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Aerospace and Electronic Systems, IEEE Transactions on

Issue 1 • Date Jan 1994

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Displaying Results 1 - 25 of 30
  • Search radar detection and track with the Hough transform. III. Detection performance with binary integration

    Publication Year: 1994 , Page(s): 116 - 125
    Cited by:  Papers (31)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    For pt.II see ibid., vol. 30, no 1, (Jan. 1994). This paper considers how well a Hough transform detector with binary integration improves the performance of a typical surveillance radar. For Hough transform detection, binary integration offers some advantages over noncoherent integration when multiple targets appear in range-time space or when the detector receives signals with a wide range of power. We derive expressions for PF and PD for a Hough transform binary integrator and apply the expressions to a typical surveillance radar. The results show that for the case considered, the binary Hough integrator improves the power budget of the radar by about 3 dB for a nonfluctuating target and 1 dB for a highly fluctuating target View full abstract»

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  • A sequential detection approach to target tracking

    Publication Year: 1994 , Page(s): 197 - 212
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1268 KB)  

    Sequential hypothesis testing is investigated for multiframe detection and tracking of low-observable maneuvering point-source targets in a digital image sequence. The proposed multiple multistage hypothesis test tracking (MMHTT) algorithm extends tracks formed from sequentially detected target trajectory segments using a multiple hypothesis tracking strategy. The MMHTT algorithm does not require a probabilistic larger maneuver model. Computational efficiency is achieved by using a truncated sequential probability ratio test (SPRT) to prune a dense tree of candidate target trajectories and score the detected trajectory segments. An analytical performance evaluation is presented and confirmed by experimental results from an optical satellite tracking application View full abstract»

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  • Czech radar technology

    Publication Year: 1994 , Page(s): 2 - 17
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1948 KB)  

    Recently Czech radars have been known almost only within the previous Eastern Bloc. Tesla Pardubice, a European manufacturer of radars with more than 1200 various radars manufactured and delivered, has achieved the leading role among other radar manufacturers in Central and Eastern Europe. Radar production has been based on the company's own research and development of systems and technologies. A brief history of Czech radars is presented. The most important parts of radar systems are dealt with. Several typical Tesla radar system are described. Descriptions are completed with numerous figures and tables View full abstract»

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  • Broadband focusing for partially adaptive beamforming

    Publication Year: 1994 , Page(s): 68 - 80
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (844 KB)  

    A broadband adaptive beamforming approach based on the concept of signal-subspace alignment is formulated and contrasted with the conventional approach. The proposed method involves a preprocessor that focuses the signal spaces at different frequencies to a common one and a narrowband beamformer following the preprocessor. The merits that result as a consequence are partial adaptivity due to single frequency weights and decorrelation of coherent signals thus combating signal cancellation. The latter effect is studied by deriving expressions for the desired-signal distortion in a minimum variance distortionless response (MVDR) beamformer and analyzing them. Implementation issues of the preprocessor are addressed. Simulation results confirm the utility of the focusing preprocessor View full abstract»

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  • Performance evaluation of track initiation in dense target environments

    Publication Year: 1994 , Page(s): 213 - 219
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    This paper describes an analysis of track initiation performance in very high target density environments. The analysis of tracking performance performed previously by S. Mori et al. (1992) yielded very simple expressions to predict average track purity in terms of tracking parameters. These results were, however, obtained mainly for the track continuation phase in which tracks are more or less well established. We extend these results to the track initiation phase View full abstract»

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  • Application of neural networks in target tracking data fusion

    Publication Year: 1994 , Page(s): 281 - 287
    Cited by:  Papers (12)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    Kalman filtering is a fundamental building block of most multiple-target tracking (MTT) algorithms. The other building block usually involves some type of data association schemes. Here it is proposed to incorporate a neural network into the normal Kalman filter configuration such that the neural network provides the adaptive capability the filter needs. As such the estimation error of the Kalman filter would be reduced, hence improving the MTT solution. Simulation results have shown that this claim is valid View full abstract»

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  • ADEPTS: space-based power system management using parallel architecture

    Publication Year: 1994 , Page(s): 275 - 280
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    A serial architecture was developed which would run on a single processor and perform the functions of state estimation, unit dispatch, and load-flow. Node profiling was done on the serial architecture to check for the total time spent in calculations, input/output (I/O) communications, and internode communication. Different parallel architectures were developed and tested which also performed the functions of state estimation, unit dispatch, and load-flow. Node profiling was done on these parallel architectures to check for the total time spent in calculations, I/O communications, and internode communication. Timing analysis revealed that some of these parallel architectures provided increases in speed and efficiency View full abstract»

