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To measure operator proficiency in identifying audio signals from the AN/TPS-33 ground surveillance radar, a test of 120 tape-recorded signals generated by representative military targets was administered to 43 trained operators. It was found that they could discriminate between personnel and vehicle targets. An experiment was run to determine whether operators can be trained to identify vehicles on the basis of signal characteristics unique to each vehicle type. After two days' training, 10 naive officer subjects learned to discriminate reliably between tracked and wheeled vehicles, although there were marked differences in operator aptitude.

The detection of ultra-wide-band (UWB) radar signals is considered. Conventional radar theory is examined in the context of ultrawideband signals and extended when necessary. Point target detectors are found for the cases when the additive interference is white Gaussian noise and correlated Gaussian noise or clutter. A conventional moving target indicator (MTI) design is generalized for UWB radar. The effects of bandwidth on the resolution of clutter and target are examined. Optimal and conventional processing are compared for single echo detection. An optimal detector is found for a distributed target with a known target profile. Additionally, optimal detectors are found under two models where only second-order statistics of the target profile are assumed known. Future work areas are suggested. Detection, Ultra-wide-band, Radar

This thesis applies time-frequency transformations to radar signals. Specifically, it considers the feasibility of applying time-frequency transformations to extract the intra-pulse modulation parameters of radar signals. In this work, we consider radar signals with analog pulse compression; specifically linear or hyperbolic intra-pulse modulation. Several time-frequency transformations are investigated to identify which one gives the most accurate image representation for signals in noisy environments. Next, image processing techniques are applied in conjunction with an adaptive curve fitting method, for the hyperbolic modulation scheme, to extract the parameters of the frequency equation. Results show that for the linear chip case the frequency equation can be estimated with small error down to SNR equal to -10dB. The proposed method for the hyperbolic chirp modulation is less immune to noise degradation and it can be used down to SNR level equal to 2dB.

During the past year, we worked on two engineering application problems: data smoothing/denoising by wavelets and reverse engineering for aircraft design, as well as other optimization problems (such as robust regressions, Huber M-estimators, merit functions for constrained minimization problems, stability analysis of feasible systems, and constrained best approximations in Euclidean spaces). While the engineering applications are obviously beneficial to the advancement of science and technology for Air Force, the basic research is also fundamental for potential applications relevant to Air Force. In this final report, we will give an overview of what we have accomplished during the last one year when our research was supported by Air Force Office of Scientific Research. The report has five parts: (1) automatic threshold selection for wavelet denoising; (2) reverse engineering for aircraft design; (3) robust regression and Huber M-estimator; (4) global error bounds for quadratic inequalities; (5) merit functions for complementarity problems.

China May Jam US Radar Signals In South Korea

China May Jam US Radar Signals In South Korea

This thesis applies time-frequency transformations to radar signals. Specifically, it considers the feasibility of applying time-frequency transformations to extract the intra-pulse modulation parameters of radar signals. In this work, we consider radar signals with analog pulse compression; specifically linear or hyperbolic intra-pulse modulation. Several time-frequency transformations are investigated to identify which one gives the most accurate image representation for signals in noisy environments. Next, image processing techniques are applied in conjunction with an adaptive curve fitting method, for the hyperbolic modulation scheme, to extract the parameters of the frequency equation. Results show that for the linear chip case the frequency equation can be estimated with small error down to SNR equal to -10dB. The proposed method for the hyperbolic chirp modulation is less immune to noise degradation and it can be used down to SNR level equal to 2dB.

A longstanding performance goal for Army ground surveillance radars is the automatic classification of moving ground targets on the battlefield. Limited classification has been achieved by splitting the radar doppler spectrum into lower and higher frequency bands, thus distinguishing between targets having different radial velocities. While this is an important feature, since only certain targets (vehicles) are capable of obtaining high radial speeds, it does not provide a distinction between a moving man and vehicles having low radial speed components. That there are distinct differences in the doppler signatures between man and vehicle is easily established by listening to typical doppler return signals. One can clearly distinguish the step modulation of a walking man from the relatively constant or slowly changing tone of a vehicle. As to be expected, a spectrogram of a walking man shows this repetitive behavior. Most obvious is a sinewave like frequency modulation at the step frequency of the main body return power appearing as a black band near 100 Hertz. This oscillatory temporal characteristic in the doppler shifted frequency is practically never seen in vehicular return and is the discriminant chosen for automatic classification.

Contents: Radar and Microwaves, Communications and Computing, Signal and Data Processing, Infrared and Lasers, Solid State Physics and Displays, Historical Review, and Publications. (Great Britain)

Compressive sensing (CS) has received considerable research interest recently. CS has been successfully applied in many applications, such as high-resolution image processing, wireless communication, electronic signal capturing and biomedical imaging systems [1]. In the context of radar, the number of potential targets is often limited. Hence, exploiting the sparsity of radar signals in various spaces, CS has been recently applied to multiple-input multiple-output (MIMO) radar systems.

