RU2273826C2 - Method for determining angles of orientation of moving object and device for realization of method - Google Patents

Abstract

FIELD: rocketry, spacecraft engineering, possible use for detecting direction of bearing rocket in flight.

SUBSTANCE: satellite navigation equipment and three gyro-integrators simultaneously determine values of projections of speed vector in starting and connected coordinates system respectively and transfer determined values to onboard digital computing machine, which, using received information, determines values of angles of orientation of moving object in space in accordance to algorithm for determining orientation of moving object.

EFFECT: decreased dimensions of device for realization of proposed method down to 40x40x40 millimeters (without consideration for size of onboard digital computing machine) while maintaining precision for determining angles of direction of moving object to 4 angular minutes.

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Description

Description of the invention

The present invention relates to the field of rocket and space technology and can be used to determine the orientation of the launch vehicle (LV) in flight.

The prototype of the alleged invention is the "Method of angular orientation of the object according to the signals of satellite radio navigation systems (options)" (RU 2185637 C1, 2002.07.20). The prototype is designed to determine the spatial orientation of moving objects by the interferometric method with an interferometer base size of up to several meters. The technical result of the prototype is to find the initial and current angular position of the moving object without forcibly changing the orientation of the base vectors at the ends of which the antennas are located. That is, a device for implementing the described method, receiving signals from two or more spaced antenna devices, determines the orientation angles of the object on which these antennas are located.

On the types of LV used at the Plesetsk launch site, the requirements for the accuracy of determining the orientation angles in flight are 4 arc minutes. This accuracy of determining the orientation angles of the PH is achieved by the described prototype with a distance between the antennas of several meters (up to 10 meters). The length of the types of LVs used is 20-30 meters, moreover, the spent stages are separated at the launch site and the length of the LVs gradually decreases to several meters (depending on the type of LVs). It becomes difficult to place prototype antenna devices onboard the LV.

The proposed method for determining orientation angles differs from the prototype in that it assumes the availability of satellite navigation equipment with one antenna device, three gyro integrators, an on-board digital computer, and uses a different method for determining spatial orientation. Currently, it is planned to install an on-board digital computer on board all promising LVs.

Signs characterizing the alleged invention:

1. Using the devices described below: satellite navigation equipment with one antenna device, three gyro-integrators, on-board digital computer;

2. Using the algorithm for determining the orientation of a moving object described below;

3. The following procedure is used: satellite navigation equipment determines the values of the projections of the absolute velocity vector in the starting coordinate system and transfers certain values to the on-board digital computer; at the same time, three gyro-integrators measure the values of the projections of the apparent speed in a connected coordinate system and transmit the measured values via communication channels to the on-board digital computer; the on-board digital computer, using the information obtained, determines the values of the orientation angles of the object in space according to the algorithm for determining the orientation of a moving object.

The technical result is to reduce the size of the device for implementing the proposed method to 40 × 40 × 40 mm (excluding the size of the on-board digital computer) while maintaining the accuracy of determining the orientation angles of a moving object to 4 arc minutes.

A block diagram of a device for implementing the proposed method is presented in figure 1. The device comprises satellite navigation equipment containing one antenna 1, three gyro integrators 2, 3, 4 located on the axes of a connected coordinate system, on-board digital computer 5, which includes an algorithm for determining the orientation of the LV in flight 6. The outputs of satellite navigation equipment 1 and three gyrointegrators 2, 3, 4 are connected to the input of the on-board digital computer 5.

Satellite navigation equipment is designed to obtain projections of the absolute velocity of the LV center of mass in an inertial coordinate system. In the present invention, an initial starting coordinate system [3] will be used (see FIG. 2). Its beginning is combined with the center of mass of the RN, standing on the starting device. The main plane is the horizon plane. The axis Ru _{c is} directed along the radius connecting the center of the Earth O with the point P, and the axis P _{c c} is tangent to the circumference of the great circle, in the plane of which the trajectory of derivation is located; the Pz _c axis complements the system to the right. As a satellite navigation equipment can be any sample of such equipment designed for rocket and space technology [1].

Three gyrointegrators are designed to obtain projections of the apparent velocity of the center of mass of the LV in the coordinate system associated with the pH (associated coordinate system) [3] (see figure 3). The origin of the associated coordinate system is located in the center of mass of the LV. The main plane coincides with one of the planes of symmetry of the rocket. The axis Px _{1 is} directed along the longitudinal axis of the pH; the axis Ru ₁ is located in the plane of symmetry, coinciding with the plane of the trajectory, and is directed upwards (with the horizontal movement of the rocket above the surface of the Earth); axis Pz ₁ complements the system to the right. As gyro-integrators can be used samples used on the Rokot rocket.

A necessary condition of the invention is the presence on board the LV of an on-board digital computer with the algorithms necessary to determine the orientation of the LV in space. There are a number of samples of on-board digital computers. In particular, the on-board digital computer is used on the Rokot launch vehicle.

To implement the proposed method and the operation of the device for implementing the proposed method, the following sequence of actions is used.

The satellite navigation equipment determines the projections of the absolute velocity vector in the starting coordinate system and transmits certain values to the on-board digital computer. At the same time, three gyrointegrators measure the increments of the projections of the apparent speed per cycle (a certain time interval Δt) in a connected coordinate system and also transmits the measured values to the on-board digital computer via communication channels. On-board digital computer, using the information obtained, determines the values of the orientation angles of the spacecraft in space according to the algorithm for determining the orientation of a moving object.

