Abstract: A navigation system includes at least one inertial sensor configured to detect motion of the system and generate inertial data; at least one aiding device configured to generate aiding device measurement data; at least one processing unit configured to generate an un-smoothed navigation solution inclusive of navigation state variable error resets based on the inertial data and the aiding device measurement data; wherein the at least one processing unit is further configured to sum the state variable error resets into a cumulative sum of the state variable error resets; wherein the at least one processing unit is further configured to high pass filter the cumulative sum of the state variable error resets; and wherein the at least one processing unit is further configured to subtract the high pass filtered cumulative sum of the state variable error resets from the un-smoothed navigation solution to generate a smoothed navigation solution.

Abstract: A system and method is provided of determining geographic positions. In one aspect, a user points the device at first and second positions on the surface of a geographic object. Based on the position of the device, the orientation of the device, and information identifying the geographic position of the surface of the object, a processor determines and displays the distance between the first and second positions.

Abstract: An electronic device 1 receives ephemeris information from a GPS satellite at intermittent timings TE1, TE2, and TE3 and stores the received information in its memory. In addition, the electronic device 1 receives time information at intermittent timings TC1, TC2, TC3, and TC4, and corrects a clocked time based on the received time information. Then, at positioning timing T1, the electronic device 1 captures a transmission signal from the GPS satellite while synchronizing timing with the GPS satellite based on the clocked time, and performs positioning based on the captured transmission signal and the ephemeris information stored in the memory.

Abstract: Embodiments of the invention provide a step detection. An accelerometer measurement in the form of a multi-dimensional acceleration vector is obtained. The magnitude of the accelerometer measurement is filtered using a low pass filter. A threshold for a down-crossing is provided as is a threshold for an up-crossing. A step detection is triggered if the magnitude of the accelerometer measurement is greater than or equal to the threshold for an up-crossing.

Abstract: A metrology device, computer program product and computer-implemented method generating survey data without having the device touch subsea objects being surveyed. The metrology device may be used with an underwater vehicle or diving personnel, and may comprise an inertial navigation system having gyroscopes to detect angular velocity and accelerometers for the detection of linear velocity and transported by an underwater robotic apparatus or diver, the inertial navigation system outputting position and orientation data of the device for storage; an aiding device for collecting image data of the subsea objects, the aiding device being positioned so that the distance and orientation between the optical scanner and the inertial navigation system is known; and a computer for using the position information and image data between a successively visited known point to determine the drift of the metrology device and to use the drift of the metrology device to correct measurements of same.

Abstract: Disclosed herein are methods and systems for fusion of sensor and map data using constraint based optimization. In an embodiment, a computer-implemented method may include obtaining tracking data for a tracked subject, the tracking data including data from a dead reckoning sensor; obtaining constraint data for the tracked subject; and using a convex optimization method based on the tracking data and the constraint data to obtain a navigation solution. The navigation solution may be a path and the method may further include propagating the constraint data by a motion model to produce error bounds that continue to constrain the path over time. The propagation of the constraint data may be limited by other sensor data and/or map structural data.

Abstract: A method for operating a longitudinal driver assist system of an automobile, in particular an ACC system, wherein environmental data of the automobile are evaluated with respect to travel in a longitudinal convoy with at least three automobiles which include the automobile and at least two additional automobiles, which are driving immediately behind one another and each have an active longitudinal driver assist system. A convoy value is formed, and at least one operating parameter of the driver assist system is adapted depending on the convoy value.

Abstract: The present disclosure provides systems and methods that improve the pointing accuracy of a spacecraft using temperature-sensitive gyros (e.g., MEMS gyros) by using a temperature bias model to compensate for temperature biases of the gyros and using attitude data (e.g., star tracker data) to automatically and continuously calibrate the temperature bias model over the life of the spacecraft. When star tracker data is unavailable (e.g., due to sun interference), the most recently updated temperature bias model is used in open-loop to provide improved estimation of the gyro biases and improved attitude estimation.

Abstract: A method of stabilizing an inertial navigation system (INS), includes the steps of: receiving data from an inertial navigation system; and receiving a finite number of carrier phase observables using at least one GPS receiver from a plurality of GPS satellites; calculating a phase wind up correction; correcting at least one of the finite number of carrier phase observables using the phase wind up correction; and calculating a corrected IMU attitude or velocity or position using the corrected at least one of the finite number of carrier phase observables; and performing a step selected from the steps consisting of recording, reporting, or providing the corrected IMU attitude or velocity or position to another process that uses the corrected IMU attitude or velocity or position. A GPS stabilized inertial navigation system apparatus is also described.