A new technique for reducing a radar's response to undesired signals entering a radar's sidelobes is described and analyzed theoretically. This technique involves moving the phase center of a phased-array antenna to Doppler-shift sidelobe signals out of the radar receiver's passband. (Author)

The requirements for an optimal sequence for SuperDARN radar are stated. Obtained quasioptimal signals up to 26-pulse sequence are based on optimal and nearly optimal Golomb rulers. It is shown that standard 7-pulse SuperDARN sequence is one of the quasioptimal sounding signals, but 8-pulse kascan SuperDARN signal is not. The characteristics are calculated for quasioptimal sounding sequences up to 26-pulse one. It is shown that the most effective signals for the spectral measurements are 10, 12, 14, 18, 20, 24 and 26 pulse sequences. We present the results of the first spectral measurements at the EKB SuperDARN radar with quasioptimal 8- and 9-pulse sequences, as well as with the optimal 10-and 12-pulse sequences. A comparison with the results obtained with standard 7-pulse SuperDARN sequence were made. The continuity of results in amplitude and velocity is shown, the expected improvement in the spectral width are also demonstrated.

In this work, we explore the feasibility of injecting data into an existing radar waveform. Specifically, we investigate how to embed communications signals within a navigation radar pulse to explore the potentials for a) receiving and demodulating the associated communications data, and b) identifying potential vulnerabilities/effects to maritime networks that inadvertently receive data in this manner. In this thesis, we advance previous work by utilizing a more practical, navigation-like radar waveform instead of an idealized, rectangular pulse previously studied. We utilize a particular radar system in order to calculate its actual throughput with the use of an embedded or combined signal. Considering that the radar waveform may not be detected at times due to modest radar-to-communications power ratio, we calculate the embedded communications’ effective symbol error ratio. We also demonstrate the spectrum of the radar-embedded communications waveform on a carrier via signal generator and spectrum analyzer.

In this work, we explore the feasibility of injecting data into an existing radar waveform. Specifically, we investigate how to embed communications signals within a navigation radar pulse to explore the potentials for a) receiving and demodulating the associated communications data, and b) identifying potential vulnerabilities/effects to maritime networks that inadvertently receive data in this manner. In this thesis, we advance previous work by utilizing a more practical, navigation-like radar waveform instead of an idealized, rectangular pulse previously studied. We utilize a particular radar system in order to calculate its actual throughput with the use of an embedded or combined signal. Considering that the radar waveform may not be detected at times due to modest radar-to-communications power ratio, we calculate the embedded communications’ effective symbol error ratio. We also demonstrate the spectrum of the radar-embedded communications waveform on a carrier via signal generator and spectrum analyzer.

In this report we present a statistical model for the signals of an acousto-optic spectrum analyzer (AOSA). Using the model, we calculate the Cramer-Rao bound for the estimation of the carrier frequency of radar signals and the performance of the peak detector estimator. We also present an algorithm for sidelobe rejection. Canada.

The acceleration and velocity signal processor developed at the Naval Research Laboratory was employed with the hf transmitter and receiving equipment located at the Chesapeake Bay Division site to observe Polaris missiles launched along the Eastern Test Range. The spectral compression and coherent integration techniques utilized in processing the return radar echoes resulted in improved resolution and signal-to-noise ratio, and provided target acceleration as a parameter, along with velocity and range. Target tracks of high definition are shown for the second stages, spent first stages, and nose fairings of ETR tests 2949 (A2 Polaris), 6075 (A3 Polaris) and 3635 (A3 Polaris).

The acceleration and velocity signal processor developed at the Naval Research Laboratory was employed with the hf transmitter and receiving equipment located at the Chesapeake Bay Division site to observe Polaris missiles launched along the Eastern Test Range. The spectral compression and coherent integration techniques utilized in processing the return radar echoes resulted in improved resolution and signal-to-noise ratio, and provided target acceleration as a parameter, along with velocity and range. Target tracks of high definition are shown for the second stages, spent first stages, and nose fairings of ETR tests 2949 (A2 Polaris), 6075 (A3 Polaris) and 3635 (A3 Polaris).

This work investigated the detection of pulses and extraction of modulation parameters from different types of time-limited chirp signals, as may be found in pulse- compression radar signals. The work is split into two parts. The first part examines the pulse detection problem, i.e., the detection of the pulse start/stop times. Such information can be used to determine the pulse width and repetition rate of the radar systems under investigation in an automated fashion. We compare the robustness of three TCF-based schemes and an envelope detection algorithm in noisy environments.

