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Showing papers on "Inertial measurement unit published in 2001"


Journal ArticleDOI
01 Oct 2001
TL;DR: The algorithm exploits nonholonomic constraints that govern the motion of a vehicle on a surface to obtain velocity observation measurements which aid in the estimation of the alignment of the IMU as well as the forward velocity of the vehicle.
Abstract: This paper presents a new method for improving the accuracy of inertial measurement units (IMUs) mounted on land vehicles. The algorithm exploits nonholonomic constraints that govern the motion of a vehicle on a surface to obtain velocity observation measurements which aid in the estimation of the alignment of the IMU as well as the forward velocity of the vehicle. It is shown that this can be achieved without any external sensing provided that certain observability conditions are met. A theoretical analysis is provided together with a comparison of experimental results between a nonlinear implementation of the algorithm and an IMU/GPS navigation system. This comparison demonstrates the effectiveness of the algorithm. The real time implementation is also addressed through a multiple observation inertial aiding algorithm based on the information filter. The results show that the use of these constraints and vehicle speed guarantees the observability of the velocity and the attitude of the inertial unit, and hence bounds the errors associated with these states. The strategies proposed provides a tighter navigation loop which can sustain outages of GPS for a greater amount of time as compared to when the inertial unit is used with standard integration algorithms.

470 citations


Patent
20 Nov 2001
TL;DR: An improved positioning and data integrating process and system can substantially solve the problems encountered in system integration for personal hand-held applications, air, land, and water vehicles, wherein an integrated global positioning system/inertial measurement unit, enhanced with optional other devices to derive user position, velocity, attitude, and body acceleration and rotation information, and distributes these data to other onboard systems, for example, in case of aircraft application, flight management system, flight control system, automatic dependent surveillance, cockpit display, enhanced ground proximity warning system, weather radar, and satellite communication system RE
Abstract: An improved positioning and data integrating process and system can substantially solve the problems encountered in system integration for personal hand-held applications, air, land, and water vehicles, wherein an integrated global positioning system/inertial measurement unit, enhanced with optional other devices to derive user position, velocity, attitude, and body acceleration and rotation information, and distributes these data to other onboard systems, for example, in case of aircraft application, flight management system, flight control system, automatic dependent surveillance, cockpit display, enhanced ground proximity warning system, weather radar, and satellite communication system.

161 citations


Journal ArticleDOI
TL;DR: In this article, an extended Kalman filter has been developed, which fuses together inertial and Doppler data, as well as the differential Global Positioning System positional fixes whenever they are available.
Abstract: This paper presents the design and development of an enhanced inertial navigation system that is to be integrated into the Morpheus autonomous underwater vehicle at Florida Atlantic University. The inertial measurement unit is based on the off-the-shelf Honeywell HG1700-AG25 3-axis ring-laser gyros and three-axis accelerometers and is aided with ground speed measurements obtained using an RDI Doppler-velocity-log sonar. An extended Kalman filter has been developed, which fuses together asynchronously the inertial and Doppler data, as well as the differential Global Positioning System positional fixes whenever they are available. A complementary filter was implemented to provide a much smoother and stable attitude estimate. Thus far, preliminary study has been made on characterizing the inertial navigation system-based navigation system performance, and the corresponding results and analyzes are provided.

102 citations


Book ChapterDOI
18 Apr 2001
TL;DR: An inertial gesture recognition framework that allows an application designer to combine recognized gestures both concurrently and consecutively to create specific composite gestures can then be set to trigger output routines.
Abstract: We describe an inertial gesture recognition framework composed of three parts The first is a compact, wireless six-axis inertial measurement unit to fully capture three-dimensional motion The second, a gesture recognition algorithm, analyzes the data and categorizes it on an axis-by-axis basis as simple motions (straight line, twist, etc) with magnitude and duration The third allows an application designer to combine recognized gestures both concurrently and consecutively to create specific composite gestures can then be set to trigger output routines This framework was created to enable application designers to use inertial sensors with a minimum of knowledge and effort Sample implementations and future directions are discussed

