airborne Internet alternatives, analyze the
advantages and disadvantages of each alternative and arrive
at a recommendation. Then, working with other SATS
organizations we will refine the architecture and document
it for use by system developers. Key elements of the
architecture will be prototyped and evaluated to better
understand their applicability to SATS. Estimates of
performance and cost will be made. A separate security
assessment will be produced.