JP2011209048A - Observation apparatus and device for estimating target of observation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy of estimating a target of observation using mobile observation apparatus accompanying multiple observation angles.SOLUTION: The observation apparatus 100 with multiple observation angles is an apparatus of observation with conical-scan-type motion. The observation apparatus 100 includes a first antenna 131 to a fourth antenna 134 having different observation angles. The lower an antenna with the smaller observation angle is placed, while the upper an antenna with the larger observation angle is placed. In addition, the length of a support rod becomes shorter as an installation position of the antenna gets lower, while the length of the support rod becomes longer, as the installation position of the antenna becomes higher. A controller 110 makes a first rotation shaft 121 to a fourth rotation shaft 124 rotate, at different speeds according to the respective observation angles of the first antenna 131 to fourth antenna 134. The controller 110 estimates the target of observation, based on a plurality of observation signals with different observation angles received by the first antenna 131 to fourth antenna 134.

Description

  The present invention relates to an observation apparatus that observes an observation object on the ground with a movement from the sky regardless of the active / passive method, for example, an aircraft or a satellite-mounted camera or radar, and an observation object estimation apparatus that estimates the observation object. Is.

Conventionally, an observation apparatus using a mobile object such as an aircraft or an artificial satellite as a platform can observe only one observation angle at any point in the observation target area. The observation angle is an angle formed by a perpendicular line from the moving body to the ground and a line connecting the moving body and one point in the observation target area.
In addition, the observation signal obtained by observing the object to be observed shows a signal strength different from the actual value due to the influence of the thermal noise of the system, the movement of the moving object itself, the trajectory of the moving object, and the topography of the observation area. End up.

It is known that the signal intensity of the observation signal strongly depends on the observation angle as well as the target material and shape.
For this reason, it is difficult to specify physical information such as the material and shape of the object to be observed based on one observation signal observed at a specific observation angle.

2. Description of the Related Art Conventionally, an observation device called a conical scan method using a mobile object as a platform is known.
A conical scan observation device scans an observation point with an antenna by rotating an antenna rotation axis to perform observation.

JP 2006-270806 A

  An object of the present invention is, for example, to improve the estimation accuracy of an object to be observed by a synthetic aperture radar.

The observation apparatus of the present invention is
A plurality of antennas for transmitting signals to the observation target from different directions and receiving observation signals from the observation targets from different directions;
An antenna rotation axis that has a length in the axial direction, attaches a plurality of antennas to different positions in the length direction, and rotates about the length direction;
Generate transmission signals for multiple antennas, rotate the antenna rotation shaft to which multiple antennas are attached, transmit transmission signals from different directions by multiple antennas, and receive observation signals from different directions by multiple antennas And a control device that stores a plurality of observation signals received by a plurality of antennas. Here, the plurality of antennas also serve as a transmission / reception function. However, for example, when it is desired to realize a passive observation system such as a camera or a radiometer, the transmission signal generation unit is excluded, and the transmission function of a plurality of antennas is also excluded.

The antenna rotation shaft has an antenna mounting portion for attaching an antenna for each antenna, and rotates for each antenna mounting portion.
The said control apparatus rotates the said antenna rotating shaft at a different speed for every antenna attaching part.

  The control device rotates each antenna attachment portion faster as the direction in which the antenna attached to the antenna attachment portion receives the observation signal is downward. This is because the directions of the plurality of transmission / reception antennas are different, and the distance from the moving body to the observation point for each antenna is different.

Multiple antennas are farther away from the antenna mounting part
As the plurality of antennas are located at the lower side, the reception direction of the observation signal is downward.

  The control device changes the transmission direction of the transmission signal and the reception direction of the observation signal for each of the plurality of antennas.

  The control device stores profile data representing a relationship between a reception direction of an observation signal and a signal strength of the observation signal as a reference profile for each type of feature, and a profile based on a plurality of observation signals received by a plurality of antennas. Data is generated as an observation profile, and the type of the observation target is specified by comparing the generated observation profile with a reference profile.

The observation apparatus of the present invention is
A plurality of antennas with different observation angles are provided, and the observation target is observed by a conical scan method using the plurality of antennas.

