49 results about "Constant error" patented technology

The invention discloses an autocollimation method of a carrier aircraft rotating type strapdown inertial navigation system under a shaking base, and belongs to the field of navigation. The autocollimation method comprises the following steps of: firstly obtaining the longitude and latitude of the position of a carrier, secondly collecting output signals of a fiber-optic gyro and a quartz flexible accelerometer in an inertia measurement unit, and then carrying out automatic compensation on a constant error of an inertia device by adopting a double-shaft rotating table rotatory IMU (inertial measurement unit) to form a rotating type strapdown inertial navigation system; and then calculating a rough initial posture array by utilizing gravity acceleration in an inertial coordinate system as a reference vector, establishing a state equation and a measuring equation again of the system, designing a vanishing adaptation Kalman filter to accurately estimate a misalignment angle of the carrier, and correcting a strapdown posture matrix by utilizing the misalignment angle to finish initial alignment and enter a navigation state. The method isolates the influence of shake of a vessel to initial alignment of a carrier aircraft, and dynamic random disturbance in measured noise is restrained through estimating the initial posture array of the system via the vanishing adaptation Kalman filter method, so that rapid autocollimation of the carrier aircraft rotating type strapdown inertial navigation system is realized.

The invention relates to a measurement error compensation method for a vehicle-mounted INS/OD integrated navigation system. The problem solved by the technology of the invention is that a vehicle-mounted odometer assisted inertial navigation system is used for vehicle navigation on a distributed drive electric intelligent vehicle, the system considers the odometer calibration factor caused by changes in vehicle driving conditions, the availability of odometer data and the judgment of providing measurement compensation, and the install offset angle and lever arm error of calibrating the INS andleft and right odometer systems in the integrated navigation, correction is made by taking the above data as measurement quantity in the measurement system of the integrated navigation system to construct a filtering system taking the inertial position, velocity, attitude error, random constant error of the inertial device, calibration factor error of the left and right odometers and the lever arm as the state quantity, and the feedback correction is performed to improve the accuracy of the integrated navigation positioning based on measurement error compensation.

A determination method of satellite antenna pointing accuracy comprises the following steps: firstly, with respect to a satellite large-scale system, determining various error sources that influence the satellite antenna pointing accuracy, wherein the error sources mainly comprise antenna characteristics, installation errors of satellite general assembly and parts, attitude control errors of a satellite system system, and satellite orbit drift; secondly, performing effect characteristic analysis of the determined various error source items, wherein the error source items are divided into constant errors, daily variable errors, short-period errors, and long-term errors; finally, calculating the rolling, pitching, yaw pointing errors of the satellite antenna on a satellite shaft, the pointing errors in the north-south and west-east directions, and the antenna pointing half cone angle errors. The method of the invention comprehensively considers various error sources and their characteristics that influence the satellite antenna pointing accuracy, can accurately provide the satellite antenna pointing accuracy, is simple in calculation, and is applicable to the engineering calculation of earth stationary orbit satellite antenna pointing accuracy.

The invention relates to an encoding method based on low-density parity check codes- cascaded codes synthesized by fountain codes in a deep space communication system. The method includes step one: information waiting for transmission is divided into a plurality of first-level information units; step two: the first-level information units are encoded by the spring codes to produce second-level information units; step three: the second-level information units are encoded by the low-density parity check codes to produce third-level information units; step four: the third-level information units are transmitted by deep space communication channels; step five: the received third-level information units are decoded by the low-density parity check codes and the successfully-decoded information units are formed into fourth-level information units; and step six: the fourth-level information units are decoded by the spring codes and decrypted. The invention needs no feedback re-transmission and can retrieve the original information by the receiving of subsequent information units and achieve a constant error rate demanded by the communication system under different channel conditions.

