267 results about "Gravimeter" patented technology

There is provided a method for phase extraction between coupled atom interferometers using ellipse-specific fitting. The method includes fitting an ellipse to data representing a first gravimeter measurement and a second gravimeter measurement, and determining a phase shift between the first gravimeter measurement and the second gravimeter measurement based on a spread of the data around the ellipse.

The invention relates to a diamond nitrogen-vacancy (NV) center-based acceleration sensor. Through high-NV center concentration diamond as a magnetic field sensing element, Rabi-flopping frequency of an NV center ensemble electronic two-level energy system produced by laser pulse is measured by an optical detection magnetic resonance (ODMR) so that under the action of extraneous acceleration, high-precision measurement of a variable magnetic field produced by change of relative displacement of a magnetostatic field and high-NV center concentration diamond is realized and thus acceleration information measurement is realized. Through combination of a traditional acceleration sensor mass-spring structure, a micro-nano light-machine-electricity technology and a diamond NV center quantum manipulation principle and use of the diamond NV center in the ultrahigh precision magnetic field measurement, the acceleration sensor member with a small volume, an ultrahigh precision, high sensitivity and a large measurement scope is obtained. The acceleration sensor has an important value in an accelerometer and a gravimeter.

The invention relates to a magnetic suspension falling body cabin system and a free falling body type absolute gravimeter of the falling body cabin system. The falling body cabin system comprises a vacuum chamber and a falling body cabin arranged in the vacuum chamber, wherein the falling body cabin comprises a top tray, a bottom tray, a guide rail, a support rail, a bracket system and a falling body mass block; the guide rail and the support rail are arranged between the top tray and the bottom tray; at least one end of the guide rail is provided with a driving electromagnetic valve, and the bottom of the falling body bay is provided with a sensor; a sliding sleeve is sheathed on the guide rail, the driving electromagnetic valve is arranged in the sliding sleeve, and the bracket system is installed on the guide rail in a sliding mode through the sliding sleeve; the bottom wall of the top tray is provided with a guide locating slot in the movement direction of the bracket system, and the upper part of the guide locating slot is provided with an electromagnetic collet; the falling body mass block is separably arranged on the bracket system; the top of the falling body mass block is provided with a guide bar which can extends into the guide locating slot; and the falling body mass block is provided with a corner cube. The magnetic force in the electrified electromagnetic valve is used as the driving force of the bracket system, and the magnitude of current is controlled to control the movement of the bracket system. Thus, the invention has the advantages of high precision and low failure rate.

An instrument for measuring gravitational acceleration from within a borehole, the instrument including: a light source having a semiconductor that comprises a bandgap greater than about two electron volts (eV); and a gravimeter for receiving light from the light source and providing output light with a characteristic related to the gravitational acceleration, the gravimeter implemented at least one of a nano electromechanical system (NEMS) and a micro electromechanical system (MEMS); wherein the light source and the gravimeter are disposed in a housing adapted for insertion into the borehole.

The invention relates to a gravity measuring method based on strapdown inertia/GPS combined auxiliary horizontal angular motion isolation; the method comprises the following steps: in an actual measurement process, a double-shaft stabilized platform is arranged outside the IMU of a gravimeter so as to isolate the horizontal angular motion of a carrier, and a horizontal torquing amount is formed bynavigation resolving under dynamic conditions so as to control the platform to track the geography level; in the anaphase processing process of the gravity measuring data, the DGPS information is combined so as to complete Kalman filter estimation of residual horizontal errors, thus rotating the IMU specific force measured value to the geography coordinate system direction through postures. In the actual measurement process, the method uses the double-shaft inertia stabilized platform to control, thus keeping the IMU the be basically at the geography horizontal position; in the anaphase processing process of the actual measurement IMU data, the high precision difference GPS information is combined to complete the Kalman filter estimation of residual horizontal errors, thus realizing estimation and compensation of the gravity sensor element errors, and improving the dynamic environment adaptability and gravity measuring precision in the gravity measurement.

The general field of the invention is that of gravimeters, of the matter-wave type, allowing the measurement of the gravitational field or of an acceleration in a given direction of measurement. This type of gravimeter uses ultracold atoms to take the measurement. It necessarily comprises an atom trap (5) making it possible to immobilize an ultracold atom cloud (10) in a determined configuration and means (7) for splitting-recombining the cloud into two atom packets placed at different heights so as to create a phase shift due to gravity. The device according to the invention combines both these functions on an atom chip (3) mainly comprising means for generating a local magnetic field minimum around a first conductor wire (30), a second conductor wire (31) and a third conductor wire (32) that are substantially parallel in the zone of the trap to the first conductor wire and are placed symmetrically on either side of this first wire, the second wire being traversed by a first alternating current, the third wire being traversed by a second alternating current of the same amplitude and of the same frequency as the first alternating current and in the opposite direction, the amplitudes of the first and of the second currents being able to vary simultaneously, the maximum amplitude and the frequency of said currents being sufficient to create at the atom cloud a magnetic field with an intensity greater than the magnetic intensity necessary to split the atom cloud into two atom packets.