95 citations


Patent
22 Jan 2001
TL;DR: In this article, a filtering mechanization method is provided for integrating a Global positioning System receiver with an Inertial Measurement Unit to produce highly accurate and highly reliable mixed GPS/IMU position, velocity, and attitude information of a carrier.
Abstract: A filtering mechanization method is provided for integrating a Global positioning System receiver with an Inertial Measurement Unit to produce highly accurate and highly reliable mixed GPS/IMU position, velocity, and attitude information of a carrier. The GPS filtered position and velocity data are first individually used as measurements of the two local filters to produce estimates of two sets of the local state vector. Then, the estimates of the two sets of local state vectors are mixed by a master filter device to produce global optimal estimates of master state vector including INS (Inertial Navigation System) navigation parameter errors, inertial sensor errors, and GPS correlated position and velocity errors. The estimates of the two sets of local state vector and master state vector are analyzed by a GPS failure detection/isolation logic module to prevent the mixed GPS/IMU position, velocity, and attitude information from becoming contaminated by undetected GPS failures.

91 citations


Proceedings ArticleDOI
25 Aug 2001
TL;DR: In this article, the feasibility of designing a gyroscope-free inertial navigation system (INS) that uses only accelerometers to compute the linear and angular motions of a rigid body relative to a fixed inertial frame is examined.
Abstract: We examine the feasibility of designing a gyroscope-free inertial navigation system (INS) that uses only accelerometers to compute the linear and angular motions of a rigid body. The accelerometer output equation is derived to relate the linear and angular motions of a rigid body relative to a fixed inertial frame. A sufficient condition is given to determine if a configuration of accelerometers is feasible. If the condition is satisfied, the angular and linear motions can be computed separately using two decoupled equations of an input-output (I/O) dynamical system; a state equation for angular velocity and an output equation for linear acceleration. This simple computation scheme is derived from the corresponding dynamical system equations for a special cube configuration for which the angular acceleration is expressed as a linear combination of the accelerometer outputs.

91 citations


Patent
20 Jul 2001
TL;DR: In this paper, an integrated Global Positioning System (GPS)/Inertial Measurement Unit (IMU) method and MicroSystem is disclosed, wherein data from an IMU, a MEMS IMU preferred, a GPS chipset, and an earth magnetic field detector are mixed in a mixed GPS/IMU/Magnetic Data microprocessor to achieve a low cost, micro size, and low power consumption mixed GPS, IMU/magnetic position, velocity, and attitude solution.
Abstract: An integrated Global Positioning System (GPS)/Inertial Measurement Unit (IMU) method and MicroSystem is disclosed, wherein data from an IMU, a MEMS IMU preferred, a GPS chipset, and an earth magnetic field detector are mixed in a mixed GPS/IMU/Magnetic Data microprocessor to achieve a low cost, micro size, and low power consumption mixed GPS/IMU/magnetic position, velocity, and attitude solution. Furthermore, to deal with sensitivity of the MEMS inertial sensors to environment temperature, a temperature based scheduler, error estimator, and a current acting error estimator are co-operated to minimize the mismatching between the filter system modules and the actual ones due to change of environment temperature, so that the system of the present invention can provide high performance and stable navigation solution over a wide range of environment temperature.

89 citations


14 Sep 2001
TL;DR: A new method to estimate the step lengths and the travelled distance using low cost MEMS inertial measurement unit is presented and INS operation in pedestrian navigation can be extended to several minutes without external aiding which is a critical issue for handheld devices.
Abstract: A typical problem with MEMS-IMU is that the orientation information of the inertial navigator degrades rapidly with time causing large error in position estimate. Pedestrian navigation provides ways to restrict navigation solution so that the error in position estimate grows at a lower rate. The object of this work is to create a pedestrian navigator using low cost MEMS inertial sensors. This type of system can extend the operation period of the GPS integrated navigation system in the unaided mode. This paper presents a new method to estimate the step lengths and the travelled distance using low cost MEMS inertial measurement unit. The sensor assembly consists of MEMS gyroscopes and accelerometers capable of 1 mrad/s and 0.7 mg rms noise levels, respectively, and also of magnetic compass and barometric altimeter. The pedestrian navigator has been realised and algorithms tested using MATLAB with real sensor data. The system implements footfall and motion state recognition from inertial measurements. IMU signals are fused with magnetic compass and barometer signals by applying Kalman filter. Step length estimations are made using acceleration measurements from a single handheld IMU. There is no need for a priori knowledge of the step length and the IMU doesn’t have to be fixed in any particular orientation. By applying this method INS operation in pedestrian navigation can be extended to several minutes without external aiding which is a critical issue for handheld devices. The longer the unaided operations of the INS the better the power consumption can be achieved. The pedestrian navigator shows improvement on navigation accuracy and power consumption of the integrated navigation system in an urban environment.

