JP2022069784A - Laser observation system - Google Patents

Abstract

To provide a laser observation system for observing a target object with laser light at high accuracy, in which the discrimination of a light-receiving signal from distance measurement data of laser observation containing noise and the light-receiving signal in a mixed state can be facilitated.SOLUTION: A laser observation system 1 includes a telescope directed to a target object, a laser oscillation unit that continuously excites a plurality of pulsed laser beams radiated toward the target object, a transmission optical unit corresponding to a path of the pulsed laser beams between the telescope and the laser oscillation unit, a reception optical unit that detects each of the reflected pulsed beams received from the telescope, and a data processing unit that sends the continuous pulsed laser beams to the target object while varying in a predetermined variation pattern and performs a distance measurement process based on each detection timing of the reflected pulsed laser beams detected in the reception optical unit, so as to generate distance measurement data.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laser observation system for observing an object flying in space.

Recently, laser light is used for various purposes. A typical laser observation system is a laser ranging system. For example, a laser observation system that observes an artificial satellite equipped with a reflector is called SLR (Satellite Laser Ranging).

With SLR, accurate distance measurement from the laser beam emission point to the artificial satellite (reflector) can be performed. By observing the exact position of the artificial satellite at many points, the observation system can derive the exact orbit of this satellite. As a result, various systems will be able to use this satellite as a trigonal point in orbit. In recent years, a method of observing space debris (hereinafter simply referred to as debris) in outer space using a distance measuring technique using a laser has also attracted attention because of its power saving and high reliability.

In order to grasp the actual situation of debris in outer space, a space situational awareness (SSA) system has been constructed. In the SSA system, a passive observation method using an optical telescope or an active observation method using a radar is used for debris observation. The SSA system observes debris and creates a database (catalog) of debris orbit information. However, due to the daily increase in debris and the variety of shapes, an accurate database has not yet been established. In addition, accurate orbit prediction of debris is still difficult at present. This is due to the size, shape, and accuracy of orbit information of debris currently being converted into data. In order to prevent damage caused by debris, it is desirable to create a more accurate database and further improve the prediction accuracy.

As the prior art related to the SSA system, for example, Patent Document 1 can be mentioned.
Patent Document 1 describes a space object observation system (SSA system) for observing space objects located in outer space. This document describes a laser observation device that observes a space object by emitting an irradiation laser from the ground into outer space and receiving the reflected laser light as a part of the space object observation system. In addition, when observing a space object, the estimated area where the space object is located at a certain observation time is calculated for the irradiation laser based on the prior observation information, and the spread angle of the irradiation laser light emitted to the space object at the observation time is estimated. It is described that the adjustment is based on the region.

Patent No. 6652816

A more accurate database (catalogization) of objects flying in outer space such as space debris is desired, and the database is updated daily by various organizations.

In order to create an accurate database of debris and further improve the prediction accuracy, the inventor examined a method to practically solve some problems of the laser observation system. Among them, when debris actually flying in space is observed by laser, the S / N ratio of noise and true distance measurement data is obtained for the distance measurement data (distance measurement value group) of any target collected by laser observation. We focused on the fact that it is difficult to distinguish between them. This problem is regarded as a more prominent problem in a laser range-finding device including a range-finding unit that receives reflected light using a photon detector.

Most debris does not have a laser reflector, and the intensity of reflected light from the debris is often very weak. For this reason, it is difficult to distinguish between noise and the true observed value in the distance measurement data, and it is practically difficult to judge whether the distance is correctly measured (whether the received signal is the reflected light from the target). There is.

Also, unlike SLR satellites equipped with laser reflectors and living satellites, many known debris have predicted orbits generated from data acquired from radars, optical telescopes, and catalogs. The accuracy of this predicted trajectory is not high enough at present, and the laser may not hit the target even if the telescope is pointed at the predicted position. For this reason, as described in Patent Document 1, it is conceivable to widen the beam divergence angle, which is generally practiced in SLR, to make it easier for the beam to hit, or to scan the telescope to search for the received light from the target. Has been done.

With these methods, once the reflected laser beam from the target is found, the beam spread angle can be narrowed down and the pointing can be adjusted accurately. In addition, by going through multiple observation processes in this way, it can be expected that pointing can be performed accurately and the S / N ratio can be improved.

However, although these ideas can be an appropriate sequence if you have a large laser or telescope, there are various problems with the new construction and use of large facilities.

On the other hand, debris observation by photon counting does not necessarily have to have a large laser or telescope, and it is possible to configure (extend) a system (observation network) on a scale that is easier to construct more realistically. In addition, it is thought that the database maintenance speed and observation accuracy can be improved by increasing the number of stations to be observed as an observation network of a realistic scale. However, in the debris observation by photon counting as described above, the received signal by the reflected laser beam is weak, and in many cases, only the reception level equivalent to the dark count noise can be expected. In such a case, it becomes very difficult to distinguish the reflected light from the target from the noise. Of course, if noise generation is not suppressed and noise is removed well, the S / N ratio will deteriorate.