The observation target estimation apparatus of the present invention is
Profile data representing the relationship between the observation angle of the observation signal and the signal strength of the observation signal is stored as a reference profile for each type of feature, and is a plurality of observation signal information obtained by observing the observation target. An observation data storage unit for storing a plurality of observation signal information representing a plurality of observation signals having different
An observation profile generation unit that generates profile data as an observation profile based on a plurality of observation signal information stored in the observation data storage unit;
An observation target estimation unit that estimates an observation target type by comparing the observation profile generated by the observation profile generation unit with a reference profile;

According to the present invention, for example, a plurality of observation signals can be received at different observation angles using a plurality of antennas.
By obtaining a plurality of observation signals having different observation angles, it is possible to improve the estimation accuracy of the observed object (observation target).

1 is an external view of a multi-observation angle observation device 100 according to Embodiment 1. FIG. The external view of the conventional conical scan type observation apparatus 801. FIG. The figure which shows the observation method using the observation device 801 of the conventional conical scan system. The figure which shows an example of the observation data obtained by the observation apparatus 801 of the conventional conical scan system. FIG. 3 shows an observation method of the multi-observation angle observation apparatus 100 in the first embodiment. FIG. 3 shows an observation method of the multi-observation angle observation apparatus 100 in the first embodiment. FIG. 5 shows an example of observation data obtained by the multi-observation angle observation apparatus 100 in the first embodiment. FIG. 2 is a functional configuration diagram of a control device 110 in the first embodiment. The figure which shows the observation method using the passive observation apparatus 802 of the conventional push bloom system. The figure which shows an example of the observation data obtained by the passive observation apparatus 802 of the conventional push bloom system.

Embodiment 1 FIG.
An observation apparatus for observing observation targets on the ground with movement from above will be described.

FIG. 1 is an external view of a multi-observation angle observation apparatus 100 according to the first embodiment.
The configuration of multi-observation angle observation apparatus 100 (an example of an observation apparatus) in Embodiment 1 will be described below with reference to FIG.

  The multi-observation angle observation device 100 is a conical-scan observation device including a plurality of antennas (antenna groups 130) having different observation angles.

  Here, a conventional conical scan type observation apparatus will be described with reference to FIGS.

FIG. 2 is an external view of a conventional conical scan type observation apparatus 801.
FIG. 3 is a diagram showing an observation method using a conventional conical scan type observation device 801.
FIG. 4 is a diagram illustrating an example of observation data obtained by a conventional conical scan type observation apparatus 801.

  In FIG. 2, a conventional conical scan type observation device 801 includes a control device 810, an antenna rotation shaft 820, an antenna 830, and a solar cell panel 840.

In FIG. 3, a conventional observation apparatus 801 is mounted on an aircraft, an artificial satellite, or other moving body (flying body) and flies over the sky.
The traveling direction of the conventional observation apparatus 801 is referred to as “azimuth direction”.

The control device 810 of the conventional observation device 801 rotates the antenna rotation shaft 820.
One antenna 830 is attached to the antenna rotation shaft 820 obliquely downward. The antenna 830 transmits and receives electromagnetic waves obliquely from below, and the control device 810 stores information on the electromagnetic waves received by the antenna 830.
Hereinafter, the electromagnetic waves received by the antenna 830 are referred to as “observation signals”.

The reception direction in which the antenna receives the observation signal is referred to as “observation angle θ _i ”. The observation angle θ _i indicates the angle formed by the observation signal traveling direction and the vertical direction. The observation angle θ _i is also called an incident angle or off-nadir angle (incident angle≈off-nadir angle).
The width of the region where the observation signal can be observed by rotating the antenna rotation shaft 820 is referred to as “observation width”.

If the mounting angle of the antenna 830 (or the directivity of the antenna) does not change, the observation angle θ _i of the observation signal is constant.
That is, the conventional observation apparatus 801 can obtain an observation signal only at the observation angle θ _i .

For example, when a graph representing the relationship between the signal intensity of the observation signal and the observation angle is created, the observation signal of the observation object x is plotted on the observation angle θ _i (see FIG. 4).

