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1996 Vol. 18, No. 3
Display Method:
1996, 18(3): 225-229.
Abstract:
This paper studies the integration tracking mechanism of centralized multiradar system, such as tracking file management, operation mechanism, etc., and presents methods for initial position-presetting of radar azimuth scanning and data rearraging. Simulation is made with multiradar system of a certain ship tracking 8 targets under various tactical maneuvering situations. The simulation results show that the methods are able to solve some special problems of multiradar tracking.
This paper studies the integration tracking mechanism of centralized multiradar system, such as tracking file management, operation mechanism, etc., and presents methods for initial position-presetting of radar azimuth scanning and data rearraging. Simulation is made with multiradar system of a certain ship tracking 8 targets under various tactical maneuvering situations. The simulation results show that the methods are able to solve some special problems of multiradar tracking.
1996, 18(3): 230-235.
Abstract:
A method is presented to assess the Synthitic Aperture Radar (SAR) resolution of coherent targets. The SAR resolution is usually considered to be a parameter of SAR system and determined by SAR itself. However, the SAR resolution is also relative to the properties of radar targets. in this paper, the relationship between SAR resolution and coherency of radar targets is analysed in details, and the separable probability is presented as a parameter to assess the SAR resolution. Numerical results are given to illuminate the assessment.
A method is presented to assess the Synthitic Aperture Radar (SAR) resolution of coherent targets. The SAR resolution is usually considered to be a parameter of SAR system and determined by SAR itself. However, the SAR resolution is also relative to the properties of radar targets. in this paper, the relationship between SAR resolution and coherency of radar targets is analysed in details, and the separable probability is presented as a parameter to assess the SAR resolution. Numerical results are given to illuminate the assessment.
1996, 18(3): 236-242.
Abstract:
A convenient implementation approach of space-time adaptive processing for airborne radar has been proposed, which is added by some auxiliary array elements in the area of main-lobe clutter. It is of practical use for its small computational load. Since this approach possesses the ideal performance in the area of main-lobe clutter so that it is adequate to the phased array radar which the array antenna is placed on the aircraft by non-facade side. In addition, the approach which is added by some auxiliary beams in the area of main-lobe clutter has been discussed.
A convenient implementation approach of space-time adaptive processing for airborne radar has been proposed, which is added by some auxiliary array elements in the area of main-lobe clutter. It is of practical use for its small computational load. Since this approach possesses the ideal performance in the area of main-lobe clutter so that it is adequate to the phased array radar which the array antenna is placed on the aircraft by non-facade side. In addition, the approach which is added by some auxiliary beams in the area of main-lobe clutter has been discussed.
1996, 18(3): 243-248.
Abstract:
This paper studies the performances of the GOSGO (Generalised Order Statistics and Greatest Of)-- and GOSSO (Generalised Order Statistics and Smallest Of)--CFAR detectors under clutter edge situation. The analytic expressions of false alarm probabilities under clutter edge situation are derived. Their performances to counter clutter edge are analysed, and compared them with the OS(Order Statistics), CA(Cell Averaging), GO(Greatest Of) and SO(Smallest Of) detectors. Results show that GOSGO possesses the better performance than GO for countering clutter edge. But the performance of GOSSO is not good.
This paper studies the performances of the GOSGO (Generalised Order Statistics and Greatest Of)-- and GOSSO (Generalised Order Statistics and Smallest Of)--CFAR detectors under clutter edge situation. The analytic expressions of false alarm probabilities under clutter edge situation are derived. Their performances to counter clutter edge are analysed, and compared them with the OS(Order Statistics), CA(Cell Averaging), GO(Greatest Of) and SO(Smallest Of) detectors. Results show that GOSGO possesses the better performance than GO for countering clutter edge. But the performance of GOSSO is not good.
1996, 18(3): 249-255.
Abstract:
A Suboptimal Maximum Likelihood Estimation(SMLE) algorithm based on full-deramp model and its implementation in satellite-borne radar altimeter are presented in this paper. The influence of both the return fluctuation and the receiver noise on the height and slope estimation precision are discussed in details. Some conclusions are obtained and verified by the computer simulation results.
A Suboptimal Maximum Likelihood Estimation(SMLE) algorithm based on full-deramp model and its implementation in satellite-borne radar altimeter are presented in this paper. The influence of both the return fluctuation and the receiver noise on the height and slope estimation precision are discussed in details. Some conclusions are obtained and verified by the computer simulation results.
1996, 18(3): 256-262.
Abstract:
The finite data estimates of the complex fourth-order moments of a signal consisting of random harmonics are analysed. Conditions for the fourth-order stationarity and ergodicity are obtained. Explicit formulas for the estimation error and its variance, as well as their limiting large sample values are derived. Finally, a special case relevant to cubic phase coupling is considered, and these results are stated for this case, the variance is shown to comprise an ergodic and a nonergodic part.