Even in debris observations that do not rely on photon counting, the S / N ratio and discrimination accuracy of noise and true distance measurement data for the distance measurement data (distance measurement value group) of any target collected by laser observation. Improvement is desired.

The present invention has been made to solve some of the above problems, and provides a laser observation system that facilitates discrimination of a received light signal from distance measurement data of laser observation in which noise and a light receiving signal are mixed. The purpose is.

The laser observation system of one embodiment according to the present invention includes a telescope aimed at a target object, a laser oscillating unit that continuously excites a plurality of pulsed laser beams emitted toward the target object, and the telescope and the laser oscillation. The transmission optics, which is the path of the pulsed laser light between the units, and the reception optics, which detects each of the reflected pulsed laser light received from the telescope, are continuously varied toward the target object while being varied by a predetermined fluctuation pattern. It includes a data processing unit that generates distance measurement data by executing distance measurement processing based on the detection timing of each reflected pulse laser light detected by the reception optical unit while executing transmission of the pulsed laser light. It is a feature.

The laser observation method of the embodiment according to the present invention uses a laser ranging device including a laser oscillating unit that continuously excites a plurality of pulsed laser beams radiated toward a target object, and is excited by the laser oscillating unit. In the process of continuously radiating the pulsed laser light from the telescope directed at the plurality of target objects via the transmission optics, the continuous pulsed laser light is transmitted toward the target object while being varied by a predetermined fluctuation pattern. It is characterized in that distance measurement data is generated by executing distance measurement processing based on the detection timing of each reflected pulse laser light detected by the receiving optical unit that executes and detects each received reflected pulsed laser light.

In the program for a laser observation system according to the present invention, the control unit of a laser ranging device including a laser oscillation unit that continuously excites a plurality of pulsed laser beams radiated toward a target object is subjected to the laser oscillation. In the process of radiating pulsed laser light excited by the unit from a telescope continuously directed at multiple target objects via the transmission optics, a continuous pulse laser toward the target object while varying in a predetermined fluctuation pattern. It operates to execute light transmission and perform distance measurement processing based on the detection timing of each reflected pulse laser light detected by the receiving optical unit that detects each received reflected pulse laser light to generate distance measurement data. It is characterized by letting it.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a laser observation system that facilitates discrimination of a received light signal from distance measurement data of laser observation in which noise and a light receiving signal are mixed.

It is a block diagram which shows the laser observation system 1 which concerns on one Embodiment. It is a block diagram which shows the laser ranging apparatus 10 which concerns on one Embodiment. It is a block diagram which shows the central processing unit 20 which concerns on one Embodiment. It is a schematic diagram which shows the structural example of the optical path length changing part 16 which concerns on one Embodiment, the configuration example (a) which constructs the optical path length changing part 16 with one movable stage, and the optical path length changing part 16 with a plurality of movable stages. It is a configuration example (b) constructed in. It is a schematic diagram which shows the structural example of the optical path length changing part 16 which concerns on one Embodiment, and is the configuration example which constructs the optical path length changing part 16 with a movable stage and a rotation unit. It is a plot diagram which shows the observation data when the reflected light is sufficiently strong (a) and the case (b) about an arbitrary target. It is a plot figure which shows the observation data which intentionally created the variation pattern in the optical path length of each pulse laser light about an arbitrary target.

An embodiment of the present invention will be described with reference to the drawings.
The laser observation system 1 described with reference to the embodiment includes a mechanism for transmitting laser light toward a target and receiving the reflected laser light which is the reflected wave, similarly to the existing laser ranging system.
For the initial capture of the target object (target), refer to the predicted trajectory information database in which the trajectory of the target object is recorded in advance. Further, this predicted orbit information database may be an internal system or an external system. Further, the initial acquisition may be performed by using one or both of the radar observation method and the optical observation method.

FIG. 1 is a block diagram showing a laser observation system 1 according to an embodiment.
In the present embodiment, as the laser observation system 1, a central processing unit 20 that performs prediction trajectory determination and the like of a target together with a laser ranging device 10 installed on the ground is described, but the center described later in the laser ranging device 10. The processing operation of the arithmetic unit 20 may be executed. The central processing unit 20 may be played by, for example, a server installed near the laser ranging device 10 or a server installed at another base in a remote location. Further, although the external predicted trajectory information providing system, which is the predicted activation information database, is described, the predicted trajectory information may be managed by the internal system. The central processing unit 20 transmits the predicted trajectory of the target to the laser ranging device 10, and also analyzes the ranging data from the laser ranging device 10.

