Inertial reference unit

About: Inertial reference unit is a research topic. Over the lifetime, 1306 publications have been published within this topic receiving 22068 citations. The topic is also known as: IRU.

Inertial system having correction means for effects of gravitational anomalies

Abstract: Conventional first and second Schuler tuned inertial platforms, that are physically displaced from each other by a predetermined distance, are employed in an inertial system to reduce navigation errors caused by the uncertainty in the earth's gravitational field. In addition to the two Schuler tuned platforms, a conventional velocity measuring instrument is employed to provide damping to the inertial system. The invention takes advantage of the fact that for a pair of ideal platforms if the relative velocity between them as displaced sensors can be measured with moderate accuracy then performance rivaling that obtainable with a gradiometer aided inertial platform can be achieved.

Methods and systems for enhanced navigational performance

Abstract: Methods and systems for navigation are disclosed. In one embodiment, data from GPS satellites within a field of view of a ground station are retransmitted to LEO satellites, such as Iridium satellites, and cross-linked if necessary before being transmitted to a user. The user is then able to combine the fed-forward data with data received directly from GPS satellites in order to resolve errors due to interference or jamming. Alternately, a method includes receiving at least one carrier signal at a user device, each carrier signal being transmitted by a distinct LEO satellite. The user device processes the carrier signals to obtain a first carrier phase information. The user device recalls an inertial position fix derived at an inertial reference unit. The user device derives a position of the user device based on the inertial position fix and the first carrier phase information.

Inertial navigation-past, present, and future

Abstract: The author describes the principles of inertial navigation (IN) at a level needed to understand the significance of the current and future trends. IN is simply a form of `dead reckoning'. A `gimballed platform' which can measure an aircraft's position, velocity, acceleration, attitude, and heading is examined. (9 pages)

Feasibility Study and Performance Analysis of a Gyroless Orientation Tracker

Abstract: Inertial orientation tracking systems commonly use three types of sensors: accelerometers, magnetometers, and gyroscopes. The angular rate signal is used to obtain a dead reckoning estimate, whereas the gravitational and local magnetic field measures allow us to apply a correction and to obtain a drift-free result. Considering the present market of inertial MEMS sensors, the current consumption of gyroscopes represents a major part of the power budget of wireless inertial sensor nodes, which should be minimized given the mobility of the application. This paper introduces an orientation tracking algorithm, based on an unscented Kalman filter, that does not require angular rate data for tracking human movements up to 450 °/s , which is a reasonable value for many applications. Since accelerometers measure other accelerations beside gravity and magnetometers are prone to magnetic disturbances, adaptive techniques are applied in order to reduce the influence on the estimations. The performance of the system is quantitatively analyzed and compared to an estimator that includes angular rate information.

Milli-HRG inertial sensor assembly – a reality

Abstract: The Hemispherical Resonator Gyro (HRG) has proven itself to be an ultra-reliable technology for space application with over 30 million operation hours and 100% mission success. Northrop Grumman Advanced Navigation Systems is developing a small size and lightweight terrestrial inertial sensor assembly (ISA) based on the HRG approach. This ISA will be the core of future inertial measurement unit (IMU) and inertial navigation system (INS) product lines.