Abstract: A navigation apparatus includes: a section that calculates a mobile object's acceleration in the direction of the motion, based on the mobile object's speed calculated from information received from a satellite; a section that calculates lateral acceleration whose direction is perpendicular to the mobile object's motion, based on the mobile object's speed and direction calculated from information received from the satellite; an acceleration sensor that observes motion acceleration of the mobile object and gravity acceleration; a section that calculates an altitude difference of road based on an atmospheric pressure value supplied from a barometric sensor; a section that calculates an inclination angle of the road in the direction of the motion, based on the altitude difference and a travel distance corresponding to the mobile object's speed; and a section that calculates an attachment angle of the acceleration sensor with respect to the mobile object by using a multidimensional function formula.

Abstract: A method for determining the position of a mobile body at a given instant and for monitoring the integrity of the position of said mobile body includes a step of determining a sustained position at the given instant by adding the integral of the hybrid speed between the preceding instant and the given instant to the position of the mobile body at the preceding instant; a step of determining the sustained protection radius associated with the sustained position by adding the integral of the hybrid speed protection radius between the preceding instant and the given instant to the position protection radius of the preceding instant; a step of determining a better position at the given instant, the better position being: when information from the first positioning device is available, the position associated with a better protection radius, the better protection radius being selected by comparing the intermediate protection radius with the sustained protection radius according to a predetermined selection criteri

Abstract: A method of determining a GPS position fix is disclosed together with a corresponding GPS receiver and server for the same. The method comprising the steps of: (i) providing standard GPS ephemeris corresponding to that transmitted by a GPS satellite; (ii) providing supplemental GPS ephemeris including at least one parameter describing the fluctuation over time of at least one satellite orbit parameter of standard GPS ephemeris; (iii) measuring psuedoranges to GPS satellites; and (iv) determining a GPS position fix from both the standard and supplemental GPS ephemeris provided in steps (i) and (ii) respectively and the psuedoranges measured in step (iii).

Abstract: The present invention includes a system and method for selecting a unique geographic feature, including a mobile device that uses position and orientation sensors to determine a user position and a user orientation. The mobile device is adapted for wireless communication with a database that houses or has access to data concerning geographic features, as well as processing and computing means for calculating specific geographic relations discussed in further detail below. The system of the present invention further includes means for selecting among those features that are topologically related to the polygon. These include means for defining the geometry of the polygon, means for filtering those features that should not be within the geometry of the polygon, and means for ranking those features within the polygon. The method of the present invention is operable in conjunction with the system through the system hardware and software.

Abstract: A processing apparatus, optionally integrated into a device having a plurality of sensors including a magnetometer, generates navigational state estimates for the device. The processing apparatus has a magnetometer-assisted mode of operation in which measurements from the magnetometer are used to estimate the navigational state and an alternate mode of operation in which the navigational state of the device is estimated without measurements from the magnetometer. For a respective time period, the processing apparatus operates in the alternate mode of operation. During the respective time period, the processing apparatus collects a plurality of magnetometer measurements and determines whether they meet measurement-consistency requirements. If the measurements meet the measurement-consistency requirements, the processing apparatus transitions to the magnetometer-assisted mode of operation.

Abstract: A method of determining an angular velocity of an aircraft includes measuring the angular velocity using at least one gyro delivering a measured angular velocity signal affected by stochastic noise; measuring the angular acceleration of the aircraft using at least one accelerometer delivering a signal representing the angular acceleration of the aircraft; and using a filtering complementary in a frequency domain to combine a sum of the measured angular velocity signal and the angular acceleration signal so as to obtain a hybrid estimated angular velocity signal with reduced stochastic noise.

Abstract: A moving body position detection system including an unit acquiring dead reckoning navigation information including a moving body direction; a unit identifying a moving body position based on the dead reckoning navigation information on the moving body; a unit predicting a predicted arrived position of the moving body after a predetermined interval from the position of the moving body based on the dead reckoning navigation information on the moving body; a unit calculating a difference direction angle between a direction from the position of the moving body to the predicted position and the direction of the moving body; a unit correcting the difference direction angle if it is equal to or larger than a threshold; and a unit updating the moving body position based on the difference direction angle.

