17 results about "Earth's magnetic field" patented technology

The invention relates to the technical field of bolt fracture detection, and provides a wind generating set bolt fracture detection method and device, and the method comprises the steps: obtaining a surrounding magnetic field signal of a to-be-detected bolt; correcting the detected magnetic field signal based on the geomagnetic field to obtain a corrected magnetic field value; on the basis of the current corrected magnetic field value, the magnetic dipole intensity change gradient of the current moment relative to the previous moment is calculated, and when the magnetic dipole intensity change gradient exceeds a set value, it is judged that an abnormal defect occurs; and when the abnormal defect exists, for the current corrected magnetic field value, based on the obtained frequency spectrum energy ratio, calculating fracture feature extraction and diagnosis, and obtaining an abnormal expansion stage of the current defect. By collecting and correcting a magnetic field signal, calculating a magnetic dipole intensity change gradient to identify abnormity, and then combining a frequency spectrum energy ratio to diagnose a fracture stage, early online monitoring of bolt fracture is realized. The method has high sensitivity and strong anti-interference capability, and is suitable for intelligent monitoring in a wind power environment.

A Hall effect thruster system (12) includes a thruster body (52) and a diffuser (1) configured to apply a torque (Td) to the thruster body (52) during operation. The diffuser (1) applies the torque (Td) by ejecting the propellant in a non-axial direction, such as a direction tangent to helical or curvilinear channels (8) formed within a body (10) of the diffuser (1). The applied torque (Td) can be used to counteract a swirl torque (Tswirl) that is induced on the thruster body (52) by the ionizing Hall current flowing in an annular channel (16) of the thruster body (52). This effective counter-torque (Td) is useful in deep space applications outside the Earth's magnetic field.

The application discloses a kind of earth magnetic field horizontal component representation methods of removing pole singularity, comprising: based on adolf schmidt semi-normalized spherical harmonic theory, the spherical harmonic representation of geomagnetic field magnetic potential function is obtained by spherical harmonic polynomial expansion calculation method;With south pole or north pole as center, mirror center symmetry extension is carried out to great circle on sphere, so that each point on sphere has a mirror point, so that the mirror extension function of geomagnetic field magnetic potential function is obtained;Two-dimensional Fourier expansion is carried out to mirror extension function using double Fourier series, and double coverage function expansion is obtained;Based on double coverage function expansion, the horizontal component of geomagnetic field is calculated, i.e. the spherical gradient of spherical magnetic potential function is calculated.The realization is based on the existing IGRF model magnetic potential expansion coefficient, the magnetic field tangent vector representation is obtained without being polluted by pole problem, and a new modeling idea and calculation method of spherical tangent vector field are provided.

Systems, methods, and devices for performing geomagnetic field distribution monitoring and correction. One system includes a reference magnetic sensor configured to detect components of a magnetic field at a first location and generate reference sensor signals, non-transitory computer-readable storage media storing instructions, and at least one electronic processor. The at least one electronic processor is configured to execute the instructions to receive the reference sensor signals from the reference magnetic sensor, compute a local adjustment factor based on the reference sensor signals, receive operational sensor signals from an operational magnetic sensor configured to detect components of the magnetic field at a second location, compute an orientation representation based on the operational sensor signals, and apply the local adjustment factor to the orientation representation to generate a corrected orientation representation.

A Hall effect thruster system includes a thruster body and a diffuser configured to apply a torque to the thruster body during operation. The diffuser applies the torque by ejecting the propellant in a non-axial direction, such as a direction tangent to helical or curvilinear channels formed within a body of the diffuser. The applied torque can be used to counteract a swirl torque that is induced on the thruster body by the ionizing Hall current flowing in an annular channel of the thruster body. This effective counter-torque is useful in deep space applications outside the Earth's magnetic field.

The present disclosure provides a method for estimating a noise of a soft magnetic core, including: acquiring a soft magnetic core, where an excitation coil is wound around the soft magnetic core; measuring an impedance value of the excitation coil under a natural geomagnetic field by frequency sweeping, and determining a peak frequency point when the impedance value reaches a peak; measuring, under different direct current bias magnetic fields, an inductance value and a resistance value of the excitation coil at the peak frequency point along an axial direction of the soft magnetic core to respectively obtain an unsaturated inductance value and a resistance peak value of the soft magnetic core; and obtaining an equivalent noise of the soft magnetic core based on the unsaturated inductance value and the resistance peak value.

The invention provides a sensor unit for measuring a magnetic field, comprising a magnetometer comprising at least one sensor medium and a flux concentrator; the flux concentrator is arranged to concentrate an external magnetic field, in particular the earth's magnetic field, at at least one location in the at least one sensor medium independently of a rotation of the at least one sensor medium about at least one axis of rotation determined by the shape of the flux concentrator.

The application discloses a method for calculating an interplanetary cross scaling coefficient according to particle phase space density correlation characteristics, comprising the following steps: obtaining particle flux sequences of a standard A star and a to-be-scaled B star; under a T89c external magnetic field model, respectively calculating a modified third adiabatic invariant and a second adiabatic invariant of the A star and the B star, and calculating a local magnetic field intensity; performing uniform grid division on time and the third adiabatic invariant, and performing logarithmic uniform grid division on the first adiabatic invariant and the second adiabatic invariant; obtaining a local pitch angle and energy in the grid; screening out points with data in the same grid to obtain particle phase space densities of the A star and the B star respectively; calculating a particle phase space density average in the grid; respectively establishing particle phase space density matrices of the A star and the B star; screening out points with data in the same grid of the particle phase space density matrices of the two stars to obtain a cross scaling coefficient of the B star.