87 citations


Patent
23 Mar 2001
TL;DR: In this article, a method and apparatus for adjusting the phase and frequency of a received GPS signal in an inertial-GPS navigation system by inputting a delta-phase at delta-time intervals into the received satellite signal is presented.
Abstract: The invention is a method and apparatus for adjusting the phase and frequency of a received GPS signal in an inertial-GPS navigation system by inputting a delta-phase at delta-time intervals into the received satellite signal. The method comprises the steps of determining two delta-phase components: (a) a Kalman delta-phase component derived from a plurality of candidate Kalman delta-phase components obtained by performing a first set of more than one Kalman filter processes and (b) an IMU delta-phase component derived from the IMU outputs and a direction-cosine matrix that translates the body coordinates of the IMU into the navigation coordinates of the inertial-GPS navigation system.

84 citations


Patent
20 Jul 2001
Abstract: A micro integrated Global Positioning System (GPS)/Inertial Measurement Unit (IMU) System, which is adapted to apply to output signals proportional to rotation and translational motion of a carrier and GPS measurements of the carrier, respectively from angular rate sensors, acceleration sensors, and GPS chipset, is employed with MEMS angular rate and acceleration sensors and GPS chipset. Compared with a conventional IMU/GPS system, the system of the present invention uses an integrated processing scheme by means of digital closed loop control of the dither driver signals for MEMS angular rate sensors, a feedforward open-loop signal processing scheme of the IMU, digital temperature control and compensation, the earth's magnetic field-based heading damping, robust error estimator, and compact sensor and circuit architecture and dramatically shrinks the size of mechanical and electronic hardware and power consumption, meanwhile, obtains highly accurate motion measurements.

81 citations


Patent
22 Oct 2001
TL;DR: In this article, a micro inertial measurement unit was adapted to apply to output signals proportional to rotation and translational motion of a carrier, respectively from angular rate sensors and acceleration sensors, and the processing method utilizes a feed-forward open-loop signal processing scheme to obtain highly accurate motion measurements.
Abstract: A micro inertial measurement unit, which is adapted to apply to output signals proportional to rotation and translational motion of a carrier, respectively from angular rate sensors and acceleration sensors, is employed with MEMS rate and acceleration sensors. Compared with a conventional IMU, the processing method utilizes a feedforward open-loop signal processing scheme to obtain highly accurate motion measurements by means of signal digitizing, temperature control and compensation, sensor error and misalignment calibrations, attitude updating, and damping control loops, and dramatically shrinks the size of mechanical and electronic hardware and power consumption, meanwhile, obtains highly accurate motion measurements.

Patent
01 Jun 2001
TL;DR: In this paper, a system for determining the heading and/or attitude of a body receives radio waves from a plurality of position-fixing satellites using at least three antennas fixedly mounted at different positions of the body.
Abstract: A system for determining the heading and/or attitude of a body receives radio waves from a plurality of position-fixing satellites using at least three antennas fixedly mounted at different positions of the body. To reliably obtain integer ambiguity solutions of carrier phases of the radio waves in a shorter time, the system directly determines integer ambiguities from attitude angle data obtained by an IMU attitude processing section when the integer ambiguities are to be redetermined in the event of an interruption of the received radio waves or a change in the combination of satellites to be used. This system provides a user with highly accurate uninterrupted heading and/or attitude angle information.

