CN106896827B - Real-time searching method for fixed star near pointing position of photoelectric tracking measuring equipment - Google Patents

Abstract

The invention provides a real-time searching method for fixed stars near the pointing position of photoelectric tracking and measuring equipment, and relates to the field of photoelectric tracking and measuring, and high-precision equipment guide control. Aiming at the requirement that stars around a track are required to be observed in the target tracking process. The invention designs a method, which can realize target tracking and simultaneously search fixed stars within a certain field angle range from a target in real time in a star catalogue. The method utilizes the characteristic that the position of the fixed star is basically constant in the second equatorial coordinate system, and avoids the related problems of large calculated amount, large searching complexity and the like caused by the fact that the fixed star and the target move in the horizontal coordinate system in the star searching process. And related errors are calculated through the virtual stars, so that direct search in the star catalogue is realized, the search amount is reduced, and the search efficiency and the search hit rate are improved.

Description

Real-time searching method for fixed star near pointing position of photoelectric tracking measuring equipment

Technical Field

The invention belongs to the field of photoelectric tracking measurement, and particularly relates to a real-time searching method for fixed stars near the pointing position of photoelectric tracking measurement equipment.

Background

In the field of photoelectric tracking measurement, in order to accurately obtain position data of a target, system errors and pointing deviations of photoelectric tracking measurement equipment need to be corrected. However, the error of the photoelectric tracking measurement device changes with time, and therefore correction is required at regular time. Because the star position is considered to have higher precision, the star position can be generally used for calibrating errors of photoelectric tracking measurement equipment, and therefore if the position of the star in a certain field range around a target can be observed when the target is tracked, the system errors and the pointing deviation can be calibrated in real time or quasi-real time. How to search stars around the target in real time or quasi real time in the process of tracking the target is a key for solving the problem.

When searching for stars while tracking a target in real time, three problems need to be solved:

(1) due to the relation between the target motion and the star motion, the star searching needs to judge the mutual motion direction, speed and other factors, and particularly, when the star enters a view field after a certain time is predicted, the complexity of searching the star is greatly increased;

(2) the position of a star in the star catalogue is unchanged, but the star cannot be directly compared and searched with a target position, when the flat position of the star in the star catalogue needs to be converted to the horizon position of the target, the processing of time processing of correction of the offset, nutation, annual parallax, annual aberration, annual movement, observation position and the like is needed, but when the number of stars is large, the time needed for conversion is long if all stars are converted;

(3) the purpose of searching for stars is to perform operations such as guidance of stars, and after a star is found, guidance calculation of the position of the star is required.

Disclosure of Invention

In order to solve the aim of tracking a target in real time and searching surrounding stars at the same time, a real-time star searching method for the pointing position of a photoelectric tracking and measuring device is provided. The method transforms the target position into a second equatorial coordinate system and establishes the motion characteristics of the target in the second equatorial coordinate system. Meanwhile, the difference between the horizontal position and the visual position caused by the precision, nutation and the like near the pointing position of the equipment is calculated by utilizing the characteristic that the star position is basically constant in the second equatorial coordinate system. And then correcting the star list according to the difference and searching the corresponding stars.

The technical scheme adopted by the invention is as follows: a real-time searching method for fixed stars near the pointing position of photoelectric tracking measuring equipment is realized by the following steps:

step (1), tracking the target by photoelectric tracking measurement equipment, converting the horizontal system position data of the target after the rough pointing deviation correction into data in a second equatorial coordinate system, and processing the data in the second equatorial coordinate system to obtain the motion characteristic of the target;

step (2), setting the current position in a second equatorial coordinate system as a center, calculating the position of the target after T time when prediction is needed, and setting the central position as (RiAc, RiDc) by taking the position as the center;

step (3), a star which is self-walking in one year and has zero parallax is arranged at the virtual current position, and the deviation between the horizontal position and a second equatorial coordinate system is calculated and set as (delta RiA, delta RiD);

step (4), calculating a search center and a search range in the fixed star table, wherein the search center is (RiAc-delta RiA, RiDc-delta RiD), and if the search range is α, the search range in the star table is as follows:

the red channel [ RiAc-delta RiA- α/cos (RiDc-delta RiD), RiAc-delta RiA + α/cos (RiDc-delta RiD) ];

declination [ RiDc-delta RiD- α -delta RiD + α ];

step (5), searching fixed stars in the star catalogue, taking the fixed star closest to the center of the star catalogue as an optimal search result, locking the fixed star once the fixed star is selected, and terminating the search process;

step (6), calculating the position of the star in the second equatorial coordinate system, the opening angle of the current target in the second equatorial coordinate system and the movement trend between the star and the target, and once the star moves out of the view field of the detector, carrying out the star searching process again; updating the pointing deviation in step (1) when the target is within the field of view;

and (7) calculating position data (A, E) of the fixed star in the horizon in real time in the process that the fixed star is locked, wherein A is an azimuth angle, and E is a pitch angle, and sending the position data to a guiding mechanism.

