RU2477866C1 - Method for shaping of information field of laser teleorientation system - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: invention is designed for shaping of information field of laser teleorientation and navigation systems, optical connection, and can be used at control, landing and docking of airborne vehicles, escort of ships through narrow zones or bridge sections, remote control of robotic devices in zones that are dangerous for human health, etc. The proposed method is based on scanning by means of acoustooptical deflectors of the laser emission with a pencil-beam directional pattern; at that, laser beam movement trajectory provides formation both of information frames used for measurement of the controlled object coordinates, and command frames used for transfer of additional commands to the controlled object. The peculiar feature of the method is simultaneous formation of two lines of the information raster, which are displaced relative to each other by N/4 lines, by alternating formation of single cycles in the first line and then in the second line, where N is number of lines in a raster.

EFFECT: improving informativity of laser teleorientation system owing to increasing the repetition frequency of information and command rasters in information field of laser teleorientation system by reducing the duration of time delays between cycles, and owing to reducing light losses.

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Description

The invention relates to laser technology and is intended to form a laser information field for tele-orientation, navigation and optical communication systems, in control systems of automatic mobile devices. The invention can be used in controlling, landing and docking aircraft, adjusting the flight path of homing missiles and missiles, guiding ships along complex fairways, remote control of robotic devices.

For the formation of the information field (IP) of the laser television orientation system (LST), a method is widely used based on the spatial coding of the light field by a modulating raster (UK application No. 1395246, application. 17.10.72, publ. 21.05.75, NCI H4D, CL G01S 1/70). However, this method and the apparatus implementing it are characterized by significant light losses on the modulating raster, and the law of encoding the information field is determined by the type of modulating raster.

More perfect is a method based on element-wise scanning of a laser beam with a "needle-shaped" radiation pattern (UK application No. 2133652, application. 14.11.83, No. 8330302, publ. 24.07.84, class. F41G 7/00, NKI H4D; patent RU No. 2093849, priority 13.12.1995, IPC G01S 1/70, 17/87). In this method, the laser beam performs a reciprocating scan, first at one coordinate with a discrete transition along the orthogonal coordinate after the completion of each reciprocating movement of the laser beam, and then, after filling a rectangular raster with laser radiation, the scanning direction changes to orthogonal. The allocation of the coordinates of the controlled object in the LST IP is based on measuring the time interval between two received laser signals during the reciprocating scanning of the laser beam. In this case, light losses are determined by the efficiency of deflectors (scanners), and the presence of a “needle-shaped” laser radiation pattern provides a higher density of laser radiation than laser systems with spatial coding of the light field by a modulating raster and, therefore, a higher signal-to-noise ratio in the photodetector managed product.

The disadvantage of this method is the inability to transmit LST additional information necessary for optimal control of the object, which should be transmitted to the control object regardless of its location in the information field. Such information can be, for example, command signals that change the gain in the transmission loop of a controlled object and are associated, for example, with the presence of an angular tracking speed due to the movement of the line of sight, wind exposure, etc.

Closest to the claimed technical solution is a method based on the alternate formation of two rectangular orthogonal information rasters formed by scanning a laser beam in each raster in N lines with the number of scan cycles per line equal to three, with specified delays between cycles, counter-scanning two adjacent measures and equal delay times between them for the first and second rasters, after the formation of P information rasters, S command rasters are formed, in which each the same scan direction along the line, the time interval between the first and second measures is proportional to the size of the transmitted command (patent RU No. 2099730, priority 01.03.1996, IPC G01S 1/70, G02F 1/11, prototype).

The disadvantage of this method is an increase in light loss and a decrease in signal-to-noise ratio with increasing repetition rate of information and command rasters. As the frequency increases, the time of formation of the beat of each line decreases, and the time of the necessary blanking of the laser beam for the time delays between the lines of the lines remains constant, since it is due to the method of forming the raster and the technical characteristics of the equipment that implements this method.

