166 results about "Inertial systems" patented technology

An apparatus and a method of its use in a marine seismic survey are disclosed. The apparatus includes a seismic survey object (106) and an inertial measurement device (130) coupled to the seismic survey object (106). The method includes taking inertial measurements of the movement of selected points on a seismic spread relative to at least one known point, and applying the inertial measurements to the known point to determine the positions of the selected points.

A non-linear alignment method of a strapdown inertial navigation system comprises the following steps of: acquiring data of an accelerometer and a fiber gyroscope of the fiber strapdown inertial navigation system and carrying out denoise processing, realizing coarse alignment and fine alignment processes by the utilization of an analysis method and a compass method, establishing a quaternion-based strapdown inertial navigation system non-linear error model under the condition that attitude angle and azimuth angle are both large misalignment angles, establishing an observation model with speed as observed quantity, carrying out iterative and filter estimation by the use of an improved UKF algorithm on the basis of the model so as to obtain the misaligned angle of the platform, continuously carrying out closed-loop feedback and correcting attitude matrix of the strapdown inertia system in the previous period, so as to accurately complete the initial alignment process. The method can be used to guarantee safety and confidentiality of the initial alignment without the utilization of other sensor information. By the introduction of the quaternion error based non-linear system error model, linearization is not required to guarantee the precision of the model. Computational complexity is reduced, and filtering is carried out on the established non-linear system so as to complete fine alignment.

A micromachined thermal and mechanical isolator for MEMS die that may include two layers, a first layer with an active temperature regulator comprising a built-in heater and temperature sensor and a second layer having mechanical isolation beams supporting the die. The isolator may be inserted between a MEMS die of a disc resonator gyroscope (DRG) chip and the leadless chip carrier (LCC) package to isolate the die from stress and temperature gradients. Thermal and mechanical stress to the DRG can be significantly reduced in addition to mitigating temperature sensitivity of the DRG chip. The small form can drastically reduce cost and power consumption of the MEMS inertial sensor and enable new applications such as smart munitions, compact and integrated space navigation solutions, with significant potential cost savings over the existing inertial systems.

The invention relates to a data fusion system and method of a differential GPS and an inertial navigation in an intelligent vehicle. The data fusion method of the differential GPS and the inertial navigation in the intelligent vehicle includes utilizing the differential GPS arranged at the top of the vehicle to obtain information provided by a space satellite and utilizing an upper computer which is to perform data fusion to extract GPS data according to the NEMA-0183 protocol to obtain information such as heading, speed and position; utilizing an inertial navigation system arranged in the middle of the inside of the vehicle body to collect data of a heading changing rate and x-axis and y-axis accelerations during vehicle operating, and transmitting the data to the upper computer which is to perform data fusion to obtain a heading angle and the speed and the displacement of the x-axis and the y-axis; and through algorithm integration, finally obtaining accurate navigational positioning information and utilizing the inertial system to provide RI (Related Information) under the condition that the GPS signals are lost. Besides, the method further includes displaying the navigational positioning data in a map and transmitting the packed data to a planning decision-making upper computer through an LAN (Local Area Network) created through a router, and controlling the intelligent vehicle according to analyzed information and actual travelling conditions.

The invention relates to a method for realizing indoor positioning based on multi-information fusion. The method comprises the following steps: performing indoor navigation map initialization by a terminal by virtue of a magnetic inductor and a camera; performing positioning system and inertia system initialization by the terminal by adopting local position coordinates; acquiring the angle information of the magnetic inductor and an accelerometer by the terminal, and performing current dead reckoning; performing space absolute position calculation and inertia system feedback correction by the terminal; estimating the current space position according to the dead reckoning information and the space absolute positioning information by the terminal; and starting a path planning algorithm according to the current position information and to-be-reached position information by the terminal, and performing feasible path selection. With the adoption of the method for realizing indoor positioning based on multi-information fusion, multiple positioning methods are comprehensively utilized, interference caused by indoor building structures is effectively reduced, the universality, feasibility and accuracy of the indoor positioning algorithm are improved, and the method has wide application range.