The horizontal system position data of the target comprise an azimuth angle and a pitch angle, the data in the second equatorial coordinate system comprise a right ascension and a declination, and the motion characteristics of the target comprise speed and acceleration.

Compared with the prior art, the invention has the advantages that: the second equatorial coordinate system is adopted as the middle coordinate system, and the conversion of all coordinate systems of fixed stars in the pointing area is not needed, so that the calculation amount is reduced, and the working efficiency is improved particularly when the fixed stars in the star bank are more; and meanwhile, the motion characteristics of the target are modeled in the second equatorial coordinate system, so that the relation between the target and the star motion is simplified.

Drawings

FIG. 1 is a schematic diagram of an electro-optical tracking measurement device tracking a target in a second equatorial coordinate system while performing a star target search;

fig. 2 is a flow chart of the target tracking and star searching process of the photoelectric tracking and measuring device.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

A real-time searching method for fixed stars near the pointing position of photoelectric tracking measuring equipment is realized by the following steps:

step (1), tracking the target by photoelectric tracking measurement equipment, converting the horizontal system position data (azimuth angle and pitch angle) of the target after the rough pointing deviation correction into data (right ascension and declination) in a second equatorial coordinate system, and processing the data in the second equatorial coordinate system to obtain the motion characteristics (speed, acceleration and the like) of the target;

step (2), setting the current position in a second equatorial coordinate system as a center, calculating the position of the target after T time when prediction is needed, and setting the central position as (RiAc, RiDc) by taking the position as the center;

step (3), a star which is self-walking in one year and has zero parallax is arranged at the virtual current position, and the deviation between the horizontal position and a second equatorial coordinate system is calculated and set as (delta RiA, delta RiD);

step (4), calculating a search center and a search range in the fixed star table, wherein the search center is (RiAc-delta RiA, RiDc-delta RiD), and if the search range is α, the search range in the star table is as follows:

the red channel [ RiAc-delta RiA- α/cos (RiDc-delta RiD), RiAc-delta RiA + α/cos (RiDc-delta RiD) ];

declination [ RiDc-delta RiD- α -delta RiD + α ];

step (5), searching fixed stars in the star catalogue, taking the fixed star closest to the center of the star catalogue as an optimal search result, locking the fixed star once the fixed star is selected, and terminating the search process;

step (6), calculating the position of the star in the second equatorial coordinate system, the opening angle of the current target in the second equatorial coordinate system and the movement trend between the star and the target, and once the star moves out of the view field of the detector, carrying out the star searching process again; updating the pointing deviation in step (1) when the target is within the field of view;

and (7) calculating position data (A, E) of the fixed star in the horizon in real time in the process that the fixed star is locked, wherein A is an azimuth angle, and E is a pitch angle, and sending the position data to a guiding mechanism.

Claims (2)

1. A real-time searching method for fixed stars near the pointing position of photoelectric tracking measuring equipment is characterized by comprising the following implementation steps:

tracking a target by photoelectric tracking measurement equipment, converting horizontal system position data of the target after correcting pointing deviation into data in a second equatorial coordinate system, and processing the data in the second equatorial coordinate system to obtain the motion characteristic of the target;

step (2), setting the current position in a second equatorial coordinate system as a center, calculating the position of the target after T time when prediction is needed, and setting the central position as (RiAc, RiDc) by taking the position as the center;

step (3), a star which is self-walking in one year and has zero parallax is arranged at the virtual current position, and the deviation between the horizontal position and a second equatorial coordinate system is calculated and set as (delta RiA, delta RiD);

step (4), calculating a search center and a search range in the fixed star table, wherein the search center is (RiAc-delta RiA, RiDc-delta RiD), and if the search range is α, the search range in the star table is as follows:

the red channel [ RiAc-delta RiA- α/cos (RiDc-delta RiD), RiAc-delta RiA + α/cos (RiDc-delta RiD) ];

declination [ RiDc-delta RiD- α -delta RiD + α ];

step (5), searching fixed stars in the star catalogue, taking the fixed star closest to the center of the star catalogue as an optimal search result, locking the fixed star once the fixed star is selected, and terminating the search process;

step (6), calculating the position of the star in the second equatorial coordinate system, the opening angle of the current target in the second equatorial coordinate system and the movement trend between the star and the target, and once the star moves out of the view field of the detector, carrying out the star searching process again; updating the pointing deviation in step (1) when the target is within the field of view;

and (7) calculating position data (A, E) of the fixed star in the horizon in real time in the process that the fixed star is locked, wherein A is an azimuth angle, and E is a pitch angle, and sending the position data to a guiding mechanism.

2. The method as claimed in claim 1, wherein the data of the object's horizon position includes azimuth and elevation angles, the data in the second equatorial coordinate system includes right ascension and declination, and the motion characteristics of the object include velocity and acceleration.

Images