JPH11160419A - Alignment adjusting apparatus for laser radar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alignment adjusting apparatus by which high-accuracy alignment adjustment of an optical system in a laser radar can be realized automatically. SOLUTION: An alignment adjusting apparatus is constituted in such a way that a part of scattered laser light received by a receiving optical system 13 is fetched, that the central position of the scattered laser light is detected, that a receiving optical system 10 is moved and controlled so as to correspond to the central position, and that the alignment of the transmitting optical system 10 with the receiving optical system 13 is adjusted. Consequently, even when a dislocation is generated in the optical axis of the transmitting optical system 10 and that of the receiving optical system 13 due to an environmental condition or the like, a laser radar is drive, and the scattered laser light is received by the receiving optical system 13. Then, the transmitting optical system 10 and the receiving optical system 13 are controlled so as to make the optical axis of the system 10 coincident with that of the system 13 is accordance with the central position of the scattered laser light, and the high-accuracy alignment adjustment of the laser radar is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser radar mounted on a spacecraft such as an artificial satellite for use in atmospheric observation and the like, and more particularly to an alignment adjusting device for the laser radar.

[0002]

2. Description of the Related Art Recently, in the field of remote sensing, a method of observing the atmosphere using a laser radar called a lidar has been studied. This laser radar is shown in FIG.
As shown in (1), laser light is generated by a laser transmitter, and this laser light is transmitted in a target direction via a transmission optical system.

On the other hand, as a laser receiving section, a receiving optical system 3 is disposed with its optical axis corresponding to the transmitting optical system 2, and reflected by the receiving optical system 3 on an object to be measured such as a cloud or an aerosol. The scattered laser light is received and output to the detector 4. The detector 4 detects the intensity and return time of the input scattered laser light, and outputs a detection signal to the signal processing unit 5. The signal processing unit 5 detects a state of a measurement target such as a cloud or an aerosol based on the input detection signal. This signal processing unit 5
Are almost determined by adjusting the alignment of the optical axes of the transmission optical system 2 and the reception optical system 3.

In the field of recent space development, a method of mounting a radar radar on a spacecraft such as an artificial satellite and observing clouds and aerosols from outer space to perform atmospheric observation on a global scale is known. Has been studied.

However, in the above-mentioned laser radar, since its detection characteristics are almost determined by adjusting the alignment of the optical axes of the transmission optical system 2 and the reception optical system 3, if it is applied to the field of space development, There is a problem that the transmission optical system and the reception optical system are misaligned due to vibration or impact at the time of launching, environmental temperature, or the like, and it is difficult to secure high-accuracy radar characteristics.

Therefore, when such a laser radar is applied to the field of space development, it is necessary to provide an alignment adjusting means for matching the optical axes of the transmitting optical system 2 and the receiving optical system 3.

[0007] This alignment adjusting means is not limited to simply making the optical axes of the transmitting optical system 2 and the receiving optical system 3 coincide with each other, and does not adversely affect the highly accurate measurement operation of the laser radar. It is required to realize the alignment adjustment with high accuracy.

[0008]

As described above, in the conventional laser radar, the optical axes of the transmission optical system and the reception optical system do not coincide with each other due to vibration, shock, or a change in environmental temperature. There is a problem that it is difficult to ensure accurate radar characteristics.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a laser radar alignment adjusting apparatus which has a simple structure and can realize high-precision alignment adjustment of an optical system. I do.

[0010]

According to the present invention, there is provided a transmission optical system for transmitting a laser beam output from a laser oscillation source in a target direction, and a reception for receiving a scattered laser beam of the laser beam transmitted from the transmission optical system. An optical system, an object to be measured detecting means for detecting an object to be measured based on the scattered laser light received by the receiving optical system, and a center position of the scattered laser light received by the receiving optical system is calculated; The laser radar alignment adjusting device is provided with optical axis control means for controlling the transmission optical system and the reception optical system to match the optical axis in accordance with the position.

According to the above arrangement, the center position of the scattered laser light received by the receiving optical system is detected, and the control is performed so that the optical axes of the transmitting optical system and the receiving optical system coincide with each other so as to correspond to the center position. By doing so, alignment control is performed. Therefore, even if the optical axis of the transmission optical system and the optical axis of the reception optical system are misaligned due to environmental conditions or the like, when the laser radar is driven and the reception optical system receives the scattered laser light, the scattered laser light is received. Control is performed so that the optical axes of the transmission optical system and the reception optical system match in accordance with the center position, and highly accurate alignment adjustment is ensured.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an alignment adjusting device for a laser radar according to an embodiment of the present invention. A transmitting optical system 10 is arranged so that its optical axis direction can be adjusted. Sends light in the target direction. An optical axis control mechanism 12 is provided in the transmission optical system 10.
Is connected to an output terminal of an optical axis detection circuit 13 described later.

As a structure for adjusting the optical axis of the transmission optical system 10, a mirror surface may be partially moved or adjusted, or the entire transmission optical system may be moved and adjusted. A receiving optical system 13 is provided corresponding to the optical axis of the transmitting optical system 10. An optical splitting element, for example, a beam splitter 14 is provided on the optical axis of the receiving optical system 13, and a detector 15 is provided in the transmitted light path. A signal processing unit 16 is connected to the detector 15, and when the scattered laser light received by the receiving optical system 13 is input via the beam splitter 14, the intensity of the scattered laser light, the return time of the laser light, etc. Is detected and output to the signal processing unit 16. The signal processing unit 16 obtains an atmospheric observation state or the like based on the input detection signal.

