Showing papers on "Inertial reference unit published in 2001"
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
Patent•
06 Nov 2001TL;DR: In this article, a system for testing inertial measurement devices on a multi-axis rate table without having to utilize slip rings to transfer signals between the measurement devices and remote processors was proposed.
Abstract: A system for testing inertial measurement devices (10) on a multi-axis rate table (14) without having to utilize slip rings to transfer signals between the inertial measurement devices and remote processors by incorporating a processor (34) internal to the inertial measurement devices and transferring (35) the signals directly to the processors for determining and storing (11) the calibration coefficients of the inertial measurement devices internally so that they are self calibrating.
56 citations
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.
40 citations
Patent•
26 Dec 2001
TL;DR: In this article, a self-correcting wireless inertial navigation system and method employ a mobile unit having an inertial sensor and a transmitter connected to the output of the initial sensor for broadcasting an RF measurement signal.
Abstract: A self-correcting wireless inertial navigation system and method employ a mobile unit having an inertial sensor and a transmitter connected to the output of the initial sensor for broadcasting an RF measurement signal. A base station has receivers responsive to the signal, an interferometer connected to the receivers and a processor programmed to obtain inertial measurements from the signal and to correct the measurements in accordance with phase difference triangulation information derived by the interferometer.
40 citations
Patent•
27 Jul 2001
TL;DR: In this paper, a method for attitude alignment of a slave inertial measurement system connected to a rotationally mobile platform supported by a vehicle that is stationary relative to a reference navigation frame is described.
Abstract: A method for attitude alignment of a slave inertial measurement system connected to a rotationally mobile platform supported by a vehicle that is stationary relative to a reference navigation frame comprises the steps of mounting a master reference inertial measurement system on the rotationally mobile platform and determining a master reference system attitude using measurements of acceleration and angular rates of the master reference inertial measurement system relative to the reference navigation frame. A slave system attitude is determined using measurements of acceleration and angular rates of the slave inertial measurement system relative to a slave system navigation reference frame and comparing the slave system attitude to the master reference system attitude to determine an attitude difference. The attitude difference is processed to obtain a correction to the slave system attitude.
19 citations
01 Jan 2001
TL;DR: CavityMicromachining (CMM) as discussed by the authors is a technology that enables to ship MEMS products like inertial sensors as Flip-Chips or in any other low-cost package.
Abstract: “Cavity-Micromachining” is a technology that enables to ship MEMS products like inertial sensors as Flip-Chips or in any other low-cost package. Moveable structures are buried inside cavities below the wafer surface. The protection against mechanical and environmental influences is done with deposited layers on wafer-level instead of using wafer-bonding. Therefore the chips are much smaller and can be made thin enough to fit into any cheap standard package or module.
18 citations
01 Mar 2001
TL;DR: In 1995, the NASA Langley Research Center conducted a series of experimental measurements that characterized the electromagnetic environment inside a Boeing 757 airliner while in flight, measurements were made of the electromagnetic energy coupled into a commercially configured aircraft as it was flown in close proximity to ground-based radio frequency (RF) transmitters operating at approximately 26, 173. and 430 MHz as mentioned in this paper.
Abstract: In 1995, the NASA Langley Research Center conducted a series of experimental measurements that characterized the electromagnetic environment (EME) inside a Boeing 757 airliner while in flight, Measurements were made of the electromagnetic energy coupled into a commercially configured aircraft as it was flown in close proximity to ground-based radio frequency (RF) transmitters operating at approximately 26, 173. and 430 MHz. The goal of this experiment was to collect data for the verification of analytical predictions of the internal aircraft response to an external stimulus. This paper describes the experiment, presents the data collected by it, and discusses techniques used to compute both the magnitude of the electric field illuminating the aircraft and its direction of propagation relative to a coordinate system fixed to the aircraft. The latter is determined from Global Positioning System (GPS) and aircraft Inertial Reference Unit (IRU) data. The paper concludes with an examination of the shielding effectiveness of the test aircraft. as determined by comparison of' the measured internal EME and computed external EME.
6 citations
Patent•
28 Jun 2001
TL;DR: In this paper, the attitude and position of a test mass can be adjusted by means of the pressures of light exerted on the optical interferometric measuring sections upon the test mass.
Abstract: An inertial sensor includes an inertial reference for determining the attitude and position of a satellite or satellite parts. A test mass is situated in a space which is essentially free of electric and magnetic fields and is enclosed by a housing, and optical measuring sections are set up between reference elements on the housing and on the test mass, for determining the attitude and/or position of the test mass relative to the reference elements on the housing. A measuring arrangement is situated outside the housing for the optical measuring sections. The optical measuring sections are constructed as optical interferometric measuring elements; and the attitude and position of the test mass can be adjusted by means of the pressures of light exerted on the optical interferometric measuring sections upon the test mass.
6 citations
Journal Article•
TL;DR: In this paper, under the condition of moving base, the general ψ、φ angle error models of the gimbaled inertial navigation system (INS) are presented in detail.
Abstract: The error models are very important in the error analysis and fault detection of inertial navigation system(INS).In this paper,under the condition of moving base,the general ψ、φ angle error models of the gimbaled INS are presented in detail,and the general ψ、φ angle error models of GINS are also addressed.
2 citations
Journal Article•
TL;DR: The principle and implementation of new IMU:HRG、MEMS-IMU、fiber-optic gyro are discussed, and the development direction is proposed.
Abstract: The development of inertial measurement unit(IMU),along with their important situation in inertial navigation system(INS),Then the principle and implementation of new IMU:HRG、MEMS-IMU、fiber-optic gyro are discussed, and finally the development direction is proposed.
12 Dec 2001
TL;DR: Fiber optic gyros used in a strap-down inertial navigation system and strap- down inertial Navigation system consisting of three-axis FOGs are discussed.
Abstract: Strap-down inertial navigation system is a low cost and high precision inertial navigation system. With the fast development of fiber optic gyros, FOG strap-down inertial navigation system is taking place of traditional electro- mechanic gyros inertial navigation system of. Discussed in this paper are fiber optic gyros used in a strap-down inertial navigation system and strap-down inertial navigation system consisting of three-axis FOGs.