Abstract: A tilt detecting unit has a tilt sensor and is rotatably supported by an inner frame through a second shaft orthogonal to a first shaft, a first encoder is provided on the first shaft, a second encoder is provided on the second shaft, motors are provided on the respective shafts, an arithmetic processing module drives the respective motors so that the tilt sensor detects the horizontality based on a signal issued by the tilt sensor, calculates a tilt of the outer frame based on the outputs from the first and second encoders when the tilt sensor detects the horizontality, reverses the tilt detecting unit 180° at least once based on the outputs from the respective encoders in a stationary state of the tilt detecting device, and performs the calibration of the tilt sensor based on the detection signals output from the tilt sensor before and after the reversal.

Abstract: A buffer unit for temporarily storing a substrate includes a housing having a space for storing a substrate therein, one or more slots disposed within the housing for placing a substrate thereon, and a holding unit disposed at a bottom portion of the housing, having a flat and non-inclined top surface, and comprising a built-in wireless charging module. A substrate type sensor is stored at the holding unit.

Abstract: A position encoder comprises: a first and second member, with the first member movable relative to the second member; a first sensor arranged at one of the first or second members, and a first track arranged at the other one of the first or second members such that the first sensor moves along the first track when the first member moves relative to the second member, with the first sensor capturing at least one of its position or displacement along the first track; a second sensor arranged at one of the first or second members, and a second track arranged at the other one of the first or second members such that the second sensor moves along the second track when the first member moves relative to the second member, with the second sensor capturing at least one of its position or displacement along the second track.

Abstract: A tracking measurement method, apparatus and device for a pose of a tail end of a manipulator. The method comprises: shooting a first calibration board mounted at the tail end of the manipulator by a monocular measurement camera, acquiring multiple sets of first transformation matrices, and mounting the monocular measurement camera on a pitch axis of a pan-tilt; shooting a second calibration board by a global camera, and acquiring multiple sets of second transformation matrices; when a calibration center of the first calibration board is in a center of a field of view of the monocular measurement camera, calculating a measured pose of the tail end of the manipulator; and when the calibration center of the first calibration board deviates from the center of the field of view of the monocular measurement camera, calculating a direction deviation angle, and adjusting the pitch axis and a horizontal axis of the pan-tilt.

Abstract: The present invention is provided to more reliably keep a work vehicle from coming into contact with an obstacle during automated driving. The work vehicle includes an electronic control system for automated driving that automatically drives the vehicle body. The electronic control system includes an obstacle detection module configured to detect presence or absence of an obstacle, and a contact avoidance control unit configured to perform, upon the obstacle detection module detecting an obstacle, contact avoidance control to keep the vehicle body from coming into contact with the obstacle. The obstacle detection module includes a plurality of obstacle searchers that are distributed on the front end portion and the right and left end portions of the vehicle body such that the front side and the right and left lateral sides of the vehicle body are search-target areas.

Abstract: A camera calibration tool for calibrating one or more cameras of a mobile machine comprising calibration targets and a net. Each of the calibration targets comprises identifiable indicia. The net is adapted to be coupled to the mobile machine. The net has one or more configurations that define predetermined target locations, with location markers, in a predetermined layout. The calibration targets are positioned respectively at the predetermined target locations in the predetermined layout to calibrate the one or more cameras by use of the calibration targets.

Abstract: Provided are systems and methods for path-based navigation of tubular networks. In one aspect, the method includes receiving location data from at least one of a set of location sensors and a set of robot command inputs, the location data being indicative of a location of an instrument configured to be driven through a luminal network. The method also includes determining a first estimate of the location of the instrument at a first time based on the location data, determining a second estimate of the location of the instrument at the first time based on the path, and determining the location of the instrument at the first time based on the first estimate and the second estimate.

Abstract: A method for calibrating a position measurement system includes receiving measurement data from the position measurement system and determining that the measurement data includes periodic distortion data. The position measurement system includes a nonius track and a master track. The method also includes modifying the measurement data by decomposing the periodic distortion data into periodic components and removing the periodic components from the measurement data.