On the reflected light path of the beam splitter 14, an optical axis detecting circuit 17 is provided. The optical axis detection circuit 17 uses a condenser lens 17a to convert a part of the scattered laser light input through a reflection optical path of a beam splitter, for example, as shown in FIG.
Guide to 7b. The detector 17b includes an arithmetic processing unit 17c
Is connected, and detects the center position of the incident scattered laser light, and outputs the detection signal to the arithmetic processing unit 17c.

The optical axis control mechanism section 12 is connected to the arithmetic processing section 17c. The optical axis control mechanism section 12 is compared with an input detection signal and a reference value set in advance. A control signal is generated to control the optical axis control mechanism 1
Output to 2. The optical axis control mechanism 12 moves and adjusts the optical axis of the transmission optical system 10 based on the input alignment control signal. As a result, the transmission optical system 10 is controlled so that its optical axis corresponds to the center position of the scattered laser light received by the reception optical system 13, and its alignment corresponds to the reception optical system 13.

In the above configuration, the laser transmitter 11
Drive control is performed by a control unit (not shown) to generate a laser beam, and the laser beam is transmitted through the transmission optical system 10 in a target direction. This laser light is scattered by a cloud or the like, and the scattered laser is received by the receiving optical system 13 and input to the detector 15 through the transmission optical path of the beam splitter 14.
The detector 15 detects the intensity and return time of the input scattered laser light, and outputs a detection signal to the signal processing unit 16. The signal processing unit 16 obtains the atmospheric state based on the input detection signal.

At the same time, the scattered laser light received by the receiving optical system 13 is input to the optical axis detecting circuit 17 through the reflected light path of the beam splitter 14. The optical axis detection circuit 17 detects the center position of the scattered laser light as described above, and generates an alignment control signal such that the difference between the center position and a preset reference value is “zero” to generate an optical control signal. Axis control mechanism 1
Output to 2. The optical axis control mechanism unit 12 controls the optical axis of the transmission optical system 10 based on the input alignment control signal, and adjusts the alignment between the optical axis of the transmission optical system 10 and the optical axis of the reception optical system 13.

As described above, the laser radar alignment adjusting device extracts a part of the scattered laser light received by the receiving optical system 13, detects the center position of the scattered laser light, and corresponds to the center position. By controlling the movement of the transmission optical system 10, the alignment of the transmission optical system 10 and the reception optical system 11 is adjusted.

According to this, even if the optical axes of the transmission optical system and the reception optical system are displaced due to environmental conditions or the like, the laser radar is driven and the reception optical system 13 receives the scattered laser light. Is controlled so that the optical axes of the transmission optical system 10 and the reception optical system 13 coincide with each other in accordance with the center position of the scattered laser light, and highly accurate alignment adjustment is ensured.
Therefore, highly accurate alignment adjustment of the laser radar can be automatically performed, and highly reliable and accurate radar characteristics can be realized even in the outer space in an extreme environment.

In the above-described embodiment, a case has been described where the beam splitter 14 is used to extract a part of the scattered laser light received by the receiving optical system 13.
Without being limited to this, various configurations are possible.

In the above embodiment, the transmission optical system 1
Although the description has been given of the case where the alignment is adjusted by moving and adjusting the optical axis of 0, the invention is not limited to this, and the alignment may be adjusted by moving and adjusting the optical axis of the receiving optical system 13. Is also possible. Therefore, it is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0022]

As described above in detail, according to the present invention, it is possible to provide a laser radar alignment adjusting apparatus which can realize high-precision alignment adjustment of an optical system with a simplified configuration. .

[Brief description of the drawings]

FIG. 1 is a diagram showing an alignment adjusting device for a laser radar according to an embodiment of the present invention.

FIG. 2 is a diagram showing an optical axis detection circuit of FIG. 1;

FIG. 3 is a diagram showing a laser radar to which the present invention is applied.

[Explanation of symbols]

 10 ... Transmission optical system. 11 ... Laser transmitter. 12 ... optical axis control mechanism. 13 ... Reception optical system. 14: Beam splitter. 15 Detector. 16 ... Signal processing unit. 17 ... optical axis detection circuit. 17a: Condensing lens. 17b Detector. 17c: arithmetic processing unit.

Claims (4)

[Claims] 1. A transmitting optical system for transmitting a laser beam output from a laser oscillation source in a target direction, a receiving optical system for receiving a scattered laser beam of the laser beam transmitted from the transmitting optical system, and a receiving optical system. An object to be measured detecting means for detecting an object to be measured based on the scattered laser light received in step (a), calculating a center position of the scattered laser light received by the receiving optical system, and transmitting the optics corresponding to the center position. An alignment adjusting device for a laser radar, comprising: an optical axis control unit that controls an optical axis of a receiving optical system to coincide with an optical axis of the receiving optical system. 2. The optical axis control means includes: a branch element disposed in an optical path of a receiving optical system; extracting a part of laser scattered light received by the branch element; calculating a center position thereof; 2. The laser radar alignment adjusting device according to claim 1, wherein the control is performed such that the optical axes of the transmission optical system and the reception optical system match in accordance with the center position of the laser scattered light. 3. The transmission optical system according to claim 1, wherein an optical axis of the transmission optical system is variably adjustable, and control is performed such that the optical axis coincides with the center position of the scattered laser light. Laser radar alignment adjustment device. 4. An alignment adjusting apparatus for a laser radar according to claim 2, wherein said branching element is a beam splitter.