Recent work concerning artificial neural networks has focused on decreasing network training times. Kernel Classifier networks, using radial basis functions (RBFs) as the kernel function, can be trained quickly with little performance degradation. Short training times are critical for systems which must adapt to changing environments. The function of Kernel Classifier networks is based on the principle that multivariate functions can be approximated via linear combinations of RBFs. RBFs can also perform probability density estimations, making classifications approximating a Baye's optimal descriminant. Methods used to set the RBF centers included matching the training data, Kohonen Training, K-Means Clustering and placement at averages of data clusters of the same class. Test results indicate the performance of these networks was equal to that of Hyperplane Classifier networks trained, via backpropagation, to optimize the Mean Square Error, Cross Entropy, and Classification Figure of Merit objective functions. However, the RBF networks trained much faster. The RBF networks also outperformed the Probability Neural Networks, (PNN) indicating the weights in the output layer offset the choice of non-optimal spreads. This ability to train quickly while obtaining high classification accuracies make RBF Kernel Classifier networks an attractive option for systems which must adapt quickly to changing environments.

Work of the radar non-destructive checking of technological parameters of wares system is considered. The algorithm of its optimum management is developed. By a matrix analysis and program Mathcad, optimization of the modes is conducted; robots and parameters of entrance knots of the system, amplitudes of the rationed reflected waves are expected; maximal value of relation a “signal to noise”, the optimum parameters of the directed waveguide coupler are got. 

This report documents work in progress on fuzzy expert systems. Pixel-level fuzzy-logic image-processing (PIXLFLIP) uses fuzzy logic on subwindows centered on each pixel of an image to determine the processing or filtering associated with the center pixel of the subwindow. Here, the PIXLFLIP is applied to enhance range-only-radar (ROR) profiles that have been stacked to produce an image chip. Because the profiles have been aligned by previous processing, the line enhancement needs only to consider vertical lines. The fuzzy, rule-based filtering not only enhances the strong consistent signals, but also suppresses the clutter forming the background. This approach offers significant potential. Further investigation is recommended.

The AN/GPA-98A countermeasures signals simulator is intended for use with Air Force radars to provide simulated electronic countermeasures signals for radar operator training in an ECM environment. It is capable of simulating two independent aircraft targets with associated ECM -- pulse jamming, chaff, and high duty cycle AM/FM jamming. The purpose of the study was to determine the modifications to adapt the simulator for use with the AN/UPS-1 air-search radar located at the Naval Postgraduate School radar laboratory. Signals required by the simulator from the radar were determined, the radar and simulator were modified, and interconnections were made. Upon solution of several minor problems, the simulator was aligned and signal levels were adjusted for proper operation with the AN/UPS-1 radar.

The characteristic of low probability of intercept (LPI) radar makes it difficult to intercept with conventional signal intelligence methods so new interception methods need to be devel-oped. This thesis initially describes a simulation of a polytime phase-coded LPI signal. The thesis then introduces a method for classification of LPI radar signals. The method utilizes a parallel tree structure with three separate \"branches\" to exploit the image representation formed by three separate detection methods. Each detection method output is pre-processed and fea-tures are extracted using image processing. After processing the images, they are each fed into three separate neural networks to be classified. The classification output of each neural network is then combined and fed into a fourth neural network performing the final classification. The outcome of testing shows only 53%, which might be the result of the image representation of the detection methods not being distinct enough, the pre -processing/feature extraction not be-ing able to extract relevant information or the neural networks not being properly trained. The thesis concludes with a brief discussion about a suitable method for image processing to extract significant parameters from a LPI signal.

This article is from Sensors (Basel, Switzerland) , volume 10 . Abstract Different speech detection sensors have been developed over the years but they are limited by the loss of high frequency speech energy, and have restricted non-contact detection due to the lack of penetrability. This paper proposes a novel millimeter microwave radar sensor to detect speech signals. The utilization of a high operating frequency and a superheterodyne receiver contributes to the high sensitivity of the radar sensor for small sound vibrations. In addition, the penetrability of microwaves allows the novel sensor to detect speech signals through nonmetal barriers. Results show that the novel sensor can detect high frequency speech energies and that the speech quality is comparable to traditional microphone speech. Moreover, the novel sensor can detect speech signals through a nonmetal material of a certain thickness between the sensor and the subject. Thus, the novel speech sensor expands traditional speech detection techniques and provides an exciting alternative for broader application prospects.

Sun shade for a Kustom Signals Inc. Golden Eagle radar display. Should fit the whole Golden Eagle line. I spray-glued some fabric to the top to make it less shiny. Included a DXF of the shade fabric if you'd like to cut it.

This theses developed computer models of two types of amplitude comparison monopulse processors using the Block Oriented System Simulation (BOSS) software package and to determine the response to these models to impulsive input signals. This study was an effort to determine the susceptibility of monopulse tracking radars to impulsing jamming signals. Two types of amplitude comparison monopulse receivers were modeled, one using logarithmic amplifiers and the other using automatic gain control for signal normalization. Simulations of both types of systems were run under various conditions of gain or frequency imbalance between the two receiver channels. The resulting errors from the imbalanced simulations were compared to the outputs of similar, baseline simulations which had no electrical imbalances. The accuracy of both types of processors was directly affected by gain or frequency imbalances in their receiver channels. In most cases, it was possible to generate both positive and negative angular errors, dependent upon the type and degree of mismatch between the channels. The system most susceptible to induced errors was a frequency imbalanced processor which used AGC circuitry. Any errors introduced will be a function of the degree of mismatch between the channels and therefore would be difficult to exploit reliably.

