1695 results about "Geodesy" patented technology

A global navigation satellite sensor system (GNSS) and gyroscope control system for vehicle steering control comprising a GNSS receiver and antennas at a fixed spacing to determine a vehicle position, velocity and at least one of a heading angle, a pitch angle and a roll angle based on carrier phase position differences. The roll angle facilitates correction of the lateral motion induced position errors resultant from motion of the antennae as the vehicle moves based on an offset to ground and the roll angle. Alternative aspects include multiple-antenna GNSS guidance methods for high-dynamic roll compensation, real-time kinematic (RTK) using single-frequency (L1) receivers, fixed and moving baselines between antennas, multi-position GNSS tail guidance (“breadcrumb following”) for crosstrack error correction, guiding multiple vehicles and pieces of equipment relative to each other, and snow grooming equipment and method applications.

A method, a map and an article of manufacture for the exploration of hydrocarbons. In one embodiment of the invention, the method comprises the steps of: accessing 3D seismic data; dividing the data into an array of relatively small three-dimensional cells; determining in each cell the semblance/similarity, the dip and dip azimuth of the seismic traces contained therein; and displaying dip, dip azimuth and the semblance/similarity of each cell in the form a two-dimensional map. In one embodiment, semblance/similarity is a function of time, the number of seismic traces within the cell, and the apparent dip and apparent dip azimuth of the traces within the cell; the semblance/similarity of a cell is determined by making a plurality of measurements of the semblance/similarity of the traces within the cell and selecting the largest of the measurements. In addition, the apparent dip and apparent dip azimuth, corresponding to the largest measurement of semblance/similarity in the cell, are deemed to be estimates of the true dip and true dip azimuth of the traces therein. A color map, characterized by hue, saturation and lightness, is used to depict semblance/similarity, true dip azimuth and true dip of each cell; true dip azimuth is mapped onto the hue scale, true dip is mapped onto the saturation scale, and the largest measurement of semblance/similarity is mapped onto the lightness scale of the color map.

Apparatus for measuring surveying parameters, such as distances and angular displacements between an instrument survey station and a mobile survey station, with improved accuracy. The invention combines a differential satellite positioning system (DSATPS), available with positioning systems such as GPS and GLONASS, with electromagnetic measurements of distances and optically encoded angles by a conventional electro-optical survey instrument to provide survey measurements that can be accurate to within a few millimeters in favorable situations. The DSATPS relies upon pseudorange measurements or upon carrier phase measurements, after removal of certain phase integer ambiguities associated with carrier phase SATPS signals. The SATPS may be retrofitted within the housing of the conventional electro-optical instrument. In a first approach, a remote station provides DSATPS corrections for the mobile station and/or for the instrument station. In a second approach, the mobile station provides DSATPS corrections for itself and for the instrument station. In a third approach, the instrument station provides DSATPS corrections for itself and for the mobile station.

A method is described for the measurement of multidirectional far-field source signatures from seismic surveys whereby a vertical cable acquisition technique is provided, vertical cable data are acquired, the proper receivers are specified to measure the signature, data are sorted into common selected receiver gathers CSRG, the direct wave within common receiver gather is properly windowed, the angles of each direct path are computed and the amplitude of the signatures is normalized, so as to obtain the multidirectional far-field signatures of the seismic source array having the same characteristics as those that generated the seismic reflections.

A method for determining the directional angle of radar objects using a multibeam radar, including the steps of:

• (a) recording the frequency spectra of the radar echoes for a plurality of beams;
• (b) seeking a measuring frequency near a frequency maximum assigned to the radar object; and
• (c) comparing the phases and/or amplitudes of the radar echoes at the measuring frequency with reference patterns known for various directional angles,

steps (b) and (c) being executed repeatedly, each time for different measuring frequencies, and the directional angles obtained for the various measuring frequencies being checked for consistency.

In accordance with embodiments of the invention, a skyward-looking sensor enables classification of points in its hemispherical field of view as either sky, partial sky or not sky, which in turn enables determination from data supplied by the GNSS receiver of whether each satellite in the GNSS antenna's field of view is in a region of sky, partial sky or not sky. Pseudrange and phase data from GNSS satellites determined to be in a region of sky can be considered reliable and used with confidence in a positioning solution. Pseudrange and phase data from GNSS satellites determined to be in a region of partial sky can be considered suspect and can therefore only contribute to a position solution with limited confidence and decreased accuracy. Pseudorange and phase data from GNSS satellites determined to be in a region of no sky can be considered unreliable and excluded from use in a positioning solution.

A method for the suppression of multiple reflections using a Kirchhoff algorithm Multiple reflections are simulated by means of a Kirchhoff-type summation applied to a pseudo zero-offset section. An adaptive filter is applied to adjust the simulated multiple. The adjusted simulated multiple is subtracted from the input data.