Abstract: A method is described for measuring workpieces, each having structural features that form test features for measurement. The method determines an unstable one and a stable one of the test features, based on expected violation or satisfaction, respectively, of a statistical control rule. The method measures workpieces such that the unstable test feature is measured more frequently than the stable test feature. The method ascertains whether the unstable test feature remains unstable and whether the stable test feature remains stable. The method measures additional workpieces if the unstable test feature remained unstable and the stable test feature remaining stable. The determining is repeated if the unstable test feature is no longer unstable, the stable test feature is no longer stable, or any other measurement feature changes, such as if a new batch of workpieces is to be measured, environmental conditions change, or measurement has proceeded longer than a predefined threshold.

Abstract: One or more computing devices, systems, and/or methods for calibrating barometric sensors and/or determining altitudes of devices are provided. In an example, a device is determined to be outdoors. In response to determining that the device is outdoors, a calibration process associated with a barometric sensor of the device is performed. The calibration process includes performing one or more barometric measurements using the barometric sensor to determine one or more barometric pressure measures, determining one or more locations of the device, wherein the one or more locations are associated with the one or more barometric measurements, and determining a barometric offset based upon the one or more barometric pressure measures and one or more reference values. An adjusted barometric pressure and/or an altitude of the device is determined based upon a first barometric pressure measure and the barometric offset.

Abstract: There is provided a program, an information processor, and an information processing method that make it possible to obtain position information for sites of a body with higher accuracy. The program causes a computer to implement a correction function of referencing a first output obtained by performing a first process on sensor data acquired by two or more motion sensors attached to two or more sites of a body and a second output obtained by performing a second process on the sensor data, and correcting position information for attachment sites to which the motion sensors are attached.

Abstract: A calibrator for a camera includes a controlling circuit, a photographing circuit, a calculating circuit, and an instructing circuit. The controlling circuit is configured to control a movable body to move into a shooting area of the camera. A marker is provided on the movable body for calibration of the camera. The photographing circuit is configured to control the camera to photograph the marker. The calculating circuit is configured to calculate at least one parameter of the camera based on the photographed marker. The instructing circuit is configured to transmit the at least one parameter to the camera to calibrate the camera.

Abstract: Provided are systems and methods for path-based navigation of tubular networks. In one aspect, the method includes receiving location data from at least one of a set of location sensors and a set of robot command inputs, the location data being indicative of a location of an instrument configured to be driven through a luminal network. The method also includes determining a first estimate of the location of the instrument at a first time based on the location data, determining a second estimate of the location of the instrument at the first time based on the path, and determining the location of the instrument at the first time based on the first estimate and the second estimate.

Abstract: A surgical system includes an arm extending from the base and having a distal end configured to be coupled to a tool, a first marker coupled in fixed relation to the base, and a tracking system. The tracking system is configured to collect first data indicative of a position of the first marker and collect second data indicative of a position an anatomical feature of a patient. The surgical system also includes a processor configured to calculate a position of the tool relative to the anatomical feature based on the first data and the second data.

Abstract: An actuator for controlling a flow regulation device. The actuator includes a drive device coupled to the flow regulation device and a motor coupled to the drive device and operable to move the drive device. The actuator further includes a processing circuit configured to receive a first measurement of a characteristic, control the actuator to reposition the flow regulation device in a first direction, receive a second measurement of the characteristic, determine an installation error associated with at least one of the actuator and the flow regulation device based on the first measurement and the second measurement.

Abstract: A machine learning device includes a virtual temperature model calculating unit having an equation including a first coefficient for determining a heat generation amount and a second coefficient for determining a heat dissipation amount. The virtual temperature model calculating unit is configured to calculate virtual temperature data by estimating a temperature of a specific portion of a machine by the equation using heat generation factor data. A thermal displacement model calculating unit is configured to calculate, using the calculated virtual temperature data and actual temperature data acquired from at least one temperature sensor mounted to a portion other than the specific portion, an error between thermal displacement estimated by the equation and actually measured thermal displacement, in which the virtual temperature model calculating unit performs machine learning to search for the first coefficient and the second efficient so that the error is minimized.

Abstract: A medical support control system comprises a medical support having memory and a control system in connection with the memory and for connection with a component for use at the medical support. The medical support control system further includes a detection system configured to detect when the component is connected to the control system, such as the control system microprocessor.

Abstract: Imaging systems projecting augmented information on a physical object that at a minimum include a processor, a memory device operably connected to the processor, a projector operably coupled to the processor, and a distance-measuring device operably connected to the processor. The memory device stores augmented image information, and the processor is configured to project augmented image information onto the physical object. The distance-measuring device is configured to measure the distance to the physical object. The processor uses distance measurement information from the distance measuring device to adjust scaling of the augmented image information. The processor provides the scale adjusted augmented image information to the projector. System can also be used for fluorescence imaging during open surgery, for endoscopic fluorescence imaging and for registration of surgical instruments.