An inertial (“INS”) / GPS receiver uses injected alignment data to determine the alignment of the INS sub-system when the receiver is in motion during start-up. The alignment data is determined from parameterized surface information, measured GPS velocity, and a known or predetermined angular relationship between the vehicle on which the receiver is mounted and an inertial measurement reference, or body, frame associated with the accelerometers and gyroscopes of the inertial measuring unit (“IMU”). The parameterized surface information, which provides a constraint, may be the orientation of the surface over which the vehicle that houses the receiver is moving. The receiver uses the initial GPS position to determine the location of the vehicle on the parameterized surface, and thus, the known surface orientation. The receiver then determines the roll, pitch and heading of the vehicle on the surface using the associated GPS velocity vector. Thereafter, the receiver uses the calculated roll, pitch and heading of the vehicle and the known or predetermined angular relationship between the vehicle and the IMU body frame to determine a rotation matrix that relates the IMU body frame to a computation or referenced frame used by the receiver.

A method and system for compensating for significant soft iron magnetic disturbances in a heading reference system, such as an aircraft heading reference system, such as an integrated standby unit; or a vehicle inertial system, provides a heading correction signal to the heading reference system when a detected difference in value between a gyro heading relative to magnetic north and a magnetometer reading during a defined measurement period exceeds a predetermined acceptable threshold value of change, such as one based on the expected gyro drift over that period. Upon receipt of the heading correction signal, the gyro heading is adjusted to maintain an accurate heading relative to true magnetic north. If this threshold value is not exceeded, then the magnetometer reading is used for the heading value. This method is iteratively repeated in order to continually maintain an accurate heading and may be employed for each heading measurement axis.

The invention discloses a tight-coupling GNSS / INS combined navigation device. The combined navigation device utilizes a tight coupling method to combine a low-precision inertial navigation system INS with a global navigation satellite system GNSS, the defects that the error of the low-cost low-precision inertial navigation system is increased along with time accumulation is made up, and meanwhile the positioning stability in the area that the signal of the global navigation satellite system (GNSS) is sheltered is guaranteed. According to the device, mainly by eliminating the error of the low-precision inertial navigation system, a leveling method is combined with single-antenna attitude determination for initial alignment, a tightly coupled filter technology and a position error modeling technology are tightly used, and the posture precision is guaranteed by regularly feeding back an attitude angle calculated by a single-antenna attitude determination method to the inertial system, so that high-performance combined navigation of the low-precision inertial navigation system is realized; and the device effectively solves initial alignment of the inertial navigation attitude angle and combined filtering in complex environments, meanwhile the precision of calculation and the stability of positioning are guaranteed, the application field of a high-overload resistant system is expanded, and low-cost and high-performance combined navigation is realized.

The invention provides a method for correcting navigation deviation and a navigation display adopting the same. The method comprises the steps of: matching with a given electronic map through the moving and running directions of the coordinates of a vehicle, pointing out a currently selected road, obtaining matching degrees of candidate road sections by means of a matching degree function by taking the road section and the vehicle running direction as one parameter and taking an Euclidean distance from a measuring point to the candidate road section as the other parameter, and selecting the matching road section with the maximum matching degree. By means of the invention, the deviation of an inertial system, caused by gyro drift, can be eliminated, and errors can be corrected in real time to obtain the accurate running position and direction of the vehicle.

