# Communications, Radar and Signal Processing, IEE Proceedings F

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• ### A complex gradient operator and its application in adaptive array theory

Publication Year: 1983, Page(s):11 - 16
Cited by:  Papers (30)
| | PDF (673 KB)

The problem of minimising a real scalar quantity (for example array output power, or mean square error) as a function of a complex vector (the set of weights) frequently arises in adaptive array theory. A complex gradient operator is defined in the paper for this purpose and its use justified. Three examples of its application to array theory problems are given. View full abstract»

• ### Digital beam forming for radar

Publication Year: 1980, Page(s):266 - 277
Cited by:  Papers (2)
| | PDF (1353 KB)

Development of digital methods for antenna beam forming in the receiving mode of a radar can be advantageous in providing the system with a high degree of flexibility in beam-pattern managementÂ¿ for countering e.c.m. and providing multiple functions efficiently. The justification for incorporating digital methods and various possible arrangements are discussed first. The main body of the paper i... View full abstract»

• ### Radar detection prediction in sea clutter using the compound K-distribution model

Publication Year: 1985, Page(s):613 - 620
Cited by:  Papers (36)
| | PDF (945 KB)

In the paper the radar detection of targets in sea clutter modelled by the compound K-distribution is examined from a statistical detection viewpoint. Optimum performance is determined for both fixed threshold and ideal constant false alarm rate (CFAR) receivers for targets modelled by Swerling cases 0, 1 and 2. In particular, the performance of dual threshold binary integrators is assessed. The c... View full abstract»

• ### The geometry of bistatic radar systems

Publication Year: 1986, Page(s):604 - 612
Cited by:  Papers (23)
| | PDF (1056 KB)

Unless the separation between transmitter and receiver is small compared with ranges of interest, bistatic radars have a number of properties which differ significantly from the monostatic equivalents. Some of these produce operational advantages which provide a motivation for deployment, while others merely bring trouble and expense. The paper considers the basic bistatic properties which depend ... View full abstract»

• ### Introduction to electronic warfare

Publication Year: 1982, Page(s):113 - 132
Cited by:  Papers (7)
| | PDF (3554 KB)

The paper discusses the overall concept of electronic warfare (EW) and defines its three main subsets: electronic support measures (ESM), electronic countermeasures (ECM) and electronic counter-countermeasures (ECCM). The requirements for ESM receivers are reviewed in the context of two specific scenarios: that of intelligence gathering for communications and radar. The different current ESM recei... View full abstract»

• ### Digital signal processing for target detection FMCW radar

Publication Year: 1981, Page(s):331 - 336
Cited by:  Papers (3)
| | PDF (717 KB)

The paper describes a method of digital signal processing for extracting and isolating targets in the return signal of an FMCW radar. Digital filtering of the frequency spectrum of the return signal is followed by nonlinear optimisation to detect the presence of multiple targets amid clutter. Results using a practical radar show that the method gives enhanced detection of weak return signals. View full abstract»

• ### Maximum entropy method in image processing

Publication Year: 1984, Page(s):646 - 659
Cited by:  Papers (1)
| | PDF (1827 KB)

Maximum entropy has proved to be an enormously powerful tool for reconstructing images from many types of data. It has a privileged position as the only consistent method for combining different data into a single image. It has been used most spectacularly in radio astronomical interferometry, where it deals routinely with images of up to a million pixels, and high dynamic range. We also give exam... View full abstract»

• ### Characterisation of radar clutter as a spherically invariant random process

Publication Year: 1987, Page(s):191 - 197
Cited by:  Papers (82)
| | PDF (1028 KB)

A statistical characterisation of clutter as a complex random process is needed in the design of optimum detection schemes. The paper considers modelling complex clutter as a spherically invariant random process (SIRP), namely assuming that its PDFs can be expressed as non-negative definite quadratic forms, a generalisation of a Gaussian process. Relevant properties of SIRPs are summarised, and sh... View full abstract»

• ### Application of efficient linear FM matched filtering algorithms to synthetic aperture radar processing

Publication Year: 1985, Page(s):45 - 57
Cited by:  Papers (53)
| | PDF (1716 KB)