The finite data estimates of the complex fourth-order moments of a signal consisting of random harmonics are analysed. Conditions for the fourth-order stationarity and ergodicity are obtained. Explicit formulas for the estimation error and its variance, as well as their limiting large sample values are derived. Finally, a special case relevant to cubic phase coupling is considered, and these results are stated for this case, the variance is shown to comprise an ergodic and a nonergodic part.
1996, 18(3): 263-269.
Abstract:
At first, a formula for computing the dimension of (narrow-sense, primitive) BCH codes over GF(q) is offered, which is better than the result given by F. J. MacWilliams et al. (1977). then a new method for calculating the dimension of BCH codes is proposed. Moreover, it is proved that BCH bound is a leader of cyclotomic cosets, and it is guessed that the minimum distance of BCH codes is also a leader of cvclotomic cosets.
At first, a formula for computing the dimension of (narrow-sense, primitive) BCH codes over GF(q) is offered, which is better than the result given by F. J. MacWilliams et al. (1977). then a new method for calculating the dimension of BCH codes is proposed. Moreover, it is proved that BCH bound is a leader of cyclotomic cosets, and it is guessed that the minimum distance of BCH codes is also a leader of cvclotomic cosets.
1996, 18(3): 270-275.
Abstract:
A method for solving fuzzy linear pregramming with neural network is described and some experimental results are given. The method for error compensation is presented to minimize the effect of errors of amplifiers and connecting resistors.
A method for solving fuzzy linear pregramming with neural network is described and some experimental results are given. The method for error compensation is presented to minimize the effect of errors of amplifiers and connecting resistors.
1996, 18(3): 276-282.
Abstract:
The time-domain Electromagnetic(EM) scattering by buried objects in dispersive media is calculated by using FD-TD method. The FD-TD formula in Debye dispersive media(both the complex permeability and the complex permittivity are described by Debye equations) are deduced, and the absorbing boundary condition is given. The validity of FD-TD method in lossy media is verified through comparing the FD-TD s result and other one. The propagation of transient pulses in dispersive media is studied in detail. The scattering pulses and the wiggle traces for typical buried objects are given.
The time-domain Electromagnetic(EM) scattering by buried objects in dispersive media is calculated by using FD-TD method. The FD-TD formula in Debye dispersive media(both the complex permeability and the complex permittivity are described by Debye equations) are deduced, and the absorbing boundary condition is given. The validity of FD-TD method in lossy media is verified through comparing the FD-TD s result and other one. The propagation of transient pulses in dispersive media is studied in detail. The scattering pulses and the wiggle traces for typical buried objects are given.
1996, 18(3): 283-291.
Abstract:
Novel finite-difference approximations of Mur s conditions are presented in frequency-domain. Combined with the FD-FD equations deduced, the new conditions are convenient and effective to solve EM problems of inhomogeneous anisotropic media. By use of the compressed storage sparse matrix technique and iteration algorithm, the computer memories demanded are decreased and the CPU time is shortened compared with those obtained by moment method (MM). RCS of cylinders and rectangular posts are given with several kinds of media. The results of cylinder are in good agreement with those of MM.
Novel finite-difference approximations of Mur s conditions are presented in frequency-domain. Combined with the FD-FD equations deduced, the new conditions are convenient and effective to solve EM problems of inhomogeneous anisotropic media. By use of the compressed storage sparse matrix technique and iteration algorithm, the computer memories demanded are decreased and the CPU time is shortened compared with those obtained by moment method (MM). RCS of cylinders and rectangular posts are given with several kinds of media. The results of cylinder are in good agreement with those of MM.
1996, 18(3): 292-297.
Abstract:
The possibility of using chiro-omega media as the substrates of microstrip antennas is discussed. With the help of the generalized spectral domain-exponential matrix technique, the far-field behaviour of dipole antenna is analysed in detail, which is located on the surface of one-layer, two-layer chiro-omega substrates, respectively, and the effects of the orientation of , chirality and -parameter on the radiation patterns are demonstrated. The lossy effect of chiro-omega substrates are also taken into consideration.
The possibility of using chiro-omega media as the substrates of microstrip antennas is discussed. With the help of the generalized spectral domain-exponential matrix technique, the far-field behaviour of dipole antenna is analysed in detail, which is located on the surface of one-layer, two-layer chiro-omega substrates, respectively, and the effects of the orientation of , chirality and -parameter on the radiation patterns are demonstrated. The lossy effect of chiro-omega substrates are also taken into consideration.
1996, 18(3): 298-303.
Abstract:
The dispersion equation of TM mode slow wave in a cylindrical waveguide having a annular plasma sheet is derived under the condition of plasma thickness effect. By means of the relativistic space charge wave theory, the space charge wave equation is obtained when the relativistic electron beam is moving along the inner surface of the plasma sheet guided by a axial magnetic field. The interaction growth rate between the electron beam and slow space wave and the frequency shifting are obtained. The influence of plasma thickness on dispersive characteristics and interaction growth rate are discussed. Someuseful results are obtained.