The invention discloses a mobile equipment attitude estimation method and device based on IMU nine-axis data, and the method comprises the steps: firstly initializing a quaternion describing the attitude of mobile equipment by taking an east-north-sky coordinate system as a world coordinate system according to the data of an acceleration sensor and a magnetic field sensor in an initial window; the environment magnetic field distribution in a complex environment is approximated to a multi-magnetic dipole magnetic field distribution model, and a weight attenuation geomagnetic field estimation method is designed according to the attenuation characteristics of the magnetic dipole model; then, a multi-layer sliding window method is used, and a gyroscope, an acceleration sensor and a magnetic field sensor are respectively used for estimating quaternion, a roll angle, a pitch angle and a yaw angle of the mobile equipment; finally, the fusion effect of nine-axis sensor data estimation equipment attitude is optimized by using a self-adaptive complementary filter. The precision and the stability of attitude estimation of the mobile equipment can be remarkably improved.

Systems, methods, and devices for performing geomagnetic field distribution monitoring and correction. One system includes a reference magnetic sensor configured to detect components of a magnetic field at a first location and generate reference sensor signals, non-transitory computer-readable storage media storing instructions, and at least one electronic processor. The at least one electronic processor is configured to execute the instructions to receive the reference sensor signals from the reference magnetic sensor, compute a local adjustment factor based on the reference sensor signals, receive operational sensor signals from an operational magnetic sensor configured to detect components of the magnetic field at a second location, compute an orientation representation based on the operational sensor signals, and apply the local adjustment factor to the orientation representation to generate a corrected orientation representation.

In various aspects, a power-generating device is provided. The power-generating device may include a three-dimensional structure. The three-dimensional structure may be composed of a conductive material having (i) a magnetically permeable material having a topology that alters Earth's magnetic field such that curl (v×B)≠0, where v is Earth's velocity of rotation and B is the component of Earth's magnetic flux density symmetric about Earth's axis of rotation and (ii) a magnetic Reynolds number less than ten (Rm<10). The three-dimensional structure may be configured to generate power and heat when carried with Earth's rotation via Earth's axially symmetric non-rotating magnetic field.

The invention discloses a closed-loop control system for measuring geomagnetic field intensity. The closed-loop control system comprises a magnetometer probe, a trans-impedance amplifier, a band-pass filter, an analog-to-digital converter, a digital lock-in amplifier, a PID controller, a first sinusoidal signal output unit, a first addition unit, a second sinusoidal signal output unit and a radio frequency output circuit, according to the invention, robust magnetic field tracking can be realized in a high-order time-delay measurement link, and theoretical guidance for high-order time-delay control parameter selection can be provided.

Disclosed is a motion detection device and method using Earth's magnetic field. The motion detection device using the Earth's magnetic field comprises a geomagnetic field sensor, a processor, and a memory operatively connected to the processor, wherein the memory stores instructions and when executed, enable the processor: to identify a first geomagnetic field data using the geomagnetic field sensor, based on the motion detection device that is not moving; to identify that the first geomagnetic field data is generated from a first exercise equipment that is moving; and to identify at least one of a type of exercise and a number of times (e.g., reps, sets) of the exercise using the first exercise equipment based on the first geomagnetic field data

Systems, methods, and devices for performing geomagnetic field distribution monitoring and correction. One system includes a reference magnetic sensor configured to detect components of a magnetic field at a first location and generate reference sensor signals, non-transitory computer-readable storage media storing instructions, and at least one electronic processor. The at least one electronic processor is configured to execute the instructions to receive the reference sensor signals from the reference magnetic sensor, compute a local adjustment factor based on the reference sensor signals, receive operational sensor signals from an operational magnetic sensor configured to detect components of the magnetic field at a second location, compute an orientation representation based on the operational sensor signals, and apply the local adjustment factor to the orientation representation to generate a corrected orientation representation.

The application relates to a SINS system level error calibration method considering the influence of a magnetic field on a gyro scale factor, the relative geomagnetic field of a strapdown inertial navigation system can be obtained through rotation of a three-axis turntable, the conventional inherent error and the gyro magnetic scale factor error of an inertial measurement element can be simultaneously excited, the structured system error and the random drift error containing the magnetic scale factor error can be calibrated; the rotation path and the period of the turntable are reasonably designed to form the geomagnetic field variation independent and complete in each axial direction, the influence of the external magnetic field on the gyro scale factor can be accurately calibrated, and the navigation precision of the strapdown inertial navigation system is improved.

The invention provides a magnetic method detection method and system capable of adaptively adjusting a measuring line direction, belongs to the technical field of ocean detection technologies, particularly provides a method for determining the putting depth of a magnetometer, carries out magnetic detection according to the determined minimum putting depth and a measuring line interval d, and proposes construction of an expansion interference model and a state vector. And real geomagnetic field calculation and total vector direction calculation results are obtained through combined online estimation of establishment of an extended measurement model containing a complete interference term and adaptive volume Kalman filtering. The direction of the measuring line is adjusted in a self-adaptive mode based on the tidal current direction and the change of the direction included angle, the detection method is optimized, and the detection precision and the resolution ratio are improved.

In various aspects, a power-generating device is provided. The power-generating device may include a three-dimensional structure. The three-dimensional structure may be composed of a conductive material having (i) a magnetically permeable material having a topology that alters Earth's magnetic field such that curl (v x B)≠0. where v is Earth's velocity of rotation and B is the component of Earth's magnetic flux density symmetric about Earth's axis of rotation and (ii) a magnetic Reynolds number less than ten (R m < 10). The three-dimensional structure may be configured to generate power and heat when carried with Earth's rotation via Earth's axially symmetric non-rotating magnetic field.