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In the early 1960s research into radar signal synthesis produced important formulas describing the action of the two-dimensional Fourier transform on auto- and crossambiguity surfaces.
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It is shown that the one-dimensional sampling sets correspond to Bessel sequences of complex exponentials that are not Riesz bases for $L^2[-R,R].$ A signal processing application in which such sampling sets arise naturally is described in detail.
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Given a bandlimited signal, we consider the sampling of the signal and some of its derivatives in a periodic manner.
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We present a method for finding the dual frame and, thereby, a method for reconstructing the signal from its samples.
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We show that if no sampling of the signal itself is involved, the sampling is not stable and cannot be stabilized by oversampling.
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| In this paper the signal generated by the small coil target is analyzedand the cause for error produced in the measurement of muzzle velocity of a riflebullet with the small coil target is researched. The method how to raise theaccuracy of measurement is also discussed. The muzzle velocity of 7.62mm 56type rifle has been measured with the small coil target and a favourabledata has been obtained. It shows that the small coil target can give the higheraccuracy and will be available to verify the accuracies... In this paper the signal generated by the small coil target is analyzedand the cause for error produced in the measurement of muzzle velocity of a riflebullet with the small coil target is researched. The method how to raise theaccuracy of measurement is also discussed. The muzzle velocity of 7.62mm 56type rifle has been measured with the small coil target and a favourabledata has been obtained. It shows that the small coil target can give the higheraccuracy and will be available to verify the accuracies of measurements withother kinds of coil targets in the same conditions. In addition, the error that may occur when measuring the muzzle velocityby the Eletronic Counter Chronograph DCS-451 associated with the small coiltarget is analyzed in more detail and the farther treatments for improvementare presented The experiments show that they have reached the desired results. | 本文通过对线圈靶产生的信号的分析,对用线圈靶测定弹丸速度时产生误差的原因和提高线圈靶精度的措施进行了探讨,并利用小直径感应线圈靶对5 6式7.62mm步枪进行实验获得良好的效果。由实验证明了小直径感应线圈靶能够达到鉴定级称准,初步认为能够用来鉴定其他各种靶圈的精度。 本文并对DCS-451型电子测时仪利用线圈靶测速时可能存在的误差进行分析,提出了改进措施,实验结果证明达到了予期的效果。 | This article reviews the commonly used methods for expression of radar's ECCM performance, points out their disadvantages and proposes that it is required to establish the formulae which consist only of the radar's technical parameters in order to measure the radar's ECCM capabilities.By means of logical argumentation and ambiguity function theory we can derive the followings: ( 1 ) The radar's 4-dimensional generalized resolution parameter can be used to express the radar's basis anti-clutter capability. The... This article reviews the commonly used methods for expression of radar's ECCM performance, points out their disadvantages and proposes that it is required to establish the formulae which consist only of the radar's technical parameters in order to measure the radar's ECCM capabilities.By means of logical argumentation and ambiguity function theory we can derive the followings: ( 1 ) The radar's 4-dimensional generalized resolution parameter can be used to express the radar's basis anti-clutter capability. The simplified expression of this parameter is T0 (the dwelling time at a radar's target, or the integration time of a echo signal of the radar) × Bs (the radar signal bandwidth) X G (the radar antenna gain); ( 2 ) The product of an average radar's transmitting power and its generalized resolution parameter PT0×BsG can be used to express the radar's anti-jamming capability, and the same formula may also be used to express the total interference rejection capability in gross.By another approach, I. e. by calculation of the radar's output signal to interference power ratio under various interference conditions, the given formulae have further been proven. The given formulae consisting of the radar's fundamental parameters are the fundamental parts of the measuring formula of the radar's ECCM capabilities. They represent the radar basic or potential ECCM performance. The supplementary factors for the ECCM capability formulae are composed of the technical specifications of the radar's ECCM devices. The general rule of com-position is to take the typical quality level (or the middle level) specification (in db) as the base figure. If the quality level of some devices is higher,a positive factor will be got, and if lower-a negative. For example, theequation for MTI supplementary factor ρM isρM(db) = SCV-25(db) where 25 db is the middle level specification for SCV of modern MTI radar.As many radar systems consist of multiple channels, in this article we propose a set of equations for the multichannel radar system's ECCM capabilities in terms of the ECCM capabilities of the individual channel.In the last part of this article, 4 radar systems are taken as examples, their ECCM capabilities are calculated by means of the given formulae. Application of obtained results to radar's system analysis and system design are discussed. | 本文论述了度量雷达抗干扰能力的方法,提出了一组通用的度量公式。这些公式的基本部分是由雷达的主要技术参数组成。代表雷达的潜在抗干扰能力。公式的补充部分是由雷达各种抗干扰技术措施的指标所组成,代表这些抗干扰措施的质量水平。用这组公式可以计算出雷达抗消极干扰能力、抗积极干扰能力与综合抗干扰能力的表征数值。本文给出了计算举例,讨论了计算结果在雷达系统分析与总体设计中的应用。 | A method to measure the main signatures-the contour dimensions and the attitude of a moving target is presented. The rationale of the measurement is to use range and doppler resolution so as to distinguish various reflecting points of a moving target. As a result, the dimensions of the target in the plane including the line of sight can be measured. By analyzing the feature of echo from a self-revolving target, we can also measure its attitude and dimensinos. The stress is put on such a problem: when target... A method to measure the main signatures-the contour dimensions and the attitude of a moving target is presented. The rationale of the measurement is to use range and doppler resolution so as to distinguish various reflecting points of a moving target. As a result, the dimensions of the target in the plane including the line of sight can be measured. By analyzing the feature of echo from a self-revolving target, we can also measure its attitude and dimensinos. The stress is put on such a problem: when target velocity can be resolved into horizontal and vertical components the precise dimensions may be measured by using iterative algorithm. Finally various patterns of signal that may be applied in this area are discussed. As stated in the thesis, the recognition of a moving target is virtually possible. | 本文阐述测量运动目标的主要特征——外形尺寸与姿态的方法。其基本原理是利用了距离,多普勒分辨力来分离散射点,以使视角平面内目标的边界尺寸可以测量。从分析回波信号调制的特点中,观察频谱边界以获取姿态及尺寸信息。还着重讲到有垂直速度分量时,如何应用迭代算法求出准确的尺寸。讨论了信号形式的选择原则,结果表明:达到识别的目的是完全可能的。 | | | | << 更多相关文摘 |
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