01 Jan 2001
TL;DR: This master thesis report presents the developement of an INS/GPS navigation loop written in ANSI C++ using a standard matrix library and the resulting navigation filter estimates the attitude within two degrees with 95% confidence and the position within two meter using 95%confidence.
Abstract: This master thesis report presents the developement of an INS/GPS navigation loop written in ANSI C++ using a standard matrix library. The filter have been tested on an Unmanned Aerial Vehicle (UAV) called Brumby. Here data have been logged from the Inertial Measurement Unit (IMU) and the Global Positioning System (GPS) receiver. This data have then been postprocessed and run through the navigation filter for estimation of position, attitude and velocity of the vehicle during the flights. The error feedback to the Inertial Navigation System (INS) is done with a complement filter implemented using a kalman filter written in information form.The resulting navigation filter estimates the attitude within two degrees with 95% confidence and the position within two meter using 95% confidence.

01 Jan 2001
TL;DR: The calibration of the different models used for pedestrian navigation using GPS positions without differential corrections to calibrate systematic errors present in inertial sensors is presented.
Abstract: This paper present the calibration of the different models used for pedestrian navigation. Information on travelled distance and azimuth sensed by inertial sensors is merged with GPS observation through Kalman filtering. All models use GPS positions without differential corrections to calibrate systematic errors present in inertial sensors.

Proceedings ArticleDOI
06 Aug 2001
TL;DR: In this article, the authors present a closed-form solution of linear Clohessy-Wiltshire equations for autonomous guidance of spacecraft to approach, to fly around, and to depart from a target vehicle in a circular orbit.
Abstract: This paper presents algorithms for autonomous guidance of spacecraft to approach, to fly around, and to depart from a target vehicle in a circular orbit. The algorithms are based on the closed-form solution of linear Clohessy-Wiltshire equations. The approach and departure algorithms are adaptations of the glideslope guidance used in the past for rendezvous and proximity operation of Space Shuttle with other vehicles with astronauts in the guidance loop. The multi-pulse glideslope algorithms in the paper are general, capable of effecting a translation motion of spacecraft in any direction in space autonomously, decelerating if approaching the target or a nearby location, and accelerating if receding away from it. The flyaround algorithm enables the spacecraft to circumnavigate a target spacecraft in any plane, the orbit plane and the local horizontal plane being two special cases thereof. The circumnavigation is performed in a specified period using a specified number of pulses; the larger the number of pulses, the smaller the deviation of flyaround from the specified radius of circumnavigation. The implementation of these algorithms requires estimates of position and velocity of the spacecraft relative to the target. This relative navigation is performed with an extended Kalman filter using range and angle measurements of target relative to the spacecraft focal plane and IMU and accelerometer measurements. The corresponding measurement models and process noise matrix are provided. Several scenarios are simulated to illustrate the guidance algorithms and relative navigation. rendezvous. This topic is treated in many textbooks 12-17? as

Proceedings ArticleDOI
01 Jan 2001
TL;DR: In this paper, the authors developed a field robot for an agricultural operating environment consisting of an RTK-GPS, a fiber optic gyroscope (FOG), and an inertial measurement unit (IMU).
Abstract: This study developed a field robot for an agricultural operating environment. The navigation sensor consisted of an RTK-GPS, a fiber optic gyroscope (FOG), and an inertial measurement unit (IMU). A sensor fusion algorithm was used to identify FOG bias and compensate for location error in real-time, thus providing sufficient navigation information to support accurate robot guidance in the field. The guidance system could guide the agricultural robot automatically to follow either straight or curve paths including crop rows at a speed of 2.5 m/s. This RMS position error of the desired pathway in the field was less than 3 cm. The results indicated that the navigation system was capable of guiding an agricultural robot accurately and robustly under normal agricultural operations.

