公开(公告)号：US4221463A

公开(公告)日：1980-09-09

申请号：US038352

申请日：1979-05-11

申请人： Edward Barsack ,  Arthur A. Chabot ,  Clarke E. Harris ,  Donald A. Kawachi ,  William A. Richardson

发明人： Edward Barsack ,  Arthur A. Chabot ,  Clarke E. Harris ,  Donald A. Kawachi ,  William A. Richardson

IPC分类号： G01S17/95 ,  G02F1/03

CPC分类号： G01S17/95 ,  G02F1/0322

摘要： Ringing caused by acoustic resonances in an electro-optical crystal modulator and commencing at the trailing edge of a pulse may be suppressed by the combination of a second electro-optical crystal and a polarizer. The polarization of the ringing passing through the second crystal is rotated 90.degree. by applying an appropriate voltage to the second crystal at the trailing edge of the pulse. The polarizer, properly oriented, then blocks the ringing. The crystals may comprise such materials as Cadmium Telluride or Gallium Arsenide.

摘要翻译： 可以通过第二电光晶体和偏振器的组合来抑制由电光晶体调制器中的声共振引起的振荡并且在脉冲的后沿开始的振铃。 穿过第二晶体的振铃的极化通过在脉冲的后缘处向第二晶体施加适当的电压而旋转90°。 偏振器正确定向，然后阻止振铃。 晶体可以包括诸如碲化镉或砷化镓的材料。

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

IPC分类号： G01S17/32 ,  G01S17/42 ,  G01S17/50 ,  G01C3/08 ,  G01B11/26 ,  G01C1/00

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。

公开(公告)号：US3950100A

公开(公告)日：1976-04-13

申请号：US518924

申请日：1974-10-29

申请人： Wayne H. Keene ,  Clarke E. Harris ,  Albert V. Jelalian ,  Christopher R. Miller ,  Richard E. Seavey

发明人： Wayne H. Keene ,  Clarke E. Harris ,  Albert V. Jelalian ,  Christopher R. Miller ,  Richard E. Seavey

IPC分类号： G01P3/36 ,  G01P5/26 ,  G01S17/58 ,  G02F2/00 ,  H01S3/13 ,  H01S3/00

CPC分类号： H01S3/1304 ,  G01P3/366 ,  G01P5/26 ,  G01S17/58 ,  G02F2/002

摘要： A laser heterodyne system is disclosed wherein received reflections of a beam of coherent light are amplified in a laser. The amplified received reflections are heterodyned with the light produced by the laser and the resulting beat frequency is detected using a photodetector. A controller, responsive to the beat frequency, controls, in one case, the frequency of a transmitting laser, and hence the frequency of the received light, and, in another case, the frequency of the light produced by the amplifying laser so that, in either case, the difference between the frequency of the received light and the frequency of the light produced by the amplifying laser is adjusted to maximize the amplification of the received light by the amlifying laser prior to detection by the photodetector.

公开(公告)号：US5110207A

公开(公告)日：1992-05-05

申请号：US698254

申请日：1991-05-06

申请人： Clarke E. Harris

发明人： Clarke E. Harris

IPC分类号： G01S7/481 ,  G01S7/491 ,  G01S7/499

CPC分类号： G01S7/4812 ,  G01S7/4917 ,  G01S7/499

摘要： An interferometer for transmitting a beam of electromagnetic energy toward a target, portions of the transmitted beam reflected by the target being directed onto a detecting surface of a detector element with a local oscillator beam to provide a beat frequency signal representative of, for example, target range. The interferometer comprises a first lens for focusing the target-reflected return beam onto substantially a point on a detecting surface. The interferometer additionally comprises a second lens, for example, for focusing the local oscillator beam through a focal point onto the first lens. The first and second lenses are disposed to align such focal point of the second lens with a focal point of the first lens to thereby direct the local oscillator beam onto the detecting surface of the detector element with a substantially uniform intensity distribution thereon. With such arrangement, the detector element may be implemented as a photoconductive, rather than a photovoltaic, detector with only a minimal net increase in the noise equivalent power (NEP) thereof, such as 5 dB, resulting in similar slight reduction in the signal-to-noise ratio of the interferometer. Since such photoconductive detector element may be cooled by thermoelectric stacks, the requirement for liquid nitrogen coolant is eliminated, thereby significantly reducing the size and weight of the interferometer system.

摘要翻译： 一种干涉仪，用于向目标传送电磁能量束，由目标物反射的部分发射光束通过本地振荡器光束引导到检测器元件的检测表面，以提供表示例如目标的拍频信号 范围。 干涉仪包括用于将目标反射返回光束基本上聚焦到检测表面上的点上的第一透镜。 干涉仪还包括第二透镜，例如用于将本地振荡器束通过焦点聚焦到第一透镜上。 第一透镜和第二透镜被设置成将第二透镜的这种焦点与第一透镜的焦点对准，从而将本地振荡器光束以其上的基本上均匀的强度分布指向检测器元件的检测表面。 通过这样的布置，检测器元件可以被实现为仅具有最小净增加其噪声等效功率（NEP）的光电检测器而不是光电检测器，例如5dB，导致信号 - 干涉仪的信噪比。 由于这种光电导检测器元件可以被热电叠层冷却，因此消除了对液氮冷却剂的要求，从而显着地减小了干涉仪系统的尺寸和重量。

公开(公告)号：US5020062A

公开(公告)日：1991-05-28

申请号：US518610

申请日：1990-05-03

申请人： Francis J. Cusack, Jr. ,  Clarke E. Harris

发明人： Francis J. Cusack, Jr. ,  Clarke E. Harris

IPC分类号： H01S3/105 ,  H01S3/139

CPC分类号： H01S3/1398 ,  H01S3/105

摘要： A CO.sub.2 waveguide laser frequency modulation (FM) system which applies the Fourier series components of a triangular drive waveform selectively to the tuning PZT at one end of the waveguide and the FM PZT at the other end to achieve an improvement over the waveform than can be achieved by applying the fundamental and its harmonics to the FM PZT alone. The system applies the fundamental component to the tuning PZT and the odd harmonics to the FM PZT. The frequency-separated drive signals are applied in proper phase to the PZT's at each end of the waveguide via waveform synthesizer, frequency splitter and amplifiers. The waveform synthesizer includes a ROM containing digitized values of segments of the waveform amplitudes and a digital-to-analog converter for converting the digital ROM data to an analog signal.

摘要翻译： 一种二氧化碳波导激光调频（FM）系统，其将三角形驱动波形的傅立叶级数分量选择性地应用于波导一端的调谐PZT和另一端的FM PZT，以实现比波形更好的改进 通过将FM基准点和谐波单独应用于FM PZT来实现。 该系统将调谐PZT和奇数谐波的基波分量应用于FM PZT。 频率分离的驱动信号通过波形合成器，分频器和放大器以适当的相位施加到波导每端的PZT。 波形合成器包括一个包含波形幅度段的数字化值的ROM和用于将数字ROM数据转换成模拟信号的数模转换器。