FIG. 2 is a block diagram showing a laser ranging device 10 according to an embodiment.
The laser ranging device 10 includes a laser oscillator 11 and a transmission / reception optical system 12 as a laser device. Further, the laser ranging device 10 includes a telescope 13 (including a gimbal mechanism and the like) that controls pointing of the transmission / reception optical axis in the predicted orbit of the target. Further, the laser ranging device 10 includes a timing measurement unit 14 and a data processing / control calculation unit 15 as a data processing unit (control unit).

The laser ranging device 10 irradiates the laser pulsed light generated by the laser oscillator 11 from the telescope 13 toward the target via the transmission / reception optical system 12. The reflected light reflected by the target enters the telescope 13 again and is detected by the transmission / reception optical system 12. This reflected laser light is converted from an optical signal to an electric signal by photon counting with a photodetector (photon detector) of the receiving optical unit 12-2, and the round-trip time is measured by the timing measuring unit 14 according to the transmission timing and the reception timing. Will be done. It should be noted that distance measurement data may be obtained by a method other than photon counting.

The laser oscillation unit 11 continuously excites a plurality of pulsed laser beams radiated toward the target object and sends them out to the transmission / reception optical system 12. Further, it is desirable that the laser oscillation unit 11 is configured so that the number of repetitions of the pulsed laser light continuously excited can be changed to an arbitrary predetermined number during laser observation.

The transmission / reception optical system 12 includes an optical element such as a photodetector for transmission / reception light, adjustment of beam spread, and transmission / reception light separation, and is divided into a transmission optical unit 12-1 and a reception optical unit 12-2. The transmission optical unit 12-1 is a path of pulsed laser light between the telescope 13 and the laser oscillation unit 11. Further, it is desirable that the transmission optical unit 12-1 includes an optical path length changing unit 16 capable of arbitrarily changing the path length of the pulsed laser beam. The optical path length changing unit 16 operates so as to change the path length of the transmission system in one or a plurality of predetermined fluctuation patterns. Further, the receiving optical unit 12-2 includes a photodetector that detects each of the reflected pulsed laser light received from the telescope 13.

The timing measurement unit 14 calculates distance measurement data (each distance measurement value) from the timing control of each unit and the transmission / reception timing of the laser.

The data processing / control calculation unit 15 calculates the transmission / reception timing predicted from the predicted trajectory of the target to be sent, the control signal of the pointing of the telescope 13, and the distance measurement data from the timing measurement unit 14 into the observation data. Or, it also generates control signals for each part.

Further, the data processing / control calculation unit 15 controls the optical path length changing unit 16 of the transmission optical unit 12-1 as a part of the observation process for obtaining the distance measurement data, and the continuous pulse laser toward the target object. It is configured to be able to execute an operation of varying the optical path length of each continuous pulsed laser beam in a predetermined fluctuation pattern when the light is transmitted. The predetermined fluctuation pattern is not limited to one type in advance, and it is desirable that there are a plurality of types and they are appropriately switched. For example, a triangular wavy pattern, a sine and cosine wavy pattern, and a rectangular wavy pattern can be exemplified as the fluctuation pattern. The data processing unit / control calculation unit 15 controls the optical path length changing unit 16 based on an arbitrary variation pattern selected, and executes an operation of varying the optical path length of each pulsed laser beam according to the selected variation pattern. Just do it.

Further, the data processing / control calculation unit 15 controls the timing measurement unit 14 as a part of the observation process for obtaining the distance measurement data, and the continuous pulse laser when the continuous pulse laser light is transmitted toward the target object. It is configured to be able to execute an operation of periodically changing the number of repetitions of light in a predetermined fluctuation pattern. The predetermined fluctuation pattern is not limited to one type, and it is desirable that there are a plurality of types and the patterns can be appropriately switched. For example, examples of the fluctuation pattern include a fluctuation pattern in which the time interval between pulses is sparsely changed for each constant excitation, and a fluctuation pattern including a non-light emitting portion for each predetermined number. The data processing unit / control calculation unit 15 controls the timing measurement unit 14 based on the selected arbitrary fluctuation pattern, and the timing measurement unit 14 controls the laser oscillation unit 11 to reduce the number of repetitions of the pulse laser beam. The operation of periodically fluctuating with a predetermined fluctuation pattern may be executed.

Further, the data processing unit / control calculation unit 15 controls the optical path length changing unit 16 to change the optical path length according to the variation pattern of the selected optical path length, and at the same time, the selected excitation repetition number. The laser oscillation unit 11 may be operated so as to periodically change the number of repetitions of the pulsed laser beam according to the fluctuation pattern.

When the step of varying the optical path length in a predetermined variation pattern is included, the optical path length changing unit 16 is operated and varied at the detection timing of each reflected pulsed laser beam detected by the receiving optical unit 12-2. Differences in optical path length appear. Further, the detection timing of the continuous reflected pulsed laser beam reflects the fluctuation according to the predetermined fluctuation pattern.
Similarly, when the step of periodically varying the number of excitation repetitions of the pulsed laser beam in a predetermined variation pattern is included, the detection timing of the continuous reflected pulsed laser beam reflects the variation according to the predetermined variation pattern. Will be done.

