Iam - CEAS. Council of European Aerospace Societies

AIR POWER
THE ELECTRONIC BEAMFORMING RADARS
Another way to detect a ballistic missile is to use electronic
beam-forming radar, based on land or ship. The radar
will scan the horizon in order to build a detection fence.
Depending on the location of the radar towards the missile
trajectory, and depending also on the radar range, the missile
trajectory will cross the fence and rings the bell, during
the missile boost phase or later, during mid-course, when
the booster is burnt out. Whenever the missile and its warhead
are within range of the radar, the beam will give a
direct measurement of the missile position and speed, and
will possibly give a “radar scan” of the payload (Figure 2).
If we compare the radar and the geostationary satellite, we
see that their geographic coverage are constrained by different
parameters. For the satellite, the covered area
20 • CEAS Quarterly Bulletin - December 2012 •
depends on the sensor sensitivity,
on the FOV (Field of View), on the
revisit time, ... , on the satellite longitude
and communication
constraints. For the radar, it
depends on its geographic location,
range and angular coverage and
search rate. This coverage can be
optimized.
For the satellite, the coverage can
be improved by a compromise between
the global area covered, the
instantaneous Field of View/accuracy,
the sensitivity and the false
alarms rate.
For the radar, the detection area can
however be maximized, either by
choosing a low frequency powerful
long range radar (UHF) which allows
to reach several thousands of km,
or by operating radars linked into a
detection network belt, where the
radar coverage are adding to each
other. The radar beam can also be
cued to the missile rough location
by the satellite detection which
helps to increase the radar range
but also to suppress the false
detections coming from the satellite
by confirming or infirming the presence
of the missile.
Furthermore, once the first detection
is performed by the radar, the latter
can track the missile during a long
time, offering a long observation duration
and accuracy, even after the
booster burnt out. The radar can track
indeed the missile in boost phase or
the cold warhead during mid-course,
when it follows a ballistic path.
> Early Warning satellite and radar are
therefore complementary.
For decades, the USA and Russia (Figure 3) have developed
and operated Early Warning satellites (Defence
Support Programme – DSP -, then Space-Based IR
System - SBIRS - for the USA) and low frequencies radars
BMEWS radars, Large Phased Array – LPA – Soviet radars;
Voronezh type Russian radars). These EW radars are fixed.
Some US radars had been located in the northern part of
Europe since the Cold War and oriented to look above the
North Pole horizon to detect the incoming Soviet ICBMs
flying inbound to the US continent. The USA have also
recently deployed in Turkey a medium range radar called
TPY2, to provide a detection capability against missiles
that could be launched from the South.
The Japanese made a choice to detect the ballistic missiles
that could be launched from North Korea by using a