Proc. SPIE. 5808, Algorithms for Synthetic Aperture Radar Imagery XII
KEYWORDS: Radar, Detection and tracking algorithms, Visualization, Sensors, Synthetic aperture radar, 3D modeling, Data archive systems, Data processing, Automatic target recognition, Algorithm development
Having relevant sensor data available during the early phases of ATR algorithm development and evaluation projects is paramount. The source of this data primarily comes from either being synthetically-generated or from measured collections. These collections, in turn, can either be highly-controlled or operational-like exercises. This paper presents a broad overview on the types of data being housed within the Automatic Target Recognition Division of the Air Force Research Laboratory (AFRL/SNA) and that are available to the ATR developer.
Over the past two decades, the types of networks used in both commercial and military systems to route information throughout a designated platform have essentially remained unchanged. Traditionally, digital networks have been used to route low data rate, low-bandwidth signals usually not exceeding 2 Ghz, amongst a variety of sensors, digital and signal processors and video displays. On the other hand, analog networks have been responsible for routing broad- banded radio-frequency signals, those ranging from 2 Ghz to well beyond 100 Ghz, between a specific antenna aperture and its designated receiver type. Current analog systems use one of either two approaches to transfer this signal information. The first approach uses microwave waveguides. This design is very efficient, albeit bulky, and has typically been used in ground-based systems. HOwever, it does not lend itself very well to airborne platforms where size and weight constraint are of primary concern. The second approach uses coaxial cable, which tends to exhibit excessive loss at higher frequencies and is much heavier than optical fiber. Like its counterpart the microwave waveguide, it too is not ideally suited for airborne platforms. However, up to now it has been the technology of choice for this particular application. This has led to other alternatives to be sought. With recent advancements being made in optoelectronics, optical fiber is becoming a viable alternative to the above mentioned approaches. It is the intent of this paper to identify airborne applications for photonic technology in analog networks and discuss the needed building blocks to implement this particular type of system.
The paper presents an approximate analysis of the conical diffraction by planar volume gratings. Explicit expressions are derived for the coupling constants and the dephasing between different diffraction orders. The results of the approximate coupled-wave theory are compared with the rigorous numerical solution of the three-dimensional boundary value problem for a specific configuration. A two-wave coupled-wave theory is presented and an analytical solution is given.
Conference Committee Involvement (3)
Radio Frequency Photonic Devices and Systems III
29 January 2003 | San Jose, CA, United States
Photonic Integrated Systems
28 January 2003 | San Jose, CA, United States
Optoelectronic Modules for Aerospace and Automotive Applications