The invention discloses a calibration method of a probe tube of an inclinometer of a mining rotary drill. The calibration method comprises the following steps: by adopting an ellipsoid fitting method of a triaxial gravity-acceleration sensor, recognizing non-orthogonal errors, sensitivity errors and constant drift errors of the triaxial gravity-acceleration sensor; by adopting a space geometry method of rotating around the axis of the probe tube, aligning a coordinate system of the triaxial gravity-acceleration sensor and a coordinate system of a carrier; by adopting a scalar-product invariant method, recognizing non-orthogonal errors, sensitivity errors and constant errors of the triaxial gravity-acceleration sensor as well as misalignment errors with the coordinate system of the carrier. The calibration method disclosed by the invention has the advantages that effective data obtained by measurement is calibrated by the method to obtain more accurate course angle, inclination angle and tool face angle, the data is utilized to draw and obtain a theoretical drilling track, and the deviation between the theoretical drilling track obtained by test and the actually-set track is not more than 1m/100m.

The invention provides a single-shaft rotation-stop scheme-based mooring and drift estimating method, which comprises the following steps: determining an initial position parameter through GPS; acquiring output of an optical fiber gyroscope and data output by and an accelerometer and processing the data; adopting 8 rotation-stop sequences as a transposition scheme of one rotation period by an IMU; performing real-time update on a strapdown matrix according to the output of the gyroscope under the rotation state of the IMU, and simultaneously performing coordinate conversion on acceleration information acquired under the rotation state of the IMU and converting the acceleration information to a mathematic platform coordinate system; establishing a Kalman drift estimation module of a separation position loop in a mooring state of a load according to a load moving base error model; and processing constant errors of inertial apparatuses obtained after Kalman filtering by an average filtering method to obtain a relatively stable estimated mean value. When the load is in a mooring state, the drift estimating method provided by the invention can accurately estimate the constant errors of the inertial apparatuses by the Kalman filtering technology.

In a cutting method of an oblique surface by a rotary tool, for analyzing in advance a stability limit depth of cut with respect to a self-excited cutting vibration in consideration of a pick feed amount and a work oblique angle and reducing the number of steps necessary for preparation and correction of NC data, a tool diameter, the number of cutting teeth and dynamic stiffness of the rotary tool, a cutting force coefficient determined by a combination of the tool and work materials, dynamic stiffness of the work, the pick feed amount, oblique angles between the tool and the work and the like are used as input values, an initial value of the stability limit depth of cut is determined based on the input values, and calculation is performed based on the initial value. In this case, the initial value is compared with the calculated value, the initial value is corrected by a certain rule, and the calculation is repeated until both the initial value and the calculated value fall in a constant error range to thereby calculate the stability limit depth of cut during the oblique cutting.

The invention discloses a constant error calibration method of a fiber-optic gyroscope based on a double-calculation program. The method utilizes a rotating mechanism to drive inertia components to rotate to six positions of each axis gyroscope in the forward direction and reversed direction of Z-axis of a navigation system respectively, wherein during the stay process of each position, measure values of a group of the inertia components are simultaneously served as input values of two groups of navigation calculation programs, and the navigation parameter setpoint values of the two groups of programs are different. Then the two groups of calculation posture information are further coupled and calculated, and constant drift and scale factor error of each axis gyroscope is estimated. The invention provides the scheme that measure values of one group of the inertia components are used as input in a navigation computer, the two groups of navigation program calculation are performed simultaneously, and the two groups of calculation results are utilized to further estimate the device error; no external criteria information is required, the calculation amount is small, and the operation is simple and easy; and the two groups of navigation calculation programs have same input information, no installation deviation and time delay exist, and output information has relativity.

The invention provides a wide range temperature error compensating method of a real-time clock and a system of the real-time clock. The compensating method comprises the following steps of: calculating the needed error compensation acc through acquiring current state information of a quartz crystal oscillator, judging whether the needed error compensation acc is in a regulating range provided by the system, if not, leading in a controllable error through regulating a crossover frequency of the quartz crystal oscillator so as to change the calculating value of the error compensation acc and cause the error compensation acc to be in the regulating range provided by the system, and compensating the temperature. The temperature error compensating method actively leads the controllable constant error amount E to the error compensation acc through regulating the crossover frequency of the quartz crystal oscillator so as to change the value of the error compensation acc and cause the error compensation acc to be in the regulating range provided by the product. Thus, the product is capable of compensating the temperature error without changing the hardware configuration and preventing theregulating range of the error compensation acc influencing the precise compensation.

