Defense Intelligence Reference Document Detection And High Resolution Tracking Of Vehicles At Hypersonic

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red penalty at close range would be significantly offset by the high speed of the
flight."
This discussion about the AJAX engine concerned the generation of ion combustion products
that would be further accelerated by an MHD (magnetohydrodynamic drive). The increased
number of various carbon-based molecules in the wake of this aircraft could be detected
using LIDAR. The increased temperature near the surface of this aircraft would also increase
its detectability due to increased emission of infrared radiation. For AJAX (AYAK) vehicles,
development of enhanced LIDAR systems and IR detectors should proceed over the next 30
years to increase their detection and tracking.
Recommendation #4 - Explore the Development of Novel Detectors
One characteristic of hypersonic flight (M > 5) is the ionization of air in the region
downstream of the bow shock and the disassociation of oxygen and nitrogen at very high
speeds. When electrons recombine with ions generated by the shock, they emit
electromagnetic radiation that can be detected. This radiation extends from the visible
range, as evidenced by the glowing trail left by meteors entering the Earth's atmosphere, but
the emitted radiation also extends into the ultraviolet and x-ray range. Although such
electro-optical sensors are likely part of the existing DARPA/USAF space surveillance system,
telescope systems that monitor the UV range should be developed, along with x-ray
detectors capable of monitoring the atmosphere.
Hypersonic objects passing through the atmosphere disassociate nitrogen and oxygen which
recombine in the object's turbulent wake. During recombination, new molecules are created,
including NO, NO2, ionized O and N, and combustion products. 32 LIDAR can detect the
presence and concentration of these compounds in vehicle wakes and improved LIDAR
systems should be a priority.
As hypersonic objects pass through the atmosphere, the object becomes ionized with a
significant positive charge. Technology should be developed to sense the flight of objects
with an electrostatic charge as they pass through the atmosphere.
SUMMARY
Each detection system discussed in the previous section has both benefits and problems. A
comparison of the various detection techniques is shown in Figure 19 based on their ability to
detect specific properties, relative cost, and accuracy.
Infrared detection systems and multispectral cameras installed on satellites, such as the KH-
II, provide surveillance of large portions of the Earth for possible missile launches, reentry
vehicle trajectories, meteor wakes, and hypersonic vehicles. RADAR systems based on
satellites, ships, and aircraft can detect the position and velocity of such hypersonic objects
at varying range. AWACS, for example, can detect objects at up to 370 km with a resolution
of 0.5 meters. TRADEX can track up to six objects at a distance of 1,400 km with an
accuracy of 3 meters and a velocity resolution of 0.01 m/s.
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