RU2471150C1 - Device to select objects of surveillance from orbital spacecraft - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: device comprises a globe with a planet surface map applied on it, a spiral element that models an orbit of a spacecraft (SC), a facility to lock the spiral element on the axis of globe rotation. The spiral element is arranged in the form of an orbit turn with a positive incline of the SC. The start of the orbit turn shall be a point of the orbit located beyond the quarter of the SC circulation period to the ascending unit of the orbit. The end of the orbit turn shall be a point of the orbit that is distant by the quarter of the SC circulation period after the next ascending unit of the orbit. The facility for fixation of the spiral element on the axis of globe rotation is arranged in the form of two connection elements, the angular size of every of which, measured from the centre of the globe, is equal to 90°-i, where i - orbit inclination.

EFFECT: expansion of functional capabilities.

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Description

The proposed technical solution relates to the field of space technology and can be used to determine and select objects of observation from an orbiting spacecraft (SC) moving in a near-circular orbit.

The globe is known (see [1], pp. 93-97), which can be used, in particular, to determine and select objects of observation performed from spacecraft. The disadvantage of this device is the lack of elements to display information about the orbit and the spacecraft. A training device for navigation is also known.

[2], including the base, the rack, the model of the planet, which is made in the form of a globe, the model of the SC orbit, made in the form of a ring and mounted on the bearing of the rack. Using this device, it is possible, among other things, to simulate the position of the SC orbit above the globe - the model of the planet - and select objects on the planet’s surface that are accessible to observation from the SC.

The closest of the analogues adopted for the prototype is a device for selecting an object of observation from an orbiting spacecraft [3], including a globe with a map on it, two rings covering the globe, the centers of which are aligned with the center of the globe, a spiral element in the form of a spiral coil, corresponding to the averaged orbit of the spacecraft moving in a circumferential orbit of the spacecraft, starting from the ascending node of the orbit, with one ring fixed over the points of the poles of the globe with the possibility of rotation around axis of rotation of the globe passing through the poles of the globe, and another ring is installed with the possibility of exhibiting the ring at any given angle to the equator of the globe.

Work with the device as follows. The spiral element is rotated relative to the globe in such a way that the start point of the turn is located above the equator point with the longitude value λ _{0 of the} ascending node of the orbit of the spacecraft under consideration. In this position, the projection of the spiral element onto the surface of the globe simulates the path of the spacecraft orbit under consideration. As possible objects of observation from the spacecraft, objects located along the simulated path of the orbit of the spacecraft are selected.

The prototype device has a significant drawback - it does not allow to display on the globe simultaneously the full path of the ascending branch of the orbit, which makes the choice of observation objects at the beginning and at the end of the loop under review not convenient and visual. In addition, the connecting elements of the device (namely, two rings), closing the parts of the card directly below them, make it difficult to read the information placed on these parts of the card.

The task facing the proposed device is to increase the convenience and visibility of the determination and selection of objects of observation performed from the spacecraft on the ascending branches of the orbit of the spacecraft by ensuring that the map of the planet displays simultaneously full paths of both ascending branches of the orbit at the beginning and at the end of the orbit under consideration while eliminating shading maps of the planet with connecting elements of the device.

The technical result is achieved by the fact that in the device for selecting objects of observation from the orbiting spacecraft, including a globe with a map of the planet’s surface plotted on it, a spiral element simulating the orbit of the spacecraft and means for attaching the spiral element to the axis of rotation of the globe, the spiral element is made modeling one and a half the orbit of the orbit moving in a circumcircular orbit with a positive inclination of the spacecraft, while the beginning of the aforementioned one and a half orbits of the orbit is taken the orbit point located a quarter of the period of revolution of the spacecraft to the ascending node of the orbit, and the end of the one and a half turns of the orbit is taken as the point of the orbit, which is a quarter of the period of revolution of the spacecraft after the next ascending node of the orbit, and the means for attaching the spiral element to the axis of rotation of the globe are made in the form of two connecting elements, the angular size of each of which, measured from the center of the globe, is 90 ° -i, where i is the inclination of the orbit, while one ends of the connecting elements comrade rigidly connected respectively to different ends of the helical member, and the other ends of the connecting elements are movably mounted on different closest to the respective ends of the spiral element portions rotation axis globe onto the globe of the poles.

The essence of the proposed device is illustrated in figures 1 and 2. Figure 1 shows the appearance of the proposed device, figure 2 shows a diagram explaining the calculation of the sizes of the connecting elements.

Figure 1 and 2 introduced the notation:

1 - globe with a map of the planet’s surface;

2 - spiral element;

3, 4 - the first and second connecting elements, respectively;

5 - track line;

6 - line of the equator;

7 - globe stand element, which is a continuation of the axis of rotation of the globe;

8 - the base of the globe stand;

9 - the plane of the orbit of the spacecraft;

A, B are the poles of the globe;

AB is the axis of rotation of the globe;

D is the descending node of the orbit;

E, F - ascending nodes of the orbit;

M, N - the ends of the spiral element;

G, H - projections of the ascending nodes of the orbit E, F on the equator of the globe;

Q, S are the projections of the ends of the spiral element M, N on the surface of the globe;

O is the center of the globe;

i is the inclination of the orbit;

g is the angular size of the connecting element.

