Under a Phase II SBIR from NASA, a data collection radar was developed to support the NASA program in Automated Napof the Earth (ANOE) guidance for helicopters. The developed radar is comprised of two parts, a sensor ...
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Under a Phase II SBIR from NASA, a data collection radar was developed to support the NASA program in Automated Napof the Earth (ANOE) guidance for helicopters. The developed radar is comprised of two parts, a sensor front end and a digital signal processor. The sensor front end is a wideband, linear FM, 94 GHz millimeter wave radar with dual circular polarization and dual axis monopulse. It provides 10 dB signal-to-noise on a 5 m/sup 2/ target at 1 km. Digital signal processing is employed to provide range compression and monopulse angle beam sharpening. To remain within funding limitations the radar generates a reduced size raster scan of 12.5/spl deg/ /spl times/250/spl times/320 m for collecting data. The range resolution is 3 m, the angle bin size is 0.34/spl deg/, and there is frequency agility over 600 MHz. data was collected from a ground location to verify operation of the radar. The data is displayed in a C-scope format using NASA supplied "Grid World" software.
For a sensor array, time/frequency and many other estimation problems, resolution increases with growing "aperture" or "data window." High resolution with few sampling points can be achieved by usi...
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For a sensor array, time/frequency and many other estimation problems, resolution increases with growing "aperture" or "data window." High resolution with few sampling points can be achieved by using sparse or interferometric-like sampling schemes. We use a combination of the Cramer-Rao and Weiss-Weinstein (1988) bounds to define the region where unambiguous resolution is realized for such sampling schemes. Real data from a frequency-jump burst radar system is used to confirm the theoretical results.
The multi-target and multi-sensor tracking problem is a major topic of interest for air surveillance systems employing one or more sensors, to form and confirm tracks of targets amid a background of noise sources such...
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The multi-target and multi-sensor tracking problem is a major topic of interest for air surveillance systems employing one or more sensors, to form and confirm tracks of targets amid a background of noise sources such as radar clutter. A practical and feasible technique, named here RBT (rule-based tracking) method, is proposed for this tracking problem. We define and implement several rules which field operators are supposed to apply to track initiation, track maintenance, track deletion and track integration. Simulation examples are given to illustrate how this RBT implementation leads to remarkable tracking performance.
Integrating instrumentation into complex systems demands careful planning, execution, and testing. Ballistic missile defense is a complex system with many distributed components: radar and imaging sensors, wireless an...
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Integrating instrumentation into complex systems demands careful planning, execution, and testing. Ballistic missile defense is a complex system with many distributed components: radar and imaging sensors, wireless and satellite communications, digital signal processing nodes, interceptor fire control, and command centers. The U.S. Navy has investigated the feasibility of missile defense through the Light Exo-Atmospheric Projectile (LEAP) experiment. This paper explains the lessons learned by The Johns Hopkins University Applied Physics Laboratory from building, integrating, and testing instrumentation in the LEAP experiment and gives insights for designing complex systems. The biggest challenge in the LEAP experiment involved people: communications between the large number of contractors and their understanding of the interactions between the various instruments. Other concerns included verifying software and system operation, robust data and satellite communications, time and coordinate conversions, and electromagnetic interference. LEAP demonstrated that complex systems and missile defense system in particular, can only work through careful design, dedicated teamwork, clear and continuous communications, and extensive testing.
The Lockheed Martin Advanced technology Laboratories (ATL), participating in the Army's largest Advanced technology Demonstration, has developed a real-time, onboard/offboard multi-sensor, multi-target data fusion...
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The Lockheed Martin Advanced technology Laboratories (ATL), participating in the Army's largest Advanced technology Demonstration, has developed a real-time, onboard/offboard multi-sensor, multi-target data fusion system that operates on 14 different sources of information. As the data fusion software developer, ATL created two additional software products in order to effectively design, build, measure, and demonstrate the capabilities of the embeddable information fusion system. A user-friendly, graphical data fusion input simulator (DFIS) was required to facilitate building multi-target, multi-sensor scenarios for fusion stimulation. In addition, since the embedded fusion system has no graphical output, a data fusion workstation (DFWS) was needed to display metrics and output data within each algorithmic step of the fusion process and to provide a fusion demonstration facility. The data Fusion Input Simulator replicates the performance of 14 onboard and offboard data sources to provide tracks, contact reports, group tracks, and line-of-bearing data.
