Optical fiber strapdown inertial navigation double-shaft rotation modulation method and double-shaft rotation mechanism

Method for error suppression of inertial concretionary coarse alignment of strapdown inertial navigation system

The invention provides an SINS (Strapdown Inertial Navigation System) error inhibiting method based on a biaxial rotation scheme. A global positioning system (GPS) is used for determining the parameters of the initial position of a carrier, and the parameters are input into a navigation computer; after preheating preparation, an SINS collects the data output by a fiber optic gyroscope and a quartz accelerometer and processes the data; primarily determining the attitude information of an inertial measurement unit (IMU) at the time according to the relationship between the output of the accelerometer and acceleration of gravity and the relationship between the output of the gyroscope and the rotational angular velocity of the earth so as to complete the initial alignment of the system; the IMU continuously rotates around the azimuth axis and the pitch axis; and the data generated by the fiber optic gyroscope and the quartz accelerometer after the rotation of the IMU is converted under a navigation coordinate system to get the modulation manner with deviated constants of inertia instruments. According to the invention, the SINS error inhibiting method based on a biaxial rotation scheme can be used for modulating the drift of the gyroscope in three directions and the zero offset of the accelerometer in the horizontal direction so as to improve the positioning precision of navigation.

SINS error inhibiting method based on biaxial rotation scheme

The invention discloses a control method of an aircraft and the aircraft. The control method comprises the following steps: monitoring a test value of a compass of the aircraft; according to the monitored test value of the compass, judging whether the compass is abnormal or invalid; when the compass is abnormal or invalid, performing protection control on the aircraft by taking preset protection measures. According to the control method and the aircraft, which are disclosed by the invention, the aircraft is effectively controlled and protected, so that the flight safety of the aircraft is improved.

Control method of aircraft and aircraft

The invention provides a geographical location information estimation method. The geographical location information estimation method comprises the following steps of step s01, determining a reference starting point: moment t0, geographical location information (x0,y0,z0), speed (vx0,vy0,vz0) and accelerated speed (ax0,ay0,az0); step s02, obtaining accelerated speed (axj,ayj, azj) at the moment tj=t0+j*dt; step s03, calculating the speed (vxj,vyj,vzj) at the moment tj=t0+j*dt; step s04, estimating the displacement (sxj,syj,szj) in the time period from the t[j-1] to tj; and step s05, estimating the geographical location information at the moment the tj: xj=x[j-1]+sxj, yj=y[j-1]+syj, and zj=z[j-1]+szj. The geographical location information estimation method provided by the invention is capable of estimating geographical location information under the condition that GPS, BeiDou and mobile communication signals are lost.

Geographical location information estimation method, restoring method and display method

The invention belongs to the technical field of modulation of a strapdown inertial navigation system and relates to a biaxial rotation modulation method of the strapdown inertial navigation system which aims at reducing the complexity and realizing the rate bias without a high angular acceleration reversing mechanism. The biaxial rotation modulation method comprises six steps of setting a coordinate system, mounting a gyroscope and an accelerometer, mounting an inertial measurement unit, carrying out biaxial rotation modulation, carrying out navigation calculation of the inertial measurement unit and carrying out demodulation and calculation of data on the strapdown inertial navigation system. The biaxial rotation modulation method adopts the biaxial rotation module and can realize the modulation of errors of an inertia device in the strapdown inertial navigation system and improve the navigation precision of the strapdown inertial navigation system. The biaxial rotation modulation method does not need the high angular acceleration reversing mechanism for the strapdown inertial navigation system using the laser gyroscope, thereby reducing the implementation complexity of the system and further reducing the implementation cost of the system.

Biaxial rotation modulation method of strapdown inertial navigation system

The invention belongs to the technical field of inertial navigation and in particular relates to a completely independent relative inertial navigation method. The purpose is to independently determine an azimuth angle and a latitude under the special condition that an accurate initial position cannot be obtained. The method comprises the following steps of: setting an initial course angle and an attitude angle as 0 degree and setting initial longitude and latitude as 0 degree; by using angular velocity and specific force output by a gyroscope and an accelerometer, figuring out a navigation parameter by using a traditional navigation calculating method; estimating and revising an initial error in a closed loop; carrying out navigation calculation relative to an initial position; and after accurate outside position information is obtained, resetting longitude information as the accurate value, and keeping the course angle, the attitude angle and the latitude invariable. By using the completely independent relative inertial navigation method provided by the invention, relative navigation can be carried out with high accuracy and true latitude information with high accuracy can be provided; moreover, the initial longitude error does not affect the relative navigation accuracy; and the relative navigation accuracy is superior to 2 nmile/9h.

Minggang Chen

Papers

Biaxial rotation modulation method of strapdown inertial navigation system

Completely independent relative inertial navigation method