Journal ArticleDOI
TL;DR: In this article, the design of a micromachined disc is described, where the disc is encaged by electrodes at its top, bottom and periphery, and electric forces are used to levitate the disc at the center position.
Abstract: In this paper the design of a micromachined disc is described The disc is encaged by electrodes at its top, bottom and periphery Electrostatic forces are used to levitate the disc at the centre position Such a device has applications for inertial sensors such as accelerometers and gyroscopes It has considerable advantages over existing approaches, including increased independence of fabrication tolerances, online characteristics adjustment and in particular, compared to vibratory rate gyroscopes, inherently rules out quadrature error and the need for modal frequency tuning A system level model of such a device is presented and the fabrication process relying on thick-film resist and electroplating is described

Journal ArticleDOI
TL;DR: The mathematical framework that is required for integrated vision/inertial navigation system design is developed and a design example for an air vehicle landing on an aircraft carrier is detailed.
Abstract: The problem of navigation system design for autonomous aircraft landing is addressed. New nonlinear filter structures are introduced to estimate the position and velocity of an aircraft with respect to a possibly moving landing site, such as a naval vessel, based on measurements provided by airborne vision and inertial sensors. By exploring the geometry of the navigation problem, the navigation filter dynamics are cast in the framework of linear parametrically varying systems (LPVs). Using this set-up, filter performance and stability are studied in an H/sub /spl infin// setting by resorting to the theory of linear matrix inequalities (LMIs). The design of nonlinear, regionally stable filters to meet adequate H/sub /spl infin// performance measures is thus converted into that of determining the feasibility of a related set of LMIs and finding a solution to them, if it exists. This is done by using-widely available numerical tools that borrow from convex optimization techniques. The mathematical framework that is required for integrated vision/inertial navigation system design is developed and a design example for an air vehicle landing on an aircraft carrier is detailed.

Proceedings ArticleDOI
20 Aug 2001
TL;DR: The problem considered is that of pose estimation for a rapidly moving camera, and it is shown that given delayed low bandwidth visual observations of line correspondences and high bandwidth rate gyro measurements the authors are able to estimate the camera orientation with respect to an inertial frame.
Abstract: We present a method for fusing data from a vision system and an inertial measurement unit. The problem considered is that of pose estimation for a rapidly moving camera, and we show that given delayed low bandwidth visual observations of line correspondences and high bandwidth rate gyro measurements we are able to estimate the camera orientation with respect to an inertial frame. This can be done without knowing or estimating the camera position. The estimates are of high bandwidth and this is consistent with real-time constraints due to the complementary characteristics of the two sensors which are fused in a multi-rate way. The algorithm has interesting mathematical properties as it does not use any local parameterization of the orientation such as Euler angles. Instead, the state estimates evolve on the group of rotation matrices.

Proceedings ArticleDOI
04 Dec 2001
TL;DR: In this article, the authors present tools for stability and performance analysis of linear parametrically varying systems with brief instabilities, where performance is evaluated in terms of L/sub 2/ induced norms.
Abstract: Concerns linear parametrically varying systems (LPVs) with brief instabilities. LPVs provide a framework for the study of nonlinear systems, by analyzing related linear time-invariant systems parameterized by a parameter p that lives in a compact set. This paper presents tools for stability and performance analysis of LPVs with brief instabilities, where performance is evaluated in terms of L/sub 2/ induced norms. The main results show that stability and performance can be assessed by examining the feasibility of parameterized sets of linear matrix inequalities (LMI). An application to the problem of designing a nonlinear vision/inertial navigation filter for an aircraft approaching an aircraft carrier is included. The results developed provide the proper framework to deal with out-of-frame events that arise when the vision system loses its target temporarily. Field tests with a prototype unmanned air vehicle illustrate the performance of the filter and illustrate the scope of applications of the new theory developed.

Patent
12 Jun 2001
TL;DR: In this article, the attitude of a spinning vehicle is determined by observing at least one of the apparent amplitude modulation and the apparent phase modulation of a navigation signal received from a navigation source, which is computed and used to determine attitude relative to the navigation source.
Abstract: Attitude of a spinning vehicle is determined by observing at least one of the apparent amplitude modulation and the apparent phase modulation of a navigation signal received from a navigation source. Vectors describing the direction from the vehicle to the navigation source are computed and used to determine attitude relative to the navigation source. Inertial sensors are demodulated to remove rotation artifacts and used to anticipate rapid maneuvers.

