De-orbit braking closed circuit guidance method satisfying constrains on reentry angles and flying ranges

A technology of off-orbit braking and re-entry angle, applied in three-dimensional position/channel control and other directions, which can solve the problems of initial position error, initial speed error, low range control accuracy, inability to guarantee range accuracy, and limitations in improving accuracy, etc.

Active Publication Date: 2016-05-11
NAT UNIV OF DEFENSE TECH
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

The iso-velocity incremental shutdown equation and the constant-velocity inclination angle shutdown equation take into account the state of the re-entry point, which can guarantee the accuracy of the re-entry angle, but cannot guarantee the high accuracy of the voyage, and there are large initial position errors and initial velocity

Method used

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  • De-orbit braking closed circuit guidance method satisfying constrains on reentry angles and flying ranges
  • De-orbit braking closed circuit guidance method satisfying constrains on reentry angles and flying ranges
  • De-orbit braking closed circuit guidance method satisfying constrains on reentry angles and flying ranges

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Embodiment Construction

[0043] Suppose a spacecraft uses a constant thrust rocket engine to de-orbit from an initial circular orbit at a height of 300km through one braking, and meet the requirements of reentry angle and range at the atmospheric boundary at a height of 120km. Because it is flying outside the atmosphere, the force on the spacecraft is mainly the thrust of the rocket engine and the gravity of the earth.

[0044] Establish the motion equation of the aircraft in the return to inertial coordinate system. When the earth is considered as a homogeneous sphere, that is, when the two-body dynamics model is adopted, the motion equation is

[0045]

[0046] Among them: (x, y, z) is the position of the spacecraft, (v x ,v y ,v z ) Is the speed of the spacecraft, m is the mass of the spacecraft, P is the thrust of the rocket engine, ψ z Is the attitude angle representing the thrust direction of the engine, μ e Is the earth's gravitational constant, r is the distance between the center of the spacecraft...

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Abstract

The invention discloses a de-orbit braking closed circuit guidance method satisfying constrains on reentry angles and flying ranges. The guidance method comprises steps of firstly on the basis of a nominal de-orbit braking track of a two-body dynamics model design, correcting effects on the reentry angles imposed by a J2 item by iterating working time of an engine; correcting effects on the flying ranges imposed by the J2 item by designing a dynamics integral model; during a guidance process, according to current movement states and information of reentry points, calculating currently required speed and speed gain by use of a closed analytical expression; determining an instruction posture angle of the engine according to direction of the speed gain; and determining a turn-off instruction according to the fact whether the speed gain is zero. According to the invention, high-precision and strong-robustness de-orbit braking guidance can be achieved.

Description

Technical field [0001] The invention relates to the technical field of guidance control, and can be applied to the guidance of spacecraft off-orbit braking, in particular to the spacecraft off-orbit braking closed-circuit guidance that satisfies the reentry angle and range constraints. Background technique [0002] Off-orbit braking refers to the process of taking a spacecraft out of its original orbit and returning to the earth’s atmosphere. De-orbit braking is the first stage of the spacecraft returning to the earth. In this stage, the spacecraft uses a rocket engine to reduce the flight speed or change the speed direction, reduce the flight altitude, and enter the earth's atmosphere. [0003] The point at which the spacecraft reaches the boundary of the Earth’s atmosphere is called the reentry point. The angle between the flight speed at the reentry point and the local horizontal plane is called the reentry angle, and the reentry angle is closely related to parameters such as h...

Claims

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Application Information

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IPC IPC(8): G05D1/10
CPCG05D1/10
Inventor 张洪波汤国建王涛
Owner NAT UNIV OF DEFENSE TECH
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