The technical result of the invention is to increase the information content of the laser TV orientation system by increasing the repetition rate of information and command rasters in the information field of the LST by reducing the length of time delays between measures and reducing light loss.

The technical result is achieved by the fact that in the known method of generating LST IP, based on the alternate generation of P pairs of rectangular orthogonal information rasters formed by scanning a laser beam in each raster in N lines with the number of scan ticks per line equal to three and the opposite direction of scanning two adjacent measures, with a scan time of the tact Т _С and the formation of S command rasters formed by scanning the laser beam in each raster in N lines with the number of clock strokes There are three lines in the line for which the same scanning direction is selected in each step in rows, the time interval between the first and second measures is equivalent to the value of the transmitted command, and the time delays between the second and third measures, which are signs of the raster type, are different for each of the information and command rasters, at the same time form two lines of the raster, shifted relative to each other by N / 4 lines, for this, one-time steps are alternately formed in the first and then in the second lines, and when forming Hovhan information rasters after the formation of the second bar of the second line is introduced time delay, which is the feature of the data frame, and when forming command rasters after the formation of the first bar of the second line is introduced time delay? T = 0 ... T _C, an equivalent value of the transmitted command, after the formation of the second bar of the second line is introduced time delay equal to the sum of time delays - the time delay, which is a sign of the raster command, and the value _(C T -ΔT) and the next pair is shifted again f rmiruemyh rows formed with respect to the pair of rows N / 4 lines.

The simultaneous formation of two lines of the information raster, shifted relative to each other by N / 4 lines, by alternately forming single measures in the first and then in the second lines, introducing a time delay, which is a sign of the information frame, after the second measure of the second line is formed, introduction after the first stroke of the second line raster command delay time? T _K = 0 ... T _C, equivalent to a transmitted command, and administering after forming the second bar of the second line command tensile s time delay equal to the sum of time delays - the time delay, which is a sign of the raster command, and the value _(C T -ΔT _K), and the shift next pair relative to the newly formed lines formed on the pair of rows N / 4 rows improved the informativeness laser system teleorientatsii by increasing the frequency of transmission of the information field of the laser television orientation system by reducing the length of time delays between clock cycles and reducing light losses.

The applicant and the authors are not found in the patent and scientific and technical literature LST, performed in this way.

Figure 1 shows the trajectory of the laser beam during the formation of two information (IR) (figa) and 1b)) and one command frame (QC) (raster) PI (figv) for the case of eight lines and three clock cycles each line. Figure 1 shows the line numbers (1 to 8) to the right or bottom, the measure numbers (1 to 24) to the left or top, showing the spatial position of each measure of the lines (and each line) in the corresponding raster, as well as the conditional position of the photodetector device (FPU) of a managed object in a laser raster having coordinates X _K and Y _K and located at the intersection of the fifth horizontal and seventh vertical lines. Three scan cycles in each row are spatially separated for the convenience of the image. Linear frame sizes are A × A.

Figure 2 presents a temporary plot of the position of the laser beam along the horizontal coordinate X (figa) and along the vertical coordinate Y (fig.2b)) when forming two information rasters containing eight lines. On the left on the diagrams are the line numbers that determine their spatial position in the raster. The diagrams show the numbers of measures (from 1 to 24), showing the spatial position of each measure of the lines in each raster.

Figures 3a), 3c) and 3d) show time plots of the position of the laser beam along the horizontal line 5 and the vertical line 7 of information frames and the horizontal line 5 of the command frame, on which, according to Fig. 1, the photodetector of the controlled object is located . On figb), 3d) and 3e) presents a temporary diagram of the output pulses U _fpu photodetector of a managed object having the coordinates X _K and Y _K in the laser raster and located at the intersection of the fifth horizontal and seventh vertical lines. The temporal diagrams of the position of the laser beam along the line indicate the numbers of measures that form the line used. For horizontal line 5 of the information frame, these are measures 13, 15, and 17. For vertical line 7 of the information frame, these are steps 19, 21, and 23. For horizontal line 5 of the command frame, these are measures 13, 15, and 17.