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  • Existence and uniqueness of motion parameters in active ranging

    Publication Year: 1994 , Page(s): 18 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (896 KB)  

    Motion estimation of distributed objects is discussed. Measurements include position plus Doppler. We show that 2D position plus Doppler is sufficient to uniquely determine the motion parameters of an object on a circular trajectory except for special cases. The uniqueness enhances occlusion tolerance and implies an approach to associating features. We show that the sensitivity of calculated motion parameters to measurement error is bounded. We also show that the error in the motion parameters tends to zero as the measurement error approaches zero View full abstract»

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  • Finite data performance of MUSIC and minimum norm methods

    Publication Year: 1994 , Page(s): 161 - 174
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (864 KB)  

    In the direction of arrival (DOA) estimation problem, we encounter both finite data and insufficient knowledge of array characterization. It is therefore important to study how subspace-based methods perform in such conditions. We analyze the finite data performance of the multiple signal classification (MUSIC) and minimum norm (min. norm) methods in the presence of sensor gain and phase errors, and derive expressions for the mean square error (MSE) in the DOA estimates. These expressions are first derived assuming an arbitrary array and then simplified for the special case of an uniform linear array with isotropic sensors. When they are further simplified for the case of finite data only and sensor errors only, they reduce to the recent results given previously (1989, 1991). Computer simulations are used to verify the closeness between the predicted and simulated values of the MSE View full abstract»

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  • True proportional navigation with maneuvering target

    Publication Year: 1994 , Page(s): 229 - 237
    Cited by:  Papers (13)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    We analytically obtain the capture regions for the true proportional navigation (TPN) missile guidance law against an intelligently maneuvering target. Two versions of TPN are considered. The first is the original TPN which assumes the commanded lateral acceleration to be directly proportional to the line-of-sight (LOS) rate only, the proportionality factor being an arbitrary constant or dependent only on the initial closing velocity. The other, known as RTPN (realistic TPN), assumes the commanded lateral acceleration to be directly proportional to the LOS rate and also the current closing velocity. The target is assumed to maneuver in such a way as to increase the LOS rate and thus directly oppose the proportional navigation (PN) philosophy of annulling the LOS rate. A necessary and sufficient condition for capture is derived for the original TPN, and using it, the exact capture region is obtained. A sufficient condition for capture is derived for RTPN and is used to obtain its capture region partially. Some necessary conditions for capture are also derived for RTPN and are used to obtain an upper bound on its complete capture region. Using these conditions some important results on the existence of capture regions and a comparative study of capturability of TPN laws are also presented View full abstract»

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  • Clutter metrics for target detection systems

    Publication Year: 1994 , Page(s): 81 - 91
    Cited by:  Papers (6)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1476 KB)  

    The problem of calculating an effective contrast for diffused targets in visual scenery is addressed. The effect of local variations of intensity in the vicinity of the target is modeled by considering the distribution of the intensity of the edges. The effect of global clutter is discussed from the vantage point of selecting the best model for background scenery. Generalized contrast measures are described and applied to real scenes View full abstract»

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  • Steady-state analysis of the constant-frequency clamped series resonant converter

    Publication Year: 1994 , Page(s): 135 - 143
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (660 KB)  

    A constant-frequency diode-clamped series resonant converter (CFCSRC) is proposed as a solution to problems associated with frequency-controlled resonant converters. This converter has two resonant frequencies, and control is achieved by varying the relative time spent at each switching frequency. Two zero-current-switching (ZCS) modes are examined and plotted in the output plane. An equation is given for the boundary between the two ZCS modes, as well as an expression for the boundary between ZCS and non-ZCS operation; both are plotted in the output plane. The output equation for the main mode is shown to be hyperbolic. Converter peak voltages limited to the input voltages, and peak currents are less than those of the frequency-controlled clamped series resonant converter over a large operating range. Data from a prototype converter are compared with theoretical data and are shown to be in good agreement with the theoretical model View full abstract»

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  • Angle of arrival estimation of coherent signals using an array doublet in motion

    Publication Year: 1994 , Page(s): 126 - 134
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB)  