Further, the laser ranging device 10 includes a function of receiving a control signal for the timing measurement unit 14 and the data processing / control calculation unit 15 from the central processing unit 20 and operating according to the control signal. The central processing unit 20 is configured to execute arithmetic processing performed by each control system of the laser ranging device 10 and notify the laser ranging device 10 of the result (control signal). As a control signal between the central processing unit 20 and the laser ranging device 10, information for operating the optical path length changing unit 16 in an arbitrary fluctuation pattern and an arbitrary number of repetitions of the pulse laser beam are arbitrary. Information that specifies the periodicity of the variation pattern may be included.

When the laser ranging device 10 observes independently, the transmission / reception timing is calculated by the data processing / control calculation unit 15 in the laser ranging device 10 based on the predicted trajectory, and the timing measuring unit 14 oscillates the laser. The trigger sequence and the gate timing signal of the photodetector are generated in consideration of the periodicity of the light detector. Further, the data processing / control calculation unit 15 may also execute the processing operation of the central processing unit 20, which will be described later.

FIG. 3 is a block diagram showing a central processing unit 20 according to an embodiment.
As shown in the figure, the central processing unit 20 includes a communication unit 21, a pattern recognition unit 22 as a data processing unit, and a calibration unit 23.

The communication unit 21 is connected to the laser ranging device 10 and the external predicted trajectory information providing system, and controls the transmission / reception timing predicted from the predicted trajectory of the target of the laser ranging device 10 and the pointing (including elevation angle) of the telescope 13. And communicate observation data.

The pattern recognition unit 22 receives the reflected pulsed laser light actually reflected by the target object by the pattern recognition process based on the fluctuation pattern of the optical path length which is predeterminedly changed for the distance measurement data observed by the laser distance measuring device 10. Extract the range measurement value group. Further, the pattern recognition unit 22 has a pattern based on the periodicity of the number of repetitions of the pulsed laser beam used for the observation (periodic change of an arbitrary predetermined number) for the distance measurement data observed by the laser distance measuring device 10. It is desirable to configure the recognition process so as to extract the range-finding value group of the reflected pulsed laser beam actually reflected by the target object.

The pattern recognition for the distance measurement data (distance measurement value group) may be performed by numerical analysis, or the distance measurement data may be imaged and performed by image analysis. In this pattern processing, the distance measurement value group having a predetermined fluctuation pattern included in the distance measurement data can be distinguished from the true received signal from the target, and the distance measurement value showing no fluctuation pattern may be noise. Can be determined to be high. Therefore, the pattern recognition process makes it easier to discriminate the received light signal from the ranging data of the laser observation in which noise and the received light signal are mixed.

As a calibration process, the calibration unit 23 adds a change arbitrarily applied at the time of emission of the pulsed laser light for each distance measurement value of the reflected pulse laser light from the observed distance measurement data (distance measurement value group). Remove based on the fluctuation pattern. This calibration process may be executed only for the distance measurement value group extracted by the pattern recognition unit 22. The ranging data after the calibration process is a true received signal from the target observed by the laser ranging device 10 with respect to the ranging data before the calibration process, and facilitates the determination of the true position of the target. can.

The pattern recognition unit 22 and the calibration unit 23 in the data processing unit may be provided in the data processing / control calculation unit 15 in the laser ranging device 10.

In the above configuration, the laser observation system 1 observes the ranging data (distance measuring value group) of the arbitrary target to which the fluctuation is applied in the laser ranging device 10, and the fluctuation pattern added from the ranging data of the arbitrary target. It becomes possible to detect the fluctuation pattern of the received light signal (distance measuring value group) similar to the above. Then, the received light signal (distance measuring value) not included in this fluctuation pattern can be treated as noise.

Here, a configuration example of the optical path length changing unit 16 provided in the transmission optical unit 12-1 will be described.
FIG. 4 is a schematic diagram showing a configuration example of the optical path length changing unit 16, and FIG. 4A is a configuration example in which the optical path length changing unit 16 is constructed by one movable stage, and FIG. 4B is shown. ) Is a configuration example in which the optical path length changing unit 16 is constructed by a plurality of movable stages. Further, FIG. 5 is a configuration example in which the optical path length changing portion 16 is constructed by a movable stage and a rotating unit.
In this configuration example, as shown in FIGS. 4 and 5, a movable stage or a rotating unit having an operating unit is used as the optical path length changing unit 16. In each of the configuration examples, a pulse detector for detecting the passing timing of the pulsed laser beam is provided, and the movable stage and the mirror group are provided after the optical path portion for detecting the passing timing of the pulsed laser beam with the pulse detector. Has been done.

The number of movable stages, the number and positions of mirrors mounted on the movable stages, the presence or absence of a rotating unit, and the like may be appropriately determined according to the type of fluctuation pattern to be given to the path length for each pulsed laser beam and the number of fluctuation patterns.