Abstract: Disclosures relate to a sensor system and arrangements having different sized removable spacers. The spacers may be mixed and matched as needed or desired to compensate for misalignment conditions. Further, different spacer combinations and adjustments may be guided by a security management computing device. Variations in configurations of mounting surfaces, such as door and window assemblies, may be accommodated. Alignment of a transmitter or a receiving device, e.g., a magnetic device, with respect to a transmitter or receiving device despite misalignment of the components due to, for example, uneven surfaces of a door or a window, or a respective frame may be achieved.

Abstract: A surveying instrument comprises a distance measuring unit configured to measure a distance to an object to be measured, an optical axis deflector configured to deflect a distance measuring light, a measuring direction image pickup module configured to acquires an observation image and an arithmetic control module, wherein the arithmetic control module is configured to continuously cut out sighting images around a tracking point set in the observation image, to set a first cutout sighting image as a reference sighting image, to calculate a movement amount of the sighting image with respect to the reference sighting image by an image matching of the reference sighting image and the sighting image and to control the optical axis deflector based on a calculation result in such a manner that the tracking point is positioned at a center of the sighting image.

Abstract: A system may include a sensor configured to output a sensor signal indicative of a distance between the sensor and a mechanical member associated with the sensor, a measurement circuit communicatively coupled to the sensor and configured to determine a physical force interaction with the mechanical member based on the sensor signal, and a compensator configured to monitor the sensor signal and to apply a compensation factor to the sensor signal to compensate for changes to properties of the sensor based on at least one of changes in a distance between the sensor and the mechanical member and changes in a temperature associated with the sensor.

Abstract: A method and control system for generating and updating digital maps using a plurality of passages along a road portion by at least one road vehicle is provided. The method comprises obtaining positioning data and sensor data of each passage from the at least one road vehicle. Further, the method comprises forming a sub-map representation of the surrounding environment at each obtained longitudinal position based on the obtained sensor data, and estimating a longitudinal error for each obtained longitudinal position within each segment. Furthermore, the method comprises determining a new plurality of longitudinal positions of each road vehicle for each passage by applying the estimated longitudinal error on each corresponding obtained longitudinal position, and applying the determined new plurality of longitudinal positions on associated sensor data in order to generate a first layer of a map representation of the surrounding environment along the road portion.

Abstract: Techniques for establishing a biomechanical model of a user performing motion are described. A plurality of sensor modules corresponding to a set of designated body parts (e.g., arms or legs) of the user generate sensing signals when the user performs a pose. Sensing data including accelerometers and/or gyroscopes data generated from the sensing signals is analyzed to detect a medio-lateral direction of each of the designated body parts to infer the pose from the captured motion of the user.

Abstract: A method and system that provides navigational related audio or haptic feedback to a user traversing a route by mapping an initial route for a user to traverse, the initial route having paths and intersections; determining a current location of the user; inputting a route characteristic change of the initial route; determining possible paths associated with an intersection for the user to traverse when the current location of the user is within the predetermined distance of the intersection; ranking the determined possible paths based upon the initial route and the inputted route characteristic change; determining the head direction of the user when the current location of the user is within the predetermined distance of an intersection; determining which of the possible paths corresponds to the calculated head direction of the user; and providing an audio/haptic cue to the user based upon the ranking of the determined possible path corresponding to the determined head direction of the user.

Abstract: A surveying instrument include a monopod installed on a reference point and a surveying instrument main body provided on the monopod, wherein the surveying instrument main body includes a measuring direction image pickup module which acquires first image including an object, a distance measuring unit which measures a distance to the object, a measuring direction detecting module which detects a measuring direction, a time detector which generates a reference time signal and an arithmetic control module, the arithmetic control module associates a distance measurement result with the reference time signal, associates a measuring direction with the reference time signal, and associates the first image with the reference time signal, associates an image change, the measuring direction, and a distance measurement result with each other based on the reference time signal, calculates a measuring direction in the distance measurement and determines a position of a measurement part of the object.

Abstract: A MEMS system includes a gyroscope that generates a quadrature signal and an angular velocity signal. The MEMS system further includes an accelerometer that generates a linear acceleration signal. The quadrature signal and the linear acceleration signal are received by a processing circuitry that modifies the linear acceleration signal based on the quadrature signal to determine linear acceleration.