Abstract: A system for processing information relating to a vehicle includes one or more electronic control units which can be connected to one another through a vehicle network. The system includes an electronic control device adapted to interface to and exchange data with the network and a nomadic device adapted to exchange data with the electronic device, wherein the electronic control device includes an automatic configuration module adapted to automatically detect parameters of the network so as to retrieve a network database of the vehicle. The network database includes the information required for properly interpreting the data circulating in the network.

Abstract: The present invention relates to a method for controlling a self-propelled robot device, such as a robot device for mowing grass, and a control system that carries out the aforementioned method. According to the invention, the self-propelled robot device is driven by an inertial navigation system for a set time period or distance and the device is periodically stopped for rectifying the position and advancing course thereof by a satellite detection system: the periodic correction of the inertial navigation system using satellite detections thus prevents course errors from accumulating. The correction based on the satellite detection system can be possibly optimized through a further selection of the obtained values according to a statistical basis. Preferably, the control method according to the invention also provides a procedure for detecting, recording and mapping the operating region wherein the device is operated.

Abstract: The invention is directed to methods and systems for locating and monitoring the status of people and moveable assets, such as first responders, including firefighters and other public service personnel, and their equipment both indoors and out. The invention provides for locating and monitoring the status of people and assets in environments where GPS systems do not operate, or where operation is impaired or otherwise limited. The system and method uses inertial navigation to determine the location, motion and orientation of the personnel or assets and communicates with an external monitoring station to receive requests for location, motion orientation and status information and to transmit the location, motion orientation and status information to the monitoring station.

Abstract: A system and method for locating, tracking, and/or monitoring the status of personnel and/or assets (collectively “trackees”), both indoors and outdoors, is provided. Tracking data obtained from any number of sources utilizing any number of tracking methods may be provided as input to a mapping application. The mapping application generates position estimates for trackees using a suite of mapping tools to make corrections to the tracking data. The mapping application further uses information from building data, when available, to enhance position estimates. Indoor tracking methods including sensor fusion methods, map matching methods, and map building methods may be implemented compute a more accurate tracking estimate for trackees. Outdoor tracking methods may be implemented to enhance outdoor tracking data by combining tracking estimates such as inertial tracks with magnetic and/or compass data if and when available, and with GPS, if and when available.

Abstract: Inertial navigation systems for wheeled vehicles with constrained motion degrees of freedom are described. Various parts of the navigation systems may be implemented in a smart-phone.

Abstract: Systems and methods are provided for compensating nonlinearities in a navigational model. In one embodiment, a system comprises an inertial measurement unit configured to measure inertial motion of a vehicle and an aiding source configured to provide observational measurements of vehicle motion. Further, the system comprises a navigation computer coupled to the inertial measurement unit and the aiding source, wherein the navigation computer is configured to calculate a predicted state and an error covariance data based on the measured inertial motion received from the inertial measurement unit and the observational measurements from the aiding source and calculate variance increments based on attitude uncertainty in the predicted state. Also, the navigation computer is configured to add the variance increments into a process noise covariance matrix for the predicted state and calculate an update for the vehicle motion based on the predicted state, the error covariance data, and the observational measurements.

Abstract: A method is provided for augmenting GPS data using an in-vehicle vision-based module. A vehicle position is determined utilizing position-related data obtained from a position module. A position error is estimated on a periodic basis. A determination is made whether the position error estimate exceeds a first predetermined error threshold. Tracking data is generated for the vehicle over a course of travel utilizing captured images from the in-vehicle vision based module. The tracking data is integrated with the position-related data to estimate the vehicle position in response to the position error estimate exceeding the first predetermined error threshold. A determination is made whether the position error estimate decreases below a second predetermined error threshold. The vehicle position is re-determined using only the position-related data when the position error estimate decreases below the second predetermined error threshold.

Abstract: Device for aiding the navigation and guidance of an aircraft, and system comprising such a device. The device (1) comprises at least three independent channels and it comprises at least one computer (2) which contains means (4) for storing and means (6, 7) for calculating positions and deviations.

