Today's radar exploitation system utilize information from both Ground Moving Target Indication (GMTI) and Synthetic Aperture Radar (SAR) obtained from various airborne platforms. GMTI detects and supports the classification of moving targets, whereas SAR detects and supports the classification of stationary targets. However, there is currently no ability to integrate the information from these two classes of radars in tracking targets that execute sequences of move-stop-move maneuvers. The solutions of this dilemma is the development of a Continuous Tracking (CT) architecture that uses distinctive GMTI and SAR features to associate stationary and moving target detections through move-stop-move maneuvers. This paper develops a theoretical model and present corresponding numeric computations of the performance of the CT syste. This theory utilizes a two- state Markov process to model the successive SAR and MTI detections are derived from typical traffic and sensor behaviors. This analysis of the sensor characteristics and the underlying traffic model provides a foundation in designing a CT systems with the maximum possible performance.
The quantity and quality of data collected by military and commercial electro-optic and radar sensors is rapidly increasing. This increase in imagery data has not been accompanied by an increase in the number of image analysts needed to rapidly screen the imagery to locate and identify military targets or other objects of interest. Automatic target recognition (ATR) technology that automates the target detection, classification, and identification process has been a promising technology for at least two decades, and recent advances make the realization of aided target recognition possible. The future military battlespace will be filled with airborne, spaceborne, and land-based sensors observing moving and stationary targets at various locations, from multiple aspects, and at multiple frequencies and wavelengths. Only through the use of computer-assisted data analysis and ATR can the vast amount of data be analyzed within the timelines required by the military. The Defense Advanced Research Projects Agency (DARPA) has a number of programs developing technology to support the exploitation and control of the future battlespace information.
Recent data collections using an infrared hyperspectral measurement system have provided a significant measurement database of military vehicles in vegetated and desert backgrounds. This paper summarizes the results of a study performed to assess the detection performance potential of multispectral sensors using this database. Specific issues addressed include approaches to optimal band selection; robustness of band combinations with target, background, and environment diversity; and sensor noise requirements. All of these issues are vital to assessing the feasibility and utility of infrared multispectral sensors in operational scenarios.
Researchers from the United States and Russia conducted laser-material interaction tests at the LOK Company, St. Petersburg, Russia. These tests were conducted using a one-of-a-kind, continuous wave, supersonic, e-beam-sustained carbon monoxide (CO) laser. The purpose of these tests were to characterize the laser while performing collaborative research between scientists from Russia and the United States. Additionally, the testing verified previously- reported laser characteristics. All planned laser-material interaction tests were successfully conducted. Several material samples were irradiated by the CO laser to allow calculation of the laser energy and power levels. Statistical errors were reduced by testing materials with different characteristics at varying laser energy and power levels. Laser-material interaction tests were also conducted at varying distances from the laser output window to assess beam quality and divergence.
Infrared multispectral sensors are being investigated as a means for day and night target detection. Infrared multispectral sensors would exploit high spectral band-to-band correlation to reject high background clutter. An infrared Fourier transform spectrometer-based field measurement system was used to collect spectral signature data of targets and desert scrub and sand backgrounds from a 100 foot tower at White Sands Missile Range. The measurements include target-to-background spectral contrast, subpixel targets, background spectral correlation, and background spatial power spectra. The measurements have been analyzed to determine multispectral signal-to-clutter ratios versus target, background, diurnal, and weather variations, background correlation versus temperature clutter variations, and spectral correlation versus spatial scale. These measurements contribute to the expanding target and background infrared hyperspectral signature database. The results of the analysis demonstrate the utility and robustness of infrared multispectral techniques for target detection.
A series of field measurements of targets and backgrounds was made by an infrared Fourier transform spectrometer as part of the Joint Multispectral Sensor Program (JMSP), a joint program involving the U.S. Navy, U.S. Air Force, U.S. Army, and ARPA. These measurements were designed to observe targets in various types of background clutter, investigate the utility of novel algorithms for the detection of resolved and sub-pixel targets, and to aid in the selection of spectral bands for a future airborne multispectral sensor. This paper gives an overview of objectives and goals of the JMSP data collections, the targets viewed, and examples of the observed data.
Pulsed photodissociation of iodine monobromide at 532 nm provides a high yield of spin-orbit excited atomic bromine. Near resonant electronic-to-vibrational energy transfer from Br(2P1/2) to NO(v equals 2) is rapid, k equals 2.4 X 10-12 cm3/molecule-s, and selective, with a branching ratio of NO(v equals 2) of 0.89 +/- 0.21. An NO(v equals 2 yields 1) laser operating at 5.4 microns was demonstrated at NO pressures from 0.1 - 1.4 Torr. Temporal profiles were obtained as a function of IBr and No pressures and photolysis energy to analyze laser gain, threshold, and efficiency. The threshold photolysis pump energy was 25 mJ/pulse. Lasing pulses were delayed by 150 ns from photodissociation and persisted for 100 - 200 ns. Device efficiency is limited by NO V yields V relaxation, and the maximum observed NO laser energy was 0.01 mJ for 85 mJ photolysis energy. Comparison to similar Br(2P1/2 yields 2P3/2) and Br(2P1/2)/CO2(101 - yields 100) is provided.