The applicability of two relatively new linear FM matched filtering algorithms to the processing of synthetic-aperture radar (SAR) data is examined and compared to the fast-convolution algorithm. The algorithms, called basic spectral analysis and the step transform, use the properties of the linear FM signal to achieve some significant performance improvements. The algorithms are evaluated on the ... View full abstract»

• ### Design and performance of airborne radomes: a review

Publication Year: 1981, Page(s):451 - 464
Cited by:  Papers (4)
| | PDF (1773 KB)

The ever increasing demands on the performance of airborne antennas place comparable demands on the design of the enclosing randome to ensure minimal degradation of the antenna radiation pattern. Radomes for airborne application can be separated into three main categories: large aircraft radomes of either the nose-cone or under-fuselage type, small aircraft radomes often flush mounted to the airfr... View full abstract»

• ### Position, velocity and acceleration estimates from the noisy radar measurements

Publication Year: 1984, Page(s):167 - 168
Cited by:  Papers (1)
| | PDF (223 KB)

A two-dimensional Kalman tracking filter is described for obtaining optimum estimates of position, velocity and acceleration of an aircraft whose acceleration is perturbed due to manoeuvres and/or other random factors. In a track-while-scan operation, a two-dimensional radar sensor is assumed to measure the range and bearing of the vehicle at uniform sampling intervals of time T seconds through ra... View full abstract»

• ### Spatial correlation in K-distributed sea clutter

Publication Year: 1987, Page(s):526 - 532
Cited by:  Papers (24)
| | PDF (921 KB)

The compound K-distribution model for sea clutter previously described in the literature provides the foundation for a quantitative treatment of the spatial and temporal correlation characteristics of the envelope of clutter returns. In the paper the compound K-distribution model is extended to cover the spatial characteristics of sea clutter. The relationship of these characteristics to the physi... View full abstract»

• ### Multinotch logic-product polarisation suppression filters: a typical design example and its performance in a rain clutter environment

Publication Year: 1984, Page(s):383 - 396
Cited by:  Papers (8)
| | PDF (1662 KB)

Polarisation filtering is applied in radar systems to improve target detection in adverse environments. Fluctuations of the polarisation states of unwanted incident signals dictate the need for filters that suppress such signals in the polarisation domain and cover a controllable area of polarisation space. This has led to the concept of the multinotch logic-product (MLP)polarisation filter which ... View full abstract»

• ### Optimum MSK-type receivers for CPM on Gaussian and Rayleigh fading channels

Publication Year: 1984, Page(s):480 - 490
Cited by:  Papers (35)
| | PDF (1153 KB)

Power efficient schemes with excellent power spectra are contained among the continuous phase modulation (CPM) schemes. This is a constant envelope digital modulation technique, which in general requires a maximum-likelihood sequence detector (Viterbi detector) for efficient detection. This optimum receiver is sometimes complex. In this paper a parallel MSK-type receiver is studied. It is useful f... View full abstract»

• ### Survey of bistatic and multistatic radar

Publication Year: 1986, Page(s):587 - 595
Cited by:  Papers (11)
| | PDF (1077 KB)

A view of the broad subject area of multistatic radar is given in an attempt to clarify the several different terms used for various possible configurations and to classify them. The potential of multistatic systems compared to monostatic ones is listed, and the dependence on different configurations, types of co-operation, implemented techniques, modes of operation and different applications are ... View full abstract»

• ### Coherent radar detection in log-normal clutter

Publication Year: 1986, Page(s):39 - 53
Cited by:  Papers (16)
| | PDF (2061 KB)

The paper deals with the problem of radar detection of a target echo embedded in log-normal clutter and white Gaussian noise. Relevant features of this article, with respect to previous papers on the same subject, refer to the coherent model assumed for the clutter and the processing chain. In more detail, the in-phase and quadrature components of clutter have been modelled to give a log-normal am... View full abstract»

• ### Design techniques and performance of digital IFM

Publication Year: 1982, Page(s):154 - 163
Cited by:  Papers (7)
| | PDF (1542 KB)

