JP2004219129A - Satellite-loaded environment observation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve absolute quantity measurement accuracy in a satellite-loaded hyper-spectral type earth observation system. <P>SOLUTION: A laser radar system is loaded on the same satellite, which comprises a condensing optical system for condensing observation light from the ground surface, a spectral optical system wherein a plurality of spectrally-diffracted wavelength regions are approximately continuous, a detection part for performing photoelectric conversion of light introduced from the spectral optical system, an optical sensor comprising a signal processing circuit for processing an electric signal outputted from the detection part, a laser transmission part for emitting pulse laser light, a laser transmission optical system for adjusting the emission direction of the pulse laser light, a laser receiving optical system for observing back-scattering light of the laser light emitted from the laser transmission optical system, and a laser light detection part for performing photoelectric conversion of the laser light introduced from the laser receiving optical system. The device is constituted so that a laser transmission visual field and a reception visual field of the laser radar are overlapped on a condensing optical reception visual field of the optical sensor on the earth. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an environment observation device that mounts an optical sensor on an artificial satellite, acquires an image of the earth, and detects short-term and long-term environmental changes on the earth's surface.
[0002]
[Prior art]
Regarding environmental observations of the earth using optical sensors mounted on satellites, it is necessary to be able to observe a wide area on a global scale, to be able to perform periodic observations by orbiting the satellite, It is well known that many artificial satellite-mounted optical sensors have already been launched and observation data has been obtained because of the fact that uniform and continuous observation is possible with the same sensor mounted on the satellite.
[0003]
It shows different reflection, absorption, and transmission characteristics of sunlight for each substance such as soil, rock, vegetation, and water on the ground surface. In order to obtain this characteristic, the optical sensor mounted on the artificial satellite divides the light into a plurality of wavelength bands, that is, performs spectroscopy, and observes the light intensity in each wavelength band. As a spectroscopic method of such an optical sensor, there is a so-called hyper-spectral sensor that spectroscopically observes a visible and near-infrared wavelength region into a super-multiband in a continuous and narrow wavelength region and observes it (for example, see Non-Patent Document 1).
[0004]
[Non-patent document 1]
Thomas M.S. Lillesand and Ralph W.C. Kiefer, "REMOTE SENSING AND IMAGE INTERPRETRATION", third edition, John Wiley & Sons, Inc., p. 413-422
[0005]
[Problems to be solved by the invention]
The conventional hyperspectral environment observation device has a problem in that it cannot measure the ground surface luminance because it measures the reflected light of sunlight on the ground surface, and thus cannot quantitatively measure it.
[0006]
In addition, in the conventional hyperspectral environment observation device, since the reflected light of the sunlight on the ground surface is measured, there is a problem that the measurement cannot be performed at night when the ground surface is not illuminated by the sunlight.
[0007]
The present invention has been made to solve the above problems, and has as its object to improve the accuracy of absolute amount measurement in a hyperspectral earth observation device.
[0008]
[Means for Solving the Problems]
An environment observation apparatus according to the present invention includes a condensing optical system that condenses observation light from the surface of the earth, and splits observation light guided from the condensing optical system into a plurality of narrow wavelength regions in a visible and near-infrared region. And a spectroscopic optical system in which the plurality of wavelength regions that have been split are substantially continuous; a detection unit that photoelectrically converts light guided from the spectroscopic optical system; and a signal that processes an electric signal output from the detection unit. An optical sensor including a processing circuit, a laser transmission unit that emits pulsed laser light, a laser transmission optical system that adjusts the emission direction of the pulsed laser light, and backscattered light of the laser light emitted from the laser transmission optical system A laser radar device comprising: a laser receiving optical system for observing a laser beam; and a laser light detecting unit for photoelectrically converting a laser beam guided from the laser receiving optical system, are mounted on the same artificial satellite, The transmission field and the reception field converging optical receiver field of view of the optical sensor and configured to overlap on earth.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 shows the configuration of the environment observation device according to the first embodiment.
