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Inertial position determination under vibration

Avrutov Vadym, Lakoza Serhii, Ryzhkov Lev, Sapegin Oleksandr

Vibrations in Physical Systems

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2020

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Vol. 31, nr 2

art. no. 2020201

EN

The main purpose of navigation systems is a position determination different moving objects. For standard inertial navigation systems algorithm, the initial position data are required. Normally these data may be determined by astronomical techniques or satellite and radio navigation systems. However, astronomical techniques depend on climate conditions and satellite and radio systems can be disturbed by electromagnetic countermeasures. It is proposed to use an Inertial Measurement Unit (IMU) and a navigation computer for autonomous determination of an initial position. IMU should be composed of three accelerometers, three gyroscopes and a signal processing circuit. The method proposed the latitude determination uses projections of the Earth’s rate measured by orthogonal IMU gyroscopes and projections of the gravity acceleration measured by orthogonal IMU accelerometers. Experimental tests of the IMU with a ring laser gyros triad and precision pendulum accelerometers confirmed the efficiency of the method on a fixed base. The behavior of the latitude determination under vibration is researched. The latitude determination under vibration was considered analytically by Power Spectral Density theory. It was estimated a variance of the latitude under the broad-band vibration. The method operability under harmonic and random vibration of the base at the real time is considered.

2

Rotary upgrading method and its experimental study of an inertially stabilized platform

Guo Rong, Wang Xueyun, Zhang Jingjuan, Song Tianxiao

Metrology and Measurement Systems

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2019

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Vol. 26, nr 4

617--629

EN

Rotation modulation can significantly improve the navigation accuracies of an inertial navigation system (INS) and a strap-down configuration dominating in this type of INS. However, this style of construction is not a good scheme since it has no servo loop to counteract a vehicle manoeuvre. This paper proposes a rotary upgrading method for a rotational INS based on an inertially stabilized platform. The servo control loop is reconstructed on a four-gimbal platform, and it has the functions of providing both a level stability relative to the navigation frame and an azimuth rotation at a speed of 1.2°/s. With the platform’s rotation, the observability and the convergence speed of the estimation for the initial alignment can be improved, as well as the biases of the gyroscopes and accelerometers be modulated into zero-mean periodic values. An open-loop initial alignment method is designed, and its detailed algorithms are delivered. The experiment result shows that the newly designed rotational INS has reached an accuracy of 0.38 n mile/h (CEP, circular error probable). The feasibility and engineering applicability of the designed scheme have been validated.

3

Analyses of Electronic Inclinometer Data for Tri-axial Accelerometer’s Initial Alignment

Šipoš M., Roháč J., Nováček P.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 1a

286-290

EN

This paper deals with the usage of a dual-axis electronic inclinometer EZ-TILT-2000-008 to improve an initial alignment of a tri-axial accelerometer, which forms a part of the inertial measurement unit ADIS16405. There were performed several measurements under various initial conditions with the usage of a precise Rotational-Tilt Platform as a reference. Based on measured data the alignment procedure accuracy, null repeatability, stability of initial null angle, hysteresis, and cross-axis dependence were analyzed and the results of these analyses are presented.

PL

Zaprezentowano wykorzystanie dwuosiowego inklinometru EZ-TILT-2000-008 do poprawy ustawiania trzyosiowego przyśpieszeniomierza. Przeprowadzono badania dokładności, powtarzalności zera, histerezy i wpływu osi w opracowanym przyśpieszeniomierzu.

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Evaluation of Fine Alignment Algorithm for inertial navigation

Reinstein M.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 7

255-258

EN

This paper describes results obtained during evaluation of a fine alignment algorithm for inertial navigation. The fine alignment algorithm is based on a full-state error model for extended Kalman filter and its purpose is to estimate random errors in accelerometers and angular rate sensors signals to improve the precision of determination of initial attitude angles. Precise determination of initial attitude is important in inertial navigation, since it is one of the most crucial sources of error during inertial data integration, which is performed to obtain velocity and position information.

PL

Opisano zastosowanie algorytmu dokładnego wyrównania (fine alignement) do nawigacji inercyjnej. Algorytm ten wykorzystuje filtr Kalmana i jego celem jest wyznaczenie błędu przypadkowego przyśpieszeniomierza oraz zmianę kąta w celu precyzyjnego wyznaczenia kątów i początkowej wysokości.