Abstract: Provided is a survey system capable of more highly accurately obtaining a product of a three-dimensional survey. A survey system includes a mobile body, a scanner including an emitting unit, a light receiving unit, a distance measuring unit, a first optical axis deflecting unit disposed on an optical axis of the distance measuring light and configured to deflect a distance measuring light, a second optical axis deflecting unit disposed on a light receiving optical axis of the reflected distance measuring light and configured to deflect a reflected distance measuring light at the same angle in the same direction as those of the first optical axis deflecting unit, and an emitting direction detecting unit to detect deflection angles and directions of the first and the second optical axis deflecting units, a posture detecting device of the scanner, and a position measuring device of the scanner.

Abstract: A process for determining the total pitch deviation of a position sensor fitted with a magnetic disk and a magnetic detector, the magnetic disk comprising pairs of magnetic poles, the process includes recording, over one mechanical turn, an angular signal of the magnetic intensity measured by the magnetic detector as a function of the angle of rotation of the magnetic disk, determining zero-crossing positions based on the angular signal recorded and the number of zero-crossing position determined, determining the pole pair lengths based on the zero-crossing positions, and determining the total pitch deviation based on the pole pair lengths.

Abstract: A vehicle driving assist apparatus comprises at least one surrounding sensor and at least one vehicle element. The surrounding sensor memorizes at least one axis difference adjustment value which adjusts at least one axis difference of a detection axis of the surrounding sensor relative to a predetermined base detection axis and provides the vehicle element with information on the axis difference adjustment value memorized in the surrounding sensor as adjustment value information. The vehicle element memorizes the axis difference adjustment value included in the adjustment value information provided from the surrounding sensor and provides the surrounding sensor with information on the axis difference adjustment value memorized in the vehicle element as the adjustment value information.

Abstract: A surveying instrument include a surveying instrument including a surveying instrument main body, a measuring direction image pickup module for acquiring a first image, a distance measuring unit for measuring a distance to the object, a projecting direction detecting module for detecting a projecting direction of the distance measuring light, a time detector for generating a signal of a reference time, a downward image pickup module for acquiring a second image, an attitude detector for detecting a tilt of the surveying instrument main body and an arithmetic control module, wherein the arithmetic control module is configured to detect a change between the first images or the second images, determine a measuring point of the object with respect to the vertical lower image based on the change between the images and the detection results of the distance measuring unit and the projecting direction detecting module and the reference time.

Abstract: Methods and systems for controlling illumination power of a LIDAR based, three dimensional imaging system based on discrete illumination power tiers are described herein. In one aspect, the illumination intensity of a pulsed beam of illumination light emitted from a LIDAR system is varied in accordance with a set of illumination power tiers based on the difference between a desired and a measured return pulse. In a further aspect, the illumination power tier is selected based on whether an intensity difference exceeds one of a sequence of predetermined, tiered threshold values. In this manner, the intensity of measured return pulses is maintained within a linear range of the analog to digital converter for objects detected over a wide range of distances from the LIDAR system and a wide range of environmental conditions in the optical path between the LIDAR system and the detected object.

Abstract: A positioning system includes: a gyro sensor configured to detect an angular velocity of a moving body; a geomagnetic sensor configured to detect a direction in which the moving body is placed; an acceleration sensor configured to detect an acceleration of the moving body; and a gyro sensor output correction part configured to correct an output of the gyro sensor, wherein the gyro sensor output correction part is configured to convert output components of the gyro sensor into at least one of a rotation matrix and a quaternion based on output components of the geomagnetic sensor and output components of the acceleration sensor, and to calculate a posture of the moving body based on the rotation matrix or the quaternion.

Abstract: The present disclosure provides substantially magnetometer-free systems and methods for motion capture of a subject including 3-D localization and posture tracking by fusing inertial sensors with a localization system and a biomechanical model of the subject. Using the novel Kalman filter based fusion techniques disclosed herein, the localization data aided with the biomechanical model can eliminate the drift in inertial yaw angle estimation.