Abstract: An attitude determination system provided with North-finding capability, comprises: a) a stage consisting of a rotating platform provided with a high precision positioning controller; b) an Inertial Navigation System (INS) comprising inertial sensors, wherein said inertial sensors comprise gyroscopes and accelerometers, and wherein at least one gyroscope is of a precision suitable to find the direction of true North; and, c) a control unit for controlling input signals and output signals of the stage and the INS and combining the signals in order to provide attitude data of the system.

Abstract: A mobile device may include a geopositioning receiver and an accelerometer, which may be engaged in an alternating manner depending on whether the mobile device is at rest or in motion. If the mobile device is in motion, the geopositioning receiver may remain engaged to provide a real-time location of the mobile device, which may be used to generate various location-triggered notifications and to control location-triggered applications. If the mobile device is at rest, the geopositioning receiver may be disengaged to reduce power usage and instead the accelerometer may be engaged to monitor whether the mobile device is put back in motion. If so, the geopositioning receiver may be reengaged. A sequence of locations where the mobile device came to rest may be stored to construct a location profile, which may allow closely targeted offers and advertisements to be generated based on the daily activity patterns of users.

Abstract: Inertial navigation systems for wheeled vehicles with constrained motion degrees of freedom are described.

Abstract: Apparatus for orientating a user in a space wherein the space comprises a plurality of zones of which only certain zones constitute functional zones wherein each functional zone includes a first type device containing information relating to the position of the zone in the space and wherein the first type device is reactive to the presence of a second type device associated with the user to provide the user with the information to determine the orientation of the user in the space. A method of orientating the user within the space and guiding the user toward one or more features in the space is also disclosed.

Abstract: Devices, methods, and programs provide vehicle navigation. A speculative heading error is acquired that corresponds to the reliability of the vehicle heading, which corresponds to an estimated vehicle position that was calculated using a previous vehicle position as a reference. A best candidate position or the estimated vehicle position is set as the vehicle position depending on whether a heading difference between the vehicle heading and a heading when the estimated point is corrected to the best candidate position falls within the speculative heading error. Therefore, false matching can be further reduced and prompt recovery is possible even if a false match occurs.

Abstract: A system and a method for commanding a spacecraft to perform a three-axis maneuver purely based on “position” (i.e., attitude) measurements. Using an “inertial gimbal concept”, a set of formulae are derived that can map a set of “inertial” motion to the spacecraft body frame based on position information so that the spacecraft can perform/follow according to the desired inertial position maneuvers commands. Also, the system and method disclosed herein employ an intrusion steering law to protect the spacecraft from acquisition failure when a long sensor intrusion occurs.

Abstract: Embodiments of the invention provide a blending filter based on extended Kalman filter (EKF), which optimally integrates the IMU navigation data with all other satellite measurements tightly-coupled integration filter. This blending filter can be easily implemented with minor modification to the position engine of stand-alone GNSS receiver. Provided is a low-complexity tightly-coupled integration filter for sensor-assisted global navigation satellite system (GNSS) receiver. The inertial measurement unit (IMU) contains inertial sensors such as accelerometer, magnetometer, and/or gyroscopes Embodiments also include method for pedestrian dead reckoning (PDR) data conversion for ease of GNSS/PDR integration. The PDR position data is converted to user velocity measured at the time instances where GNSS position/velocity estimates are available.

Abstract: Systems and methods for determining a position of a vehicle are described. The system includes at least one GNSS sensor mounted to the vehicle for receiving GNSS signals of a global positioning system and at least one physical sensor mounted to the vehicle for generating physical data indicative of a physical parameter of at least a part of the vehicle. The system also includes a recursive statistical estimator, such as a Kalman Filter, in communication with the GNSS sensor(s) for seeding the recursive statistical estimator with an output of the GNSS sensor(s) to determine an estimated position of the vehicle. A data fusion module combines the estimated position and velocity of the vehicle with the physical data thus generating combined data, which is used to seed the recursive statistical estimator to determine an updated estimated position of the vehicle.

Abstract: A method and apparatus for estimating a location of a device. For each of a plurality of locations of a device, a set of positional data is determined from signals received from a plurality of satellites. The positional data is filtered and compared with data from a road network database. This comparison may be a function of a distance from at least one point defined by a set of the filtered positional data to a road in the road network database and an angle between a line representing a best fit for plural points defined by corresponding plural sets of the filtered positional data to a line defined by a road in the road network database.