On figa) presents a temporary plot of the position of the laser beam in the horizontal coordinate during the formation of one more complex information raster containing 16 lines. Temporal diagrams of the position of the laser beam in rows and the position of the laser beam in the horizontal coordinate for each line during the formation of one information raster containing 16 lines are conventionally presented in Fig. 4b) and Fig. 4c).

The method is as follows.

In the formation of each of the information and command frames, the laser beam form the clock, as shown in figure 1. Each measure relative to the previous one is shifted by N / 4 = 2 lines in the coordinate orthogonal to the scanning direction along the line. After the completion of six measures, for example 1 ... 6, two lines are formed - the first and second, spaced along the coordinate orthogonal to the scanning direction along the line, also by N / 4 = 2 lines. Next, the formation of the next two lines begins - the third and fourth.

The scan time of each of the measures on the line is the same and equal to T _C. When forming information frames, time delays T ₃ in the lines (Fig. 2) are introduced only after the formation of two measures of two simultaneously generated lines. For example, with the simultaneous formation of the first and second IR lines (Fig. 1a)), 1, 2, 3 and 4 cycles of the first and second lines are formed, then the laser radiation is extinguished for the time T ₃ , and then 5 and 6 cycles of the first and second lines are formed IR The delay values for IR with horizontal and vertical lines are different and equal, respectively, T _PX and T _PU . These values are a sign of horizontal or vertical frames. For each line, the temporal plot of the position of the laser beam along the line (Fig. 2 and Fig. 4a), 4c)) is three measures. The time delay between the first and second measures is equal to T _C (since at this time, for example, for the fifth line of the IR, according to FIG. 2b), a measure 14 of the sixth line is formed between 13 and 15 measures of the fifth line). The time delay between the second and third measures is (T _C + T _PX ) or (T _C + T _PU ). It is equal to the scanning time T _{C of} one measure in another line (for the fifth IR line, this is the formation of 16 measures of the sixth line) and the laser beam blanking time T _PX or T _PU .

When forming command frames (Fig. 1c)), in which the scan direction along the clocks has the same direction, the first time delay ΔТ _K in the lines (laser damping) (Fig. 3d)) is introduced after the formation of the first beat of two simultaneously generated lines, and the second delay (T _C -ΔT _K + T _PC ) is introduced after the formation of two measures of two simultaneously generated lines.

The repetition rate of command frames is usually 5-10 times lower than the repetition rate of information frames. Team frames, as a rule, have two features: one feature for transmitting amendments horizontally, and the second feature for transmitting amendments vertically.

When irradiating a photodetector (FPU) of a controlled object located at the IP point with coordinates X _K and Y _K and located at the intersection of the fifth horizontal and seventh vertical lines (Fig. 1), the laser beam generates three pulses during line scanning of the FPU (Fig. .3b), 3d), 3e)).

For information frames, the time interval T _{1X, 1Y} between the first two pulses determines the magnitude of the FPU coordinate in the IP, and the time interval (T _{1X, 1Y} + T _{2X, 2Y} ) between the first and third pulses _determines its sign (X or Y). The duration of the time interval T _{1X, 1Y} can vary from T _C to 3T _C. As follows from figa) and 3c), the total duration T _{∑X, ∑Y of} intervals T ₁ and T ₂ for information frames is equal to: T _∑X = (4T _C + T _PX ) or T _∑Y = (4T _C + T _PU ).

For a command frame, the time interval T _1K between the first and second pulses determines the value of the transmitted command ΔT _K , the time interval (T _1K + T _2K ) between the first and third pulses determines the sign of command transmission. For the command frame, the value of the time interval T _1K does not depend on the location of the FPU in the IP and is determined by the value of the time delay ΔT _K , introduced during the formation of the first and second clock periods. Duration of the time interval T _1K can vary from 3T to 2T _{C C.} As follows from fig.3d), the total duration T _∑K intervals T _1K and T _2K for the command frame is equal to T _∑K = (5T _C + T _PC ).