01 Jan 2001
TL;DR: The core Applanix technology consists of sophisticated algorithms and advanced signal processing techniques for the integration of GPS and Inertial Measurement Unit data, for the purpose of real-time navigation and post-mission, high precision positioning and attitude determination.
Abstract: In this paper the Applanix approach of integrating inertial data with GPS to produce products for Geomatics applications is presented. The core Applanix technology consists of sophisticated algorithms and advanced signal processing techniques for the integration of GPS and Inertial Measurement Unit data, for the purpose of real-time navigation and post-mission, high precision positioning and attitude determination. The Applanix products are briefly described. The airborne system is then discussed in some detail, followed by the theoretical and practical accuracy analysis of using such a system for photogrammetric mapping and LIDAR.

Patent
20 Dec 2001
TL;DR: In this article, a two-axis (azimuth and elevation) stabilized common gimbal (SGC) is proposed for use on a wide variety of commercial vehicles and military vehicles.
Abstract: A two axis (azimuth and elevation) stabilized common gimbal (SGC) for use on a wide variety of commercial vehicles and military vehicles which are employed in combat situations capable of stabilizing a payload of primary sensors and of mounting a secondary sensor payload that is independent of the moving axes. The SCG employs three gyroscopes, inertial angular rate feedback for providing gimbal control of two axes during slewing and stabilization. In addition the third (roll) gyroscope is used for performing automatic calibration and decoupling procedures. In this regard, the SCG provides an interface for the primary suite of sensors comprising one or more sensors having a common line-of-sight (LOS) and which are stabilized by electronics, actuators, and inertial sensors against vehicle motion in both azimuth and elevation. Remote positioning of the LOS of sensors in the primary suite is also accomplished, with the SCG providing an inertial navigation system (INS) which provides navigation and which detects the LOS for the primary suite of sensors relative to the vehicle. The aforementioned stabilized gimbal employs unique features such as automotive gyro calibration and decoupling algorithm that increases the producibility of the system and the stabilized gimbal has the capability of being remotely controlled via its system serial link where commands may originate from devices such as radio links or target trackers.

Proceedings ArticleDOI
06 Aug 2001
TL;DR: In this paper, a lateral pulse jet control mechanism is considered, which consists of a finite number of small thrusters spaced equally around the circumference of the rocket, and three different control laws are compared: proportional navigation, parabolic and proportional navigation guidance, and trajectory tracking control laws.
Abstract: : Compared to gun launch ammunition, uncontrolled direct fire atmospheric rockets are terribly inaccurate, to the point where they are used most effectively on the battlefield as area weapons. Dispersion characteristics can be dramatically improved by outfitting the rocket with a suitable control mechanism and sensor suite. In the work reported here, a lateral pulse jet control mechanism is considered. The lateral pulse jet mechanism consists of a finite number of small thrusters spaced equally around the circumference of the rocket. Using a simulation model that includes projectile, flight control system, and inertial measurement unit dynamics, three different control laws are contrasted, namely, proportional navigation guidance, parabolic and proportional navigation guidance, and trajectory tracking control laws. When the number of individual pulse jets is small, a trajectory tracking control law provides superior dispersion reduction. However, as the number of pulse jets is increased, the relative performance of the parabolic and proportional navigation guidance control law is slightly better than the trajectory tracking control law. When the number of pulse jets is small, the proportional navigation guidance, as well as the parabolic and proportional navigation guidance control laws, exhibits large mean miss distance. All control laws appear to be equally susceptible to accelerometer and gyroscope errors that corrupt inertial measurement unit rocket state feedback.

Patent
24 May 2001
TL;DR: In this paper, the authors proposed a method for measuring motion of a user, which is adapted to apply to output signals proportional to rotation and translational motion of the carrier, respectively from angular rate sensors and acceleration sensors.
Abstract: A method for measuring motion of a user, which is adapted to apply to output signals proportional to rotation and translational motion of the carrier, respectively from angular rate sensors and acceleration sensors, is more suitable for emerging MEMS angular rate and acceleration sensors. Compared with a conventional IMU, said processing method utilizes a feedforward open-loop signal processing scheme to obtain highly accurate motion measurements by means of signal digitizing, temperature control, sensor error and misalignment calibrations, attitude updating, and damping control loops, and dramatically shrinks said size of mechanical and electronic hardware and power consumption, meanwhile, obtains highly accurate motion measurements.