The invention discloses an optical-fiber strap-down inertial measurement unit reciprocating-type two-position north finding method for inhibiting slope error influence of devices, which is characterized in that: a reciprocating-type two-position alignment process is adequately utilized, on the basis of a traditional best two-position alignment and under the situation that hardware cost is not increased, constant errors of the devices can be effectively eliminated through reasonable design of rotation time intervals, rotation ways, the design parameters of a filter, and the like, influence of slope errors of the devices can also be inhibited, and the north finding precision of an optical-fiber inertial measurement unit can be improved.

The invention discloses a vehicle-mounted autonomous navigation method based on rotation modulation and a virtual odometer. The MEMS IMU is installed near the rotation axis of the wheel, that is, the wheel is used as the rotation mechanism of the MEMS rotary inertial navigation to realize rotation modulation, and the rotation of the wheel is used to periodically change the inertia. The position of the device relative to the navigation system can offset the influence of the constant value error of the inertial device on the navigation accuracy, and calculate the driving distance and speed of the vehicle through the rotation angle of the wheel, realize the virtual odometer, and assist the navigation of the MEMS rotary inertial navigation system.

The invention discloses a rotation type grid inertial navigation level damping method based on a damping network, and belongs to the technical field of inertial navigation systems. On the basis of a mechanical layout of grid inertial navigation, for effectively inhibiting the adverse effect of a constant error of an inertial device on the navigation precision, a single-axis rotation modulation grid inertial navigation system suitable for a polar region is designed; and in order to effectively inhibit the adverse effect of a random error of the inertial device on the navigation precision, an outer level damping algorithm of the single-axis rotation modulation grid inertial navigation system suitable for the polar region is designed. A grid inertial navigation system resolving model, a single-axis rotation modulation technology and an outer level damping technology are combined, so that a navigation error, accumulated with time, of the grid inertial navigation system caused by an error of an inertial measurement assembly can be effectively inhibited, and the navigation precision of a ship during sailing in the polar region is improved.

The invention discloses a sixteen-position error modulation method of a dual-axis rotation inertial navigation system. The method comprises the following steps: determining a carrier coordinate system, determining a rotating axis, determining a rotating coordinate system, defining constant errors, calibration factor errors and installation errors of a gyroscope and an accelerometer, determining arotational angular velocity, a position stopping frequency and a rotational angular velocity, sequentially determining rotating axes, rotating directions, rotating angles and stopping times under 1-16rotating orders, determining an attitude error within one rotating period, determining a velocity error within one rotating period, and determining long-endurance latitude and longitude errors. Underthe condition that the system cost and complexity are not increased, by changing the rotating orders of sixteen positions, an attitude error and a velocity accumulation error within one rotating period of the system are effectively reduced, and simultaneously, the oscillation amplitudes of the caused latitude and longitude errors are obviously reduced, thereby further improving the navigation accuracy of the dual-axis rotation inertial navigation system.

The invention provides a less complex successive cancellation decoding method for a Polar code, aiming to lower the calculation complexity of a Successive Cancellation (SC) decoding solution. The invention solves a problem that the original SC decoding solution is highly complex in calculation. A log likelihood ratio is calculated in the receiving terminal by comparing a constant error linear piecewise function to a hyperbolic function in an SC decoding solution rather than by using recursive calculation of a hyperbolic tangent function directly, that is, multiplication and summation operations replace log, exponential and division operations in the SC method. Compared with the original SC decoding solution, the improved method greatly lowers the calculation complexity while maintaining the property.

The invention provides an on-orbit calibration method. The on-orbit calibration method comprises a preparation step, a posture adjustment reset step, an observation step and a static drift measurementstep; the preparation step specifically comprises: connecting a redundant inertial group, a GPS, a star sensor and an acquisition computer; after an aircraft enters a predetermined orbit, beginning to acquire redundant inertial group data, GPS data and star sensor data; the posture adjustment reset step specifically comprises: the star sensor rotates at a certain angle around an axis; the observation step specifically comprises: performing star observation and GPS speed observation; and, the acquisition computer performs iterative calculation solving by utilizing a standard Kalman filter, sothat a calibration result is obtained; and the calibration result comprises the gyro zero bias, a scale factor, the installation error, the meter adding zero bias and the star inertial installation error; by adoption of the technical scheme in the invention, all observable error terms of the redundant inertial group can be estimated for one time; the calibration value is greater than 90% of the constant error item; and the calibration result is correct.