In the configuration example shown in FIG. 4A, two mirrors (mirror 2 and mirror 3) are installed as a part of the optical path on the movable stage. The optical path length changing unit 16 moves the mirror 2 and the mirror 3 installed on the movable stage back and forth according to a known rule, so that the optical path length of each pulsed light changes a known pattern for each pulsed light. When the movable stage is operated in a reciprocating motion at a constant velocity in this configuration example, a triangular wave-like variation can be added to the distance measurement value of the reflected light of the continuous laser beam.

In the configuration example shown in FIG. 4B, one mirror (mirror 2, mirror 3 and mirror 4) is installed as a part of the optical path on three movable stages. The optical path length changing unit 16 moves the mirror 2, the mirror 3, and the mirror 4 installed on the movable stage back and forth and left and right according to a known rule, so that the optical path length of each pulsed light changes in a known pattern for each pulsed light. Add. In this configuration example, when each movable stage is operated in conjunction with each other according to a predetermined rule, an arbitrary fluctuation pattern added to the distance measurement value of the reflected light of the laser beam that is more continuous than that of the configuration example shown in FIG. 4 (a) can be obtained. Freedom is given. For example, it is possible to give a sinusoidal variation or a rectangular wave variation to the observation data (distance measuring value group).

In the configuration example shown in FIG. 5, two mirrors (mirror 2 and mirror 3) are installed on the movable stage as a part of the optical path, and the movable stage is operated by a rotating unit. The optical path length changing unit 16 moves the mirror 2 and the mirror 3 installed on the movable stage back and forth according to a known rule, so that the optical path length of each pulsed light changes a known pattern for each pulsed light. In this configuration example, when the rotating unit is made to make a circular motion to cause a simple vibration of the movable stage, a sinusoidal fluctuation can be added to the distance measurement value of the reflected light of the continuous laser beam. Further, it is desirable that the optical path length changing unit 16 is configured so that the rotation speed of the rotating unit can be changed. By changing this rotation speed, the periodic component portion of the sinusoidal fluctuation can be changed.

The operation of the transmission optical unit 12-1 adopting the above configuration example is as follows.
Each laser pulse emitted from the laser oscillation unit 11 is input to the start pulse detector and the mirror 1 via a beam splitter. Each laser pulse is sequentially reflected by four mirrors and radiated toward the target through the telescope 13.
At this time, each mirror installed on the movable stage moves together with the movable stage so as to match the fluctuation pattern (variation signal) from the timing measurement unit 14, and the optical path length of each laser pulse changes. The optical path length may be changed by operating the optical path length changing unit 16 and changing the optical path length in a known variation pattern, and it is not always necessary to use the timing control by the timing measuring unit 14. For example, the optical path length changing unit 16 may be provided with an operating unit and its control unit, and may be directly controlled by the data processing / control calculation unit 15. In the configuration example shown in FIG. 5, the rotation unit is artificially rotated. A known variation pattern of the optical path length may be added by controlling the rotation of the optical path.
Since the optical path length changes in a known fluctuation pattern, the reception timing of each reflected wave changes as a result in the same manner as in the known fluctuation pattern. That is, it produces the effect of varying the received signal according to a known variation pattern.

In the configuration example of the transmission optical unit 12-1 (optical path length changing unit 16), the mirror is moved in order to change the optical path length, but another optical path length variation method may be used. For example, the transmission optical unit 12-1 (optical path length changing unit 16) may be constructed by combining a wave plate and a polarizing device together with a mirror. When a wave plate or a polarizing device is combined, the path length of each pulsed laser beam can be changed by changing the mirror on one axis. This change of the path length is made to have a predetermined fluctuation pattern as in the above configuration example.

In this way, the optical path length of a part of the optical path of the transmission / reception optical system 12 can be changed by the optical path length changing unit 16. By this means, it is possible to give an arbitrary pattern change (variation to the observed value) to the distance measurement distance during observation. This observation data is observation data including noise for a certain period of time, but it is easy to discriminate distance measurement data having a known pattern change by visual recognition or pattern recognition. In addition, the S / N ratio is improved by bringing this observation data closer to only the distance measurement data estimated to be true distance measurement data by pattern recognition.

Here, the present invention will be described by showing a drawing obtained by visualizing observation data for a certain target by an OC mapping process.
The OC process (Observed Minus Calculated) here is a process of calculating a value obtained by comparing the actually measured distance measurement value with the predicted value of the target acquired in advance by another station, another method, or the like.