The digital instantaneous-frequency-measuring receiver using delay-line discriminators was developed in the early 1960s specifically as a wideband and accurate analyser of pulsed radar signals. Various receiver configurations are incorporated in most of the more comprehensive EW systems currently in use. In the paper, the basic operating principles and design philosophy are reviewed, together with... View full abstract»

• ### Crosscorrelation between the envelopes of 900 MHz signals received at a mobile radio base station site

Publication Year: 1986, Page(s):506 - 512
Cited by:  Papers (89)
| | PDF (757 KB)

An experimental investigation is reported of the crosscorrelation of 900 MHz signals received by two spatially separated antennas at a base station. The investigation embraced vertical, horizontal and combined horizontal and vertical separation of the antennas, for transmission from test routes 1.3 km from the base station. It was found that a crosscorrelation ¿¿0.7 (i.e. when diversity improvemen... View full abstract»

• ### Adaptive airborne MTI: an auxiliary channel approach

Publication Year: 1987, Page(s):269 - 276
Cited by:  Papers (33)
| | PDF (943 KB)

The suppression of ground clutter returns received by an airborne radar is basically a two-dimensional filtering problem, because the clutter echoes depend on two parameters (velocity, azimuth) instead of velocity only as in case of ground-based radars. This requires two-dimensional sampling (in space and time) of the backscattered echo field, which in practice is fulfilled by a coherent pulse Dop... View full abstract»

Publication Year: 1987, Page(s):245 - 252
Cited by:  Papers (8)
| | PDF (970 KB)

Least-mean-square (LMS) algorithms for adaptive infinite impulse response (IIR) filters are proposed which sequentially adjust the parameters of the feedforward and feedback paths so as to minimise the equation error. Both the feed-forward and feedback paths are implemented in cascade second-order sections. However, instead of adapting the coefficients of the second-order sections, the actual root... View full abstract»

• ### Dyadic symmetry and Walsh matrices

Publication Year: 1987, Page(s):141 - 145
| | PDF (547 KB)

A unified matrix treatment which is defined for binary Walsh matrices is presented. This unified treatment, based on the concept of dyadic symmetry, defines Walsh matrices of different orderings using a simple equation. This equation in turn provides a straightforward derivation of various reordering schemes and Walsh matrix properties. Various fast computational algorithms can also be derived wit... View full abstract»

• ### Airborne pulse-Doppler radar: false-alarm control

Publication Year: 1987, Page(s):127 - 134
| | PDF (1056 KB)

Constant false-alarm rate (CFAR) techniques are compared in an airborne pulse-Doppler detection application. Standard methods such as CA-CFAR, GO-CFAR and OS-CFAR prove to be inadequate in dealing with the extreme variations of power between radar cells, resulting in large CFAR losses. Two new techniques, nadir-blanked CFAR and gradient CFAR, were specifically designed to accommodate these variati... View full abstract»

Publication Year: 1986, Page(s):649 - 657
Cited by:  Papers (50)
| | PDF (1311 KB)

The paper discusses the use of illuminators of opportunity¿¿ for bistatic radar systems. Experiments in the London area using the Crystal Palace transmitters are reported, including the use of TV pictures designed to make the transmission more closely resemble a pulsed radar signal. It is shown that the separation of targets from the direct signal and clutter requires extensive signal processing ... View full abstract»

• ### Overview of detection theory in multistatic radar

Publication Year: 1986, Page(s):613 - 623
Cited by:  Papers (11)
| | PDF (1262 KB)

The detection problem with multistatic radar systems is considered, resorting to the theory of detection of coherent target signals having a Gaussian probability density embedded in coherent Gaussian-distributed disturbances (i.e. clutter and/or directional jamming). A novelty of the paper is related to the capability of dealing with any type of time autocorrelation function of both target and dis... View full abstract»

• ### Adaptive variable update rate algorithm for tracking targets with a phased array radar

Publication Year: 1986, Page(s):277 - 280
Cited by:  Papers (1)
| | PDF (461 KB)

The analysis postulates an algorithm for adaptively varying the target-track update rate as a function of target manoeuvring. The algorithm proposes to vary the target observation time interval by an amount that tends to maintain a constant residual error. As an example, the algorithm is shown to be implemented with a two-dimensional alpha-beta filter. Simulated results are calculated for a target... View full abstract»