The signal processing requirements of military avionics systems are constantly increasing to meet the threats of the next century. This is especially true as the digital interface moves closer to the sensor/antenna an...
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The signal processing requirements of military avionics systems are constantly increasing to meet the threats of the next century. This is especially true as the digital interface moves closer to the sensor/antenna and the analog-to-digital converter (ADC) performance requirements become a major contributor to spaceborne data and signal/sensor processors and mission management specifications. The benefits of moving the digital interface closer to the sensor/antenna in avionics systems can be classified in four different categories: affordability, reliability and maintainability, physical, and performance. This reduction in RF downconversion stages as the digital interface migrates toward the sensor can result in some difficult ADC requirements that can not currently be met by commercial technologies. It is the intention of this presentation to expose the aerospace community to these emerging requirements for radar, communication and navigation (CNI), and electronic warfare missions. In addition to these requirements, we are presenting some examples of current state-of-the-art ADCs, their technology limitations, and briefly discuss potential applications in avionics systems. We have also included in this presentation a brief discussion on the fundamental and physical limitations that impair the progress of current and future ADC technologies. This presentation will conclude with a technology forecast, and an estimate on ADC availability for future avionics systems.
Development of new air sovereignty control system-which is basically the ASOC (Air Sovereignty Operations Center) of Hungary suitable for the present and future is under preparation. This system has extremely high cos...
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Development of new air sovereignty control system-which is basically the ASOC (Air Sovereignty Operations Center) of Hungary suitable for the present and future is under preparation. This system has extremely high cost of production therefore, not only to prepare it technically, but owing to the fact that existing radar has to be modernized and prepared for connecting to the planned new air sovereignty control system. During preparation time we must pay attention to the following facts: (a) the single reconnaissance sensors have to be integrated into reconnaissance system and in addition the air surveillance has high priority; (b) information of sensors (radar) would have to get through to users within the possible shortest time (within a few seconds); (c) there is great civilian air traffic in peace-time-in case of military threats cooperation between the military and civilian air traffic control has great importance; (d) data of air surveillance has different types of radar we have to use, process in real time and spread information to users according to their requirements. This article is a brief overview of input radar signal processing equipment for the air sovereignty control system having importance especially in field of the radar plot extractors and data processing.
In this paper, a novel technique is presented for blindly estimating the channel matrix in an M-sensor K-source system. A special estimated higher-order cumulant matrix of the received data is first constructed. The c...
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In this paper, a novel technique is presented for blindly estimating the channel matrix in an M-sensor K-source system. A special estimated higher-order cumulant matrix of the received data is first constructed. The channel matrix is then estimated by the eigendecomposition of the cumulant matrix. This method does not need any prior information of the signal. Computer simulation results are presented showing that the proposed algorithm is very promising.
A major issue in space-time adaptive processing (STAP) for airborne moving target indicator (MTI) radar is the so-called sample support problem. Often, the available sample support for estimating the interference cova...
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A major issue in space-time adaptive processing (STAP) for airborne moving target indicator (MTI) radar is the so-called sample support problem. Often, the available sample support for estimating the interference covariance matrix leads to severe rank deficiency, thereby precluding STAP beamforming based on the direct sample matrix inversion (SMI) method. The intrinsic interference subspace removal (ISR) technique, which is a computationally useful form of diagonally loaded SMI method, can handle this case, although the performance is poor in low sample situations. In this context, new subarray-subpulse schemes using forward and backward data vectors are introduced to overcome the data deficiency problem. It is shown that a multiplicative improvement in data samples can be obtained at the expense of negligible loss in space-time aperture of the steering vector.
The detection of buried or surface laid mines by ultrawideband, ground-probing radar systems is currently receiving much attention. The radar signature of the mine may be known, in which case a range of techniques can...
The detection of buried or surface laid mines by ultrawideband, ground-probing radar systems is currently receiving much attention. The radar signature of the mine may be known, in which case a range of techniques can be used to characterise the received signal. These range from, in the case of surface laid mines, characterisation of the sequence of reflections caused by external reflections, creeping waves and internal reflections such as the Glory wave; singularity expansion methods (SEM); resonance characterisation via such techniques as Prony; through to wavelet analysis. For buried mines the range of classification options is more limited as the host material significantly modifies the impulse response of the target, but shallow mines may still be identifiable. The extent of validation trials on most of these processing methods is limited. This paper considers some of the parameters, whereby the discrimination of the spatial signature of the mine is based solely on a statistical assessment of the radar image data and a characterisation of the radarsensor.
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