In FIG. 4, the reference profile of the observation object x is graph data (function data) obtained experimentally or theoretically for each observation angle of the signal intensity of the observation signal of the observation object x.
The signal intensity of the observation signal varies depending on the observation angle of the observation signal and the material, shape, and state of the observed object (observation target).
The reference profile varies depending on the material, shape, and state of the object to be observed.

  Since the observation by the synthetic aperture radar 801 is affected by thermal noise (noise), attitude variation, orbit variation, the observation signal obtained by the conventional observation device 801 includes an error and shows a signal intensity different from the reference profile.

  Returning to FIG. 1, the description of the multi-observation angle observation apparatus 100 in the first embodiment will be continued.

  The multi-observation angle observation device 100 (an example of the observation device) includes a control device 110, an antenna rotation shaft 120, an antenna group 130, and a solar cell panel 140.

The antenna rotation shaft 120 is divided into four in the axial direction (length direction, vertical direction).
Hereinafter, the divided parts of the antenna rotating shaft 120 are referred to as a first rotating shaft 121, a second rotating shaft 122, a third rotating shaft 123, and a fourth rotating shaft 124 in order from the bottom.

The first rotating shaft 121 to the fourth rotating shaft 124 (an example of an antenna mounting portion) rotate separately.
The first rotating shaft 121 to the fourth rotating shaft 124 have support rods 121A to 124A, respectively.

The support rods 121 </ b> A to 124 </ b> A have different lengths l from each other, the shorter the support rod positioned below, the longer the support rod positioned above.
The antennas of the antenna group 130 are attached to the tips of the support rods 121A to 124A.
Hereinafter, the antennas attached to the support rods 121A to 124A are referred to as the first antenna 131, the second antenna 132, the third antenna 133, and the fourth antenna 134 in the order of the support rods.

The first antenna 131 to the fourth antenna 134 are attached at different angles and have different observation angles θ _i . However, the first antenna 131 to the fourth antenna 134 may have different observation angles θ _i by having different directivities.
As for the 1st antenna 131-the 4th antenna 134, the antenna located below is facing downward, and the antenna located above is upward (horizontal). Downward and upward mean the antenna mounting angle or direction.
As for the 1st antenna 131-the 4th antenna 134, the observation angle (theta) _i is so small that the antenna located below, and the observation angle (theta) _i is large as the antenna located above.

  The solar cell panel 140 receives sunlight to generate electric power, and supplies the obtained electric power to the control device 110.

  The control device 110 rotates the first rotating shaft 121 to the fourth rotating shaft 124 at different angular velocities (rotational speeds).

The first antenna 131 to the fourth antenna 134 have a shorter distance from the observation point as they are directed downward, and the distance from the observation point is longer as they are upward (laterally directed). Therefore, in the active method of observation in which the observation signal is transmitted and the observation signal reflected at the observation point is received, the propagation time of the observation signal required from the transmission of the observation signal to reception is different for each antenna.
Therefore, the control device 110 calculates the distance to the observation point based on the observation angle θ _i (or the attachment angle, the pointing direction) of each of the first antenna 131 to the fourth antenna 134, and based on the distance to the observation point. The propagation time of the observation signal is calculated, and the angular velocities of the first rotation shaft 121 to the fourth rotation shaft 124 are calculated based on the propagation time of the observation signal.
The angular velocity calculated by the control device 110 is such a speed that each of the first antenna 131 to the fourth antenna 134 can receive the observation signal reflected at the observation point.

The control device 110 can independently control the rotation speed of each rotary shaft, but usually the lower rotary shaft rotates faster and the upper rotary shaft rotates slower.
That is, the control device 110 normally rotates the first antenna 131 to the fourth antenna 134 faster as the antenna is downward with respect to the antenna rotation axis 120 and rotates slower as the antenna is upward (lateral).

5 and 6 are diagrams showing an observation method of multi-observation angle observation apparatus 100 in the first embodiment.
An observation method of multi-observation angle observation apparatus 100 in the first embodiment will be described below with reference to FIGS.