A method for performing bridge monitoring by using multiple strapdown inertial systems belongs to the bridge monitoring technology and includes: performing position setting for the strapdown inertial systems according to the dynamic characteristic of a bridge structure and performing installation calibration and initial calibration for the strapdown inertial systems; carrying out bridge dynamic load tests which include a pulsating test, a sports car test and a bumping test, and performing continuous monitoring by using deformation and vibration information of the strapdown inertial systems relative to a reference point and measurement points; obtaining static deformation angles and dynamic deformation angles of the measurement points of the bridge at each moment by using the deformation information obtained in an inertial test matching method; obtaining a girder deflection curve of the bridge by using the dynamic deformation angles of the inertial systems calculated at the reference point and the measurement points, and obtaining an impact coefficient of the bridge through further processing; using accelerometer output information to obtain acceleration time history curves of all the measurement points and obtaining displacement time history curves through integration; and analyzing the acceleration time history curves and the displacement time history curves in a time domain analysis method and a frequency domain analysis method to obtain structural parameters including bridge amplitude, damping ratio and vibration mode. The method has the advantages of being free of weather variation interference, little in manual operation, high in automatic degree and capable of performing continuous measurement.

A computational air data method and system for estimating angle-of-attack and angle-of-sideslip of an aircraft utilizing a detailed aerodynamic model of the aircraft, extended Kalman filters, inertial system measurements of body rates and body accelerations, and computation of dynamic pressure.

A command input method makes use of a three-dimensional motion recognition device embodied with an inertia system and is particularly directed to extend the total number of inputable commands using initial posture information as well as movement pattern of a motion recognition device. The command input method includes the steps of: determining initial posture at start point when movement of the motion recognition device is generated; determining a pattern of the movement at the end of the movement; and deciding a command from the determined initial posture and the movement pattern. Since the three-dimensional spatial motion can be further differentiated into different commands by the initial posture of the input device, the command input system can be simplified in structure with less number of recognizable motions.

The invention discloses an instrument grade silicon carbide reinforced aluminum matrix composite for aviation and a preparation method thereof. The composite is prepared from the following raw materials by volume percent: 1%-8% of nano silicon carbide particles, 35% of micron silicon carbide particles, and the balance of aluminum alloy powder. The total volume percent of silicon carbide can be regulated between 36% and 43% at will, so that lower coefficient of thermal expansion of the material is guaranteed; due to the addition of nano silicon carbide particles, the strength of the composite is effectively improved and the composite has good machining performance and plastic deformability; the prepared aluminum matrix composite has high specific strength, large specific stiffness, good thermal stability, high thermal conductivity, low density and the like, can be matched with various materials, can substitute for materials such as beryllium, bearing steel and carbon steel for aerospace inertial systems, and can be used in industries such as aerospace and automobiles.

The invention relates to an indoor-flying intelligent body inertial system and a laser range finder combination type navigation improving method. The navigation improving method is characterized in that a sensor portion (6) comprises a laser range finder URG (1), an IMU (Inertial Measurement Unit) (7), an atmospheric pressure altimeter (4), a magnetic field intensity sensor (5), a gyroscope (2) and an accelerometer (3); a navigation information calculation portion (14) comprises a USB (Universal Serial Bus) (8), a navigation computer (9), a converting device (10), an electric collecting line (11), a bus (12) and navigation information (13). The navigation improving method comprises the steps of acquiring position information by utilizing the laser range finder (1), acquiring attitude information by utilizing an inertial navigation system, fusing the position information with the attitude information by utilizing a unscented Kalman filter (UKF) method and a linear feature extraction algorithm, and finally performing a strapdown algorithm to realize track plotting. According to the navigation improving method, the indoor autonomous navigation of a flying intelligent body can be realized, the divergence and track plotting invalidation problems of a flying intelligent body combination type navigation system are effectively solved, and the navigation accuracy is improved.

A method for providing dynamic disturbance compensation to an inertial system is described. The method includes determining estimated correction factors based on received acceleration components, and dynamically determining filter coefficients for a filter configured to receive velocity and position signals and output a prediction error. The method further includes combining the estimated correction factors and the prediction error into adjustment factors, where the prediction error is configured to be a feedback control signal, and applying the adjustment factors to compensate the inertial system such that effects of the dynamic disturbance are removed.