This theses developed computer models of two types of amplitude comparison monopulse processors using the Block Oriented System Simulation (BOSS) software package and to determine the response to these models to impulsive input signals. This study was an effort to determine the susceptibility of monopulse tracking radars to impulsing jamming signals. Two types of amplitude comparison monopulse receivers were modeled, one using logarithmic amplifiers and the other using automatic gain control for signal normalization. Simulations of both types of systems were run under various conditions of gain or frequency imbalance between the two receiver channels. The resulting errors from the imbalanced simulations were compared to the outputs of similar, baseline simulations which had no electrical imbalances. The accuracy of both types of processors was directly affected by gain or frequency imbalances in their receiver channels. In most cases, it was possible to generate both positive and negative angular errors, dependent upon the type and degree of mismatch between the channels. The system most susceptible to induced errors was a frequency imbalanced processor which used AGC circuitry. Any errors introduced will be a function of the degree of mismatch between the channels and therefore would be difficult to exploit reliably.

The characteristic of low probability of intercept (LPI) radar makes it difficult to intercept with conventional signal intelligence methods so new interception methods need to be developed. This thesis initially describes a simulation of a polytime phase-coded LPI signal. The thesis then introduces a method for classification of LPI radar signals. The method utilizes a parallel tree structure with three separate 'branches' to exploit the image representation formed by three separate detection methods. Each detection method output is pre-processed and features are extracted using image processing. After processing the images, they are each fed into three separate neural networks to be classified. The classification output of each neural network is then combined and fed into a fourth neural network performing the final classification. The outcome of testing shows only 53%, which might be the result of the image representation of the detection methods not being distinct enough, the pre -processing/feature extraction not being able to extract relevant information or the neural networks not being properly trained. The thesis concludes with a brief discussion about a suitable method for image processing to extract significant parameters from a LPI signal.

With increasing demand of air traffic, there is a need to optimize the use of available airspace. Effective utilization of airspace relies on quality of aircraft surveillance. Active research is carried out for enhancements in surveillance techniques and various methods are evaluated for future use. This paper evaluates the use of multiple signal classification (MUSIC) based angle of arrival (AOA) estimation along with multiangulation for locating aircrafts from their electromagnetic wave emission. The performance evaluation of the system is presented by evaluating the AOA estimation errors and position estimation (PE) errors. The errors are evaluated by comparing the estimated value to the actual value. An analysis on the system parameters, AOA error and PE error are presented in the end. AOA errors are affected by the AOA value (emitter bearing), number of array elements, SNR and resolution of AOA estimation algorithm. Errors in AOA estimation lead to PE errors. The simulation results show small errors for short ranges. The system performance can be improved at the expense of computational time by using higher MUSIC resolution and larger antenna arrays.

The parameters of Low Probability of Intercept (LPI) radar signals are hard to identify by using traditional periodogram signal processing techniques. Using the Wigner Distribution (WD), this thesis examines eight types of LPI radar signals. Signal to noise ratios of 0 dB and -6dB are also investigated. The eight types LPI radar signals examined include Frequency Modulation Continuous Wave (FMCW), Frank code, P1 code, P2 code, P3 code, P4 code, COSTAS frequency hopping and Phase Shift Keying/Frequency Shift Keying (PSK/FSK) signals. Binary Phase Shift Keying (BPSK) signals although not LPI, are also examined to further illustrate the principal characteristics of the WD.

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The goal of this thesis is to investigate the effects of an orthogonal frequency-division multiplexing (OFDM) signal versus a linear frequency modulated or chirp signal on simulated synthetic aperture radar (SAR) imagery. Various parameters of the transmitted signal, such as pulse duration, transmitted signal energy, bandwidth, and (specifically for the OFDM signal) number of subcarriers and transmission scheme were examined to determine which parameters are most important to reconstructing a SAR image. Matched filtering and interpolation are two techniques used to reconstruct the SAR image. SAR systems are used in various military and civilian sector applications. Some SAR application examples include ground surveillance, reconnaissance and remote sensing. These applications demand high resolution imagery; therefore, knowledge of exactly which parameters of the transmitted radar signal are more important in producing fine resolution imagery is worth investigating. This research will also aid in providing flexibility in terms of what type of signal and signal parameters are best suited for a particular SAR application and associated military missions. In addition to improving the method attaining high resolution images, SAR process improvement can potentially reduce military SAR system design cost.