Abstract: A system for navigation and tracking may include an inertial navigation system adapted to generate a replica GNSS signal and a global navigation satellite system. The global navigation satellite system may include a module to digitize a GNSS signal received from a constellation of global navigation satellites. A correlator receives the digitized GNSS signal and the replica GNSS signal. The correlator correlates the digitized GNSS signal to the replica GNSS signal to generate a correlated GNSS signal. A coherent integration module coherently integrates the correlated GNSS signal to generate an integrated signal having a predetermined rate. A filter receives the integrated signal and generates a data signal for navigation and tracking. An output device may present the navigation and tracking information based on the data signal, or the navigation and tracking information may be used to provide guidance for a vehicle or may be used to track a target.

Abstract: The navigation system described here utilizes GPS and Galileo satellite signals combined with Inertial Navigation Systems (INS), where a Coupled Antenna (CAN) provides both GNSS and Inertial Measurement Unit (IMU) data to a Highly Integrated GNSS-Inertial (Hi-Gi) receiver. Such receiver makes use of a high fidelity relation between GNSS unprocessed Correlator Output (COUT) I and Q data and the user trajectory, and inertial sensor data, which in turn are combined within a Kalman Filter (KF). The KF determines the navigation solution that is also used to provide feedback to the receiver demodulation signal processing stage, thus eliminating the need of dedicated structures such as Delayed Locked Loops (DLL) and Phase Locked Loops (PLL), allowing a significant improvement in navigation performance.

Abstract: An inertial navigation system, including at least one personal inertial navigation module (including accelerometers, gyroscopes, and magnetometers) and at least one controller, which: obtains rotation origin data and reference magnetic field data; generates inertial navigation data using a navigation routine; generates azimuth correction data using a separate azimuth correction routine; and generates output data. Common azimuth reference determination methods are also disclosed.

Abstract: The invention generally relates to a system for generating and transmitting a telemetry formatted message containing raw Global Positioning System (GPS) information, processed Inertial Measurement Unit (IMU) information corresponding to the position and attitude of a high speed vehicle in motion. This telemetry formatted message is received on the ground and used to improve Kalman filter operation. In particular, the telemetry formatted message is used as an input to a ground based Kalman filter that is set to track and predict the trajectory of the high speed vehicle. The telemetry formatted message content improves the overall operation of the Kalman filter by preventing Kalman filter resets that occur when a bit error is encountered in the IMU data and improves the time correlation of high data rate IMU information and low data rate GPS information, both necessary for accurate tracking of the high speed vehicle.

Abstract: Method and apparatus of increasing location accuracy of an inertial navigational device is described. The inertial navigation device generates real-time data and transmits the real-time data to a second device so that the second device may obtain a location of the inertial navigational device. The inertial navigational device receives an update message from the second device, wherein the update message is created at the second device based on a comparison of the real-time data generated by the inertial navigational device against a magnetic field database and adjusts the depicted location of the inertial navigational device based on the update message in order to increase the location accuracy of the inertial navigational device.

Abstract: A system vitally determines a position of a train. The system includes a plurality of diverse sensors, such as tachometers and accelerometers, structured to repetitively sense at least change in position and acceleration of the train, a global positioning system sensor, which is diverse from each of the diverse sensors, structured to repetitively sense position of the train, and a track map including a plurality of track segments which may be occupied by the train. A processor cooperates with the diverse sensors, the global positioning system sensor and the track map. The processor includes a routine structured to provide measurement uncertainty for each of the diverse sensors and the global positioning system sensor. The routine cross-checks measurements for the diverse sensors, and cross-checks the global positioning system sensor against the track map. The routine provides the vitally determined position of the train and the uncertainty of the vitally determined position.

Abstract: A system and method for determining a position of a remote object comprising inertial sensors and three axis magnetic sensor, together with a target sighting device aligned with the observation platform to determine a target line of sight and a target range finder to determine a distance to the target along the line of sight. A GPS receiver may be included for determining an observation platform position and orientation, The three axis magnetic sensor provides both magnetic north and vertical attitude information for improved rapid initialization and operation in motion. Magnetic anomaly information is detected by comparing IMU and magnetic navigation information and by other methods. Target identification may be determined by a human operator and/or by computer. The system may be integrated with a weapon system to use weapon system sights. The system may be networked to provide target location and/or location error information to another identical unit or a command information system.

