JPH09222479A - Relative distance and relative attitude detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve smaller size and lighter weight of the apparatus by a method wherein reflected light of a plurality of beams emitted simultaneously to an object is received and one of the reflected waves is selected sequentially in a time sharing manner to determine a relative distance and a relative attitude to the object from time and phase differences between the transmitted and received lights. SOLUTION: Laser light emitting sections 13-1 to 13-3 amplify signals of oscillators 11-1 to 11-3 simultaneously and continuously with drivers 12-1 to 12-3 and modulate the signals by frequencies f1 to f3 to emit laser lights to an object. The reflected lights of the laser lights are taken by a CCD 4 through a lens 2 and a halfmirror 3 while being reflected by the mirror 3 to be detected by a distance measuring reception detector 1. The resulting detection signals are mixed with a local oscillation signal by a mixer 6 via a preamplifier 5 and a phase difference is detected by a phase difference comparator 8 via a BPF7. As for the local oscillation signal, differences between the frequencies f1 to f3 and a reference frequency of a reference signal oscillator 10 are mixed on use one at a time by a switch 9 in a time sharing manner to determine a phase difference with a comparator 8 in a time sharing manner between the frequencies f1 to f3 and irradiation light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relative distance and relative attitude for emitting a plurality of beams to a target object and detecting the relative distance and relative attitude with respect to the target object from the time difference or phase difference from the reflected light. Regarding the detection sensor, for example, the relative distance suitable for detecting the relative distance and attitude with respect to the target celestial body of the probe during landing or after landing on the probe landing on the target celestial body such as moon, planet, comet, etc. The present invention relates to a relative attitude detection sensor.

[0002]

2. Description of the Related Art FIG. 4 shows an outline of a conventional relative distance and relative attitude detection sensor.
It has 1, 22, and 23. Also, if it is necessary to monitor the target object, separately to obtain an image of the target object,
An image acquisition device 24 such as a CCD is used, and a floodlight 25 is used to illuminate the target object when the target object does not receive sunlight. Distance measurement system 21-2
3 have the same configuration, but distance measuring systems 21 to 23
In this case, different frequencies f1, f2, f3 are used.

Each of the laser beam emitting units 13 of the distance measuring systems 21 to 23 is modulated at the frequencies f1 to f3 by amplifying the signal of the modulation frequency oscillator 11 of the frequencies f1 to f3 by the driver 12, and is modulated to the target object. Laser light is emitted. In this case, each laser beam of the distance measuring systems 21 to 23 is applied to each area obtained by dividing the field of view of the distance measuring detection system into approximately three as shown in FIG.

The laser light reflected from the target object passes through each lens 2 of the distance measuring systems 21 to 23 and the distance measuring receiver 1
The signal detected by the distance measuring reception detector 1 is amplified by the preamplifier 5, and the mixer 6 then amplifies the difference f1 between the frequencies f1, f2, f3 of the modulation frequency oscillator 11 and the reference signal Δf of the reference signal oscillator 10. -Δf, f
By mixing with 2-Δf and f3-Δf, a signal of frequency Δf is obtained. The noise of the signal of the frequency Δf is reduced by the band pass filter 7, and then the phase difference with the reference signal Δf is detected by the phase difference comparator 8. Therefore, the distances to the three regions shown in FIG. 2 are detected, and the posture is detected based on these three distances.

[0005]

However, in the above-mentioned conventional device, three independent distance measuring systems 21, 2 are used.
Since it is composed of 2 and 23, there is a problem that the scale becomes large. Further, when it is necessary to monitor the target object, the image acquisition device 24 such as a CCD is additionally required, which causes a problem that the scale is further increased. Also, since the receiving system is independent, the distance bias of each system is different due to the difference in the characteristics of each processing circuit,
Due to this difference in the distance bias, detection errors of the relative distance and the relative attitude occur.

Further, the floodlight 25 is necessary when the image pickup object does not receive sunlight.
Is generally large and consumes a large amount of power, so that it is extremely disadvantageous to an artificial satellite having a limited weight and limited power supply capacity when it is mounted on an artificial satellite to measure a target celestial body.

In view of the above conventional problems, it is an object of the present invention to provide a relative distance and relative attitude detection sensor which can be reduced in size and weight and which can prevent detection errors.

[0008]

In order to achieve the above object, the present invention receives a plurality of transmitting systems which simultaneously emit a plurality of beams to a target object and a plurality of beams which are reflected by the target object. One of them is sequentially selected in a time division manner, and one reception system is provided for detecting the relative distance and relative attitude of the target object based on the time difference or phase difference between the transmitted light and the received light.

The present invention also receives a plurality of transmission systems that sequentially select and emit one of a plurality of beams in a time division manner, and receives a beam reflected by a target object, and obtains the time difference or position of the transmitted light and the received light. It is characterized by having one receiving system that detects a relative distance and a relative attitude with respect to the target object based on the phase difference.

Further, the receiving system is characterized in that a light receiving section for receiving the beam reflected by the target object and an image pickup section for imaging the target object are integrated.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a relative distance and relative attitude detection sensor according to the present invention, and FIG. 2 is an explanatory diagram showing a laser beam irradiation area of the sensor of FIG.