In book questions of use/application of digital computers for optimum processing of radar signals are examined. Primary attention is given to the detection of signals from the targets, hidden by interferences, and to the determination of the target coordinates. Is described the work of the simplest diagrams of working/treatment, their operating principle, and also work of some nodes of digital computers. Subsequently are given the more complicated cases, special theory and algorithms of working/treatment. Shows how it is realized the synthesis of the structures of machines and their algorithms on the base of the theory of statistical solutions. The necessary information according to the theory of statistical solutions is given on the course of presentation. Book is intended for cabets of military colleges, students of military academies, military engineers and can be used by civil/ civilian specialists, who work in the region of radar.

Contents: Radar signals and the method of their processing; Output signals of filter devices; Detection of signals against a background of interference and other signals; Signal parameter measurements; Signal processor design principles; Methods for the technical realization of signal-processing devices; Analog electronic filters; Digital electronic filters; Optical filters.

The acceleration and velocity signal processor developed at the Naval Research Laboratory was employed with the hf transmitter and receiving equipment located at the Chesapeake Bay Division site to observe missiles launched along the Eastern Test Range. The spectral compression and coherent integration techniques utilized in processing the return radar echoes resulted in improved resolution and signal-to-noise ratio, and provided target acceleration as a parameter, along with velocity and range. Target tracks of high definition are shown for the second stages, spent first stages, and nose fairings of ETR tests 0169 (Saturn) and 3670 (A3 Polaris).

A microwave radar signal is generated for transmission through an antenna. Before transmission, the signal is phase modulated by 0 deg or 90 deg amounts during each alternate half-cycles of an intermediate frequency (IF) clock signal. After transmission and return, the signal is again phase modulated the same amounts during each alternate half-cycles. The return phase modulated signal is mixed with a leakage signal component of the microwave signal, leaving an IF Doppler. The IF Doppler signal may then be amplified, removing any requirement that direct current level signals be amplified and also removing the effect of detector noise from the Doppler signal.

Several on line and off line data processing techniques are used to remove interfering signals due to ground clutter, aircraft, instrumental effects, and external transmissions from the desired atmospheric echoes of Mesosphere Stratosphere, Troposphere (MST) radar. The on line, real time techniques are necessarily simple in order to minimize processing delays. This algorithm examines the individual Doppler spectra which are computed every two to four seconds (for oblique antenna beams). The total spectral power in each individual spectrum is computed by summing all the spectral points. If this integrated power increases from one spectrum to the next by a factor greater than a preselected threshold, then that spectrum is not added to the spectral sum. Succeeding spectra are compared to the last acceptable spectrum. Only a certain maximum number of spectra are allowed to be rejected in succession.

The effect of coherent integration on the periodogram method to estimate the power spectra of MST radar signals is examined. The spectrum estimate usually is biased, even when care is taken to reduce the aliasing effects. Due to this bias, the signal power for Doppler shifted signals is underestimated by as much as 4 dB. The use of coherent integration in reducing the effect of aliased power line harmonics is pointed out.

A search of scientific literature, both printed and electronic, was undertaken to provide quantitative estimates of attenuation effects of rainfall on weather radar radomes. The emphasis was on C-band (5 cm) and S-Band (10 cm) wavelengths. An empirical model was developed to estimate two-way wet radome losses as a function of frequency and rainfall rate for both standard and hydrophobic radomes. The model fits most of the published data within +/- 1 dB at both target wavelengths for rain rates from less than ten to more than 200 mm/hr. Rainfall attenuation effects remain under 1 dB at both frequencies regardless of radome type for rainfall rates up to 10 mm/hr. S-Band losses with a hydrophobic radome such as that on the WSR-88D remain under 1 dB up to 100 mm/hr. C-Band losses on standard radomes such as that on the Patrick AFB (Air Force Base) WSR-74C can reach as much as 5 dB at 50 mm/hr. In addition, calculations were performed to determine the reduction in effective reflectivity, Z, when a radar target is smaller than the sampling volume of the radar. Results are presented for both the Patrick Air Force Base WSR-74C and the WSR-88D as a function of target size and range.

Interior Target Tracking Using Digital Communications Signals for Bistatic Radar with Gnu Radio presented by Todd K. Moon, Thomas Bradshaw, Mirelle Despain, Jacob H. Gunther at GNU Radio Conference 2021 Wireless communication systems employed in buildings (such as WiFi) can be used for bistatic radar to track targets moving in the building. The transmit and receive hardware and software can be readily implemented using Gnu radio. The general processing steps at the receive include Doppler frequency extraction, using FFT or MUSIC-algorithm based processing, following by Viterbi or BCJR algorithm to smooth the frequency trajectory, followed by track extraction using an extended Kalman filter. The method has been implemented and tested using real hardware. https://events.gnuradio.org/event/8/contributions/123/ Source: https://www.youtube.com/watch?v=lHl4fMBp8DY Uploader: GNU Radio

This report is concerned with the performance of M-ary sequential hypothesis tests applied to the classification of radar signals. In the first part of this report, several available M-ary sequential algorithms are considered. These include the algorithms due to Reed, Armitage and Palmer. Modifications of the existing algorithm are considered and their effects on the average number of required measurements and the resulting error performance are examined. Three other techniques are also proposed, a tree algorithm and a sequential maximum a posteriori test as well as a sequential version of the various algorithms by means of Monte-Carlo simulations of the radar signal observations. The performance of these techniques is compared and the relative merits of each algorithm are discussed.