FIG. 6A is a plot diagram showing observation data regarding an arbitrary target when the reflected light from the arbitrary target is sufficiently strong. On the other hand, FIG. 6B is a plot diagram showing observation data when the reflected light from an arbitrary target is weak.
When the intensity of the received light is sufficiently strong, when the ranging data of an arbitrary target is plotted by the mapping process after OC processing, the reflected light data and the noise data by the target can be discriminated as shown in FIG. 6A. A simple plot diagram is output. The plot shown as the original ranging data in the figure is the true observation data, and the other plots are noise.
On the other hand, when the intensity of the received light is weak, when the ranging data of an arbitrary target is plotted by the mapping process after the OC process, the reflected light data and the noise data by the target can be discriminated as shown in FIG. 6 (b). Difficult plots are output.

FIG. 7 is a plot diagram showing observation data for an arbitrary target in which a variation pattern is intentionally created in the optical path length of each pulsed laser beam.
OC processing is performed on the observation data in which the optical path length of each pulsed laser beam is changed into a triangular wave shape by the transmission optical unit 12-1 (optical path length changing unit 16), and then mapping processing is executed, as shown in FIG. Plot diagram can be obtained. In this plot diagram, it is easy to distinguish between the data of the reflected light (true received signal) by the target and the data of noise.
If the observation data is such that the optical path length of each pulsed laser beam is fluctuated by giving a simple vibration so as to have a sinusoidal shape, the triangular wave-shaped locus shown in FIG. 7 changes to a sinusoidal locus. Therefore, for example, when it is difficult to discriminate the true light-receiving signal with an arbitrary fluctuation pattern, it may be easier to discriminate the true light-receiving signal by using another fluctuation pattern.
In the observation obtained from the observation data of the plot shown in FIG. 7, the excitation of the pulsed laser light by the laser oscillation unit 11 is repeated (maintained) at the same period for a certain period. On the other hand, when the laser oscillation unit 11 is controlled by the data processing unit to periodically change the number of repetitions of the pulsed laser light, for example, the triangular wave-shaped locus shown in FIG. 7 is a dense locus. It is possible to repeat the part and the sparse locus part, and the locus of the sparse and dense wave like a triangular wave can be obtained. Further, for example, when the number of repetitions of the pulsed laser light is switched to a fluctuation pattern that periodically fluctuates every predetermined number including the non-light emitting portion, the locus changes to a locus without the plot portion of the non-transmitting portion. Therefore, for example, when it is difficult to discriminate the true light-receiving signal with an arbitrary fluctuation pattern, it may be easier to discriminate the true light-receiving signal by using another fluctuation pattern.

The information processing of the central processing unit 20 and the observation control of each laser ranging device 10 may be performed by the laser ranging device 10. In this case, the processing operation of the data processing unit of the central processing unit 20 may be performed by the data processing unit of the laser ranging device 10.

As described above, the laser observation system 1 intentionally applies a predetermined variation to the continuity of each laser pulse light in the transmission system of the laser ranging device 10. This ranging data has a feature that it is easy to distinguish between noise and a received light signal. This makes it easy to distinguish between noise and true observation data based on intentionally given fluctuations when analyzing ranging data. As a result, it becomes possible to improve the S / N ratio and display it in a way that is easy for humans to recognize in data processing.

Further, in the description of the above embodiment, although it has been described on the premise that one wavelength is used, it is assumed that a plurality of wavelengths are used, and the path length of the pulsed laser light is applied to the transmission optical unit 12-1 for each pulsed laser light having a different wavelength. The optical path length changing unit 16 may be provided so as to be arbitrarily changeable.
In laser observation with multiple wavelengths, the laser oscillating unit 11 continuously excites pulsed laser light of multiple wavelengths, and while operating the optical path length changing unit, the receiving optical unit 12-2 receives light from the telescope at each wavelength. Each of the reflected pulsed laser beams of is detected.
At the time of this observation, the data processing / control calculation unit 15 controls the optical path length changing unit 16 according to a variation rule different for each wavelength, and continuously emits pulsed laser light for each continuous wavelength toward the target object. The optical path length of each pulsed laser beam is changed to a predetermined value for each wavelength. In addition, distance measurement data is generated by executing distance measurement processing based on the detection timing of each reflected pulsed laser beam for each wavelength detected by the receiving optical unit.

Further, the laser observation system 1 can switch the type and output of the laser as necessary, and in addition to detecting the target and extracting information, it can also have a function of interfering with or destroying a space object by the laser.

As described above, the laser observation system to which the present invention is applied can provide a laser observation system that facilitates the discrimination of the received light signal from the ranging data of the laser observation in which noise and the received light signal are mixed.

The data processing unit of the laser observation system may be realized by using a combination of hardware and software of the computer system. Further, this computer system may be realized by deploying a program for the arithmetic unit in the memory and operating hardware such as one or a plurality of processors based on the program. At this time, if necessary, this program may realize the desired function in cooperation with the function provided by the software such as the operating system, the microprogram, and the driver.