• ### Waveform design and doppler sensitivity analysis for nonlinear FM chirp pulses

Publication Year: 1986, Page(s):163 - 175
Cited by:  Papers (1)
| | PDF (1251 KB)

The use of pulse compression to obtain simultaneous long-range detection and good range resolution is described. The types of modulation that can be used to obtain pulse compression are outlined with particular emphasis on their performance under Doppler shift. It is shown that nonlinear frequency-modulated (FM) signals are capable of providing low range-sidelobes while being compressed using a ma... View full abstract»

• ### Autocorrelation function of the multiplexed sequence

Publication Year: 1984, Page(s):169 - 172
Cited by:  Papers (1)
| | PDF (426 KB)

A multiplexed sequence is one produced in a specific way by two linear feedback shift registers generating PN sequences, in conjunction with a multiplexer. Such a sequence may be a possible candidate for use as a building block in a sequence generator of a stream cipher system. In this paper, we derive some results concerning the autocorrelation function of this sequence. View full abstract»

• ### Log-Weibull distributed sea clutter

Publication Year: 1980, Page(s):225 - 228
Cited by:  Papers (5)
| | PDF (426 KB)

Sea clutter was measured using and L-band long-range air-route surveillance radar (a.r.s.r.) at very low grazing angles between 0.13¿¿ and 0.25¿¿. From the stored data of six scans, it is shown that the sea-clutter amplitude statistics obey a log-Weibull distribution. View full abstract»

Publication Year: 1982
Cited by:  Papers (42)
| | PDF (1090 KB)

A description of the physical mechanism causing multipath propagation in built-up areas is followed by a discussion of the various ways in which fading radio communiction channels can be described. It is shown that characterisation in the time-delay/Doppler-shift domain explicitly illustrates the multipath nature of the channel and provides parameters relevant to system design. A brief discussion ... View full abstract»

• ### Relation between the Karhunen Loève and cosine transforms

Publication Year: 1981, Page(s):359 - 360
Cited by:  Papers (45)
| | PDF (239 KB)

The cosine transform is nowadays widely used in image data compression studies as a result of its observed near optimum performance with respect to variance redistribution andits property of reducing block edge effects which occur at extreme values of compression. The reason for its good performance for a widely used class of sources is now demonstrated theoretically by showing that it can be deri... View full abstract»

• ### Effect of Fresnel ripples on sidelobe suppression in low time-bandwidth product linear FM pulse compression

Publication Year: 1982, Page(s):41 - 44
Cited by:  Papers (10)
| | PDF (457 KB)

The paper discusses the effects of Fresnel ripples on the suppression of peak time sidelobes in low time-bandwidth (TB) product linear-FM pulse compression systems employing internally Hamming weighted compression filters. Two methods for the reduction of these effects are investigated. The first, amplitude tapering of the rectangular FM pulse, yields significantly diminished sidelobes for TB prod... View full abstract»

• ### Maximum-likelihood receiver for low-angle tracking radar. Part 1: The symmetric case

Publication Year: 1982, Page(s):261 - 272
Cited by:  Papers (11)
| | PDF (1246 KB)

A new maximum-likelihood processor is described for estimating the elevation angle of a target in the combined presence of specular multipath and receiver noise, as encountered in a low-angle tracking-radar environment. The processor makes special use of the symmetry of the incident direct and specular multipath components with respect to the normal to the receiving array. The theory of the proces... View full abstract»

• ### Singular-value decomposition approach to time series modelling

Publication Year: 1983, Page(s):202 - 210
Cited by:  Papers (19)
| | PDF (1182 KB)

In various signal processing applications, as exemplified by spectral analysis, deconvolution and adaptive filtering, the parameters of a linear recursive model are to be selected so that the model is most¿¿ representative of a given set of time series observations. For many of these applications, the parameters are known to satisfy a theoretical recursive relationship involving the time series' ... View full abstract»

• ### Millimetre-wave propagation along railway lines

Publication Year: 1983, Page(s):688 - 694
Cited by:  Papers (3)
| | PDF (1504 KB)