Patent
28 Jun 2001
TL;DR: In this paper, the roll angle and pitch angle of a two-wheeled vehicle is measured in relation to the gravitational field using an adaptive filter in the shape of a Kalman filter.
Abstract: Methods for determining the roll angle and pitch angle of a two-wheeled vehicle wherein the roll angle is measured in relation to the gravitational field. The invention is based on dynamic parameters detected by means of inertial sensors, for example accelerometers and rate gyros. The general sensor fusion approach requires a parameter that indicates the lateral acceleration of the vehicle. In a further development of the invention the lateral acceleration is combined with a parameter indicating the velocity of the vehicle. Advantageous embodiments of the invention comprise an adaptive filter in the shape of a Kalman filter. The yaw rate can also be generated as an addition sensor signal to achieve higher performance.

13 Jun 2001
TL;DR: In this article, a GPS/INS integration, fundamentally different from all existing approaches, is defined and successfully validated with low-cost IMU data updated with GPS code and carrier at 1 - Hz.
Abstract: A GPS/INS integration, fundamentally different from all existing approaches, is defined and successfully validated with low-cost IMU data updated with GPS code and carrier at 1 - Hz . Carrier measurements are used without resolving cycle ambiguities. Correlations are addressed, with influence on processing algorithms.

Proceedings ArticleDOI
16 Aug 2001
TL;DR: In this paper, the authors summarize principles of operation, review recent research and development efforts, and discuss potential applications and the future market of silicon-based micromachined gyroscopes.
Abstract: Micromachined gyroscopes are probably the most challenging type of transducers ever attempted to be designed in micro-world. A nail-size dynamic system integrated with control electronics on the same silicon chip is designed to be a very sensitive sensor which is potentially able to detect maneuvers and motions beyond human perception. Along with exciting opportunities which MEMS gyroscopes could bring to everyday life, the miniaturization introduces many new technical challenges. Multi-degree of freedom dynamics, sensitivity to fabrication imperfections, dynamic instability, limited control resources - all these raise a number of fundamentally challenging issues in the design, analysis, and control of micromachined gyroscopes. In this paper, we summarize principles of operation, review recent research and development efforts, and discuss potential applications and the future market of silicon based micromachined gyroscopes.

01 Jan 2001
TL;DR: The European Organisation for Experimental Photogrammetric Research (OEEPE) has embarked on a test investigating integrated sensor orientation using GPS and IMU in comparison and in combination with aerial triangulation as discussed by the authors.
Abstract: The European Organisation for Experimental Photogrammetric Research (OEEPE) has embarked on a test investigating integrated sensor orientation using GPS and IMU in comparison and in combination with aerial triangulation. The test consists of two phases. The first phase comprises the system calibration and the determination of the exterior orientation parameters. The second phase deals with the integration of the GPS/IMU data into the bundle block adjustment, i. e. the integrated sensor orientation itself. 13 test participants processed the distributed data and returned their results. In this paper we shortly describe the test setup and report about the results of phase I. The accuracy potential of direct georeferencing for 1:5000 imagery was found to lie at approximately 5-10 cm in planimetry and 10 – 15 cm in height in object space and at 15 - 20 μm in image space. The most important finding is the fact that direct georeferencing has proven to be a serious alternative to conventional bundle adjustment and currently allows for the generation of orthophotos and other applications with less stringent accuracy requirements. However, stereo plotting is not yet possible due to the relatively large remaining y-parallaxes. Future developments in the areas of GPS and IMU sensors and data processing will probably also reduce this problem. The best results in terms of accuracy and in particular in terms of reliability are expected from an intergration of GPS/IMU data into the bundle adjustment

Journal ArticleDOI
TL;DR: Recent improvements to the SANS hardware, latest testing results and development of an asynchronous Kalman filter for improved position estimation are reported.
Abstract: A Small AUV Navigation System (SANS) is being developed at the Naval Postgraduate School. The SANS is an integrated GPS/inertial navigation system composed of low-cost, small-size components. It is designed to demonstrate the feasibility of using a low-cost inertial measurement unit to navigate between intermittent GPS fixes. This paper reports recent improvements to the SANS hardware, latest testing results and development of an asynchronous Kalman filter for improved position estimation.