公开(公告)号：US3704626A

公开(公告)日：1972-12-05

申请号：US3704626D

申请日：1970-08-07

Applicant: LITTLE INC A

Inventor： STONE RICHARD S

IPC: G01V7/14 ,  G01V7/04 ,  G01V7/12

CPC classification number: G01V7/14

Abstract: Method and apparatus for measuring gravity gradients directly. Two retroreflectors are caused to experience free flight and the radiation reflected by those retroreflectors during this free flight is directed to a radiation receiver which senses and measures the temporal variations of intensity of the interfering reflected radiation beams. The rate of change in interference frequency over a number of consecutive time periods of equal duration is determined and the rate of change of this signal frequency is used as a direct measurement of a gravity gradient.

Abstract translation: 直接测量重力梯度的方法和装置。 导致两个后向反射器经历自由飞行，并且在该自由飞行期间由那些后向反射器反射的辐射被引导到辐射接收器，该辐射接收器感测并测量干涉反射辐射束的强度的时间变化。 确定相等持续时间的连续时间段的干扰频率的变化率，并将该信号频率的变化率用作重力梯度的直接测量。

公开(公告)号：US3493275A

公开(公告)日：1970-02-03

申请号：US3493275D

申请日：1967-12-18

Applicant: LITTLE INC A

Inventor： STONE RICHARD S ,  EMSLIE ALFRED G

IPC: F16C39/06 ,  G01R33/00 ,  G01V7/02

CPC classification number: F16C32/0444 ,  G01R33/00 ,  G01V7/02

Abstract: 1,225,129. Photo-electric apparatus; electrophysical measurement. ARTHUR D. LITTLE, Inc. Dec.2, 1968 [Dec.18, 1967], No. 57176/68. Headings G1A and GIN. [Also in Divisions F2 and H1J A bearing assembly suitable for use in an accelerometer, seismometer, gravimeter, galvanometer, electro-meter, flowmeter, or pressure gauge, comprises a vertical axle 12 supported radially by magnetic bearings 13-15, upper and lower magnets 22, 24 defining between them a magnetic field, and a magneticallyresponsive mass 10 affixed to the axle and supported axially within the said field. The radial bearing comprises a solid diamagnetic cylinder of graphite or beryllium which may be surrounded by a sheath of copper or aluminium. The cylinder is repelled by a field created by magnets of alternating polarities, Fig.2 (not shown). The mass 10 may consist of a permanent magnet or a paramagnetic or diamagnet body, and may be supported by both repulsive and attractive forces acting against gravity, Fig. 1, or repulsive forces alone, Fig. 7, (not shown). Annular members or polepieces 28 of soft iron may be positioned in the horizontal plane of the mass to modify the magnetic field and provide shielding. Provision is made for the detection and/or correction of axial misalignment. An optical path 42-44 is provided between a radiant energy source 34 and two balanced detectors 38, which are connected to a differential amplifier 40. Relative motion of the mass 10 causes imbalance in the detectors, which is then transmitted to the amplifier to be recorded on a chart-recording self-balancing potentiometer 45. The signal may also control the amount of current entering a coil 30, thus creating a feedback circuit to correct misalignment. In an alternative embodiment, Fig. 12, the axle is provided with cores 150, 151 of copper; axial misalignment is detected by imbalance between the inductances of the coils 152, 153 associated with the cores.

公开(公告)号：US3688584A

公开(公告)日：1972-09-05

申请号：US3688584D

申请日：1971-02-09

Applicant: LITTLE INC A

Inventor： STONE RICHARD S ,  LAPSON LAWRENCE B

IPC: G01V7/14 ,  G01V7/04

CPC classification number: G01V7/14

Abstract: Apparatus for measuring gravity gradients directly. Two retroreflectors are caused to experience free flight, and the radiation reflected by these retroreflectors during free flight is directed to a radiation receiver which senses and measures the temporal variations of intensity of the interfering reflected radiation beams. The time rate of change of the frequency of the output signal of the receiver is directly related to the vertical gradient of gravity. The instrument of this invention has means to correct for any shifting of the retroreflectors relative to each other and to the radiation beam in planes normal to the radiation beam.

Abstract translation: 直接测量重力梯度的装置。 导致两个后向反射器经历自由飞行，并且在自由飞行期间由这些回射器反射的辐射被引导到辐射接收器，其感测并测量干涉反射辐射束的强度的时间变化。 接收机输出信号频率的时间变化率与垂直重力梯度直接相关。 本发明的仪器具有校正反射器相对于彼此的任何偏移以及垂直于辐射束的平面中的辐射束的装置。

公开(公告)号：US3626364A

公开(公告)日：1971-12-07

申请号：US3626364D

申请日：1969-07-15

Applicant: LITTLE INC A

Inventor： SIMON IVAN ,  SMALLMAN CARL R ,  COHEN MARTIN L ,  STONE RICHARD S

IPC: G01V1/18 ,  G01V1/16

CPC classification number: G01V1/184

Abstract: A three-axis seismometer in which three masses are suspended for essentially frictionless movement within certain directions in magnetic fields. Detecting means sense movement of the masses and generate signals used to actuate feedback means. The amount of feedback required is used as a measure of seismic motion. Since motion sensing and the measurement of the magnitude of the motion are separated, output of the instrument may be linear. Responses in unwanted frequency ranges may be filtered out.