The operation of modern railway systems requires a high degree of safety and reliability. This can be accomplished by using millimetre waves for communication and control. Besides high-data-rate relaying, this approach enables the transmission of highly concentrated radio beams; thus a radio tube¿¿ can be shaped and limited to the railway track only. There are two frequency ranges of interest: th... View full abstract»

• ### Application of Gram-Schmidt algorithm to optimum radar signal processing

Publication Year: 1984, Page(s):139 - 145
Cited by:  Papers (9)
| | PDF (730 KB)

The paper deals with the application of Gram-Schmidt decorrelation algorithm to the clutter cancellation and useful signal enhancement in radar signal processing. The proposed system architecture is an adaptive implementation of the well known optimum processor. The performance of the selected approach is evaluated and compared with that of the optimum one. As a general result, the adaptation time... View full abstract»

• ### Cryptographic techniques and network security

Publication Year: 1984, Page(s):684 - 694
| | PDF (1704 KB)

In the paper some of the cryptographic techniques, algorithms and applications in computer networks are reviewed. Symmetric and asymmetric cryptosystems, possible cryptanalytical attacks, cryptosecurity and the relevance of complexity theory to the security of ciphers are described. The major threats and counter-measures in computer-network communications are outlined. Finally, cryptographic appli... View full abstract»

• ### Intercept time and its prediction

Publication Year: 1985, Page(s):215 - 220
Cited by:  Papers (6)
| | PDF (927 KB)

Intercept time is a key factor in the performance of electronic warfare (EW) surveillance and reconnaissance equipments. Interception relates to the probability of time coincidence of two or more parametric windows; scanning antennas, sweeping or stepping receivers and frequency-agile emitters give examples of such windows, where alignment or coincidence is required before detection can occur. For... View full abstract»

• ### Detection of complex and simultanceous signals using an instantaneous frequency measurement receiver

Publication Year: 1985, Page(s):267 - 274
| | PDF (799 KB)

IFM receivers using delay line discriminators for frequency measurement exhibit good performance characteristics in a pulsed signal environment. However, performance degrades for degrades for time-overlapped or complex signals. The paper presents an analysis with experimental verification for signal types such as pulsed, CW, linear FM and phase coded signals. More details are given for the case of... View full abstract»

• ### Line code design for digital pulse-position modulation

Publication Year: 1985, Page(s):441 - 446
| | PDF (1066 KB)

A class of finite-state alternate alphabetic line codes, designated mBL-K, is identified and studied in the context of digital pulse-position modulation (PPM). The influence on code properties of the number of time slots per PPM frame and the number of frames per code word is considered, and a specific 9B2-33 code is identified which is particularly well suited to digital optical-fibre PPM transmi... View full abstract»

• ### Cell-averaging CFAR for multiple-target situations

Publication Year: 1986, Page(s):176 - 186
Cited by:  Papers (8)
| | PDF (1027 KB)

The performance of a mean-level detector is considered when one or more interfering target returns is present in the set of cells used in estimating the reference level. A serious degradation of detection probability is demonstrated for Swerling target fluctuation models 1 and 3. To alleviate the problem we analyse an alternative procedure. A censoring scheme is proposed whereby samples exceeding ... View full abstract»

• ### Fifty years of bistatic and multistatic radar

Publication Year: 1986, Page(s):596 - 603
Cited by:  Papers (1)
| | PDF (1262 KB)

The article begins with a review of the history of bistatic and multistatic radars, including the simultaneous introduction of radar technology in several countries during the 1930s and the various areas of technology development pursued by those countries. Technical descriptions are presented of nine different experimental systems. The article continues with a discussion of the potential military... View full abstract»

• ### Effects of correlated fading on level crossing rates and average fade durations with predetection diversity reception

Publication Year: 1988, Page(s):11 - 17
Cited by:  Papers (25)
| | PDF (648 KB)

General expressions for the level crossing rate (LCR) and average fade duration (AFD) are obtained for several diversity combining schemes employing two-branch predetection reception of correlated Rayleigh fading signals. These expressions are obtained from joint and conditional probability density functions (PDFs) of the received signals, and lead to a unified treatment. This simplified method co... View full abstract»

