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Dey D.,Carnegie Mellon University | Geyer C.,iRobot | Singh S.,Carnegie Mellon University | Digioia M.,Penn State Electro Optics Center
International Journal of Robotics Research | Year: 2011

Unmanned Aerial Vehicles (UAVs) have played vital roles recently in both military and non-military applications. Oneof the reasons UAVs today are unable to routinely fly in US National Airspace (NAS) is because they lack the senseand ability to avoid other aircraft. Although certificates of authorization can be obtained for short-term use, it entailssignificant delays and bureaucratic hurdles. Therefore, there is a great need to develop a sensing system that is equivalent to or has greater performance than a human pilot operating under Visual Flight Rules (VFR). This is challengingbecause of the need to detect aircraft out to at least 3 statute miles, while doing so on field-of-regard as large as30°( vertical) × 220°( horizontal) and within the payload constraints of a medium-sized UAV. In this paper we report on recent progress towards the development of a field deployable sense-and-avoid system and concentrate on the detectionand tracking aspect of the system. We tested a number of approaches and chose a cascaded approach that resulted in100% detection rate (over about 40 approaches) and 98% tracking rate out to 5 statute miles and a false positive rate of 1every 50 frames. Within a range of 3.75 miles we can achieve nearly 100% tracking rate. © SAGE Publications 2011.

Mazurowski J.,Penn State Electro Optics Center
2011 IEEE Avionics, Fiber- Optics and Photonics Technology Conference, AVFOP 2011 | Year: 2011

Understanding complete behavior of a system during testing may require many- perhaps hundreds- of sensors. Wavelength division multiplexing using single mode fiber can help simplify this. Three decisions assist with the selection of connection methods. © 2011 IEEE.

Mazurowski J.,Penn State Electro Optics Center | Habiby S.F.,Applied Communication science
AIAA/IEEE Digital Avionics Systems Conference - Proceedings | Year: 2013

This paper describes the use and value of digital Wavelength Division Multiplexed (WDM) networks on-board small avionic and space platforms. Packaging and heat transfer efficiency are achieved when all of the optical wavelength sources occupy a common location. Each receiver is allocated a specific addressable wavelength that can be selected or tuned at the source (transmitter). Individual delays may be applied to assure synchronization at each receiver. The output of each individual source wavelength is pre-modulated with a clock signal. Signal modulation is applied by passing or rejecting the clock signals. Control plane functions can be merged with the data plane functions. Although based on a single data rate, this implementation of the digital WDM LAN concept can possibly be extended to process packet and analog payloads. © 2013 IEEE.

Farrell S.,George Mason University | Brill G.,U.S. Army | Chen Y.,U.S. Army | Wijewarnasuriya P.S.,U.S. Army | And 3 more authors.
Journal of Electronic Materials | Year: 2010

We present the results of ex situ thermal cycle annealing (TCA) of molecular beam epitaxy grown mercury cadmium telluride (HgCdTe) on Cd(Se)Te/Si(211) composite substrates. We examined the variation in the etch pit density (EPD) and overall crystalline quality with respect to annealing temperature, number of annealing cycles, total annealing time, pre-annealed EPD/crystal quality, buffer layer quality, and buffer layer lattice constant. Using TCA we observed an order of magnitude reduction in the dislocation density of the HgCdTe layers and a corresponding decrease in x-ray full width at half maximum, when the as-grown layer EPD was on the order of 1 × 10 7 cm -2. Among all the parameters studied, the one with the greatest influence on reducing EPD was the number of annealing cycles. We also noticed a saturation point where the HgCdTe/Si EPD did not decrease below ∼1 × 10 6 cm -2, regardless of further TCA treatment or the as-grown EPD value. © 2009 TMS.

Agency: Department of Defense | Branch: Missile Defense Agency | Program: STTR | Phase: Phase I | Award Amount: 100.00K | Year: 2009

Phase I will conduct modeling and breadboard experiments to assess whether VHGM laser technology can achieve laser sources that enable active LADAR performance that surpasses present technology by a factor or 4, while packaging the laser head into a volume of 3 cubic inches. Phase II will build laser prototypes based on Phase I results.

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