The invention provides an inertia gravity combined navigation semi-physical simulator which is a device suitable for the theoretical method and engineering application research of an inertia/gravity combined navigation system. A path generator generates ideal data inputted to an inertia measuring unit, a gravimeter simulator, a Doppler log simulator, a deep sounding apparatus simulator and a combined navigation computer; wherein the gravimeter simulator comprises a gravity sensor, a chart of digital gravity anomaly, and a computer; the Doppler log simulator comprises a Doppler log and a computer; the deep sounding apparatus simulator comprises a deep sounding apparatus and a computer; the combined navigation computer is realized by an industrial computer, the synchronous control of the path generator, the inertia measuring unit, the gravimeter simulator, the Doppler log simulator and the deep sounding simulator is realized by a serial port, the transmission and receiving of information are performed on the inertia measuring unit, the gravimeter simulator, the Doppler log simulator and the deep sounding apparatus simulator, the combined navigation calculation and estimation analysis are performed, and the result is displayed through a terminal.

A method for evaluating confidence of measuring parameters of a strap-down air-borne gravimeter includes: (1) evaluating accuracy and stability of a sensor of the strap-down air-borne gravimeter; (2) evaluating initial alignment accuracy of the strap-down air-borne gravimeter; (3) evaluating integrated navigation accuracy of the strap-down air-borne gravimeter; (4) evaluating carrier acceleration calculating accuracy; and (5) integrating evaluation parameters by reflecting confidence of a measuring data source through the accuracy and the stability of the sensor, reflecting confidence of data acquisition and calculation in measuring process through performance parameters in the measuring process, accordingly calculating final measuring results, namely, calculating confidence indexes of gravity anomalies, respectively calculating confidence of an acceleration meter, a gyroscope, initial alignment, integrated navigation and carrier acceleration calculating accuracy, and finally distributing corresponding weight of the calculated confidence to evaluate the confidence of the sensor of the strap-down air-borne gravimeter. The method has the advantages of simple principle, fine operability, high practicability, easiness in popularization and the like.

A gravimeter for detecting a gravity difference between two points is disclosed. The gravimeter comprises an interferometric arrangement wherein the length of a reference arm is dependent upon the gravity local to a first accelerometer and the length of a sample arm is dependent upon the gravity local to a second accelerometer. A pair of photodetectors that operate in complimentary fashion provide electrical signals based on a first signal conveyed by the reference arm and a second signal conveyed by the sample arm. A change in the differential gravity between the two points induces equal and opposite changes to the magnitudes of the two electrical signals.

The invention discloses a portable vibration noise correction and compensation method and device suitable for an atomic interference gravimeter. The method comprises the following steps: step S1, vibration phase shift measurement: monitoring the phase shift of interference fringes of a Michelson type homodyne laser interferometer caused by the vibration of a reflector by a four-channel phase shiftdetector; step S2, vibration phase shift extraction: through data processing, extracting total phase shift caused by the vibration of the reflector in the action process of three beams of Raman light; step S3, vibration phase shift correction: correcting and compensating phase shift caused by the vibration of the reflector in real time in a measured Raman laser phase-atomic transition probabilitysignal, and outputting the Raman laser phase-atomic transition probability signal without vibration noise. The device is used for implementing the method. The device has the advantage that the measuring sensitivity, stability and portability can be improved.

The invention discloses a vibration noise correction and compensation method suitable for an atomic interference gravimeter. The method comprises the steps of: collecting vibration signals of three dimensions of a Raman light mirror; performing preprocessing including denoising and distortion correction on the vibration signals of three dimensions; correcting the coupling of the vibration signalsof three dimensions after preprocessing to obtain the phase shift caused by the vibration in a corrected vertical direction; and subtracting the phase shift caused by the vibration in the corrected vertical direction by using the relationship between the vibration signals of three dimensions recorded in advance and an atomic population signal of the gravimeter to obtain the atomic population signal of the gravimeter without vibration noise. The vibration noise is greatly eliminated, and the sensitivity and stability of gravity measurement are improved by means of the above vibration noise correction and compensation method.