, где А - линейный размер ИП, T_1X,1Y - время между первым и вторым импульсами ФПУ, Т_C - время сканирования одного такта строки.The location of the FPU in the IP relative to the center of the IP is determined, for example, by the expression:

where A is the linear size of the SP, T _{1X, 1Y} is the time between the first and second pulses of the FPU, T _C is the scan time of one bar of the line.

The value of the received additional command U _d can be determined, for example, by the expression: U _d = T _1K -T _C = ΔT _K.

The sign of the measured coordinate X _K and Y _K or the command signal U _d is determined by the time interval between the first and third pulses of the FPU, which for horizontal and vertical lines of the information frame or for the command frame are respectively: (4Т _С + Т _ПХ ), (4Т _С + T _PU ) or (5T _C + T _PC ).

The delay values T _{PX, PU, PC} , which are a sign of horizontal information, vertical information or command frames, can be set by the following values: T _PX = 5 μs, T _PU = 15 μs, T _PK1 = 5 μs, T _PK2 = 15 μs, where T _PK1 and T _PK2 are signs of the first and second command frames. The time interval ΔT _PS between adjacent features for this example is 10 μs. Since the received pulses of the FPU fluctuate in time, the confidence interval of signal reception is usually set. The duration of the waiting time for the reception of the third impulse of the sign ΔТ ПХ _{, ПУ, PC} can be set equal to ± 0.4ΔТ _ПС relative to the central value.

, где А - линейный размер ИП, Т₂ - время между вторым и третьим импульсами ФПУ, Т_С - время сканирования одного такта строки. Величина принятой дополнительной команды U_д, при измерении временного интервала между вторым и третьим импульсами ФПУ, может определяться, например, выражением:Note that information about the position of the FPU in the IP or the transmitted value of the commands is also contained in the duration of the time interval between the second and third pulses of the FPU. The location of the FPU in the IP relative to the center of the IP is determined by the expression:

where A is the linear size of the PI, T ₂ is the time between the second and third pulses of the FPU, T _C is the scan time of one bar of the line. The value of the received additional command U _d , when measuring the time interval between the second and third pulses of the FPU, can be determined, for example, by the expression:

U _d = 2T _C + T _PC -T _2K = ΔT _K.

When calculating the average value of the data determined by the time intervals between the first and second and between the second and third pulses of the FPU, the mean-square error of the obtained averaged data will be reduced by about 1.4 times relative to single measurements, which increases the information content of the television orientation system (B.R. Levin Theoretical Foundations of Statistical Radio Engineering (Book 1, Moscow: Sov. Radio, 1969, p. 80).

Comparison of the proposed method and the prototype will be carried out according to two criteria: the time of formation of the information frame and the loss of light power due to the damping of laser radiation for technological pauses.

Define the time T _{∑ 2 the} formation of two lines of the information frame with three bars of the line with the original values of the time intervals, which are described in the prototype:

- the time of the formation of the tact of the line T _C = 100 μs,

- the delay time between the first and second bars of the string T ₀ = 10 μs,

- the delay time between the second and third ticks of the line T _PX = 20 μs,

- the delay time between the lines T ₆ = 10 μs.

. Длительность задержек равна

.After calculating, we get for the prototype:

. The duration of the delays is

.

. Проведя вычисления, получим η_T=8,8%.The formation time of two lines of an information frame with three line strokes in the proposed method, as follows from figure 2, is numerically equal to 6T _C + T _PX . Assuming T _C = 100 μs, and T _PX = 20 μs, we obtain the value of T _∑2 = 620 μs and T _{ад zader.} = 20 μs. The resulting gain in time of the formation of two lines (and the frame as a whole) for the proposed method in relation to the prototype is

. Having performed the calculations, we obtain η _T = 8.8%.