The invention discloses a timing trigger switching method based on ephemeris and user position calculation, and belongs to the field of low-orbit satellite communication. The working principle is as follows: (1) a gateway station receives a position and speed measurement report periodically sent by a user, (2) the gateway station calculates and judges a target wave beam/satellite/gateway station and a switching mode according to the ephemeris; (3) a delta t1 value is calculated according to the conditions of the source gateway station, the target gateway station and the switching mode, (4) a toff-treport value and a delta t2 value are calculated based on the ephemeris and the user position; (5) pre-switching judgment is carried out according to the calculated value; (6) if a pre-switchingcondition is met, a timer is established; (7), pre-switching is initiated by the gateway station according to the timing of the timer; and (8), a switching command is issued to a user by the gateway station after the timing of the timer (toff-treport-delta t1-delta t2). By means of the method, the low-orbit satellite system switching preparation stage depends on gateway station calculation, the terminal does not need to conduct neighbor cell/wave beam pilot frequency measurement, the switching problem of a small wave beam overlapping area is effectively solved, and meanwhile the method is widely applied to various scenes of the low-orbit satellite system.

The invention discloses a low-orbit satellite constellation system cell switching method and device based on ephemeris information. The method comprises the steps of enabling a mobile terminal to receive the signal intensity of a service satellite; judging a switching triggering moment, then predicting a subsatellite point position of a low-orbit satellite according to a received satellite ephemeris parameter; calculating a coverage satellite set of the switching triggering moment according to the predicted subsatellite point position; and comparing a mobile terminal with a beam feature pointset of all beams of each satellite in the coverage satellite set to obtain an adjacent cell list. The mobile terminal calculates the visual time of each beam in the neighbor cell list, screens out thebeams of which the visual time is less than a beam visual time threshold, selects the beam with the maximum switching weight in the screened neighbor cell list as a target beam, and finally sends a request of switching to the target beam to a source beam. The method has the characteristics that the beam cell switching reliability is improved; the ping-pong switching probability is reduced; the number of system control signaling is reduced; and the network efficiency is improved.

A shorter spatial wavelength static correction method for exploration seismic data using first arrivals according to the invention includes the steps of: based on a quadratic curve fitting to the first arrivals, which are picked up from seismic wave records of receiver gathers after the field statics, obtaining the difference DELTAi,j between the observed first arrival time tij of the receiver point j with respect to the shot point i and the corresponding time value of the fitted quadratic curve; and forming the original matrix DELTA having mxn elements DELTAi,j, where n is the total number of shot points and m is the total number of receiver points of the line; substituting the elements of each row by the difference between the value of each element and the row average; and substituting the elements of each column by the difference between the value of each element and the column average; repeating the iteration until less than a predetermined error; the sum of the averages of the ith row for all iterations and the sum of the averages of the ith column for all iterations are the static correction value at the ith shot point and the static at the jth receiver point respectively. Said method is applicable to 3-D seismic survey by mean of using a formula of rij={square root}{square root over (DELTAxij2+DELTAyij2)} to transform 3-D seismic data into 2-D data, so that the 3-D seismic data processing is as simple as that of 2-D data.

A method of producing images of formations surrounding a borehole, comprises: obtaining values of a first parameter in the borehole as a function of depth and azimuth at a first resolution; obtaining values of a second parameter in the borehole as a function of depth only at a second resolution; establishing a relationship between the first and second parameters at a matched resolution; using the relationship to derive values of the second parameter as a function of depth and azimuth; and producing an image of the second parameter as a function of depth and azimuth using the derived values of the second parameter. A method of producing three dimensional images comprises obtaining values of a first parameter in the borehole as a function of depth and azimuth at a first resolution; obtaining values of a second parameter in the borehole as a function of depth only at a second resolution; establishing a relationship between the first and second parameters at a matched resolution; using the relationship to derive values of the second parameter in a three dimensional array; and producing an image of the second parameter in three dimensions using the derived values of the second parameter.

The invention relates to a three-dimensional focus imaging method for a side-looking chromatography synthetic aperture radar, which comprises the steps: converting collected original echoed data of the side-looking chromatography synthetic aperture radar to a slope distance wave-number domain and an azimuth wave-number domain, performing elevation frequency spectrum aliasing-free recovery on converted signals and converting the signals to a slope distance three-dimensional wave-number domain, an azimuth three-dimensional wave-number domain and an elevation three-dimensional wave-number domain; converting the signals in the three-dimensional wave-number domains to a rectangular coordinate system by coordinate mapping; and reconstructing a three-dimensional microwave image containing slope distance, azimuth and elevation spatial location information of imaging areas and magnitude-phase information by inverse Fourier transform and image space selection. The method can precisely reconstruct three-dimensional microwave images in the imaging areas without geometry correction on the condition that elevation hits are less, the distribution of elevation synthetic aperture centers is arbitrary or the size of the imaging areas are arbitrary. The method can be also used for the reconstruction of three-dimensional microwave images in imaging observation geometries such as downward-looking, downward side-looking chromatography SARs, and the like.