The inertial system for gravity difference measurement uses COTS nano accelerometer and a strapdown Global Navigation Satellite System (GNSS)-aided inertial measurement unit (IMU). The former has low measurement noise density, while the latter is used to analytically stabilize the platform. Stochastic modeling of the gravity anomaly is utilized (as opposed to the deterministic modeling of causes and effects) to simplify the algorithm. The algorithm aims at finding relative changes between points, as opposed to absolute values at the points, which allows for high relative precision required in many applications.

The invention discloses an initial alignment method for an MEMS-IMU. Through the initial alignment method, the initial rough alignment time of a strapdown inertial system is further shortened, and the precision of the strapdown inertial system is further improved. The initial alignment method comprises the following steps that 1, sensor data are acquired, wherein the sensor data comprise the data of an MEMS gyroscope and an MEMS accelerometer; 2, initial alignment coordinate systems are established, wherein the initial alignment coordinate systems comprise the solidified carrier coordinate system, the earth coordinate system, the navigation coordinate system and the carrier coordinate system; 3, initial alignment objective functions are established, and an optimal speed reducing method of quick alignment is constructed; 4, a parameter equation of the optimal speed reducing method is determined through the complementary filter principle; 5, a carrier attitude angle is resolved through an quaternion updating algorithm, and calculation of an initial attitude matrix is achieved. According to the initial alignment method for the MEMS-IMU, the calculation precision and efficiency of an initial alignment algorithm are effectively improved, and the application range is wide.

The invention provides a gyro-free inertial system error calibration method.According to the method, accelerometer output combinations at multiple positions are formed by changing space positions of a gyro-free inertial system reference coordinate system by means of the uniqueness of a gravity vector module value under the condition that no external equipment provides a reference, and zero offset, scale factor errors and installation errors of all accelerometers of a gyro-free inertial system are estimated by adopting a nonlinear iterative method.The method has the advantages that no precise external equipment is needed, operation is simple and the cost is low, and can be used for calibration of the gyro-free inertial system in a laboratory or external environment.

The invention relates to a high-precision surveying and mapping method based on an inertial system. The high-precision surveying and mapping method comprises the steps of: forming a strapdown inertialnavigation system by means of a three-axis gyroscope and a three-axis accelerometer, and carrying out inertial navigation calculation; using a position increment output by an odometer to perform deadreckoning, and output attitude heading, speed and position information; establishing a mathematical model for inertial navigation strapdown solution and odometer dead reckoning errors, and adopting aKalman filtering method for estimating and measuring odometer and inertial navigation errors; and using position information of magnetic mark points outside a pipeline for measuring specified equidistant points in advance to perform data correction, and adopting an RTS filtering method for backtracking filtering, such that each sampling point is the optimal smooth point of Kalman filtering. The high-precision surveying and mapping method utilizes the inertial device and odometer data acquired by post-processing, combines with the external precise magnetic mark point signals, gives the position information of the specific measuring point and the position trajectory of a path of the whole measured pipeline through combining a navigation algorithm, and satisfies the high-precision surveyingand mapping requirements in fields of petroleum pipelines, tunnels, railways and the like.

The invention relates to a damping method for forced vibration of an inertially stabilized platform. Electric connection is added between a vibration absorber and the inertially stabilized platform by introducing an active feedback link consisting of an angle sensor, an amplifier and a torquer to a passive vibration absorber, therefore, the added active feedback link increases comprehensive rotary inertia of an active part and a passive part of the vibration absorber in an electric manner; when external disturbance acts on the inertially stabilized platform, and under the condition that a control system does not participate in working, the passive part of the vibration absorber and the active feedback link generate the torque for resisting disturbance action simultaneously, so as to damp angle vibration of the inertially stabilized platform caused by external disturbance. By optimization of parameters of the vibration absorber, and under the condition that the specification of the passive vibration absorber is smaller, the purposes of improving the dynamic characteristic of the inertially stabilized platform, expanding damping the bandwidth of vibration of the system and reducing the steady-state error of the system are achieved. The damping method has the characteristics of independence, flexibility, simplicity and convenience and is applicable to an inertial system and a gyro device.