The invention provides a bayesian estimation-based particle filter gravity-assisted inertial navigation matching method. When solving non-linear problems, particle filter prevents linearization-caused errors and solves the problem that the traditional point matching Sandia algorithm easily produces divergence in a large-gravity anomalous change matching area. Through use of inertial navigation position information as quantity of state, a gravimeter measured value as observed quantity, bayesian estimation-based particle filter, and a random sample average replacing a probability density function conditional mean, inertial navigation system state variable is estimated.

The invention provides an underwater pulling type high-precision gravity-magnetism detection system and method. The system comprises a detection towed body, a depth-keeping towed body, a mother ship used for towing the detection towed body and the depth-keeping towed body and a detection device group arranged on the detection towed body. The mother ship is further provided with a deck measurementand control unit, the mother ship is mechanically connected with the depth-keeping towed body through a photoelectric composite cable, and the depth-keeping towed body is mechanically connected with the detection towed body through a light composite cable. The detection device group is used for detecting a gravitational field and a magnetic force field so as to obtain gravity-magnetism measurementdata, the detection device group is electrically connected with the deck measurement and control unit, the deck measurement and control unit is electrically connected with the depth-keeping towed body through the photoelectric composite cable, and the deck measurement and control unit is electrically connected with the detection towed body sequentially through the photoelectric composite cable, the depth-keeping towed body and the light composite cable. The depth-keeping towed body and the detection towed body can be kept in a stable posture under the deep sea of 2000 m and finish precise gravity-magnetism detection, and a gravity meter and a magnetic device can bear the high pressure and low-temperature environment in the deep sea.

The invention discloses an omni-directional tide observation system under the well, which relates to a tide observation system. In the invention, a system mainframe box (B) on the ground (A) is connected with an instrument body (E) which is arranged in a protecting pipe (D) of a drilling well through the transmission cable (C). The structure of the interior of instrument body (E) comprises a hoisting hole (1), a pressing spring (3), a supporting pole (4), a location device (5), a ball head joint (6), a circuit unit, a gravimeter (9), a clinometer (11), a primary leveling device (12) and a precise leveling device (13), which are connected in turn from top to bottom. The invention integrates the gravity instrument with the clinometers, which is put under the well; the gravity solid tide in the upright direction and the horizontal solid tide in two directions can be observed synchronously at the same time and place; the invention provides reliable, precise and continuous observation data; the invention can also be used in a general cave with the qualification of a triangle base.

The invention discloses a simple-pendulum absolute gravimeter based on two-point fixed differential measurement, which comprises a vacuum cavity, a metal wire, a quality inspector, two pairs of knife-edge fixtures, two pairs of horizontal displacement adjusting devices, a displacement sensor, an oscillator and two length reference blocks, wherein the metal wire is respectively clamped through the two pairs of knife-edge fixtures; the knife-edge fixtures are shifted through the displacement adjusting devices so as to fix a first suspension point and a second suspension point; the length reference blocks are used for adjusting the vertical distance between the two pairs of knife-edge fixtures; and the displacement sensor is used for detecting the motion displacement of the quality inspector. According to the invention, due to the fixed measurement idea through the two suspension points at different heights, the suspension points at different heights are respectively fixed through the two pairs of knife-edge fixtures; therefore, the problem of directly measuring the absolute pendulum length is solved; direct measurement of the relative pendulum length is easier to realize; furthermore, influence of the pendulum length caused by the external environment and indefinite suspension points is effectively reduced; the measurement precision of the relative pendulum length is 10-7 m; therefore, the precision of measuring the g value through single pendulum is increased and can be up to mGal level.

The invention relates to a new algorithm for correcting the sea and air gravimeter scale value based on the repeat line. The main technical characteristics are that a repeat measuring point scale value correction model is established according to the basic mathematic model of airborne gravity measurement; and the most probable estimation value of the scale value deviation is solved according to the principle of least squares and the sea and air gravimeter scale value is compensated. The formation mechanism of the sea and air gravity measuring system error is analyzed and the sea and air gravimeter scale value calibration error is discovered to be one of the main factors causing the systematic measurement deviation, the calculation model and the compensation method of using the repeat measuring line to detect and correct the sea and air gravimeter scale value are utilized, numerical verification is performed on the reasonableness and effectiveness of the method by using the actual airborne gravity observation network data, the test indicates that the algorithm has a significant effect for eliminating the sea and air gravity measuring systematic deviation, and the method is simple and can meet the requirements of the sea and air gravity measurement user.