    Shown here is how the estimation of signal parameters via relational invariance techniques (ESPRIT) algorithm may be used with a single pair of antennas in motion to estimate angles of arrival (AOA) for coherent signals. The approach exploits the Doppler frequency shifts caused by the doubler in motion. With this estimator, the number of signals that can be handled is not limited by the size of the array, as in the usual ESPRIT application, but by an adjustable parameter. A theoretical performance analysis of the estimator and typical examples showing the use of this estimator are given View full abstract»

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  • Adaptive detection using low rank approximation to a data matrix

    Publication Year: 1994 , Page(s): 55 - 67
    Cited by:  Papers (81)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (972 KB)  

    Using an accurate formula for the error in approximating a low rank component, we calculate the performance of adaptive detection based on reduced-rank nulling. In this principal component inverse (PCI) method, one temporarily regards the interference as a strong signal to be enhanced. The resulting estimate of the interference waveform is subtracted from the observed data, and matched filtering is used to detect signal components in the residual waveform. We also present a generalized likelihood-ratio test (GLRT) for adaptively detecting a low rank signal in the presence of low rank interference. This approach leads to a test which is closely related to the PCI method and extends the PCI method to the case where strong signal components are present in the data. A major accomplishment of the work is our calculation of the statistics of the output of the matched filter for the case in which interference cancellation and signal detection are carried out on the same observed data matrix. That is, no separate data is used for adaptation. Examples are presented using both simulated data and real, active-sonar reverberation data from the ARSRP, the Acoustic Reverberation Special Research Program of the Office of Naval Research View full abstract»

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  • Search radar detection and track with the Hough transform. I. system concept

    Publication Year: 1994 , Page(s): 102 - 108
    Cited by:  Papers (76)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    A method of viewing search radar signals and data is described and analyzed in which the image processing technique of the Hough transform is used to extract detections and simultaneous tracks from multi-dimensional data maps. System design concepts are considered and simulation examples are given that illustrate the concept. The technique offers many advantages when compared with more traditional techniques. These advantages include improved detection, a solution to the range walk problem, flexibility of implementation, elimination of slow scan-rate latency and automatic track acquisition without revisit. The concept is similar to track-before-detect algorithms that use preliminary information from previous scans to aid in target declarations View full abstract»

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  • Use of Hopfield neural networks in optimal guidance

    Publication Year: 1994 , Page(s): 287 - 293
    Cited by:  Papers (6)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    A Hopfield neural network architecture is developed to solve the optimal control problem for homing missile guidance. A linear quadratic optimal control problem is formulated in the form of an efficient parallel computing device known as a Hopfield neural network. Convergence of the Hopfield network is analyzed from a theoretical perspective, showing that the network, as a dynamical system approaches a unique fixed point which is the solution to the optimal control problem at any instant during the missile pursuit. Several target-intercept scenarios are provided to demonstrate the use of the recurrent feedback neural net formulation View full abstract»

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  • Improved 3-D tracking using the mode-S down link

    Publication Year: 1994 , Page(s): 267 - 274
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    The use of airborne measurements to assist in three-dimensional (3-D) tracking is investigated and a simple filter is developed. This filter is derived from an earlier, flight-dynamics-based 3-D tracker, through simplifications. The performance of the simplified filter is evaluated using real data, is compared against the performance of the initial 3-D tracker and is found to be very satisfactory, while its computational requirements are significantly reduced View full abstract»

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  • On-line diagnostics of a self-contained flight actuator

    Publication Year: 1994 , Page(s): 186 - 196
    Cited by:  Papers (16)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (736 KB)  

    A mathematical model describing the dynamics of a self-contained flight control actuator is established. Typical failures of the actuator are defined in the space of the model parameters in the form of a failure pattern library. A diagnostic model of the actuator, intentionally sensitive to particular failures, is defined. A diagnostic procedure, featuring on-line parameter estimation of the diagnostic model, failure detection, and isolation, is proposed. A failure prediction procedure, utilizing trends exhibited by parameter estimates, is formulated. The results are verified by computer simulation View full abstract»

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  • Gram-Schmidt forward-backward generalized sidelobe canceller