The invention provides an SINS (Strapdown Inertial Navigation System)-based method for restraining the speed measuring error of a DVL (Doppler Velocity Log). The method comprises the following steps of: starting the DVL and an SINS, comprehensively processing the output speeds of the DVL and the SINS, performing high pass digital filtering and outputting the optimized speed. By means of method provided by the invention, the high-frequency noise of the DVL can be filtered while the motion high-frequency information is not filtered; and speed and acceleration references are provided for initial alignment and navigation of other inertial systems.

A method and system for compensating for soft iron magnetic disturbances in multiple heading reference systems, such as aircraft heading reference systems, integrated standby units; or vehicle inertial systems, detects and provides a heading correction signal to the error prone heading reference system when a detected difference in value between a gyro heading relative to magnetic north and a magnetometer reading during a defined measurement period exceeds a predetermined acceptable threshold value of change, such as one based on the expected gyro drift over that period. Upon receipt of the heading correction signal, the gyro heading is adjusted to maintain an accurate heading relative to true magnetic north. If this threshold value is not exceeded, then the magnetometer reading is used for the heading value. This method is periodically repeated in order to continually maintain an accurate heading and may be employed for each heading measurement axis.

The invention relates to a systematic compensation method of fixed-precision navigation of a ship optical inertial navigation system when in long voyage. The method comprises the following steps: step I, determining a coordinate system of a ship, and marking the head direction of the system; step II, installing an optical gyroscope and a gauge on a high-strength high-precision hexagonal body; step III, debugging a single-shaft rotating mechanism control system, and designing a transposition scheme by utilizing a mature PID control algorithm; step IV, fixedly installing an IMU to a table-board of a transposition mechanism; step V, acquiring original data of a strap-down inertial navigation system, processing the acquired data, such as temperature compensation, sailing direction effect compensation, systematic calibration and the like; step VI, updating an attitude and calculating speed and position in the design of a pure inertial system in a single-shaft rotating modulation system; and step VII, demodulating the single-shaft rotation in real time. The constant high precision and stability of the inertial navigation system on a working carrier when a water ship is in long voyage can be guaranteed.

The invention discloses a distributed inertial network-based high accuracy transfer alignment method, belonging to the application category of the technical fields of inertial navigation and transfer alignment. According to the method, a distributed inertial network is established according to the demands and the actual situation, and a plurality of inertial systems are configured at the different parts of a carrier (such as an aircraft, a ship or the like), so that information of a plurality of inertial nodes can be obtained. The reliability of the data output of an inertial device is guaranteed by means of fault detection and isolation; the information of all the nodes is transferred to a certain sub-node for performing data fusion according to a transfer matrix, and inertial measurement information at the certain sub-node is obtained. On the basis of error modeling, a filtering equation is established so as to realize the transfer alignment between the inertial navigation main nodes and the inertial navigation sub-nodes. After the scheme is adopted, external equipment does not need to be additionally arranged, effective redundant inertial information can be provided for the carrier, and local measurement is provided for carrier equipment such as radar tracking and weapon load, so that the accuracy and reliability of the transfer alignment are guaranteed; furthermore, the method has the characteristics of being low in cost, high in autonomy, and the like.

