High Altitude Aeronautical Platform | Electronics Seminar Topic
High Altitude Aeronautical Platform
High Altitude Aeronautical Platform Stations (HAAPS) is the
name of a technology for providing wireless narrowband and broadband
telecommunication services as well as broadcasting services with either
airships or aircrafts. The HAAPS are operating at altitudes between 3 to 22 km.
A HAAPS shall be able to cover a service area of up to 1'000 km diameter,
depending on the minimum elevation angle accepted from the user's location.
The platforms may be airplanes or airships (essentially
balloons) and may be manned or un-manned with autonomous operation coupled with
remote control from the ground. HAAPS mean a solar-powered and unmanned
airplane or airship, capable of long endurance on-station –possibly several
years.
A high altitude telecommunication system comprises an airborne
platform – typically at high atmospheric or stratospheric altitudes – with a
telecommunications payload, and associated ground station telecommunications
equipment. The combination of altitude, payload capability, and power supply
capability makes it ideal to serve new and metropolitan areas with advanced
telecommunications services such as broadband access and regional broadcasting.
The opportunities for applications are virtually unlimited.
The possibilities range from narrowband services such as paging and mobile
voice to interactive broadband services such as multimedia and video
conferencing.
For future telecommunications operators such a platform could
provide blanket coverage from day one with the added advantage of not being
limited to a single service. Where little or unreliable infrastructure exists,
traffic could be switched through air via the HAAPS platform.
Technically, the concept offers a solution to the
propagation and rollout problems of terrestrial infrastructure and capacity and
cost problems of satellite networks. Recent developments in digital array
antenna technology make it possible to construct 100+ cells from one platform.
Linking and switching of traffic between multiple high altitude platforms,
satellite networks and terrestrial gateways are also possible. Economically it
provides the opportunity for developing countries to have satellite-like
infrastructure without the funds flowing out of the country due to gateways and
control stations located outside of these countries.
The platform is positioned above the coverage area. There
are basically two types of HAAPS. Lighter-than air HAAPS are kept stationary,
while airplane-based HAAPS are flown in a tight circle. For broadcast
applications, a simple antenna beams signals to terminals on the ground.
For
individualized communication, such as telephony, "cells" are created
on the ground by some beam forming technique in order to reuse channels for
spatially separated users, as is done in cellular service.
Beam forming can be as sophisticated as the use of
phased-array antennas, or as straightforward as the use of lightweight,
possible inflatable parabolic dishes with mechanical steering.
In the case of a
moving HAAP it would also be necessary to compensate motion by electronic or mechanical
means in order to keep the cells stationary or to "hand off"
connections between cells as is done in cellular telephony