Algorithm for determining the orientation of a moving object

1. The source data.

,

,

, полученные от аппаратуры спутниковой навигации, и значения приращений проекций кажущейся скорости за один такт в связанной системе координат

,

,

, полученные от трех гироинтеграторов.The initial data for calculating the orientation angles of the LV are the values of the projections of the absolute velocity in the starting coordinate system

,

,

obtained from satellite navigation equipment, and the values of the increments of the projections of the apparent speed per cycle in a connected coordinate system

,

,

obtained from three gyro integrators.

2. Determination of the orientation angles of the spacecraft in space.

The position of the associated coordinate system relative to the starting coordinate system is determined by three angles: ϑ - pitch angle, ψ - yaw angle, γ - rotation angle (figure 4).

To move from a linked coordinate system to a starting coordinate system, the system of equations is used:

where t is the instant of determining the orientation angles, counted from the moment of the beginning of movement.

(t),

(t),

(t) определяются следующим образом:Projection values of the absolute velocity of the LV center of mass in a coupled coordinate system

(t)

(t)

(t) are defined as follows:

(t),

(t),

(t) - проекции ускорения РН в связанной системе координат, вызванного наличием гравитационного ускорения Земли на момент времениWhere

(t)

(t)

(t) - projections of the acceleration of the LV in a coupled coordinate system caused by the presence of gravitational acceleration of the Earth at a time

(t-Δt),

(t-Δt),

(t-Δt) - значения проекций абсолютной скорости движения центра масс РН в связанной системе координат, вычисленные на предыдущем такте.

(t-Δt),

(t-Δt),

(t-Δt) are the values of the projections of the absolute velocity of the LV center of mass in the associated coordinate system, calculated on the previous measure.

As a method of numerical integration for finding the integrals in (2), one can use the trapezoid method as the most simple to implement on a digital computer and acceptable in accuracy.

(t),

(t),

(t),

,

,

известны, а значения углов ϑ, ψ, γ - необходимо найти.Thus, in the system of equations (1), the values

(t)

(t)

(t)

,

,

are known, and the angles ϑ, ψ, γ - must be found.

The system of nonlinear equations (1) in this algorithm is solved by the iterative method [4].

For this, the system of equations (1) is represented in the form:

where are the functions

определяются методом наискорейшего спуска [4]:where the value of the parameters

determined by the steepest descent method [4]:

According to the described algorithm, calculations were performed to evaluate the accuracy of determining the orientation angles of the launch vehicle. As the initial data for the calculations, the kinematic parameters of the Cyclone-3 launch vehicle motion were used throughout the entire Strela spacecraft launch site (from 2 seconds to 2650 seconds of the LV flight). The accuracy indicators for determining the projections of the absolute velocity vector using satellite navigation equipment were adopted identical to the “Terminator” equipment [1]. The accuracy indicators for determining projections of the apparent velocity vector using gyro integrators were taken identical to those used on the Rokot rocket. The accuracy indicator used is the standard deviation of the determination of orientation angles. As a result, the accuracy in determining the angle of heel is 4 arc minutes throughout the flight. Pitch angle accuracy: up to 20 seconds - up to 36 arc minutes, from 20 seconds - 3 arc minutes. Yaw angle accuracy: up to 20 seconds - up to 34 arc minutes, from 20 seconds - 4 arc minutes.

Mass and overall characteristics of the component parts of the sample of the proposed device without taking into account the on-board digital computer are:

- Satellite navigation equipment of the “Terminator” type - overall characteristics 220 × 260 × 80 (mm), weight 3.5 kg [1];

- Gyrointegrator - height 250 mm, diameter 104 mm, weight 5 kg;

Information sources

1. Edited by V.N. Kharisov, A.I. Perov, V.A. Boldin, GLONASS Global Satellite Radio Navigation System, M., IPPRZhR, 1998, 400 pp.

2. Ed. A.V.Solodova, Engineering reference book for space technology, M., USSR Ministry of Defense. 1969, 694 p.

3. G. Korn and T. Korn, Handbook of mathematics for scientists and engineers. Definitions, Theorems, Formulas, Edition 4, M .: Nauka, 1978, 832 p.

Claims (2)

1. A method for determining the orientation of a moving object using satellite navigation equipment, characterized in that the satellite navigation equipment contains one antenna device, three gyro integrators are used, located on the axes of the coordinate system associated with the object, and an on-board digital computer (BCM) is used, which implements an algorithm for determining the orientation of a moving object, based on the determination of the elements of the transition matrix between the initial starting and coordinate systems associated with the object tension; The following procedure is used: satellite navigation equipment and three gyrointegrators simultaneously determine the values of the projections of the velocity vector in the start and coordinate systems associated with the object, respectively, and transmit certain values to the digital computer, which, using the information received, determines the values of the orientation angles of the object in space using the algorithm for determining the orientation of a moving object. 2. A device for determining the orientation of a moving object, containing an on-board digital computer (BCMB), which implements an algorithm for determining the orientation of a moving object, based on the determination of the elements of the transition matrix between the initial launch and coordinate systems associated with the object, satellite navigation equipment containing one antenna device , the output of which is connected to the input of the digital computer, and three gyro integrators located on the axes of the coordinate system associated with the object, the outputs of which are connected to the input BCVM house.

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