The invention provides an inertial navigation system random error suppression technology by biaxial rotary modulation. Through selecting parameters such as a damping coefficient and an angular frequency parameter, an external horizontal damping network is designed, a rotation scheme for biaxial rotary modulation is designed, the best scheme is determined through comparing simulation results of different rotation breakoff schemes, the information measured and obtained by an inertial device is inputted to a biaxial rotary modulation system part, the navigation information with constant errors and slowing varying errors removed is obtained, and the navigation information obtained in the third step and external velocity information acquired by a Doppler log are inputted to an external horizontal damping network part, and a navigation result is solved. Biaxial rotary modulation and the external horizontal damping technology are adopted to achieve the damping effects and compensate the errors generated as Schuler adjustment conditions are damaged, the errors generated due to the acceleration and the speed can be compensated, 84.4 min of Schuler periodic oscillation and Foucault oscillation can be suppressed effectively, and the positioning, speed fixing and attitude determination precision of a fiber optic gyro inertial navigation system can be increased by more than 3 times.

The invention discloses a pregnancy robot which comprises a shell, a moving system arranged in the shell and a content service system. The content service system comprises a data module, a clock module, an input-output module, an analysis module, a retrieval module and a communication module, data information with number of days attribute is stored in the data module, the clock module calculates number of days starting from starting time input by a user, the input-output module receives input of the user, outputs data information acquired by retrieving and sends out reminding on the basis of number of days according to timing of the clock module, the analysis module analyzes the input and extracts keywords, the retrieval module receives the keywords acquired by the analysis module to retrieve the data module, and the communication module communicates with a remote server and is used for uploading or downloading the data information. The pregnancy robot can remind the user for corresponding operation according to date and can offer help to the user; a background database can realize a constant error correction function through accumulation of big data, so that data are more accurate and more complete.

The invention relates to an infrasound source orientation method based on a PMCC algorithm. The method is characterized in that an infrasound sensor is calibrated through a number of calibration signals generated by an infrasound calibrator, high frequency points and low frequency points of cut-off frequency points on an infrasound sensor frequency sensitivity curve are obtained through calibration data, further diaphragm performance constant error and phase error of a single infrasound sensor are calculated, speed error and phase error generated by a single sensor and speed error and phase error of a sensor network consisting of a number of infrasound sensors are obtained, finally the speed error and the phase error are used as parameters for calculating weighting distance among detection elements in the PMCC algorithm, and an infrasound source orientation graph is obtained based on the PMCC algorithm. The infrasound source orientation method based on the PMCC algorithm is characterized in that the speed error and phase error of a network are objectively described, orientation faults which are caused because the speed error and phase error are conventionally set according to experience in the PMCC algorithm can be prevented, the calculation is simple, and convenience of project realization is realized.

The invention discloses a comprehensive compensation strategy construction method for a constant error of a vehicle acceleration sensor. The comprehensive compensation strategy construction method comprises the steps: firstly building a dynamic expression related to the lateral and yawing movement of a vehicle, and achieving the observation of the lateral speed of the vehicle; secondly, determining the state quantity and quantity measurement of an estimator according to the acceleration sensor error drift model and the transverse and longitudinal kinematics relationship of the vehicle, and estimating the constant error of the acceleration sensor by using a Kalman filter; and finally, compensating and updating the constant error of the acceleration sensor by correcting the tire positive pressure model and the tire cornering stiffness and feeding back the input information of the vehicle lateral velocity observer. The comprehensive compensation strategy construction method can realize estimation and iterative updating of the constant error of the vehicle acceleration sensor at a relatively high frequency, does not excessively lose the real-time performance while improving the overallprecision of vehicle motion state estimation, and has has the characteristics of simplicity and high efficiency.