The ends of the spiral element M, N are connected to one end of the connecting elements 3, 4. The other ends of the connecting elements 3, 4 are connected to the poles of the globe A, B. In the diagram shown in figure 2, it is illustrated that the angular size of the connecting element g is determined as a complement to the inclination angle of the orbit i to 90 ° and is equal to:

The shape of the spiral element 2, simulating one and a half turns of the orbit of the spacecraft, can be calculated, for example, according to the following relationships.

The orbit of a spacecraft moving in a circumcircular orbit around the planet is defined in the right Cartesian coordinate system OXYZ with the center in the center of the planet and the OZ axis directed along the axis of rotation of the planet with coordinates calculated by the formulas (see [4], p. 18):

Where

R is the distance from the points of the spiral element to the center of the globe;

λ is the longitude of the ascending node of the orbit,

u is the spacecraft latitude argument, taking values in the range from -π / 2 to 2π + π / 2;

λ ₀ is the longitude of the ascending node of the considered orbit of the spacecraft (corresponds to the value of the argument of the latitude of the spacecraft u = 0);

Δλ is the angular interturn distance along the equator ([5], p. 149):

ΔΩ is the orbital precession of the SC orbit in the inertial coordinate system;

T is the spacecraft circulation period;

ω is the angular velocity of rotation of the planet in inertial space.

Work with the device as follows.

The spiral element 2 is rotated relative to globe 1 so that point E (the point of the ascending node of the considered orbit of the spacecraft orbit) is located above the equator point G with a value of longitude equal to λ ₀ - the value of the longitude of the ascending node of the considered turn of the spacecraft orbit. In this position, the projection of the spiral element 2 onto the surface of the globe 1 simulates a line of track 5 on a time interval of one and a half spacecraft revolution, starting from point S (projection of point N, located over a quarter of the spacecraft's revolution to the point of the ascending node of the orbit E) and ending with point Q (projection of point M, which is a quarter of the spacecraft orbital period after the next point of the ascending node of the orbit F). This flight time interval of one and a half spacecraft rotation period is set by the values of the latitude argument and, measured from the point of the ascending node of the considered orbit of the orbit E, in the range from -π / 2 to 2π + π / 2.

Then, the initial branch of the spiral element 2, given by values of u in the range from -π / 2 to π / 2, shows the path of the ascending branch of the orbit at the beginning of the considered turn (point G is the central point of the path of the ascending branch of the orbit at the beginning of the considered turn), and the final branch spiral element 2, given by values of u in the range from 2π-π / 2 to 2π + π / 2, shows the trace of the ascending branch of the orbit at the end of the loop (point H is the center point of the trace of the ascending branch of the orbit at the end of the loop).

The user selects objects located along simultaneously simulated full paths of both ascending branches of the orbit, both at the beginning and at the end of the considered coil, as possible objects of observation on the ascending branches of the considered orbit of the spacecraft.

In this case, the connecting elements 3 and 4, fastening the spiral element 2 to the globe 1, do not obscure the information read by the user from the surface of the globe 1 located along the simulated orbit of the spacecraft 5.

We describe the technical effect of the invention.

The proposed device makes it more convenient to determine and select the objects of observations performed from the spacecraft on the ascending branches of the orbit of the spacecraft, by ensuring that the map of the planet displays simultaneously complete paths of both ascending branches of the orbit at the beginning and at the end of the considered revolution. At the same time, shading of the planet map by connecting elements of the device is simultaneously excluded. The technical result is achieved by performing a spiral element simulating one and a half turns of the SC orbit, located in the proposed manner relative to the points of the ascending nodes of the orbit, and by performing the fastening of the spiral element on the axis of rotation of the globe in the form of the proposed two connecting elements having the proposed size and installed on the globe, and connected with a spiral element of the proposed method.

LITERATURE

1. Krasavtsev B.I. Nautical astronomy. M .: Transport, 1986.

2. Application for invention No. 93045113/12 of 1993.09.14.

3. RF patent №2327112 from 01/26/06, IPC: G01C 21/24 - prototype.

4. Bebenin G.G., Skrebushevsky B.S., Sokolov G.A. Spacecraft flight control systems. // M .: Engineering, 1978.

5. Engineering reference for space technology. Publishing House of the Ministry of Defense of the USSR. M., 1969.

Claims (1)

A device for selecting objects of observation from an orbiting spacecraft, including a globe with a map of the planet’s surface plotted on it, a spiral element modeling the orbit of the spacecraft, and means for attaching the spiral element to the axis of rotation of the globe, characterized in that the spiral element is designed to simulate one and a half turns of the orbit of the moving in a circumcircular orbit with a positive inclination of the spacecraft, with the point of the orbit being for a quarter of the period of revolution of the spacecraft to the ascending node of the orbit, and for the end of the mentioned one and a half revolutions of the orbit, we take the point of the orbit that is one quarter of the period of revolution of the spacecraft after the next ascending node of the orbit, and the means for attaching the spiral element to the axis of rotation of the globe are made in the form of two connecting elements, the angular size of each of which, measured from the center of the globe, is 90 ° -i, where i is the inclination of the orbit, while one end of the connecting elements is rigidly connected respectively, with different ends of the spiral element, and the other ends of the connecting elements are movably fixed on different sections of the axis of rotation of the globe closest to the corresponding ends of the spiral element, emerging from the poles of the globe.

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