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公开(公告)号：US4721385A
公开(公告)日：1988-01-26
申请号：US940156
申请日：1986-12-09
申请人： Albert V. Jelalian , Wayne H. Keene , Charles M. Sonnenschein , Clarke E. Harris , Clifford E. Morrow
发明人： Albert V. Jelalian , Wayne H. Keene , Charles M. Sonnenschein , Clarke E. Harris , Clifford E. Morrow
CPC分类号： G01S17/42 , G01S17/325 , G01S17/50
摘要： A scanning laser radar system utilizing a frequency modulated (fm)-continuous wave (cw) beam to coherently detect echo signal returns from an object in a predetermined region. The frequency of the beam is repeatedly changed as a function of time to produce a symmetrical triangular-shaped frequency modulated waveform. The echo signals received are frequency shifted, as a function of range and Doppler shift, from the signal being transmitted at that time. The frequency shift is detected by homodyning a portion of the instantaneous transmitted signal with the received echo signal to produce an output signal having a frequency which is substantially constant during a portion of the frequency modulation period. The constant frequency portion of the output signal is related to the range and Doppler speed of the target. Target information such as range, Doppler speed, intensity and angle information are derived by processing the output signal. The signal to noise ratio of the output signal is improved by using a frequency modulation period greater than the scanning time across an arc of a size equal to a predetermined multiple of the beamwidth because with such relationship the time duration of the constant amplitude portion of the output signal is increased. Further, with such arrangement, because of the relatively long modulation period, the ambiguity in detection of the range to the target is reduced. The system is particularly useful in terrain following or obstacle avoidance applications.
摘要翻译： 利用频率调制（fm） - 连续波（cw）波束的扫描激光雷达系统相干地检测来自预定区域中的物体的回波信号返回。 光束的频率作为时间的函数重复改变以产生对称的三角形调频波形。 接收到的回波信号作为距离和多普勒频移的函数从当时发送的信号进行频移。 通过用接收到的回波信号对瞬时发送信号的一部分进行差分来检测频移，以产生在频率调制周期的一部分期间具有基本恒定的频率的输出信号。 输出信号的恒定频率部分与目标的范围和多普勒速度有关。 通过处理输出信号来导出诸如范围，多普勒速度，强度和角度信息的目标信息。 通过使用大于等于波束宽度的预定倍数的大小的弧的扫描时间的频率调制周期来改善输出信号的信噪比，因为这样的关系是恒定振幅部分的持续时间 输出信号增加。 此外，通过这样的配置，由于相对长的调制周期，检测到目标的范围的模糊性降低。 该系统在地形跟踪或避障应用中特别有用。
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公开(公告)号：US3984686A
公开(公告)日：1976-10-05
申请号：US637247
申请日：1975-12-03
申请人： James C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher , James W. Bilbro , Werner K. Dahm , Ronald B. Campbell, Jr. , Robert M. Huffaker , Harold B. Jeffreys , Albert V. Jelalian , Wayne H. Keene , Michael C. Krause , Thomas R. Lawrence , Charles M. Sonnenschein , David J. Wilson , James A. L. Thomson
发明人： James C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher , James W. Bilbro , Werner K. Dahm , Ronald B. Campbell, Jr. , Robert M. Huffaker , Harold B. Jeffreys , Albert V. Jelalian , Wayne H. Keene , Michael C. Krause , Thomas R. Lawrence , Charles M. Sonnenschein , David J. Wilson , James A. L. Thomson
摘要： A system for remotely measuring velocities present in discrete volumes of air in which a CO.sub.2 laser beam is focused by a telescope at such a volume, a focal volume, and within the focusable range, near field, of the telescope. The back scatter, or reflected light, principally from the focal volume, passes back through the telescope and is frequency compared with the original frequency of the laser, and the difference frequency or frequencies represent particle velocities in that focal volume.
摘要翻译： 远程测量存在于离散体积的空气中的速度的系统，其中CO 2激光束由望远镜在望远镜的这种体积，焦点体积和可聚焦范围的近场内聚焦。 主要来自焦点体积的背散射或反射光通过望远镜返回，并且与激光器的原始频率相比频率，而差频率或频率表示该焦点体积中的粒子速度。
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公开(公告)号：US4167329A
公开(公告)日：1979-09-11
申请号：US859904
申请日：1977-12-12
摘要： An optically focussed laser radar operating with a radiation wavelength of typically ten microns is focussed on an object to be observed. Doppler data is obtained with a continuous wave signal by mixing a reference of the transmitted signal with a signal reflected from airborne scattering centers. The system is particularly useful for clear air turbulence applications wherein aerosols such as dust and pollen serve as the scattering centers for reflecting the radiation. The radar converts to a pulse Doppler system when the depth of field exceeds the desired range resolution.
摘要翻译： 以通常为10微米的辐射波长工作的光聚焦激光雷达集中在要观察的物体上。 通过将发射信号的参考与从空中散射中心反射的信号混合，通过连续波信号获得多普勒数据。 该系统对于清洁空气湍流应用特别有用，其中气溶胶如灰尘和花粉用作反射辐射的散射中心。 当景深超过所需范围分辨率时，雷达转换为脉冲多普勒系统。
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公开(公告)号：US4176959A
公开(公告)日：1979-12-04
申请号：US897062
申请日：1978-04-17
IPC分类号： G01N21/39 , H01S3/1055 , G01J3/42 , G01N21/04
CPC分类号： G01N21/39 , H01S3/1055
摘要： A spectrometer for measuring the spectra and concentration of airborne chemicals at long ranges wherein the optical signals may be occluded by dust. A single lasing medium is utilized both for producing a transmitted optical signal and for amplifying a received optical signal, the frequencies of radiation of the transmitted and received optical signals being offset as the radiation propagates to a distant reflector and back to the lasing medium. The frequency offset is obtained by sweeping the transmitted frequency at a rate commensurate with the round trip propagation time whereby the offset is sufficient to place the received frequency at a peak at the amplifying spectrum of the lasing medium. A laser containing the laser medium further incorporates an interferometric structure within the optical path for sequentially shifting the frequency of oscillation to produce a comb spectrum for sampling the spectra of the chemicals to provide identifying signatures thereof.
摘要翻译： 用于测量长距离范围内的空气传播化学品的光谱和浓度的光谱仪，其中光信号可能被灰尘遮挡。 利用单个激光介质来产生传输的光信号和用于放大接收到的光信号，当辐射传播到远处的反射器并返回到激光介质时，发射和接收的光信号的辐射频率被偏移。 通过以与往返传播时间相称的速率扫描发射频率来获得频率偏移，由此偏移足以将接收频率置于激光介质的放大光谱处的峰值处。 包含激光介质的激光进一步包括在光路内的干涉结构，用于顺序地移动振荡频率以产生用于对化学品的光谱进行采样以提供其识别标记的梳状光谱。
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