As shown in FIG. 5, the multi-observation angle observation apparatus 100 receives transmitted, and an observation signal a signal at four observation angle theta _i ¹ through? _I ⁴ using the first antenna 131 through the fourth antenna 134.
Thus, the multi-observation angle observation apparatus 100 includes a first antenna 131, if the area observed width of the (observation angle θ _{i ^1),} 4 single observation angle θ _i ¹ ~θ _i ⁴ by a signal from any observation point Can be transmitted, and observation signals can be received.

  For example, the multi-observation angle observation apparatus 100 transmits a signal and receives an observation signal as follows to the observed object x located in the observation width region of the first antenna 131.

In FIG. 6, the multi-observation angle observation apparatus 100 receives the observation signal at the observation angle θ _i ⁴ at the fourth antenna 134 (time T ₄ ), and receives the observation signal at the observation angle θ _i ³ at the third antenna 133. At time T ₃ , the second antenna 132 receives the observation signal at the observation angle θ _i ² (time T ₂ ), and the first antenna 131 receives the observation signal at the observation angle θ _i ¹ (time T ₁ ). In addition, the control apparatus 110 calculates the transmission timing of a transmission signal for every antenna so that such reception can be achieved, and transmits a signal from each antenna at the calculated timing. In addition, when the multi-observation angle observation apparatus 100 is a passive observation apparatus, the reception timing is arbitrary (it does not matter whether it is simultaneous or not).

FIG. 7 is a diagram illustrating an example of observation data obtained by the multi-observation angle observation apparatus 100 in the first embodiment. This is not related to active / passive.
Observation data obtained by the multi-observation angle observation apparatus 100 will be described below with reference to FIG.

The multi-observation angle observation apparatus 100 receives four observation signals (observation angles θ _i ^{1 to} θ _i ⁴ ) from the observed object x using the first antenna 131 to the fourth antenna 134.
The control device 110 generates an observation profile of the observation object x based on the observation angle and signal intensity of each of the four observation signals.
The observation profile of the object to be observed x is graph data indicating signal intensities that are more approximate to the four observation signals.

  For example, the control device 110 plots each of the four observation signals in association with the observation angle and the signal intensity, and calculates a curve that minimizes the difference between each of the four plot points. The calculated curve is the observation profile of the observation target x.

The control device 110 compares the observation profile of the observation object x with the reference profiles of the observation objects A to C obtained from experimental results or theoretical values, and based on the comparison result, the type (material, Shape).
In FIG. 7, since the observation profile of the observation object x approximates the reference profile of the observation object B, it is estimated that the material and shape of the observation object x are similar to the observation object B.

FIG. 8 is a functional configuration diagram of the control device 110 according to the first embodiment.
The functional configuration of the control device 110 in the first embodiment will be described below with reference to FIG.

  The control device 110 (an example of an observation target estimation device) includes an observation signal communication unit 111, a rotation axis control unit 112, an observed object estimation unit 113 (an example of an observation profile generation unit and an observation target estimation unit), and an observation data communication unit 114. And an observation data storage unit 119.

The observation data storage unit 119 stores data used by the control device 110.
The observation data storage unit 119 stores in advance the observation angles of the first antenna 131 to the fourth antenna 134.
The observation data storage unit 119 stores a reference profile in advance for each type (material, shape, etc.) of the object to be observed.

The observation signal communication unit 111 communicates observation signals.
In the case of the active method, the observation signal communication unit 111 generates an electromagnetic wave having a predetermined waveform as an observation signal, and transmits the generated observation signal from the antenna group 130. Then, the observation signal communication unit 111 receives the observation signals reflected and backscattered by the observed object by the antenna group 130, and the waveform information (signal intensity, phase, etc.) of the received observation signals is measured with the observation angle and the observation of the antenna. It is stored in the observation data storage unit 119 in association with the time.
In the case of the passive method, the observation signal communication unit 111 receives the electromagnetic wave radiated from the observed object as an observation signal by the antenna group 130. The observation signal communication unit 111 stores the waveform information of the received observation signal in the observation data storage unit 119 in association with the observation angle and the observation time of the antenna.

