The Defense Advanced Research Projects Agency (DARPA) is developing a Video Synthetic Aperture Radar (ViSAR) system designed to provide a targeting capability for the AC-130 gunship in conditions where the current electro-optic systems will not perform. By using radar, the gunship’s availability rises from 35% to 72%, as clouds currently obscure the EO/IR camera’s view of the ground. Several technical issues must be addressed in the program in order to be successful. In order to achieve frame rates fast to track maneuvering targets, the radar must operate at frequencies over 170 which requires the development of new electronics. Secondly, as targets move in the FOV of a Synthetic Aperture Radar (SAR) their apparent position is translated in the generated imagery. Thirdly, as the imagery generated is range versus azimuth rather than elevation versus azimuth, tall objects appear to be “laid over” unless corrections are made for the true height of the object imaged. This paper will describe the DARPA program striving to overcome these issues and review the approaches be taken to achieve the imagery required for the close air support mission.
Helicopters experience nearly 10 times the accident rate of fixed wing platforms, due largely to the nature of their
mission, frequently requiring operations in close proximity to terrain and obstacles. Degraded visual environments
(DVE), including brownout or whiteout conditions generated by rotor downwash, result in loss of situational awareness
during the most critical phase of flight, and contribute significantly to this accident rate. Considerable research into
sensor and system solutions to address DVE has been conducted in recent years; however, the promise of a Synthetic
Vision Avionics Backbone (SVAB) extends far beyond DVE, enabling improved situational awareness and mission
effectiveness during all phases of flight and in all visibility conditions. The SVAB fuses sensor information with high
resolution terrain databases and renders it in synthetic vision format for display to the crew. Honeywell was awarded the
DARPA MFRF Technical Area 2 contract in 2011 to develop an SVAB1. This work includes creation of a common
sensor interface, development of SVAB hardware and software, and flight demonstration on a Black Hawk helicopter. A
“sensor agnostic” SVAB allows platform and mission diversity with efficient upgrade path, even while research
continues into new and improved sensors for use in DVE conditions. Through careful integration of multiple sources of
information such as sensors, terrain and obstacle databases, mission planning information, and aircraft state information,
operations in all conditions and phases of flight can be enhanced. This paper describes the SVAB and its functionality
resulting from the DARPA contract as well as Honeywell RD investment.
Significant efforts are underway to use either passive or active MMW and Sub-MMW imaging systems to detect objects
concealed under clothing. Some have reached the point of commercial availability and have proved useful for
contraband detection under controlled conditions. Studies have shown that when the conditions are uncontrolled,
passive techniques become less desirable for contraband detection at standoff ranges which give the operators a margin
of safety. In recent years, several programs have been funded to investigate using active techniques in the range of 100
to 1000 GHz for standoff detection out to ranges of 100m, a range which has been cited by some to be a desirable
operating range. This paper will build on previous work to compare the performance of passive and active sub-MMW
imagers used for detecting objects concealed under clothing. The analysis is designed to separate the effects of
phenomenology and system components so that tradeoffs in transmitter and receiver characteristics can be performed.
The derivation of the analysis and various examples of tradeoffs will be presented.
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