The optical sensor 10 and the laser radar device 20 are mounted on the same artificial satellite 30. The optical sensor 10 is an optical sensor condensing optical system 1 for condensing radiated light or reflected light from the earth 50, and the light condensed by the optical sensor condensing optical system 1 is divided into a plurality of narrow wavelength bands and the band is substantially An optical sensor spectral optical system 2 that splits light into continuous light, an optical sensor detecting unit 3 that photoelectrically converts light split by the optical sensor spectral optical system 1, and an optical sensor signal processing that processes an output electric signal of the optical sensor detecting unit 3. It comprises a circuit 4. The output electric signal of the optical sensor signal processing unit 4 is transmitted to a receiving station installed on the earth 50 via the artificial satellite 30. The laser radar device 15 includes a laser transmission unit 11 having a function of generating a transmission laser beam and monitoring the intensity thereof, a laser transmission optical system 12 for emitting the light generated by the laser transmission unit 11 in a desired direction, and a laser. A laser receiving optical system 13 that collects backscattered light and reflected light of the laser light emitted from the transmitting unit 12, and a laser that transmits light near the emitted laser light among the light collected by the laser receiving optical system 13. It is composed of a radar spectroscopic optical system 14, a laser radar detecting unit 15 for photoelectrically converting light split by the laser radar spectroscopic optical system 14, and a laser radar signal processing unit 16 for processing an output electric signal of the laser radar detecting unit 15. . An output electric signal from the laser radar signal processing unit 16 is transmitted to a receiving station installed on the earth 50 via the artificial satellite 30. Further, by superimposing the optical sensor observation light receiving visual field 21 of the optical sensor 10 and the transmitting visual field 22 and the receiving visual field 23 of the laser radar device 20 on the earth 50, it is possible to observe almost the same place on the earth 50. I have.
[0010]
Next, the operation will be described.
The laser beam transmitted by the laser radar device 20 has a wavelength substantially the same as the absorption wavelength band of the observation object on the earth (for example, when observing a dimer of photosynthetic I-chlorophyll, the wavelength is around 700 nm, and the wavelength of the photosynthetic II chlorophyll a is For observation, the wavelength is set to around 680 nm). Therefore, when the earth 50 is irradiated with the laser light emitted from the laser radar device, a part of the laser light is absorbed when there is an observation object on the ground. The light absorbed by the observation target emits light called fluorescence after a certain period of time. The fluorescent light propagates in the space, is collected by the optical sensor condensing optical system 1 of the optical sensor 10, passes through the optical sensor spectral optical system 2, and is detected as an electric signal by the optical sensor detecting unit 3. At this time, since the light passes through the optical sensor spectral optical system 2, the spectral distribution of the fluorescence to be observed is observed as the electric signal intensity for each wavelength band.
[0011]
As shown in FIG. 2, the fluorescence is light having a spectral distribution having a peak generally at a longer wavelength than that of the absorbed light (in the case of chlorophyll a, around 685 nm). Although the amount of fluorescent light changes due to absorption, in the first embodiment, the laser transmitting section 12 measures the intensity of the emitted laser light, so that the laser light intensity and the fluorescent light intensity can be quantitatively observed. Therefore, the state of the observation target (for example, the growth state of the plant if the observation target is chlorophyll a because it is contained in a plant) can be known quantitatively.
[0012]
As described above, the wavelength of the laser light needs to be changed according to the observation object. When there are a plurality of observation targets, a plurality of laser transmitters having different laser oscillation wavelengths may be mounted on the laser radar device 20, or the wavelengths may be continuously changed in a visible wavelength region represented by Ti: sapphire laser. A tunable laser that can change the wavelength may be mounted.
[0013]
Further, in order to obtain a fluorescence intensity spectrum distribution, a method capable of narrow-band and continuous spectrum is required as a spectral method. Such a spectral method includes a prism spectral method, a diffraction grating spectral method, a wedge glass spectral method, and the like.
[0014]
According to the present embodiment, the state of the observation target is observed by observing the laser light intensity and the fluorescence intensity of the observation target in which the sunlight intensity is not unknown and the emission intensity is clear as in the fluorescence measurement by sunlight absorption. High-precision and quantitative observation is possible.