η_P=3%. Величина световых потерь в предлагаемом способе значительно меньше, чем у прототипа. Уменьшение световых потерь при формировании лазерного растра увеличивает отношение сигнал/шум фотоприемного устройства управляемого объекта и, следовательно, повышает информативность системы телеориентации.The quantity of light loss can be estimated by the following expression: η _P = T _Σzader / T _Σ2. Substituting the above values of time intervals, we obtain:

η _P = 3%. The amount of light loss in the proposed method is significantly less than that of the prototype. Reducing light losses during the formation of a laser raster increases the signal-to-noise ratio of the photodetector of a controlled object and, therefore, increases the information content of the teleorientation system.

In reality, the gain is much greater. The delay time between the first and second ticks of the line should be selected taking into account the inertia of the scanning system (deflector) of the laser. So, when using acousto-optical paratellurite deflectors to scan a laser beam with a light aperture, as noted in the prototype, equal to 10 mm, the acoustic wave settling time is approximately 15 μs. Therefore, the time delay between the first and second ticks of the line to provide temporary resolution of the FPU pulses from two adjacent clocks of the line should be at least 15 μs.

In order to increase the information content of the teleorientation system, it is necessary to increase the refresh rate of frames by decreasing the time of formation of the line measures. Assuming the time of formation of the line clocks to be 50 μs and the necessary time T ₀ = 15 μs, we carry out calculations similar to the above. As a result of the calculations, we obtain: η _Т = 18%, η _Р ^prot = 23%, η _Р = 6%. With a further decrease in the time of formation of the line measures, the gain will be more substantial.

Thus, the simultaneous formation of two lines of the information raster, shifted relative to each other by N / 4 lines, by alternately forming single measures in the first and then in the second lines, introducing a time delay after the formation of the second measure of the second line, which is a sign of the information frame, the introduction after the formation of the first measure of the second line of the command rasters of the time delay ΔT _K = 0 ... T _C , equivalent to the value of the transmitted command, and the introduction after the second measure of the second line command rasters, the time delay equal to the sum of the time delays - the time delay, which is a sign of the command raster, and the value (T _C -ΔT _K ), as well as the shift of the next pair of newly formed lines relative to the formed pair of lines by N / 4 lines allowed to increase the information content of the laser teleorientation systems by increasing the transmission frequency in the information field of the laser teleorientation system by reducing the length of time delays between clock cycles and reducing light losses.

The invention also provides increased accuracy of the selection of useful signals along two orthogonal coordinates with an increased frequency of formation of the information field frames by the laser system, which increases the accuracy of the orientation of a moving object and the functional reliability of control and correction of its trajectory.

Claims (1)

A method for generating an information field of a laser teleorientation system based on the alternate formation of P pairs of rectangular orthogonal information rasters formed by scanning a laser beam in each raster in N lines with the number of scan cycles in a line equal to three and the opposite direction of scanning two adjacent cycles, with the scan time of the tact T _C and the formation of S command rasters formed by scanning the laser beam in each raster in N lines with the number of scan cycles in a line equal to three, in which the same scanning direction is selected in each step in rows, the time interval between the first and second measures is proportional to the size of the transmitted command, and the time delays between the second and third measures, which are signs of the raster type, are different for each of the information and command raster, characterized in that at the same time form two lines of the raster, shifted relative to each other by N / 4 lines, for this, one-time steps in the first and then in the second lines are alternately formed, moreover, when generating information rasters after the formation of the second measure of the second line, a time delay is introduced, which is a sign of the information frame, and when forming command rasters after the formation of the first measure of the second line, the time delay ΔT = 0 ... T _C , equivalent to the value of the transmitted command, is introduced after the formation of the second measure the second row is administered a time delay equal to the sum of time delays - the time delay, which is a sign of the raster command, and the value _(C T -ΔT) and following shift th pair of relatively newly formed lines formed on the pair of rows N / 4 lines.

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