Heaving measurement method with lever arm compensation and suitable for strapdown inertial navigation system

Abstract

The invention relates to a heaving measurement method with lever arm compensation and suitable for a strapdown inertial navigation system. The heaving measurement method comprises the following methods that the initial navigation parameter t=0 time is given, specifically, the strapdown inertial navigation system is subjected to initial alignment to obtain an initial pitching attitude angle theta (0), an initial rolling attitude angle gamma (0), an initial yawing angle psi (0) and a main course angle zeta (0); a sampling period h is set by the system, and output signals of gyroscopes and accelerometers on three axes are collected in real time; a relationship matrix between a carrier coordinate system b and a semi-fixed coordinate system s at tk time is recursively measured; the heaving acceleration at the installation point of the strapdown inertial navigation system is calculated by using a direction cosine matrix and the output of the accelerometers; the heaving acceleration at the gravity center is obtained by using the output of the gyroscopes and the projection of lever arm errors between the installation point of the strapdown inertial navigation system and the gravity centerpoint of a ship in the carrier coordinate system; and the heaving acceleration at the gravity center is subjected to filtering processing by a heaving filter F (k). According to the heaving measurement method, the heaving measurement of the strapdown inertial navigation system and with the lever arm compensation is achieved, and the operability of the ship is improved.

Description

technical field [0001] The invention relates to the field of heave measurement methods, in particular to the field of a heave measurement method with lever arm compensation suitable for a strapdown inertial navigation system. Background technique [0002] Ships will be disturbed by marine environmental factors such as waves during operation, and passively generate six degrees of freedom swaying motion, that is, rotational motion (rolling, pitching, yawing) and translational motion (swaying) along the three coordinate axes. , surge, and heave), among which the heave motion along the skyward axis has the greatest influence and harm on the ship. Accurate extraction of heave motion plays a very important role in ship replenishment, hovercraft landing, cargo (container, etc.) hoisting and handling, and accurate measurement of ship heave motion is very necessary. Traditional altimetry methods (such as air pressure altimetry, radio altimetry, etc.) have low measurement accuracy, a...

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Problems solved by technology

Traditional altimetry methods (such as air pressure altimetry, radio altimetry, etc.) have low measurement accuracy, are greatly affected by the external environment, and have strict requirements on equipment, so they are not suitable for the measurement of ship heave motion in the marine environment; and The measurement method based on the inertial navigation system has strong anti-interference, can work autonomously in various complex environments, and has high short-term accuracy and good stability. It is currently the main means of measuring ship heave motion

[0003] But in published articles, such as "A Kalman filter algorithm based on exact modeling for FOG GPS / SINS integration" article by Liu Jianye and Zeng Qinghua in Volume 125, Issue 14 of "Optik-International Journal for Light and Electron Optics" Using the combination of inertial navigation and satellites to measure heave, although it can achieve meter-level absolute positioning accuracy of ships, satellite signals are susceptible to interference in marine environments, and the measurement results cannot meet the centimeter-level short-term relative measurement accuracy requirements in heave applications.

In addition, in the article "Measurement Technology of Ship Heave and Heave Based on Inertial Navigation Solution" by Sun Wei and Sun Feng in Volume 33, Issue 1 of "Journal of Instrument and Apparatus", the analysis process of the strapdown inertial navigation system on the The influence of ship heave measurement, summarizes the specific implementation plan of measuring heave motion and proposes to use digital high-pass filter to complete the separation of high-frequency disturbances such as ocean waves, but there is a problem of phase error

Yan Gongmin, Su Xingjun, Weng Jun, and Qin Yongyuan used a no-delay filter for heave measurement in the article "Measurement of Ship Heave and Heave Based on Inertial Navigation and No-Delay Filter" in Volume 4, No. 2 of "Journal of Navigation and Positioning". Shen measurement, which solves the problem of phase error, but has the disadvantages of slow attenuation of low frequency and long convergence time

[0004] The above published articles have described and explored the heave measurement, but they have not considered the rods between the installation point of the strapdown inertial navigation system and the center of gravity of the ship, the observation point and the center of gravity of the ship in practical engineering applications. Influence of Arm Error on Heave Information

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