May 19, 2007: Both India and Pakistan are using
radar aerostats (blimps) to fill in the many gaps in the radar coverage of
their mutual border. India is getting
theirs from Israel, while the United States is providing aerostats to Pakistan.
India already has two aerostats, bought three years ago, and is getting four
more. It needs a total of 13 to cover all its borders. Pakistan is getting six
L-88 Aerostat Systems. Indias decision to move ahead on its aerostat system is,
in part, motivated by the recent success of LTTE rebels in Sri Lanka, using
single engine commercial aircraft to bomb military targets (without much
success, but the potential of such low flying aircraft was demonstrated.)
Aerostat systems use a 100-250 foot long, helium
filled, unmanned blimp equipped with radar and other sensors. The larger of
these blimps are more than twice the size as the more familiar advertising
blimps. An aerostat is designed to always turn into the wind and stay in the
same place. An aerostat is unpowered, and secured by a cable that can keep the
aerostat in position at its maximum altitude of 15,000 feet. At that altitude,
a large aerostat can carry a two ton payload. The cable also supplies power,
which means the blimp can stay up for about 30 days at a time before it has to
be brought down for maintenance on its radars. Often, two radars are carried.
One is a surveillance radar, the other is a precision track and illumination
radar (PTIR). The surveillance radar provides long-range coverage (nearly 400
kilometers), while the PTIR, which is a steerable system capable of tracking
multiple targets, can focus in on items of interest.
Aerostat systems cost varies from $5 million, to
over $100 million each, depending on the size of the aerostat and the
capabilities of the radar and other sensors. Aerostats work. Kuwait had one in
1990, and the ground radar spotted the Iraqis as soon as they crossed the
border. The U.S. uses dozens of aerostat systems in Iraq and Afghanistan, to
guard bases.