The present invention has been described by exemplifying embodiments. However, the specific configuration of the present invention is not limited to the above-described embodiment, and is included in the present invention even if there are changes to the extent that the gist of the present invention is not deviated. For example, changes such as separation and merging of the block configuration of the above-described embodiment and replacement of procedures are free as long as the gist of the present invention and the functions described are satisfied, and the above description does not limit the present invention.

In addition, some or all of the above embodiments may also be described as follows. The following notes do not limit the present invention in any way.

[Appendix 1]
A telescope aimed at a target object,
A laser oscillator that continuously excites a plurality of pulsed laser beams emitted toward the target object,
The transmission optics section, which is the path of the pulsed laser beam between the telescope and the laser oscillation section,
A receiving optical unit that detects each reflected pulsed laser beam received from the telescope, and a receiving optical unit.
While continuously transmitting pulsed laser light toward the target object while varying with a predetermined fluctuation pattern, distance measurement processing is executed based on the detection timing of each reflected pulsed laser light detected by the receiving optical unit. A laser observation system characterized by including a data processing unit that generates distance measurement data.

[Appendix 2]
The laser oscillating unit is configured so that the repetition of continuously excited pulsed laser light can be arbitrarily changed.
The laser observation system according to Appendix 1, wherein the data processing unit controls the laser oscillation unit to periodically change the number of repetitions of pulsed laser light in a predetermined fluctuation pattern.

[Appendix 3]
The transmission optical unit includes an optical path length changing unit that can arbitrarily change the path length of the pulsed laser beam between the telescope and the laser oscillation unit.
The data processing unit controls the optical path length changing unit to change the optical path length of each of the continuous pulsed laser beams at the time of transmitting the continuous pulsed laser beam toward the target object in a predetermined variation pattern. The laser observation system according to Appendix 1 or 2, which is characterized.

[Appendix 4]
The transmission optical unit is
A pulse detector that detects the passage timing of the pulsed laser beam,
One or a plurality of movable stages for moving one or a plurality of mirrors provided after the optical path portion for detecting the passage timing of the pulse laser beam by the pulse detector, and
Including
The description in Appendix 3 is characterized in that in the optical path length changing unit, the one or a plurality of movable stages are operated according to a predetermined rule, and the path length for each pulsed laser beam is changed according to the fluctuation pattern. Laser observation system.

[Appendix 5]
The optical path length changing unit is configured to be switchable with a plurality of different fluctuation patterns.
The description in Appendix 3 or 4, wherein the data processing unit controls the optical path length changing unit based on an arbitrary variation pattern selected, and changes the optical path length of each pulsed laser beam according to the selected variation pattern. Laser observation system.

[Appendix 6]
A pattern recognition unit that extracts the range-finding value group of the reflected pulsed laser light actually reflected by the target object by the pattern recognition process based on the fluctuation pattern that is variated in a predetermined manner with reference to the observed range-finding data. The laser observation system according to any one of Supplementary note 1 to 5, further comprising.

[Appendix 7]
It further includes a calibration unit that removes changes arbitrarily applied at the time of emission of the pulsed laser light for each distance measurement value of the reflected pulsed laser light from the observed distance measurement data based on a predeterminedly variable fluctuation pattern. The laser observation system according to any one of Supplementary note 1 to 6, wherein the laser observation system is characterized by the above.

[Appendix 8]
The laser oscillating unit continuously excites pulsed laser light having a plurality of wavelengths.
The transmission optical unit includes an optical path length changing unit capable of arbitrarily changing the path length of each pulsed laser beam for each pulsed laser beam having a different wavelength.
The receiving optical unit detects each reflected pulsed laser beam of each wavelength received from the telescope.
The data processing unit controls the optical path length changing unit according to a variation rule different for each wavelength, and the optical path length of each continuous pulsed laser beam when the pulsed laser beam for each continuous wavelength is transmitted toward the target object. Is characterized in that distance measurement data is generated by performing distance measurement processing based on the detection timing of each reflected pulse laser beam for each wavelength detected by the receiving optical unit. The laser ranging system according to any one of 1 to 6.

[Appendix 9]
The laser observation system according to any one of Supplementary note 1 to 8, wherein the receiving optical unit detects the presence or absence of reflected pulsed laser light using a photon detector.

[Appendix 10]
Using a laser ranging device equipped with a laser oscillator that continuously excites multiple pulsed laser beams emitted toward a target object,
In the process of continuously radiating pulsed laser light excited by the laser oscillation unit from a telescope directed at a plurality of target objects via a transmission optical unit, the pulsed laser beam is continuously varied toward the target object while being varied by a predetermined fluctuation pattern. Executes the transmission of the pulsed laser beam
A laser observation method characterized in that ranging processing is executed based on the detection timing of each reflected pulsed laser beam detected by the receiving optical unit that detects each of the received reflected pulsed laser beams to generate ranging data.