    Publication Year: 1994 , Page(s): 151 - 160
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    Addressed here is the the discrete-time and the continuous-time recursive least-squares (RLS) modified Gram-Schmidt orthogonalization (MGSO) algorithms for forward-backward (FB) generalized sidelobe cancelling (GSC) adaptive beamformers. The FB-GSC requires processing each input data twice, forward and conjugated backward, and hence its adaptation would require a rank-two update each time. This paper first derives a discrete-time rank-two-update RLS MGSO algorithm for this purpose. Then, by imposing the conjugate symmetry constraints, the backward data processing can be removed without any loss and the complex-valued algorithm can be further transformed into an equivalent real-valued algorithm Therefore, significant computation savings can be achieved. Also described here is the continuous-time RLS MGSO algorithms for the FB-GSC and the conjugate symmetric FB-GSC. Computer simulations of the FB-GSC and the forward-only GSC are presented View full abstract»

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  • Modified input estimation technique using pseudoresiduals

    Publication Year: 1994 , Page(s): 220 - 228
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    An adaptive tracking filter for maneuvering targets is proposed using modified input estimation technique. Pseudoresiduals are defined using measurements and the velocity estimate at the hypothesized maneuver onset time. With the pseudoresiduals and a new target model representing transitions of nominal accelerations, a new input estimation method for tracking a maneuvering target is derived. Since the proposed detection technique is more sensitive to maneuvers than previous work, the shorter window length can be employed to detect and compensate target maneuvers. Also shown is that the tracking performance of the proposed filter is similar to that of interacting multiple model method (IMM) with 3 models, while computational loads of our method are drastically reduced View full abstract»

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  • Random tropospheric effects in command guidance by multilateration and interferometry

    Publication Year: 1994 , Page(s): 249 - 257
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    Statistical models are developed for the random spatial variations in refractivity in the troposphere, and are used to derive spatial correlation functions for the errors in range measurement and interferometer angle measurement. These are then used to analyze the relative errors between two tracked targets, for application to command-guided intercept problems. It is shown that multilateration, using range measurements, yields much smaller relative errors than does the interferometer approach View full abstract»

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  • A comparison of two adaptive detection schemes

    Publication Year: 1994 , Page(s): 30 - 40
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    Two schemes for adaptive detection are compared: Kelly's generalized likelihood ratio test (GLRT) and the mean level adaptive detector (MLAD). Detection performance, PD, is predicted for the two schemes under the assumptions that the input noises are zero-mean complex Gaussian random variables that are temporally independent but spatially correlated; and the amplitude of the desired signal is Rayleigh distributed. PD is computed as a function of the false alarm probability, the number of input channels, the number of independent samples per channel, and the matched filtered output signal-to-noise (S/N) power ratio. In this analysis the GLRT is shown to have better detection performance than the MLAD. The difference in detection performance increases as one uses fewer input samples. However, the required number of samples necessary to have only a 3 dB detection loss for both detection schemes is approximately the same. This is significant since for the present, the MLAD is considerably less complex to implement than the GLRT View full abstract»

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  • Search radar detection and track with the Hough transform. II. detection statistics

    Publication Year: 1994 , Page(s): 109 - 115
    Cited by:  Papers (23)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    For pt.I see ibid., vol.30, no.1, (Jan.1994). This paper describes the calculation of PF and PD for the Hough transform technique when the primary threshold crossings are weighted by their power before transforming (i.e., noncoherent integration). After expressions for PF and PD are derived, we examine the question of optimal granularity of the Hough accumulator space. We also investigate the relationship between primary and secondary thresholds and its effect on detectability View full abstract»

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  • Steady-state analysis and design of a switched-capacitor DC-DC converter

    Publication Year: 1994 , Page(s): 92 - 101
    Cited by:  Papers (60)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    A representative switched-capacitor DC-DC converter topology is presented, circuit operation is explained, and control strategies are identified. State-space averaging is used to analyze steady-state performance and to develop control criteria and design equations. The analytical results are verified by SPICE simulation View full abstract»

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  • Inversion of all principal submatrices of a matrix

    Publication Year: 1994 , Page(s): 280 - 281
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    Let Am be an m×m principal submatrix of an infinite-dimensional matrix A. We give a simple formula which expresses Am+1-1 in terms of Am-1, and based on this formula, an algorithm which computes the inverses of Am for m=1, 2, 3, ..., n using only 2n3-2n2 +n arithmetic operations. This is an improvement over the naive method of computing the inverses separately which would require Σ m=1n m3=O(n4) arithmetic operations View full abstract»

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Aims & Scope

IEEE Transactions on Aerospace and Electronic Systems focuses on the equipment, procedures, and techniques applicable to the organization, installation, and operation of functional systems designed to meet the high performance requirements of earth and space systems.

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Editor-in-Chief
Lance Kaplan
Army Research Laboratory