The invention relates to a strapdown underwater dynamic gravity measurement instrument and belongs to the field of gravity measurement. The system is mainly composed of an inertia measurement unit, adata system, a Doppler velocimeter, a depthometer, an ultrashort baseline hydroacoustic positioning device and an underwater pressure cabin, wherein installing holes are formed in the bottom of the underwater pressure cabin, and the underwater pressure cabin can be fixedly connected with an underwater dynamic carrier through bolts; the Doppler velocimeter measures the velocity to a seabed or a seacurrent, the depthometer measures the depth of a gravity meter, and the ultrashort baseline hydroacoustic positioning device measures the position of the gravity meter; and measurement results of themeters are used as external observation quantities, united filtering is performed on the measurement results and a strapdown inertial navigation solving result of the inertia measurement unit, and gravity anomaly solving is performed after all navigation parameters and specific force measurement values are obtained. The strapdown underwater dynamic gravity measurement instrument meets the demandof underwater dynamic gravity measurement and has the advantages of being low in manufacturing cost, high in measurement efficiency, large in covering area, adaptive to a dynamic measurement environment, close to a seabed gravity signal source and the like.

The invention relates to a dynamic precision assessment method based on a movable base gravity meter, and the method comprises the steps: enabling the movable base gravity meter to be installed on a specially designed test vehicle, and selecting a proper test road segment for reciprocating running measurement; and achieving the precise and effective assessment of inner coincidence precision of the movable base gravity meter through the comparison of multiple gravity abnormal values of the same road segment. Moreover, the method is simple, is easy to implement, is low in cost, and is high in efficiency. In addition, a processing method for gravity abnormality data is strong in anti-interference capability, is higher in data processing precision, and is especially suitable for the gravity abnormality extraction of a high-precision movable base gravity meter. The method can be used for assessing the inner coincidence measurement precision of the movable base gravity meter, and is suitable for the field running test of the movable base gravity meter.

The invention discloses a two-dimensional static relative inclinometer. The two-dimensional static relative inclinometer can simultaneously measure inclination change along two directions. The two-dimensional static relative inclinometer comprises a probe, a capacitive displacement sensing circuit, a control unit, a voltage amplifier circuit and an analog-digital conversion circuit. The probe is composed of a test mass and a capacitance plate framework. In work, the test mass is suspended in the center of the capacitance plate framework by an electrostatic force; in a vertical direction, 600-1000V of control voltage is used so that the gravity of the test mass is overcome; and in a horizontal direction, less than 10V of control voltage is used so that a gravity component force produced by base inclination is balanced. Through detection of control voltage in two horizontal directions, information of inclination change in the two horizontal directions can be obtained. Only through the two-dimensional static relative inclinometer, two-dimensional detection of an inclination change is finished. A mechanical support between the test mass and the outer framework is avoided and thus the problem that the traditional pendulum gravimeter produces mechanical drift is solved.

The invention discloses a track section occupation condition monitoring system and method. The track section occupation condition monitoring system comprises a plurality of gravimeter shaft devices which are installed at ports of a section, a counter and a first judgment unit; when vehicle wheels pass through the gravimeter shaft devices, the gravimeter shaft devices output signals expressing passing of the vehicle wheels; the counter receives the signals expressing passing of the vehicle wheels from the gravimeter shaft devices and accordingly counts the vehicle wheels passing the gravimeter shaft devices; if the number of the vehicle wheels entering the section is equal to that of the vehicle wheels leaving from the section, the first judgment unit judges the section is in an idle state and judges the section in an occupation state if not. The track section occupation condition monitoring system has the advantages of being low in cost, high in reliability, wide in applicability, easy to construct, beneficial to maintenance, not easy to be influenced by weather and environment and the like.

The invention provides a compensation method for gravity meter biax gyrostabilized platform course error effect. The method comprises the following steps: collecting the gyroscope signal and the accelerometer signal, the GPS output position and the speed signals of the gravity meter biax gyrostabilized platform; obtaining the output acceleration and the gyroscope angular rate compensation dosage according to the error characteristic equation of the accelerometer and the gyroscope; introducing external speed damping; filtering the external speed, and combining with the speed damping, so that maneuvering influence to a carrier is reduced to the minimum; obtaining the course and the course error according to the output equation of the gyroscope and the accelerator; determining a compensation scheme of the course error effect; carrying out horizontal error correction on the measured gravity signal. According to the invention, the horizontal error caused by course error is corrected by the external speed damping and the latitude information provided by GPS, and the horizontal precision of the gravity meter biax gyrostabilized platform can be effectively improved, so that the gyrostabilized platform can quickly restore to be steady after maneuvering, thus having strong actual practical meaning.