The invention provides an underwater carrier positioning method which comprises the following specific steps: 1) equipping an inertial navigation system and an underwater acoustic ultra-short baseline positioning system to a carrier; 2) judging whether an underwater transponder exists within a range that underwater acoustic information of the underwater acoustic ultra-short baseline positioning system can reach, and if so, turning to the step 6), or otherwise, turning to the step 3); 3) the carrier releasing a buoy equipped with a GPS receiver; 4) the carrier receiving GPS signals of the buoy, and the underwater acoustic ultra-short baseline positioning system measuring position information of the buoy in an ultra-short baseline array coordinate system; 5) calculating position of the carrier in the navigation coordinate system according to the GPS signals and the position information, and carrying out calibration on the inertial navigation system; and 6) calculating the position of the carrier in the navigation coordinate system according to the position information of the underwater transponder in the navigation coordinate system and the position information thereof in the ultra-short baseline array coordinate system, and carrying out calibration on the inertial navigation system. The method realizes underwater positioning of the carrier.

The invention discloses an inertial reference measurement method for detecting bridge deformation, and the method is used for detecting bridge deformation and subsidence. The method comprises a step of planning a track path at the surface of a measured bridge, marking a plurality of reference points on the track path, establishing a reference by using high precision GPS information, and establishing an inertial reference by using an inertial system, a step of collecting the output of the inertial system and the output of an odometer, compensating the output of the odometer and identifying a bridge surface uneven influence test, then carrying out combined dead reckoning, completing the whole test of selected track, carrying out a closed correction process, and finally giving a tested accurate track and calculating the deformation and subsidence of the bridge. According to the method, based on the combination of an inertial navigation system, the odometer and a GPS, by using a three-dimensional inertial measurement mode, and the rapid and continuous measurement of bridge 3D small dynamic deformation is realized without the restrictions of the track and no track.

The invention discloses the method for measuring the beat frequency of the non-mechanical optical gyro by using the ring travelling wave resonant cavity. Further, the angular speed of inertial systemis measured. The ring travelling wave resonant cavity is positioned on the inertial system, which is rotated at certain angular speed. The otpical signal feeds-in-the ring travelling wave resonant cavity by usnig 2X2 wave-guide coupler, thus light wave field propagates to both of the clockwise direction and anti-clockwise direction. The beat frequency signal can be obtained by superposing the tworesonant optical signals with different frequencies, which can be obtained by using the wave guide coupler to couple directly from the travelling wave resonant cavity. The low-pass filter takes out the beat frequency signal, whose frequency value and variety is corresponding to the angular speed and variety of inertial system.

An inertial system measures the attitude of an aircraft consisting at least in determining the angle of pitch and / or the angle of heading and / or the angle of roll of the aircraft, each of the said angles of attitude being determined by successive double integration of their second derivative. A pair of accelerometers to determine the angle of pitch being are disposed on either side of the centre of gravity along an axis substantially merged with the longitudinal axis of the aircraft. A pair of accelerometers to determine the angle of heading are disposed on either side of the centre of gravity along an axis substantially merged with the transverse axis of the aircraft. A pair of accelerometers to determine the angle of roll are disposed on either side of the centre of gravity along a vertical axis perpendicular to the plane formed by the other axes.

The invention discloses a method for evaluating the stability of a north orientation benchmark for inertial measurement unit calibration. The method comprises the following steps: (1) measuring polaris orientation by utilizing a theodolite to acquire a true north direction, leading the true north direction to a prism on a pillar position, namely the mirror surface of a north orientation benchmark prism, and collimating; and fixing the north orientation benchmark prism on the pillar position after being collimated to serve as the north orientation benchmark; (2) leading the north orientation benchmark determined by the north orientation benchmark prism to a prism, namely a north orientation location prism, on a rotary table of inertial measurement calibration equipment by using the theodolite, and collimating the theodolite and the mirror surface of the north orientation positioning prism to take the north orientation location prism as location north orientation of the inertial measurement equipment; and (3) acquiring north orientation benchmark data for many times according to the location north orientation by using the inertial measurement equipment, and processing the data to acquire a stability evaluation test result of the north orientation benchmark. According to the method, the problem of stability monitoring of the north orientation benchmark is solved, and the technical support is effectively provide for inertial systems; the testing method is safe and reliable to carry out, and test curves are visual and accurate.