• ### Introduction to subsurface radar

Publication Year: 1988, Page(s):278 - 320
Cited by:  Papers (34)
| | PDF (8750 KB)

Subsurface radar techniques are increasingly being used for the detection and location of buried artefacts and structures within the upper regions of the earth's surface. The paper reviews the work done to date in this field, laying emphasis on the range of applications and the need for system design to match the intended application. An overall design strategy is outlined, together with a more de... View full abstract»

• ### Tracking systems for satellite communications

Publication Year: 1988, Page(s):393 - 407
Cited by:  Papers (11)
| | PDF (2247 KB)

Satellites in nominally geostationary orbits possess diurnal motion which causes the apparent position of the spacecraft to wander in the sky as seen by an earth station. If uncompensated this causes a variation in the performance of the communications link. The motion of the satellite therefore has to be tracked by the earth station antenna. During the past twenty years or so a considerable amoun... View full abstract»

• ### Performance of a 16-ARY DEQAM modem employing a baseband or RF predistorter over a regenerative satellite link

Publication Year: 1988, Page(s):547 - 557
Cited by:  Papers (7)
| | PDF (1270 KB)

The paper presents the results of a series of computer-simulation tests that determine the effects of bandlimiting (nonlinear distortion with and without predistortion) on the tolerance to additive white Gaussian noise of a digital modem. The modem transmits a 16-ary differentially encoded quadrature amplitude modulation (16-ary DEQAM) signal over a regenerative satellite link, where the high powe... View full abstract»

• ### F.M.-C.W. Delft atmospheric research radar

Publication Year: 1980, Page(s):421 - 426
Cited by:  Papers (2)
| | PDF (1018 KB)

At the Delft University of Technology a high-resolution S-band f.m.-c.w. radar system for remote sensing of the troposphere has been built to extend knowledge about layered and turbulent structures in clear air and to investigate the reflectivity levels of hydrometeors. Design considerations and performance characteristics of the radar are given. Separate antennas for transmitting and receiving on... View full abstract»

• ### New class of double inductive binary error correcting codes based on the class of ReedÂ¿Muller codes

Publication Year: 1988, Page(s):507 - 512
| | PDF (683 KB)

A new class of binary codes is introduced. The codes have length n = 1.5 Â· 2m (m Â¿ 3), and have a similar `double inductiveÂ¿ structure to that possessed by the class of Reed-Muller (RM) codes. The new codes are structured such that their length-to-distance ratio n/d = 2m, m Â¿ 2. For rates less than 1/2, the new codes have a higher rate than the next Reed-Muller code of the same order and lengt... View full abstract»

• ### Multipath and interference effects in secondary surveillance radar systems

Publication Year: 1981, Page(s):43 - 53
Cited by:  Papers (1)
| | PDF (1425 KB)

Secondary surveillance radar (SSR) offers many advantages for air traffic control (ATC) compared to normal (or primary) radar including substantially lower cost and improved performance. Because of the increasing reliance being placed on SSR by ATC a number of the system problems associated with SSR are becoming less easily tolerated. The paper discusses these problems, which mainly arise from mul... View full abstract»

• ### Suboptimal reception of binary CPSK signals

Publication Year: 1981, Page(s):125 - 134
Cited by:  Papers (2)
| | PDF (1040 KB)

A general class of binary continuous-phase shift keying (CPSK) signals is defined, of which continuous-phase FSK (CPFSK) and continuous-phase chirp (CPC) signals are special cases. The structure and performance of suboptimal average matched filter (AMF) receivers with multibit observation are considered; both coherent and noncoherent detection of binary CPSK signals are investigated. Expressions s... View full abstract»

• ### Ground-wave propagation. Part 1: Theory for short distances

Publication Year: 1981, Page(s):275 - 284
Cited by:  Papers (2)
| | PDF (964 KB)

Ground-wave propagation over a curved earth with a troposphere whose refractive index varies with height is considered. Series expansions are derived whose first term is the Sommerfeld flat-earth formula. These expansions generalise previous results by the inclusion of the effects of the inhomogeneous refractive-index variation. The methods described are induded in the ground-wave-propagation prog... View full abstract»