Abstract: The present disclosure relates to a design for operating an angle sensor. A first sensor signal is output from a first sensor element on the basis of a magnetic field, which is dependent on an angle of rotation of a measurement object, at the location of the first sensor element. A second sensor signal is output from a second sensor element on the basis of the magnetic field that is dependent on the angle of rotation of the measurement object at the location of the second sensor element. During a calibration mode of the angle sensor, in which a rotation of the measurement object is performed, a first offset value of the first sensor signal, a second offset value of the second sensor signal and an amplitude correction value are determined on the basis of signal amplitudes of the first and second sensor signals. The first and second offset values ascertained during the calibration mode and the amplitude correction value are stored for use in an operating mode of the angle sensor.

Abstract: The survey system includes a mobile body equipped with a scanner configured to perform scanning by a distance measuring light, a position measuring device configured to measure a position of the scanner, and a posture detecting device configured to detect a posture of the scanner, the posture detecting device includes an imaging unit configured to periodically acquire image data, a 3-axis angular velocity sensor configured to detect 3-axis posture angles of the scanner, and an arithmetic control unit, and the arithmetic control unit is configured to calculate posture information of the scanner by summing photographing-time 3-axis posture angles (SP0, SP1, SPn) of the scanner acquired in each photographing by image analysis of the image data, and 3-axis posture relative displacement angles of the scanner calculated from detection values of the 3-axis angular velocity sensor.

Abstract: An assembly for measuring a relative position of two movable elements with respect to one another. The assembly includes a ribbon having a magnetic strip, and two magnetic sensors. The ribbon is intended to be fastened to one of the two elements, and the magnetic sensors both to be fastened to the other element. One of the two magnetic sensors serves to precisely measure a relative position of the two elements within a period of orientation alternation of magnetic poles, and the other magnetic sensor serves to define an origin of the measurements in order to obtain an absolute-measurement result for the relative position of the two elements with respect to one another.

Abstract: Systems and methods for electromagnetic (EM) distortion detection and compensation are disclosed. In one aspect, the system includes an instrument, the system configured to: determine a reference position of the distal end of the instrument at a first time based on EM location data, determine that the distal end of the instrument at a second time is static, and determine that the EM location data at the second time is indicative of a position of the distal end of the instrument having changed from the reference position by greater than a threshold distance. The system is further configured to: determine a current offset based on the distance between the position at the second time and the reference position at the first time, and determine a compensated position of the distal end of the instrument based on the EM location data and the current offset.

Abstract: The present disclosure is directed towards computer-based systems and methods for evaluating a user's body motion based on motion data obtained via a series of wireless sensors attached to a user's body. In one embodiment, a computer-implemented method is disclosed herein. A server system receives motion data from one or more input devices. The motion data corresponds to movement of a user. The server system generates a motion profile based on at least the motion data received from the one or more input devices. The server system retrieves a pre-defined target motion profile from a database structure. The server system objectively evaluating the extracted motion profile by comparing one or more parameters of the generated motion profile with one or more parameters of the retrieved pre-defined target motion profile.

Abstract: Examples include systems and methods for decomposition of error components between angular, forward, and sideways errors in estimated positions of a computing device. One method includes determining an estimation of a current position of the computing device based on a previous position of the computing device, an estimated speed over an elapsed time, and a direction of travel of the computing device, determining a forward, sideways, and orientation change error component of the estimation of the current position of the computing device, determining a weight to apply to the forward, sideways, and orientation change error components based on average observed movement of the computing device, and using the weighted forward, sideways, and orientation change error components as constraints for determination of an updated estimation of the current position of the computing device.

Abstract: Methods and apparatus consistent with the present disclosure may receive different sets of image or sensor data that may be compared for inconsistencies. Each of these sets of received data may include images of a roadway or intersection that are processed to identify objects and object locations at or near the roadway/intersection. In certain instances data received from a camera at a traffic control system may be compared with data received from a computer at a vehicle. Alternatively or additionally, different sets of data acquired by a same or by different cameras may be compared for discrepancies. When one or more discrepancies are identified in different sets of received data, corrective actions may be initiated. In certain instances, such corrective actions may include recalibrating an image acquisition system or may include sending message to a vehicle computer that identifies the discrepancy.

Abstract: A cell reselection method applied to a base station, includes: configuring a measurement parameter adjustment rule to be used by an unmanned aerial vehicle (UAV) in cell reselection, the measurement parameter adjustment rule including at least one UAV altitude level and each UAV altitude level corresponding to at least one altitude adjustment parameter; and sending the measurement parameter adjustment rule to the UAV.