  The rotation axis control unit 112 calculates and calculates the angular velocities of the first rotation axis 121 to the fourth rotation axis 124 based on the observation angles (or attachment angles and directivity directions) of the first antenna 131 to the fourth antenna 134, respectively. The first rotating shaft 121 to the fourth rotating shaft 124 are rotated at an angular velocity.

The observed object estimation unit 113 calculates an observation profile of the observed object based on the waveform information of the observation signals obtained from the first antenna 131 to the fourth antenna 134 (observation profile calculation processing).
The observed object estimation unit 113 compares the observation profile with various reference profiles to estimate the type of observed object (observed object estimation process) (see FIG. 7).
The observed object estimation unit 113 stores the observed object estimation result in the observation data storage unit 119.
The observation profile calculation process and the observed object estimation process constitute an observed object estimation method (an example of an observation target estimation method).

  The observation data communication unit 114 transmits the waveform information of the observation signal stored in the observation data storage unit 119 and the estimation result of the observed object to the observation center apparatus on the ground using the antenna group 130 or an antenna provided separately.

  The observation object may be estimated by the observation center device instead of the multi-observation angle observation device 100.

The control device 110 includes a CPU (Central Processing Unit).
The CPU is connected to a ROM, a RAM, a communication board, a power supply device, a battery, a motor, and the like via a bus and controls these hardware devices.
The ROM or RAM stores an OS (Operating System), a program group, and a file group.
The program group includes a program that executes a function described as “unit” in the embodiment. The program is read and executed by the CPU. That is, the program causes the computer to function as “to part”, and causes the computer to execute the procedures and methods of “to part”.
The file group includes various data (input, output, determination result, calculation result, processing result, etc.) used in “˜unit” described in the embodiment.

  In the embodiment, what is described as “to part” may be “to circuit”, “to apparatus”, and “to device”, and “to step”, “to procedure”, and “to processing”. May be. That is, what is described as “to part” may be implemented by any of firmware, software, hardware, or a combination thereof.

In the first embodiment, the conical scanning observation device including a plurality of antennas having different observation angles has been described.
By providing a plurality of antennas having different observation angles, a plurality of observation signals having different observation angles can be acquired.
By estimating the observation object based on a plurality of observation signals having different observation angles, the estimation accuracy of the observation object can be increased (see FIG. 7).

FIG. 9 is a diagram illustrating an observation method using a conventional push bloom type passive observation device 802.
FIG. 10 is a diagram illustrating an example of observation data obtained by a conventional push bloom passive observation apparatus 802.

As shown in FIG. 9, a conventional passive observation device 802 (for example, an optical camera) of the push bloom method can widen the observation width by changing the direction of the antenna.
Although the observation angle of the observation signal varies depending on the observation point, the observation signal can be obtained from only one observation point from one observation point.
For example, it is not possible from the observed object A to obtain only the observation signal of the observation angle theta _i ^a, it is impossible from the observation object B to obtain only the observation signal of the observation angle theta _i ^b, from the observed object C the observed signal of the observation angle θ _i ^c can only get.

As shown in FIG. 10, when each observation signal is plotted based on the observation angle and the signal intensity, the observation signal includes an error and does not match the reference profile.
For example, the observation signal of the observation object A is plotted closer to the reference profile of the observation object B than the reference profile of the observation object A, and the observation object A is estimated as the observation object B.

  On the other hand, the multi-observation angle observation apparatus 100 described in the first embodiment can improve the estimation accuracy of the observed object by obtaining observation signals at a plurality of observation angles (see FIG. 7).

The control device 110 of the multi-observation angle observation device 100 may include an antenna control unit that changes the magnitude or directivity of each of the first antenna 131 to the fourth antenna 134.
Thereby, the observation angle of each of the first antenna 131 to the fourth antenna 134 can be changed.
For example, the antenna control unit sets the observation angle of the first antenna 131 to the fourth antenna 134 to “0 degree to 90 degrees” in a specific region or time zone, and the first antenna 131 to the fourth antenna in another region or time zone. The observation angle of the antenna 134 is set to “20 degrees to 40 degrees”.