[0015]
In addition, according to the first embodiment, since observation is performed using laser light emitted by itself instead of reflected light of sunlight, there is an advantage that observation is possible even at night.
[0016]
It is needless to say that the laser radar device 20 has an aerosol observation and distance measurement function of the laser radar device 20 and a surface observation function of the optical sensor in the daytime.
[0017]
Further, it is possible to measure the emission laser intensity and the reception laser intensity of the laser radar device 20. Since the wavelengths of the laser light and the fluorescence are almost the same, there is an advantage that the attenuation of the fluorescence in the atmosphere can be calculated with high accuracy.
[0018]
Embodiment 2 FIG.
FIG. 3 shows the configuration of the environment observation device according to the second embodiment. The same elements as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0019]
In the first embodiment, the optical sensor 10 and the laser radar device 20 are mounted on the same artificial satellite 30. However, in the second embodiment of FIG. 3, the optical sensor 10 and the laser radar device 20 are separate artificial satellites 30a, 30a, respectively. It is mounted on the artificial satellite 30b.
[0020]
Since the fluorescence of the observation target is radiated isotropically, the optical sensor 10 and the laser radar device 20 are mounted on separate artificial satellites 30a and 30b, and even if observed from different directions, almost the same point on the surface of the earth is observed. As long as observation is made, the same effect as in the first embodiment can be expected. In addition, by changing the optical axis direction of the laser light transmission visual field 22 of the laser radar device 20 and the optical sensor observation light reception visual field 21, the laser beam emitted from the laser radar device 20 incident on the optical sensor 10 at the ground surface is positive. The contribution of the reflection component can be reduced, and the accuracy of the fluorescence intensity observed by the optical sensor 10 can be improved.
[0021]
Embodiment 3 FIG.
FIG. 4 shows the configuration of the environment observation device according to the third embodiment. The same elements as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0022]
In the first embodiment, the optical sensor 10 and the laser radar device 20 are mounted on a single artificial satellite 30, but in the third embodiment, a plurality of optical sensors 10 and the laser radar device 20 are mounted on the same artificial satellite 30. Are mounted on the artificial satellites 30a and 30b.
[0023]
According to the third embodiment, it goes without saying that effects similar to those of the first and second embodiments can be obtained. In addition, even if the optical sensor 10 or the laser radar device 20 mounted on one artificial satellite 30 fails, there is an advantage that the effect of the second embodiment can be obtained if the other artificial satellite is sound.
[0024]
【The invention's effect】
In the environment observation device according to the present invention, as described above, since observation is performed using laser light emitted by itself, observation is possible even at night, and sunlight intensity is unknown as in fluorescence measurement by sunlight absorption. In addition, by observing the laser beam intensity and the fluorescence intensity of the observation target whose emission intensity is clear, it is possible to observe the state of the observation target with high precision and quantitatively.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of the present invention.
FIG. 2 is a diagram showing a relationship between absorption light and fluorescence of an observation target.
FIG. 3 is a diagram showing a second embodiment of the present invention.