The dispersion equation of TM mode slow wave in a cylindrical waveguide having a annular plasma sheet is derived under the condition of plasma thickness effect. By means of the relativistic space charge wave theory, the space charge wave equation is obtained when the relativistic electron beam is moving along the inner surface of the plasma sheet guided by a axial magnetic field. The interaction growth rate between the electron beam and slow space wave and the frequency shifting are obtained. The influence of plasma thickness on dispersive characteristics and interaction growth rate are discussed. Someuseful results are obtained.
1996, 18(3): 304-309.
Abstract:
The use of a background plasma in a dielectric Cherenkov maser can effectively increase the efficiency and the microwave power output of the device. Here, the effect of the longitudinal uniform magnetic field on the wave-beam interaction of the plasma dielectric Cherenkov maser is examined by solving the beam-plasma, dielectric lined waveguide dispersion equation. And the effects of the longitudinal magnetic field, plasma density and dielectric parameters on the linear spatial growth rate and the energy ratio are presented.
The use of a background plasma in a dielectric Cherenkov maser can effectively increase the efficiency and the microwave power output of the device. Here, the effect of the longitudinal uniform magnetic field on the wave-beam interaction of the plasma dielectric Cherenkov maser is examined by solving the beam-plasma, dielectric lined waveguide dispersion equation. And the effects of the longitudinal magnetic field, plasma density and dielectric parameters on the linear spatial growth rate and the energy ratio are presented.
1996, 18(3): 317-321.
Abstract:
A technique is analysed for the determination of complex permittivity of MIC substrates for deposition of high- superconducting (HTS) thin films. By using high Q factor TM circular cavity, several monocrystals which are often used for deposition of HTS thin films are measured. The results show that the technique covers accurate measurements of the low-loww monocrystal and isotropy dielectric materials at different temperature, and the test is simple, rapid and automatic, and some directional complex permittivity of the dielectric materials can be measured.
A technique is analysed for the determination of complex permittivity of MIC substrates for deposition of high- superconducting (HTS) thin films. By using high Q factor TM circular cavity, several monocrystals which are often used for deposition of HTS thin films are measured. The results show that the technique covers accurate measurements of the low-loww monocrystal and isotropy dielectric materials at different temperature, and the test is simple, rapid and automatic, and some directional complex permittivity of the dielectric materials can be measured.
1996, 18(3): 322-326.
Abstract:
The principle of the generalized multipole technique (GMT) is studied, and the cause is discovered that the technique can not be applied to perfectly conducting scatterers with sharp edges. Then a new method, combining GMT with finite difference technique, is proposed. Using the new method, the scatterings from sharp edges can be analyzed effectively.
The principle of the generalized multipole technique (GMT) is studied, and the cause is discovered that the technique can not be applied to perfectly conducting scatterers with sharp edges. Then a new method, combining GMT with finite difference technique, is proposed. Using the new method, the scatterings from sharp edges can be analyzed effectively.
1996, 18(3): 327-331.
Abstract:
Electric-field integral equation(EFIE) method is one of most widely used methods for solving the electromagnetic scattering problems. Unfortunately, inconsistencies in the numerical results are observed when the method is used in the 2-D TE and the 3-D situations. In this paper, the authors try to discuss why the difficulties occurred and point out that the numerical results will be more accurate if the calculations of the charge terms are improved.
Electric-field integral equation(EFIE) method is one of most widely used methods for solving the electromagnetic scattering problems. Unfortunately, inconsistencies in the numerical results are observed when the method is used in the 2-D TE and the 3-D situations. In this paper, the authors try to discuss why the difficulties occurred and point out that the numerical results will be more accurate if the calculations of the charge terms are improved.
1996, 18(3): 332-336.
Abstract:
This paper, first, analyzes self-doping mechanism, then develops an optimization technology by using the contrary compensation principle, adsorption-desorption mechanism and transform of viscous flow layer between static and dymanic conditons. It results in controlling efffectively self-doping under normal condition.
This paper, first, analyzes self-doping mechanism, then develops an optimization technology by using the contrary compensation principle, adsorption-desorption mechanism and transform of viscous flow layer between static and dymanic conditons. It results in controlling efffectively self-doping under normal condition.
1996, 18(3): 310-316.
Abstract:
Cyclostationary signal is an important class of non-statinary signal. many signals and/or inteferences show certain degree of cyclostatioinarity. Therefore, signal processors considering this property of the signal can obtain many performance advantages over conventional signal processors. This paper first reviews some fundamental conceptions and methods of cyclostationary signal processing theory, followed by a comparatively thorough summary of its applications. Finally, directions of future development and application are dicussed.
Cyclostationary signal is an important class of non-statinary signal. many signals and/or inteferences show certain degree of cyclostatioinarity. Therefore, signal processors considering this property of the signal can obtain many performance advantages over conventional signal processors. This paper first reviews some fundamental conceptions and methods of cyclostationary signal processing theory, followed by a comparatively thorough summary of its applications. Finally, directions of future development and application are dicussed.
