The passive combined indoor positioning system and method based on an intelligent terminal sensor, and is applied to the technical field of real-time positioning, can include a data collection module, a dead reckoning module, a geomagnetic matching determining module, a single-point matching module, a sequence matching module, a single-point positioning module, a sequence positioning module, and an error correction module. The system collects sensor data of a current location by using an intelligent terminal, and performs dead reckoning and geomagnetic matching based on the sensor data of the current location, so as to obtain a fusion positioning result of the current location through particle filter.

This disclosure relates to an underground mining vehicle comprising a three-axis MEMS gyroscope rotatable about a rotation axis and a gyroscope interface that calculates a first rotation rate bias with respect to a first axis different to the rotation axis, a second rotation rate bias with respect to a second axis different to the first axis and different to the rotation axis, a rotation rate about the rotation axis based on the Earth rotation rate vector by correcting the rotational measurement data using the first rotation rate bias and the second rotation rate bias and a third rotation rate bias with respect to the rotation axis based on the calculated rotation rate about the rotation axis. A navigation unit receives the first rotation rate bias, the second rotation rate bias and the third rotation rate bias and calculates a pose of the vehicle.

An attitude measurement method, which relates to the technical field of measurement while drilling in directional drilling, which can improve the observability of inertial instrument errors, suppress the repeatability errors of gyroscopes and improve the attitude measurement accuracy. The method adopts the method of fine alignment at multiple positions to carry out initial alignment; the method includes the steps of: S1, taking current attitude data and velocity data of the strapdown inertial navigation system as first initial values, and performing fine alignment at a first position; S2, changing the position of a strapdown inertial navigation system to an nth position, and performing attitude update and velocity update according to the last fine alignment result in the position changing process; and S3, taking the results of attitude update and velocity update as the nth initial values, performing the nth fine alignment at the nth position to complete the initial alignment of the strapdown inertial navigation system, thereby realizing attitude measurement. The solution of the present invention is suitable for measuring the horizontal attitude and azimuth of the whole inclined section of a horizontal well, especially the application of directional drilling gyro measurement while drilling in the attitude measurement of large inclined wells and horizontal wells.

Model based inertial navigation for a spinning projectile is provided. In one embodiment, a navigation system comprises: a strapdown navigation processor; a propagator-estimator filter, the processor inputs inertial sensor data and navigation corrections from the filter to generate a navigation solution comprising projectile velocity and attitude estimates; an upfinding navigation aid that generates an angular attitude measurement indicative of a roll angle; and a physics model performing calculations utilizing dynamics equations for a rigid body, the model inputs 1) projectile state estimates from the navigation solution and 2) platform inputs indicative of forces acting on a projectile platform, and outputs a set of three orthogonal predicted translational acceleration measurements based on the inputs; the filter comprises a measurement equation associated with the physics model and the upfinding navigation aid and calculates the navigation corrections as a function of the navigation solution, the predicted translational acceleration measurements, and attitude measurement.

A navigation apparatus determines an estimated position of an object. Navigation information that includes a sequence of quantized measurements is received. Each quantized measurement has a corresponding quantization error that is negatively correlated with the quantization error of a prior quantized measurement. The apparatus iteratively performs a navigation update operation that includes determining a state and a covariance matrix of the object for a current iteration based on a state and covariance matrix in a prior iteration. The state includes an end quantization error and a start quantization error. The covariance matrix includes end and start covariance values corresponding to the end and start quantization errors, respectively. Determining the state and the covariance matrix for the current iteration includes replacing the start quantization error with the end quantization error determined in a prior iteration, and updating the state and the covariance matrix via a Kalman filter update operation.

Anchor points associated with point of sale information may be ordered by segmenting a trajectory derived from sensor data defined by adjacent turns to generate candidate links for each segment from which possible paths for the trajectory are derived. Each derived possible path may be scored with a multi-objective function using a global optimization algorithm to select a solution path from the derived possible paths that may be used to order a plurality of anchor points.

A method and an electronic device for detecting pedestrian stride length and walking path. A peak value of longitudinal acceleration data is detected. The longitudinal acceleration data between two adjacent peaks are integrated twice. A longitudinal displacement amplitude value is obtained based on the integration result. The stride length data is obtained based on the longitudinal displacement amplitude value, user's foot length and user's leg length. The method and the electronic device for detecting pedestrian stride length and walking path provided improves the positioning accuracy of the pedestrian and reduce the implementation cost.

A method, apparatus and computer program product are configured to mitigate error in an inertial navigation system (INS) that relies upon a reference system to determine or update filter parameters. In a method, a determination is made of (i) deviation or divergence of a filter of the INS and/or (ii) invalidity of observation(s) by the reference system. The method also identifies the filter parameters from a history buffer associated with a prior point in time at which performance of the filter is stable. The filter parameters were updated at least once based upon observation(s) by the reference system after the prior point in time. The method forward processes sensor samples of the INS obtained subsequent to the prior point in time using the filter parameters from the history buffer at which performance of the filter was stable to mitigate the error.

A camera-based localization system is provided. The camera-based localization system may assist an unmanned vehicle to continue its operation in a GPS-denied environment with minimal increase in vehicular cost and payload. In one aspect, a method, a computer-readable medium, and an apparatus for localization via visual inertial odometry are provided. The apparatus may construct an optical flow based on feature points across a first video frame and a second video frame captured by a camera of the apparatus. The apparatus may refine the angular velocity and the linear velocity corresponding to the second video frame via solving a quadratic optimization problem constructed based on the optical flow, the initial values of the angular velocity and the linear velocity corresponding to the second video frame. The apparatus may estimate the pose of the apparatus based on the refined angular velocity and the refined linear velocity.

A system (10) for pedestrian use includes an accelerometer (110) having multiple electronic sensors; an electronic circuit (100) operable to generate a signal stream representing magnitude of overall acceleration sensed by the accelerometer (110), and to electronically correlate a sliding window (520) of the signal stream with itself to produce peaks at least some of which represent walking steps, and further operable to electronically execute a periodicity check (540) to compare different step periods for similarity, and if sufficiently similar then to update (560) a portion of the circuit substantially representing a walking-step count; and an electronic display (190) responsive to the electronic circuit (100) to display information at least in part based on the step count. Other systems, electronic circuits and processes are disclosed.