FIG. 4 is a diagram showing a third embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 1 optical sensor condensing optical system, 2 optical sensor spectral optical system, 3 optical sensor detecting unit, 4 optical sensor signal processing unit, 10 optical sensor, 11 laser transmitting unit, 12 laser transmitting optical system, 13 laser receiving optical system, 14 Laser radar spectroscopic optical system, 15 laser radar detection unit, 16 laser radar signal processing unit, 20 laser radar device, 21 optical sensor observation light reception field of view, 22 laser radar device transmission field of view, 23 laser radar device reception field of view, 30 satellite, 50 Earth

Claims (9)

A condensing optical system for condensing light emitted from the earth's surface, a spectroscopic optical system for dispersing the light condensed by the condensing optical system into a plurality of narrow wavelength band bands, and the band is continuous in a substantially wavelength region. A detection unit that photoelectrically converts the light separated by the spectral optical system, an optical sensor including a signal processing circuit that processes an output electric signal of the detection unit,
A laser transmission unit having a function of generating laser light and monitoring the intensity of the laser light, a transmission optical system for emitting light generated by the laser transmission unit in a desired direction, and a laser light emitted from the transmission optical system A receiving optical system for condensing the backscattered light and the reflected light, a laser spectral optical system for transmitting light near the emitted laser light among the light condensed by the receiving optical system, A detection unit for photoelectrically converting light, a laser radar device including a signal processing unit for processing an output electric signal of the detection unit, mounted on the same artificial satellite,
In addition, an observation environment of a satellite mounted environment is characterized in that an observation light reception field of view of the optical sensor and a transmission field of view and a reception field of view of the laser radar device are superimposed on the earth to observe almost the same place on the earth. A condensing optical system for condensing light emitted from the earth's surface, a spectroscopic optical system for dispersing the light condensed by the condensing optical system into a plurality of narrow wavelength band bands, and the bands are continuous in a substantially wavelength region. System, a detection unit that photoelectrically converts the light separated by the spectral optical system, an artificial satellite equipped with an optical sensor including a signal processing circuit that processes an output electric signal of the detection unit,
A laser transmission unit having a function of generating laser light and monitoring the intensity of the laser light, a transmission optical system for emitting light generated by the laser transmission unit in a desired direction, and a laser light emitted from the transmission optical system A receiving optical system for condensing the backscattered light and the reflected light, a laser spectral optical system for transmitting light near the emitted laser light among the light condensed by the receiving optical system, A detection unit for photoelectrically converting light, and an artificial satellite equipped with the laser radar device including a signal processing unit for processing an output electric signal of the detection unit,
An artificial satellite characterized in that the observation light reception field of view of the artificial satellite-mounted optical sensor, and the transmission field of view and the reception field of view of the artificial satellite-mounted laser radar device are almost superimposed on the earth, thereby observing almost the same place on the earth. On-board environment observation device. A condensing optical system for condensing light emitted from the earth's surface, a spectroscopic optical system for dispersing the light condensed by the condensing optical system into a plurality of narrow wavelength band bands, and the bands are continuous in a substantially wavelength region. System, a detection unit that photoelectrically converts light split by the spectral optical system, an optical sensor including a signal processing circuit that processes an output electric signal of the detection unit,
A laser transmitting unit having a function of generating laser light and monitoring the intensity thereof, a transmitting optical system for emitting light generated by the laser transmitting unit in a desired direction, and a rear side of the laser light emitted from the transmitting optical system. A receiving optical system that collects scattered light and reflected light, a laser spectral optical system that transmits light near the emitted laser light among the light collected by the receiving optical system, and a light that is spectrally separated by the spectral optical system. A detection unit that performs photoelectric conversion, and a laser radar device that includes a signal processing unit that processes an output electric signal of the detection unit, include a plurality of artificial satellites mounted on the same artificial satellite,
In addition, the observation light reception field of view of the optical sensor mounted on at least one artificial satellite and the transmission field of view and the reception field of view of the laser radar device are superimposed on the earth, and substantially the same location on the earth is observed. Environmental observation equipment onboard artificial satellites. 4. The environment observation system according to claim 1, wherein the laser transmission unit has a plurality of laser oscillation wavelengths, and the oscillation wavelength can be switched. 5. The environment observation device according to any one of claims 1 to 4, wherein the laser oscillation wavelength of the laser transmission unit includes 680 nm. The environment observation device according to any one of claims 1 to 4, wherein the laser transmission unit includes a laser oscillation wavelength of 700 nm. The artificial satellite-mounted environment observation device according to any one of claims 1 to 6, wherein a prism spectral system is used as a spectral optical system of the optical sensor. 7. The environment observation device according to claim 1, wherein a diffraction grating spectroscopy system is used as a spectral optical system of the optical sensor. 7. The environment observation device mounted on a satellite according to claim 1, wherein a wedge glass spectroscopy system is used as a spectral optical system of the optical sensor.

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