Abstract: 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.

Abstract: A missile has a pair of systems to provide acceleration information during flight. The primary system is a microelectromechanical systems (MEMS) inertial measurement unit (IMU) that provides accurate rate sensor output, such as providing pitch and yaw rates, at low cost, over a wide range of conditions. However MEMS IMUs are susceptible to temporary incorrect responses when subjected to shocks, such as acoustic-range shocks, for instance in the range of 10-20 kHz. The missile includes a secondary system to temporarily provide acceleration data during the periods following shocks, when the MEMS IMU does not provide valid (reliable or usable) rate sensor output, for use in estimating pseudo pitch and yaw rates. The secondary system may be an accelerometer that does not provide navigation-quality acceleration data, but does provide a sufficiently accurate response in order to maintain stable flight during the post-shock period.

Abstract: A method for processing data in an inertial navigation system having a Kalman filter and computer-readable storage medium containing instructions to configure a processor to perform the same. The method produces more accurate estimates of the position, velocity and attitude of the inertial measurement unit. The method is fully automatic and enables zero-velocity updates and fixed-azimuth updates to be performed simultaneously. The method may also include a multi-stage filtering process to filter digital compass data when used in an environment with extraterrestrial magnetic field sources. The method may also include a fixed-lag smoother to improve estimates of the position, velocity and attitude of the inertial measurement unit. The method also may include processes to constrain altitude errors.

Abstract: An apparatus and method for providing an improved heading estimate of a mobile device in a vehicle is presented. First, the mobile device determines if it is mounted in a cradle attached to the vehicle; if so, inertia sensor data may be valid. While in a mounted stated, the mobile device determines whether it has been rotated in the cradle; if so, inertia sensor data may no longer be reliable and a recalibration to determine a new relative orientation between the vehicle and the mobile device is needed. If the mobile device is mounted and not recently rotated, heading data from multiple sensors (e.g., GPS, gyroscope, accelerometer) may be computed and combined to form the improved heading estimate. This improved heading estimate may be used to form an improved velocity estimate. The improved heading estimate may also be used to compute a bias to correct a gyroscope.

Abstract: A cooperative engagement group-position determining system employs a group of at least three cooperative units, for example a group of unmanned aerial vehicles (UAV's), with each unit including a GPS system for determining a GPS-based position, an inter-distance measurement module for measuring a distance of the unit relative to at least one other unit, and a computer having a computer-readable storage medium encoded with a program algorithm for correcting the GPS-based position based on at least one relative distance between two units, providing an improved GPS-based position for the unit and for the group. The system can also include a ground controller, for example, for providing flight control for UAV's.

Abstract: A method of stabilizing an inertial navigation system (INS), includes the steps of: receiving data from an inertial navigation system; and receiving a finite number of carrier phase observables using at least one GPS receiver from a plurality of GPS satellites; calculating a phase wind up correction; correcting at least one of the finite number of carrier phase observables using the phase wind up correction; and calculating a corrected IMU attitude or velocity or position using the corrected at least one of the finite number of carrier phase observables; and performing a step selected from the steps consisting of recording, reporting, or providing the corrected IMU attitude or velocity or position to another process that uses the corrected IMU attitude or velocity or position. A GPS stabilized inertial navigation system apparatus is also described.

Abstract: Methods and apparatus are described for a navigation system. A method includes providing a global positioning system fix having a plurality of tracking parameters; providing a theater positioning system fix; monitoring the plurality of tracking parameters for predetermined conditions; and, when the predetermined conditions are met, sending a notifying signal and switching to the theater positioning system fix as a primary fix. An apparatus includes a system controller; a global positioning system receiver coupled to the system controller; a radio frequency locating receiver coupled to the system controller; and an operator interface coupled to the system controller.

Abstract: A system for retrieving information about a position of an inertial computing device (ICD) for use in an application, which includes a network of local positioning docks (PDs), each capable of docking an ICD by restricting three dimensions of a physical position of the ICD near one of the PDs; a database capable of storing information about the positions of the PDs within the network; a calculator capable of determining, based on a position of a positioning dock (PD), the position of the ICD; and an application programming interface (API) connected to the database and capable of outputting the position of a PD to the ICD.