Thereby, resources can be concentrated in the angular range of interest and highly accurate estimation can be performed.
For example, the temperature of the ground surface and sea surface, the roughness of the ground surface and sea surface, the type and growth of vegetation (for example, agricultural products), the state of cutting, and the water content of vegetation and ground can be estimated with high accuracy.
If the surface and sea surface temperatures can be estimated, nuclear facilities and factory effluent can be identified, and if vegetation and ground water content can be estimated, the possibility of landslides and traffic restrictions can be determined.

The rotation axis control unit 112 of the control device 110 controls the angular velocity of each of the first rotation axis 121 to the fourth rotation axis 124, so that the time difference in the propagation time of the observation signal can be adjusted for each antenna.
Furthermore, it is also useful for a technique for estimating the moving speed of a moving body (an observed object, an example of an observation target) such as a ship or a vehicle.

  The multi-observation angle observation apparatus 100 may have two, three, five, or more antennas instead of four.

  The multi-observation angle observation device 100 may be another type of observation device (for example, a synthetic aperture radar).

  100 multi-observation angle observation device, 110 control device, 111 observation signal communication unit, 112 rotation axis control unit, 113 observed object estimation unit, 114 observation data communication unit, 119 observation data storage unit, 120 antenna rotation axis, 121 1st Rotating shaft, 121A Support rod, 122 Second rotating shaft, 122A Support rod, 123 Third rotating shaft, 123A Support rod, 124 Fourth rotating shaft, 124A Support rod, 130 Antenna group, 131 First antenna, 132 Second antenna 133 Third antenna, 134 Fourth antenna, 140 Solar panel, 801 Observation device, 802 Passive observation device, 810 Control device, 820 Antenna rotation axis, 830 Antenna, 840 Solar cell panel.

Claims (8)

A plurality of antennas for transmitting signals to the observation target from different directions and receiving observation signals from the observation targets from different directions;
An antenna rotation axis that has a length in the axial direction, attaches a plurality of antennas to different positions in the length direction, and rotates about the length direction;
Generate transmission signals for multiple antennas, rotate the antenna rotation shaft to which multiple antennas are attached, transmit transmission signals from different directions by multiple antennas, and receive observation signals from different directions by multiple antennas And a control device for storing a plurality of observation signals received by a plurality of antennas. The antenna rotation shaft has an antenna mounting portion for attaching an antenna for each antenna, and rotates for each antenna mounting portion.
The observation apparatus according to claim 1, wherein the control apparatus rotates the antenna rotation shaft at a different speed for each antenna mounting portion. The observation apparatus according to claim 2, wherein the control device rotates each antenna attachment portion faster as the direction in which an antenna attached to the antenna attachment portion receives an observation signal is downward. Multiple antennas are farther away from the antenna mounting part
The observation apparatus according to claim 3, wherein the reception direction of the observation signal is downward as the plurality of antennas are located below.   The observation apparatus according to claim 1, wherein the control apparatus changes a transmission direction of a transmission signal and a reception direction of an observation signal for each of a plurality of antennas. The control device stores profile data representing a relationship between a reception direction of an observation signal and a signal strength of the observation signal as a reference profile for each type of feature, and a profile based on a plurality of observation signals received by a plurality of antennas. 6. The observation apparatus according to claim 1, wherein data is generated as an observation profile, and the type of the observation target is specified by comparing the generated observation profile with a reference profile.   An observation apparatus comprising a plurality of antennas having different observation angles and observing an observation object by a conical scan method using the plurality of antennas. Profile data representing the relationship between the observation angle of the observation signal and the signal strength of the observation signal is stored as a reference profile for each type of feature, and is a plurality of observation signal information obtained by observing the observation target. An observation data storage unit for storing a plurality of observation signal information representing a plurality of observation signals having different
An observation profile generation unit that generates profile data as an observation profile based on a plurality of observation signal information stored in the observation data storage unit;
An observation target estimation apparatus comprising: an observation target estimation unit that estimates the type of the observation target by comparing the observation profile generated by the observation profile generation unit with a reference profile.

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