A primary goal in radar waveform design is to achieve a prescribed discrete time radar ambiguity function. Radar waveform design to meet a given ambiguity function specification is an important issue under the waveform diversity technology. Much of the development in this area is for continuous time signals. For the discrete time case, the sampling rate becomes an important design issue. On the one hand, too low of a sampling rate results in spectral aliasing, on the other hand, a sampling rate chosen higher than necessary increases the computational burden. We show in this project that aliased spectra, arising from sampling below the Nyquist rate, may be completely eliminated. We plot the effects of quantization noise and timing jitter for subjective evaluation.

There has been a continuing problem of estimating a radar signal when the noise and the signal have the same power spectra. This is particularly troublesome when one tries to resolve two close targets with a tracking radar. The purpose of this research is to show theoretically that there are practical ways to solve the problem. Two approaches are introduced here. The first is to add a process filter to the radar, and the second is to design a new measuring technique with processing such that the signals will be separable. These two main approaches have led to several new or extended theories which were developed in the course of this work: the Probability filter; a modified Kalman filter (MKF); a measurement modification technique for monopulse radar; and a new approach to the design of a monopulse tracking radar. Simulations were performed to check the two major theories (the M.K.F. and the probability filter). According to the simulations we can say that a tracking radar can be modified in order to solve the problem of separating unresolved targets. (Author)

The performance of high-frequency skywave radar systems is customarily referred to in terms of single-hop propagations, a mechanism which provides illumination of the earth's surface out to ranges of around 4000 kilometers. In practice, the process of ionospheric reflection often supports multiple hops, though the signals are inevitably subjected to much greater distortion and contamination. In this paper, the author addresses the issue of adequacy of conventional models of multi-hop propagation. He formulates a detailed model that accounts for intermediate surface scattering, and obtains a representation in terms of integrals in chi - kappa space. He proceeds to evaluate the resulting expressions for several cases of interest. The results demonstrate that it is vital to understand the complexities of multi-hop propagation if this method of observation is to be exploited for remote sensing of the ocean at extreme ranges.

Information matrices are derived for estimates of the range parameters of moving targets as obtained by combining apriori information (if available with reflected radar signals observed in the presence of additive white Gaussian noise. The inverse of the information matrix provides a lower bound on the covariance matrix of any unbiased parameter estimates. This bound can be approached with a high signal to-noise ratio and optimum data processing (matched filters). Arbitrary frequency modulation, amplitude modulation and target motion as well as various assumptions on processing the R-F phase are considered. The multiple target case enables investigation of a signal's resolution ability as well as its accuracy potentials. Results for a carrier frequency much greater than the effective signal bandwidth are obtained as a special case. A main purpose of the report is the reduction of the original radar problem to a linear model which is equivalent in the sense of having the same information matrix. The various special cases of interest are obtained by simple modifications of the general case and thus the algorithm can provide a very versatile tool for evaluating and designing radar signals.

Document number CIA-RDP89B00709R000500970008-0 declassified and released through the CIA's CREST database. Previously available only on four computers located outside of Washington D.C., the Agency was successfully pressured into putting the files online as a result of a MuckRock lawsuit and the efforts of Emma Best. The metadata was collected by Data.World, and the files are now being archived and made text searchable by the Internet Archive.

The proposed adaptive array beamformer is to be considered as a component which will be added to an existing radar system with minimal change in the overall configuration. Measurements were taken under conditions representative of the environment in which an HF system must operate. Specifically, one-hop backscatter signals generated by an FM/CW transmitter format were received in the presence of relatively high noise and interference levels. Adaptive beamforming techniques are ideally suited to these conditions and can provide time variable null-tracking of both the frequency and spatial direction of arrival of interference sources.

A computer program is described that processes a Doppler radar signal to provide the position, velocity, and acceleration histories of a model in the barrel of a hypervelocity gun. The program uses the Hilbert transform as obtained via the Fourier transform. Algorithms for dealing with poor signal quality are described. Results from actual and simulated signals are presented. It is shown that the unique properties of the Hilbert transform result in a program that is fast, accurate, and easy to use.

