JP2853640B2 - Relative distance and relative attitude detection sensor - Google Patents

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 a relative distance and a relative attitude to the target object from a time difference or a phase difference from the reflected light. Regarding the detection sensor, for example, a moon, a planet, a relative distance and a suitable distance when mounted on a spacecraft to land on a target celestial body such as a comet to detect the relative distance and attitude of the spacecraft during or after landing with the target celestial body The present invention relates to a relative attitude detection sensor.

[0002]

2. Description of the Related Art FIG. 4 schematically shows a conventional relative distance and relative attitude detection sensor, and includes three independent distance measurement systems 2.
1, 22, and 23. Also, when it is necessary to monitor the target object, to obtain an image of the target object,
An image acquisition device 24 such as a CCD is used, and when the target object is not receiving sunlight, a floodlight 25 is used to illuminate the target object. Distance measurement systems 21 and 2
3 have the same configuration, but the distance measurement systems 21 to 23
Use different frequencies f1, f2, and f3.

Each of the laser beam emitting units 13 of the distance measuring systems 21 to 23 is modulated at a frequency f1 to f3 by amplifying a signal of a modulation frequency oscillator 11 having a frequency f1 to f3 by a driver 12 so as to modulate a target object. Laser light is emitted. In this case, the respective laser beams of the distance measurement systems 21 to 23 are applied to respective regions obtained by substantially dividing the field of view of the distance measurement detection system into three as shown in FIG.

[0004] The laser beam reflected from the target object passes through each lens 2 of the distance measuring systems 21 to 23 and receives a distance measuring detector 1
The signal detected by the distance detection detector 1 is amplified by the preamplifier 5 and then the difference f1 between the frequencies f1, f2 and f3 of the modulation frequency oscillator 11 and the reference signal Δf of the reference signal oscillator 10 by the mixer 6. −Δf, f
2-Δf and f3-Δf to obtain a signal of frequency Δf. After the signal of this frequency Δf is reduced in noise by the band-pass filter 7, the phase difference from the reference signal Δf is detected by the phase difference comparator 8. Therefore, distances to the three regions shown in FIG. 2 are detected, and the posture is detected based on the three distances.

[0005]

However, in the above-mentioned conventional apparatus, three independent distance measuring systems 21 and 2 are provided.
There is a problem that the scale is increased because the configuration is made up of 2, 23. Further, when it is necessary to monitor the target object, an image acquisition device 24 such as a CCD is separately required, and thus there is a problem that the scale is further increased. In addition, since the receiving system is independent, the distance bias of each system is different due to the difference in the characteristics of the individual processing circuits,
Due to the difference in the distance bias, a detection error of the relative distance and the relative attitude occurs.

When the object to be imaged is not receiving sunlight, a floodlight 25 is required.
Is generally large and consumes a large amount of power, which is extremely disadvantageous for an artificial satellite having a limited weight and limited power supply capability when measuring an object on a satellite.

The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide a relative distance and relative attitude detection sensor that can be reduced in size and weight and that can prevent a detection error.

[0008]

In order to achieve the above object, the present invention provides a plurality of transmission systems for simultaneously emitting a plurality of beams to an object, and a method for receiving a plurality of beams reflected by the object. One of the receiving systems is sequentially selected in a time-division manner, and one receiving system for detecting a relative distance and a relative attitude to the target object based on a time difference or a phase difference between the transmitted light and the received light is provided.

[0009] The receiving system is characterized in that a light receiving section for receiving a beam reflected by the target object and an image pickup section for imaging the target object are integrated.

[0010]

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

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 continuously output signals from the modulation frequency oscillators 11-1 to 11-3 having frequencies f1 to f3, respectively, to the drivers 12-1 to 1-3.
Amplification by 2-3 causes modulation at frequencies f1 to f3, and laser light is emitted to the target object. In this case, as shown in FIG. 2, each laser beam is applied to an area obtained by substantially dividing the field of view of the camera / distance detection system into three.

The camera / distance detection system is composed of one system,
In the optical system, a lens 2, a half mirror 3, and a CCD 4
Are arranged coaxially, and a distance measuring detector 1 is arranged on 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 measuring detector 1. The signal detected by the distance detection 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.
After the noise of the signal of this frequency Δf is reduced by the band-pass filter 7, the phase difference comparator 8 outputs the reference signal Δf.
The phase difference from f is detected.

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

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

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 and is imaged by the CCD 4, and is also reflected by the half mirror 3 to be detected by the distance measurement detector. 1 is detected. The signal detected by the distance detection 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, and the frequency Δf Is obtained. After the signal of this frequency Δf is reduced in noise by the band-pass filter 7, the phase difference from the reference signal Δf is detected by the phase difference comparator 8. Therefore,
In the phase difference comparator 8, phase differences for the three regions shown in FIG.

[0016]

As described above, according to the present invention, since the receiving system is composed of one system, the size and weight can be reduced and the detection error can be prevented.

Further, since the light receiving section for receiving the beam reflected by the target object and the imaging section for picking up the target object are integrated, the light receiving optical system can be downsized.
Further, imaging can be performed even if the illumination system is omitted.

[Brief description of 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.

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

FIG. 3 is a configuration diagram illustrating 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]

REFERENCE SIGNS LIST 1 distance measuring 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 beam emitting unit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01S 7/48-7/51 G01S 17/00-17/95 G01B 11/26 G01C 15/00

Claims (2)

(57) [Claims] A plurality of transmission systems for simultaneously emitting a plurality of beams to a target object; a plurality of beams reflected by the target object; receiving one of the plurality of beams; A relative distance and relative attitude detection sensor comprising one receiving system for detecting a relative distance and a relative attitude to a target object based on a time difference or a phase difference of received light. 2. The relative distance and the relative distance according to claim 1, wherein the receiving system includes a light receiving unit that receives a beam reflected by the target object and an imaging unit that captures an image of the target object. Relative attitude detection sensor.