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Measurement delay filtering method for small field star sensor

A star sensor, delay filtering technology, applied in astronomical navigation and other directions, can solve problems such as cumbersome, affecting the real-time output of attitude information and time delay.

Inactive Publication Date: 2018-12-14
HARBIN ENG UNIV
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

We need to select star points of different magnitudes to construct a navigation star catalog. The constructed navigation star catalog is larger than that of a star sensor with a large field of view, so in the stage of star map recognition and matching, the time for star map recognition increases Caused delay, affecting the real-time performance of attitude information output
At the same time, due to the cumbersomeness of the optical system and the steps of determining the attitude, the attitude sensor output information is accompanied by a delay phenomenon.

Method used

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  • Measurement delay filtering method for small field star sensor
  • Measurement delay filtering method for small field star sensor
  • Measurement delay filtering method for small field star sensor

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Experimental program
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Effect test

Embodiment 1

[0180] The initial state value is x 0 =[0 0 0 1 0.1 0.1 0.1] T , the corresponding initial quaternion part is q 0 =[0 00 1] T , the initial gyro drift part is β 0 =[0.1 0.1 0.1] T deg / h, the three reference vectors of the star sensor are set to r 1 =[1 0 0] Τ , r 2 =[0 1 0] Τ , r 3 =[0 0 1] Τ . The sampling frequency of star sensor and gyro is 1Hz. The initial three attitude angle error variance matrices are expressed as (0.1deg) 2 Ι 3×3 , the error variance matrix of gyro drift is expressed as (0.2deg / h) 2 Ι 3×3 . The actual star sensor has high precision, we can ignore the high-order terms obtained by Taylor expansion, B k ,D k+1 Set to 0. adjustment matrix In order to ensure the accuracy that the system can achieve, the parameters λ and μ are both set to 0.0001, and the parameter ε is set to 0.1. It can be seen from the state model and measurement model given in Chapter 2, which includes additive noise, and we consider the impact of noise and delay on t...

Embodiment 2

[0182] Assuming that there is a delay phenomenon when the star sensor is working, the vector delay rates in the three directions are different and satisfy the Bernoulli distribution, as follows:

[0183]

[0184] Simulation results:

[0185] combine figure 2 and image 3 , when it is assumed that there is no delay in the system, the performance of each filtering algorithm is not much different, and the accuracy can basically reach about 0.0001deg. On the whole, the REKF and RKF filtering algorithms are slightly better than the AEKF filtering algorithm, because the AEKF algorithm has certain errors after nonlinear estimation, resulting in slightly worse filtering accuracy.

[0186] combine Figure 4 and Figure 5 , the robust extended Kalman filter algorithm (REKF) proposed by us is much better than the RKF filter algorithm and the AEKF filter algorithm in dealing with nonlinear systems with delay and multiplicative noise, because we have established a The time error m...

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Abstract

The invention discloses a measurement delay filtering method for a small field star sensor, and belongs to the technical field of aircraft attitude estimation. In view of the conditions that multiplicative noise exists in a non-linear attitude estimation system state model and unknown interference exists in a measurement model, an aircraft attitude estimation model with the existence of the indetermination of the two models is established, meanwhile, the upper boundary ranges of prediction variance and estimation variance are found by using a robust algorithm design based on an expansion Kalman filtering structure, and then optimal filtering gain is designed by using a minimum variance theoretical design. The aircraft attitude is determined by using expansion Kalman filtering, the truth isminimum variance criterion estimation which is different from that of general frequency domain filters, the method can be used for processing attitude estimation under undetermined conditions, the method has the advantages of high instantaneity, and low dependence degree on prior information, the problem that delay exists in the star sensor is solved, and relatively high attitude estimation accuracy can also be guaranteed even if in information uncertainty conditions.

Description

technical field [0001] The invention belongs to the technical field of aircraft attitude estimation, and in particular relates to a measurement delay filtering method of a small field of view star sensor using a robust extended Kalman filter. Background technique [0002] The attitude estimation system combined with gyroscope and star sensor is widely used in aircraft due to its high accuracy of attitude determination. Euler angles, modified Rodrigues parameters, direction cosines, quaternions, etc. are the main attitude description parameters of the aircraft. Quaternions are often used as attitude description parameters in attitude estimation systems because of their simple calculations, no trigonometric operations, and the ability to avoid the singularity of Euler angles. For the quaternion pose estimation model of the system, many pose estimation methods based on Extended Kalman Filter (EKF) have been proposed, such as Additive Extended Kalman Filter (AEKF) and multiplic...

Claims

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Application Information

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IPC IPC(8): G01C21/02
Inventor 钱华明王迪黄智开吴永慧文雯
Owner HARBIN ENG UNIV
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