Most current radars are designed to transmit short duration pulses with relatively high peak power. These radars can be detected easily by the use of relatively modest EW intercept receivers. Three radar functions, namely search, anti-ship missile (ASM) seeker and navigation, are examined in this report to evaluate the effectiveness of potential low probability of intercept (LPI) techniques, such as waveform coding, antenna profile control and power management, that a radar may employ against current Electronic Warfare (EW) receivers. The general conclusion is that it is possible to design a LPI radar which is effective against current intercept EW receivers. LPI operation is most easily achieved at close ranges and against a target with a large radar cross section. The general system sensitivity requirement for the detection of current and projected LPI radars is found to be on the order of -100 dBmi which cannot be met by current EW receivers. Finally, three potential LPI receiver architectures, using channelized, superhet and acousto-optic receivers with narrow RF and video bandwidths are discussed. They have shown some potential in terms of providing the sensitivity and capability in an environment where both conventional and LPI signals are present.

This report investigates the bispectral processing of complex-valued radar target scattering signatures and the impact of such processing on target identification. The concept of 'birange profile' as two-dimensional display of target scattering mechanisms in the range domain is introduced. It is shown that the birange profile can detect responses due to multiple scattering interactions. An algorithm is proposed to estimate the birange profiles of radar targets. Using this algorithm, multiple interactions of real aircraft are extracted, and interpreted in terms of target geometry. An algorithm that uses autoregressive parametric modeling of radar signatures to obtain high resolution birange profiles was introduced and tested using synthesized data and real scattering data. An alternative estimation procedure, which does produce the true bispectrum, was developed. The classification aspect of birange features was investigated using cross-correlation of birange profile of unknown target with that of a catalog target. It was shown that classification using birange features is inferior to classification using impulse response features if the additive noise is Gaussian. Classification with the birange when the noise is non-Gaussian yields relatively reasonable results in comparison with other classifiers. Finally, it was shown that when scattering from extraneous point scatterers is added to the data, then classification with the birange outperforms other classifiers if the signal-to-extraneous scatterers ration is low. Keywords: Identification, Signal processing, Targets, Radar, Statistical.

1Voyage Towards the South Pole and Round the World Volume 1

By James Cook

Having, on his first voyage, discovered Australia, Cook still had to contend with those who maintained that the Terra Australians Incognita (the unknown Southern Continent) was a reality. To finally settle the issue, the British Admiralty sent Cook out again into the vast Southern Ocean with two sailing ships totalling only about 800 tons. Listen as Cook, equipped with one of the first chronometers, pushes his small vessel not merely into the Roaring Forties or the Furious Fifties but becomes the first explorer to penetrate the Antarctic Circle, reaching an incredible Latitude 71 degrees South, just failing to discover Antarctica. (Introduction by Shipley)

LibriVox volunteers bring you 16 recordings of Be Kind When You Can by Eliza Cook. This was the Weekly Poetry project for January 30, 2011.<br><br>Eliza Cook was an English author, Chartist poet and writer born in London Road, Southwark.<br><br>She was the daughter of a local tradesman. She attended the local Sunday Schools and was encouraged by the son of the music master to produce her first volume of poetry. From this she took confidence and in 1837 began to offer verse to the radical Weekly Dispatch, then edited by William Johnson Fox. She was a staple of its pages for the next ten years. She also offered material to The Literary Gazette, Metropolitan Magazine and New Monthly. (summary from Wikipedia)

3Life of Florence Nightingale, Volume 1

By Edward Tyas Cook

A history of Florence Nightingale (1820-1910), the founder of modern nursing. Here's the definitive biography, gleaned from a lifetime of her notes, letters and writings, that goes way beyond the mere legend of "The Lady With The Lamp", and the "Founder Of Modern Nursing". This well written saga covers the vastly more expanded story of her development into an intelligent woman with a high purpose, her social standing and family connections that opened many doors for her, her extensive work after the Crimean War working with governments to develop better health care delivery systems to the indigent in England and in India, and her voluminous writings on numerous topics. Volume 1 recounts her life from childhood through 1861. (Summary by Michele Fry)

4Life of Florence Nightingale, Volume 2

By Edward Tyas Cook

A history of Florence Nightingale (1820-1910), the founder of modern nursing. Here's the definitive biography, gleaned from a lifetime of her notes, letters and writings, that goes way beyond the mere legend of "The Lady With The Lamp", and the "Founder Of Modern Nursing". This well written saga covers the vastly more expanded story of her development into an intelligent woman with a high purpose, her social standing and family connections that opened many doors for her, her extensive work after the Crimean War working with governments to develop better health care delivery systems to the indigent in England and in India, and her voluminous writings on numerous topics. Volume 2 recounts her life from 1861 through her death in 1910. (Summary by Michele Fry)

The first of 3 voyages of Captain Cook - this one is to New Zealand and the South Pacific. - Summary by Lynda Marie Neilson