The transmission system shown in FIG. 1 has three frequencies f.
1, f2, f3 modulation frequency oscillators 11-1, 11-
2, 11-3 and drivers 12-1, 12-2, 12-
3 and laser light emitting units 13-1, 13-2, 13-3. The laser light emitting units 13-1 to 13-3 simultaneously and successively output the signals of the modulation frequency oscillators 11-1 to 11-3 having frequencies f1 to f3, respectively, to the drivers 12-1 to 12-1.
By being amplified by 2-3, it is modulated at frequencies f1 to f3, and laser light is emitted to the target object. In this case, each laser beam is applied to an area obtained by dividing the visual field of the camera / distance detection system into approximately three, as shown in FIG.

The camera / distance detection system is composed of one system,
In the optical system, the lens 2, the half mirror 3 and the CCD 4
Are arranged coaxially, and the distance-measuring reception detector 1 is arranged in the optical path reflected by the half mirror 3. Therefore, the laser light reflected by the target object passes through the half mirror 3 and is imaged by the CCD 4, and is reflected by the half mirror 3 and detected by the distance measurement reception detector 1. The signal detected by the distance measurement reception detector 1 is amplified by the preamplifier 5 and then mixed with the local oscillation signal by the mixer 6 to obtain a signal of frequency Δf.
The noise of the signal of the frequency Δf is reduced by the band pass filter 7, and then the reference signal Δ is obtained by the phase difference comparator 8.
The phase difference from f is detected.

In this case, the modulation frequency oscillators 11-1 to 11-1
Differences f1-Δf, f2-Δf, and f3-Δf between the respective frequencies f1 to f3 of 1-3 and the reference signal Δf of the reference signal oscillator 10.
One of them is sequentially selected by the switch 9 in a time division manner and applied to the mixer 6 as a local oscillation signal. Therefore, in the mixer 6, the received signal and the local oscillation signals f1-Δf, f2-
One of Δf and f3-Δf is sequentially mixed in a time division manner, and therefore the phase difference comparator 8 obtains a phase difference with the irradiation light of the frequencies f1, f2 and f3 in a time division manner.

Next, a second embodiment will be described with reference to FIG. The transmission system shown in FIG. 3 includes a modulation frequency oscillator 11 having a frequency f1 of one system, a switch 9, drivers 12-1, 12-2, 12-3 of three systems, and a laser light emitting unit 1.
3-1, 13-2, 13-3, and the signal of the oscillator 11 is output to the drivers 12-1, 12-2, 12 by the switch 9.
-3 are sequentially applied in time division. Therefore, one of the laser beam emitting units 13-1 to 13-3 sequentially outputs the frequency f.
The laser light is emitted to the target object after being modulated by 1. Also in this case, each laser beam is applied to an area obtained by dividing the visual field of the camera / distance detection system into approximately three, as shown in FIG.

In the optical system of the camera / distance detection system, similarly, the laser light reflected by the target object passes through the half mirror 3 to be imaged by the CCD 4 and is reflected by the half mirror 3 to detect the distance measurement reception detector. Detected by 1. The signal detected by the distance measuring reception detector 1 is amplified by the preamplifier 5, and then mixed by the mixer 6 with the difference f1−Δf between the frequency f1 of the modulation frequency oscillator 11 and the reference signal Δf of the reference signal oscillator 10 to obtain the frequency Δf. Signal is obtained. The noise of the signal of the frequency Δf is reduced by the band pass filter 7, and then the phase difference with the reference signal Δf is detected by the phase difference comparator 8. Therefore,
The phase difference comparator 8 time-divisionally obtains the phase differences for the three regions shown in FIG.

[0017]

As described above, according to the present invention, since the receiving system is constituted by one system, it is possible to reduce the size and weight and prevent the detection error.

Further, since the light receiving section for receiving the beam reflected by the target object and the image pickup section for imaging the target object are integrated, the light receiving optical system can be downsized.
Further, it is possible to take an image even if the illumination system is omitted.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a relative distance and relative attitude detection sensor according to the present invention.

2 is an explanatory diagram showing a laser light irradiation region of the sensor of FIG. 1. FIG.

FIG. 3 is a configuration diagram showing a relative distance and relative attitude detection sensor according to a second embodiment.

FIG. 4 is a configuration diagram showing a conventional relative distance and relative attitude detection sensor.

[Explanation of symbols]

1 distance measurement reception detector 2 lens 3 half mirror 4 CCD 5 preamplifier 6 mixer 7 bandpass filter 8 phase difference detector 9 switch 10 reference signal oscillator 11, 11-1, 11-2, 11-3 modulation frequency oscillator 12- 1, 12-2, 12-3 Driver 13-1, 13-2, 13-3 Laser light emitting unit

Claims (3)

[Claims] 1. A plurality of transmission systems that simultaneously emit a plurality of beams to a target object, and a plurality of beams that are reflected by the target object are received, and one of them is sequentially selected in a time-division manner. A relative distance and relative attitude detection sensor having one reception system for detecting a relative distance and a relative attitude with respect to a target object based on a time difference or a phase difference of received light. 2. A plurality of transmission systems that sequentially select and emit one of a plurality of beams in a time division manner, and receive a beam reflected by a target object, and based on the time difference or phase difference between the transmitted light and the received light. A relative distance and relative attitude detection sensor having one receiving system for detecting a relative distance and relative attitude with respect to a target object. 3. The receiving system, wherein a light receiving section for receiving a beam reflected by the target object and an image capturing section for capturing the target object are integrated with each other.
The relative distance and relative attitude detection sensor described.