[Appendix 11]
A control unit of a laser ranging device including a laser oscillation unit that continuously excites a plurality of pulsed laser beams emitted toward a target object.
In the process of continuously radiating pulsed laser light excited by the laser oscillation unit from a telescope directed at a plurality of target objects via a transmission optical unit, the pulsed laser beam is continuously varied toward the target object while being varied by a predetermined fluctuation pattern. Executes the transmission of the pulsed laser beam
A program characterized in that distance measurement processing is executed based on the detection timing of each reflected pulse laser light detected by the receiving optical unit that detects each received reflected pulsed laser light, and the operation is performed so as to generate distance measurement data. ..

The present invention can be used to determine the debris orbit in outer space.

1 Laser observation system 10 Laser range measuring device 11 Laser oscillating unit 12 Transmission / reception optical system 12-1 Transmission optical unit 12-2 Reception optical unit 13 Telescope 14 Timing measurement unit 15 Data processing / control calculation unit 16 Optical path length change unit 20 Central calculation Device 21 Communication unit 22 Pattern recognition unit 23 Calibration unit

Claims (10)

A telescope aimed at a target object,
A laser oscillator that continuously excites a plurality of pulsed laser beams emitted toward the target object,
The transmission optics section, which is the path of the pulsed laser beam between the telescope and the laser oscillation section,
A receiving optical unit that detects each reflected pulsed laser beam received from the telescope, and a receiving optical unit.
While continuously transmitting pulsed laser light toward the target object while varying with a predetermined fluctuation pattern, distance measurement processing is executed based on the detection timing of each reflected pulsed laser light detected by the receiving optical unit. A laser observation system characterized by including a data processing unit that generates distance measurement data. The laser oscillating unit is configured so that the repetition of continuously excited pulsed laser light can be arbitrarily changed.
The laser observation system according to claim 1, wherein the data processing unit controls the laser oscillation unit to periodically change the number of repetitions of pulsed laser light in a predetermined fluctuation pattern. The transmission optical unit includes an optical path length changing unit that can arbitrarily change the path length of the pulsed laser beam between the telescope and the laser oscillation unit.
The data processing unit controls the optical path length changing unit to change the optical path length of each of the continuous pulsed laser beams at the time of transmitting the continuous pulsed laser beam toward the target object in a predetermined variation pattern. The laser observation system according to claim 1 or 2, wherein the laser observation system is characterized. The transmission optical unit is
A pulse detector that detects the passage timing of the pulsed laser beam,
One or a plurality of movable stages for moving one or a plurality of mirrors provided after the optical path portion for detecting the passage timing of the pulse laser beam by the pulse detector, and
Including
The third aspect of claim 3, wherein the optical path length changing unit operates the one or a plurality of movable stages according to a predetermined rule to change the path length for each pulsed laser beam according to the fluctuation pattern. Laser observation system. The optical path length changing unit is configured to be switchable with a plurality of different fluctuation patterns.
The data processing unit controls the optical path length changing unit based on an arbitrary variation pattern selected, and changes the optical path length of each pulsed laser beam according to the selected variation pattern according to claim 3 or 4. The laser observation system described. A pattern recognition unit that extracts the range-finding value group of the reflected pulsed laser light actually reflected by the target object by the pattern recognition process based on the fluctuation pattern that is variated in a predetermined manner with reference to the observed range-finding data. The laser observation system according to any one of claims 1 to 5, further comprising. It further includes a calibration unit that removes changes arbitrarily applied at the time of emission of the pulsed laser light for each distance measurement value of the reflected pulsed laser light from the observed distance measurement data based on a predeterminedly variable fluctuation pattern. The laser observation system according to any one of claims 1 to 6, wherein the laser observation system is characterized in that. The laser observation system according to any one of claims 1 to 7, wherein the receiving optical unit detects the presence or absence of reflected pulsed laser light using a photon detector. Using a laser ranging device equipped with a laser oscillator that continuously excites multiple pulsed laser beams emitted toward a target object,
In the process of continuously radiating pulsed laser light excited by the laser oscillation unit from a telescope directed at a plurality of target objects via a transmission optical unit, the pulsed laser beam is continuously varied toward the target object while being varied by a predetermined fluctuation pattern. Executes the transmission of the pulsed laser beam
A laser observation method characterized in that ranging processing is executed based on the detection timing of each reflected pulsed laser beam detected by the receiving optical unit that detects each of the received reflected pulsed laser beams to generate ranging data. A control unit of a laser ranging device including a laser oscillation unit that continuously excites a plurality of pulsed laser beams emitted toward a target object.
In the process of continuously radiating pulsed laser light excited by the laser oscillation unit from a telescope directed at a plurality of target objects via a transmission optical unit, the pulsed laser beam is continuously varied toward the target object while being varied by a predetermined fluctuation pattern. Executes the transmission of the pulsed laser beam
A program characterized in that distance measurement processing is executed based on the detection timing of each reflected pulse laser light detected by the receiving optical unit that detects each received reflected pulsed laser light, and the operation is performed so as to generate distance measurement data. ..

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