A wavefield separation method and apparatus for 3D VSP data, which handles arbitrary 3D source and receiver geometries, and common shot 3C data oriented to North, East and Vertical geographical coordinates and makes use of anisotropic medium properties at the downhole receivers. When given a range of propagation angles, slowness and polarization vectors are computed for each plane wave and a linear system is solved at each frequency to yield the scalar plane-wave amplitudes. A novel regularization scheme is used that obviates the need for eigen analysis of the steering matrix. Sums within subsets of these scalar plane waves are constructed to provide up and down qP (P), qS (Sv) and Sh wavefields. Vector residuals can be computed for parameter testing, quality control and imaging purposes.

A system and method for state estimation of a surface of a platform at sea, includes receiving sensor signals indicative of LIDAR data for the platform; applying a Bayesian filter to the LIDAR data for a plurality of hypotheses; determining vertical planes representing azimuth and elevation angles for the LIDAR data; applying a robust linear estimation algorithm to the vertical planes; and determining candidate points in response to the applying of the robust linear estimation algorithm.

The invention relates to a method for quickly and precisely positioning a passive mine focus. The method includes steps of (1), optimally arranging passive focus sensors based on numerical analyzing and monitoring results; (2), detecting events of the passive focus; and (3), positioning the passive focus based on travel time of P-waves. The step (3) particularly includes using existing geophysical parameters as a known condition and a constraint condition; solving equations to obtain results including origin delay time and focus coordinates according to the principle of least squares; judging reasonableness of the results after the equations are solved; adjusting input parameters if the results are unreasonable; computing again until a final reasonable solution is obtained; and accordingly determining coordinates of the passive focus. The method has the advantages that unreasonable and excessive excavation is stopped fundamentally, coal mining utilization rate is increased, re-exploration for distribution of gobs by a geophysical exploration mean is omitted for monitored areas, and cost is saved.

The invention discloses a beam switching method, system and device based on a low earth orbit satellite and a storage medium, and the method is applied to a satellite terminal, and comprises the steps: obtaining the ephemeris information of the low earth orbit satellite; according to the ephemeris information and the geographic position information of the satellite terminal, obtaining a target beam to be switched and a target moment when switching occurs; switching to the target beam at a target moment; selecting the strongest adjacent beam with the strongest signal quality of the target beam;and switching to the strongest adjacent beam. According to the invention, switching parameters are flexibly configured according to the position information and ephemeris information of the satelliteterminal; the wave beam becomes a target wave beam more easily; and switching the beam to the target beam according to the switching moment, according to the invention, the switching accuracy is improved, the switching accuracy and the strongest beam reservation time are also improved by selecting and residing in the strongest adjacent beam under the target beam, the difficulty of link capture and tracking caused by Doppler frequency shift is reduced, the beam switching efficiency is improved, and the network searching efficiency of the satellite terminal is improved.

The invention relates to a method for improving the imaging quality of a vertical seismic profile in oil geophysical prospecting. The method comprises the following steps: picking up downlink longitudinal wave first-arrival time of different receiving points in zero-offset and nonzero-offset vertical seismic profile wave field data; establishing an aclinic initial interval speed model; pushing the first-arrival time of longitudinal wave outwards to a well side point to obtain a time field of downlink wave; seeking ray angles of downlink and uplink waves; forming a theoretical uplink wave field by utilizing the radial angle of the downlink wave and adopting a ray tracking method; obtaining a series of corresponding different interface dip angle values; and determining the maximal corresponding interface dip angle as the well side reflecting interface dip angle needing to be sought. The method can effectively reduce the influence of the estimated result of an overlying stratum on the reflecting interface dip angle and the influence of the estimated result of pickup error on the reflecting interface dip angle in the traveling of primary reflecting wave and improve the imaging quality by utilizing the vertical seismic profile.

A walkaway VSP survey is carried out using a receiver array. Using a vertical VSP survey and arrival times of surface multiples on the walkaway VSP, vertical interval velocities and the anisotropy parameters δ and ε are estimated. This may then be used to process surface seismic data to do a prestack depth migration of surface seismic data and used for interpretation. For multi-azimuthal walkaway or 3D VSP data, we determine two VTI parameters ε and δ for multi-azimuth vertical planes. Then we determine five anisotropic interval parameters that describe P-wave kinematics for orthorhombic layers. These orthorhombic parameters may then be used to process surface seismic data to give a stacked image in true depth and for the interpretation purposes.