6Adrift in the Unknown; or Queer Adventures in a Queer Realm

By William Wallace Cook

A delightful, imaginative, and sometimes silly adventure in early science fiction. Join a noble scientist and some of his less noble associates as they take flight in a newly constructed, seemingly magical spaceship. After they land on the planet Mercury, they are caught in the crossfire in a war between futuristic Mercurean city-states which wield high-tech weaponry. As they fight for their own survivial and that of their fellow humans, each man is challenged to confront his own moral failings. Set aside your 21st-century knowledge of physics and settle in for a lighthearted, somewhat predictable romp through outer space. - Summary by Amanda Rumbaugh

7Voyage Towards the South Pole and Round the World Volume 2

By James Cook

Having disproved the myth of Terra Australis Incognita (The unknown Southern Continent), Cook returns to New Zealand via the Friendly Islands, Easter Island, Norfolk Island, New Caledonia, and Vanuatu. Cook then returns home via Cape Horn, discovering South Georgia and the South Sandwich Islands before putting into Cape Town to refit before finally sailing home. Volume 2 also includes the Journal of Captain Furneaux during the period when he was separated from Captain Cook - Summary by David Cole

8First Voyage of James Cook Volume 1

By James Cook

In May 1768, the Admiralty commissioned the 39-year old Cook to command a scientific voyage to the Pacific Ocean to observe and record the 1769 transit of Venus across the Sun. The expedition sailed aboard HMS Endeavour in August 1768, rounded Cape Horn and continued to Tahiti, where the observations of the transit were made. Cook then opened sealed orders for the second part of his voyage: to search the south Pacific for signs of the postulated rich southern continent of Terra Australis. Cook proceeded to circumnavigate New Zealand's two main islands, which is where this volume ends. - Summary by David Cole

9First Voyage of James Cook Volume 2

By James Cook

Following his discovery and circumnavigation of New Zealand recorded in Volume 1, Cook sailed westwards to Australia, whose east coast was at that time unknown. After initially sighting Port Hicks, Cook landed at Botany Bay, where he tried but failed to make contact with the native inhabitants. He proceeded northward, mapping about a thousand miles of coastline and discovering the Great Barrier Reef by severely damaging his ship in running into one of the reefs. The ship was in danger of sinking and limped to the mainland where, over a period of seven weeks, major repairs were made by the ship's crew. Cook then proceeded to Cape York, the northern tip of Australia and completed his circumnavigation of the globe via Batavia (modern Jakarta, Indonesia), the Cape of Good Hope and St. Helena. - Summary by David Cole

10Third Voyage of James Cook, Volume 1

By James Cook

Only months after his return from his mammoth Second Voyage, the Admiralty ordered Cook back to the Pacific, ostensibly to return Omai, a young man from Raiatea, to his homeland, but in fact to attempt the discovery of the Northwest Passage (a proposed route from the Pacific to the Atlantic north of Canada). Cook commanded HMS Resolution and was accompanied by Captain Clerke commanding HMS Discovery. After sailing to the Pacific via Tenerife, Cape Town and New Zealand, Omai was returned to his home, after which Cook became the first European to visit the Sandwich Islands (Hawaii) and then mapped the West Coast of North America. After many delays, he penetrated the Bering Strait, but was unable because of ice to proceed either East or West. He eventually returned to Hawaii, where Cook was killed by the natives. Following the death of Captain Clerke from tuberculosis, the ships eventually returned to Britain under the command of Captain Gore. This first volume covers only the portion of the voyage up to the first visit to Hawaii. - Summary by David Cole

Only months after his return from his mammoth Second Voyage, the Admiralty ordered Cook back to the Pacific, ostensibly to return Omai, a young man from Raiatea, to his homeland, but in fact to attempt the discovery of the Northwest Passage (a proposed route from the Pacific to the Atlantic north of Canada). Cook commanded HMS Resolution and was accompanied by Captain Clerke commanding HMS Discovery. After sailing to the Pacific via Tenerife, Cape Town and New Zealand, Omai was returned to his home, after which Cook became the first European to visit the Sandwich Islands (Hawaii) and then mapped the West Coast of North America. After many delays, he penetrated the Bering Strait, but was unable because of ice to proceed either East or West. He eventually returned to Hawaii, where Cook was killed by the natives. Following the death of Captain Clerke from tuberculosis, the ships eventually returned to Britain under the command of Captain Gore. This second volume covers the portion of the voyage from leaving Tonga, sailing through the Bering Strait and attempting to find a Northwest or Northeast passage, and sailing to Hawaii, up to immediately before Cook's death there. (Summary by David Cole)

From the darkest corners of the Amazon to the idyllic island paradise of Borneo, the early years of Weird Tales were chocked full of dread tales of jungle terrors. Fierce beasts, deadly cannibals and all other manner of unknown horrors await beneath the lush canopies of trees. Even if you aren't foolish enough to brave the dangers of the jungle, the jungle may come to you instead! Join us for another fright-filled collection of stories from the celebrated halls of Weird Tales magazine! - Summary by Ben Tucker