Abstract: An apparatus for sensing a rotating body includes a unit to be detected, including a first pattern portion having at least one first pattern and a second pattern portion having at least one second pattern, and configured to rotate around a rotating shaft, a sensor module comprising a first sensor disposed opposite to the first pattern portion and a second sensor disposed opposite to the second pattern portion, and a rotation information calculator configured to calculate a difference value by differentiating output signals of the first sensor and the second sensor, and to compare comparison values, determined according to a target sensing angle and a size of the first pattern and the second pattern, with the difference value.

Abstract: In one aspect, a magnetic field angle sensor includes a bridge structure that include a sine bridge configured to generate a sinusoidal signal indicative of a magnetic field along a first axis and a cosine bridge configured to generate a cosinusoidal signal indicative of the magnetic field along a second axis that is orthogonal with respect to the first axis. One of the sine bridge or the cosine bridge includes a first set of at least two magnetoresistance elements, a second set of at least one magnetoresistance element, a third set of at least one magnetoresistance element and a fourth set of at least one magnetoresistance element. An average reference direction of the first set of at least two magnetoresistance elements is equal to an average reference direction of the third set of at least one magnetoresistance element.

Abstract: A method for determining the position of a construction platform for additive manufacturing of a component, includes marking a construction platform for additive manufacturing, providing a marking region of the construction platform with reference features, wherein the reference features are arranged and designed in such a way that a position of the reference features relative to a reference point are captured using an optical scanning method, and optically scanning the construction platform in the marking region and capturing the relative position with the aid of the reference features and the reference point.

Abstract: A method for creating a digital map for an automated vehicle, including identifying a first vehicle by a second vehicle or the second vehicle by the first vehicle, the first vehicle and/or the second vehicle being identified as data-detecting members of a creation process of the digital map; ascertaining a distance of the first vehicle from the second vehicle and/or a distance of the second vehicle from the first vehicle; and transmitting defined data of the vehicles and the distance between the vehicles to a creation unit for creating the digital map.

Abstract: Systems and techniques for the collection and display of athletic information. Athletic data relating to a single person or group of people is collected at a central location, and subsequently displayed at a desired remote location so that the person or people can review and critique their performance. In addition, athletic data for multiple persons can be collected at a central location, and subsequently displayed to a user at a desired remote location, so that the user can compare his or her athletic activities to others.

Abstract: Using a pressure sensor of a mobile device to improve the reliability of determined contexts. Particular embodiments described herein include machines that determine a context of a mobile device, and determine if the determined context is accurate using one or more measurements of pressure from a pressure sensor of the mobile device.

Abstract: Head-mounted augmented reality (AR) devices can track pose of a wearer's head or pose of a hand-held user input device to enable wearer interaction in a three-dimensional AR environment. A pose sensor (e.g., an inertial measurement unit) in the user input device can provide data on pose (e.g., position or orientation) of the user input device. An electromagnetic (EM) tracking system can also provide pose data. For example, the handheld user input device can include an EM emitter that generates an EM field, and the head-mounted AR device can include an EM sensor that senses the EM field. The AR device can combine the output of the pose sensor and the EM tracking system to reduce drift in the estimated pose of the user input device or to transform the pose into a world coordinate system used by the AR device.

Abstract: A method for automatic calibration of a camshaft sensor for a motor vehicle. The sensor includes a processing module configured to generate, from a raw signal indicative of the variations in a magnetic field which are caused by the rotation of a toothed target and measured by a cell, an output signal indicative of the moments at which the teeth pass past the cell. The calibration method makes it possible, for each tooth, to determine a switching threshold not only as a function of a local minimum and of a local maximum for the tooth during the preceding revolution of the target, but also as a function of a corrective value calculated from a local maximum and/or a local minimum of the raw signal during the passage of a preceding tooth past the cell during a new revolution.

Abstract: A computer-implemented method includes acquiring a plurality of received signal strength indicators obtained by a target wireless terminal which observes a plurality of wireless signals transmitted from a plurality of transmitters, selecting a set of received signal strength indicators which is a portion of the plurality of received signal strength indicators, acquiring a set of reference received signal strength indicators corresponding to the set of received signal strength indicators, from a database of a plurality of reference received signal strength indicators that serve as a reference for the plurality of received signal strength indicators, and estimating a received signal strength indicator offset of the target wireless terminal, based on the set of received signal strength indicators and the set of reference received signal strength indicators.