Patent Description:
In recent years, research has been conducted on techniques of predicting a movement of a mobile object, especially a flying object such as a small unmanned aerial vehicle (UAV).

Patent Literature <NUM> discloses an image data processor that periodically captures images of a mobile object and predicts a movement of the mobile object based on the captured images.

In addition, as a method of remotely measuring a position of a mobile object, Patent Literature <NUM> and Non-Patent Literature <NUM> disclose methods of using two optical frequency combs.

In connection with the above situation, an objective is to provide a movement prediction apparatus that can predict a movement of a flying object with high accuracy. Other objectives will be understood from following disclosures and descriptions of the embodiments.

A movement prediction apparatus according to an embodiment in order to achieve the above objective is provided with a first light output device, a second light output device, a light reception device, and a processor. The first light output device outputs output-light having a spectral component of a first optical frequency comb of which a frequency comb interval is a first interval. The second light output device outputs reference light having a spectral component of a second optical frequency comb of which a frequency comb is a second interval different from the first interval. The light reception device receives first combination light that is a combination of the output-light, reflection light that is the output-light reflected by a first rotor wing of a flying object having a plurality of rotor wings, and reference light, to measure a first distance to the first rotor wing based on the first combination light. The processor calculates a first rotation amount that represents a rotational speed of the first rotor wing based on a change amount of the measured first distance, and predicts a movement of the flying object based on a change of the calculated first rotation amount.

According to the above embodiment, the movement prediction apparatus can predict a movement of a flying object with high accuracy.

(Embodiment <NUM>) As shown in <FIG>, a movement prediction apparatus <NUM> according to an embodiment outputs output-light <NUM> to a flying object <NUM> and receives reflection light <NUM> thereof to predict a movement of the flying object <NUM> such as an ascent, a descent, a turning, an acceleration, a deceleration, a change of attitude, or the like. The flying object <NUM> has a plurality of rotor wings <NUM> and controls the movement by changing a number of revolutions per unit of time of the rotor wings, for example. The flying object <NUM> is a small unmanned aerial vehicle (UAV), a multi-copter, or the like. The movement prediction apparatus <NUM> measures a distance to a wing provided to the rotor wings <NUM> of the flying object <NUM> to acquire a change amount of the distance. The distance from the movement prediction apparatus <NUM> to the wing periodically changes in accordance to a rotational speed of the rotor wings <NUM>. The movement prediction apparatus <NUM> calculates a rotation amount that represents the rotational speed of the rotor wings <NUM> based on this change amount of the distance and calculates a change of the rotational speed of the rotor wings <NUM>. As the flying object <NUM> moves by changing the rotational speed of the rotor wings <NUM>, the movement prediction apparatus <NUM> predicts the movement of the flying object <NUM> based on the change of the rotational speed of the rotor wings <NUM>.

(Configuration of the movement prediction apparatus) The movement prediction apparatus <NUM> is communicably connected with an observation device <NUM>. The observation device <NUM> detects a surrounding flying object <NUM> and transmits information of the detected flying object <NUM> such as positional information to the movement prediction apparatus <NUM>. The observation device <NUM> includes for example a radar device, an imaging device, or the like.

The movement prediction apparatus <NUM> outputs the output-light <NUM> to the flying object <NUM> based on the information of the flying object <NUM> detected by the observation device <NUM>. The movement prediction apparatus <NUM> is provided with a controller <NUM> and one or more ranging devices <NUM>. A ranging device <NUM> outputs output-light <NUM> and receives reflection light <NUM> from a rotor wing <NUM> of a flying object <NUM> to measure a distance from the movement prediction apparatus <NUM> to the rotor wing <NUM>. The controller <NUM> predicts a movement of the flying object <NUM> based on the distance from the movement prediction apparatus <NUM> to the rotor wing <NUM>. In addition, the controller <NUM> controls the ranging devices <NUM> based on the predicted movement of the flying object <NUM>.

The ranging device <NUM> is provided with an optical oscillator <NUM>, a first light output device <NUM>, a second light output device <NUM>, a light reception device <NUM>, and a plurality of optical devices such as a first beam splitter <NUM>, a mirror <NUM>, and a second beam splitter <NUM>. The optical oscillator <NUM> is configured to output seed light <NUM> and irradiate the first light output device <NUM> and the second light output device <NUM> with the seed light <NUM>.

The first light output device <NUM> is configured to receive the seed light <NUM> and output the output-light <NUM>. As shown in <FIG>, the output-light <NUM> has a plurality of frequencies that are lined up by a predetermined frequency interval fr, (this frequency interval will be referred to as comb frequency interval hereinafter) in a frequency domain and referred to as optical comb or optical frequency comb, and has a spectral component with a comb-like shape. A frequency f that the output-light <NUM> has may be represented by f=Nfr+f<NUM>. In addition, optical intensity of the output-light <NUM> having a spectral component as shown in <FIG> continuously changes over time as a curved line <NUM> shown in <FIG>. Curved lines <NUM> that connect positions showing local maxima or position showing local minima of the optical intensity that changes over time are similar to pulse waves with a period Tr. The period Tr is calculated by an equation Tr=<NUM>/fr using the comb interval fr.

The second light output device <NUM> is configured to receive the seed light <NUM> and output reference light <NUM>. The reference light <NUM> has a comb-like shaped spectral component that is referred to as optical comb, similarly to the output-light <NUM>. Herein, the comb interval fr of the reference light <NUM> is different from the comb interval fr of the output-light <NUM>. For this reason, the period Tr of the reference light <NUM> is also different from the period Tr of the output-light <NUM>. For example, the comb interval fr of the reference light <NUM> is set to approximate the comb interval fr of the output-light <NUM> and so that an optical beat is generated by combining the reference light <NUM> and the output-light <NUM>.

The first beam splitter <NUM> is configured to split the output-light <NUM> into two of which one is transmitted and another one is reflected. The output-light <NUM> that has been transmitted through the first beam splitter <NUM> irradiates the flying object <NUM>. The output-light <NUM> radiated to the flying object <NUM> is reflected by the flying object <NUM> as the reflection light <NUM>. The reflection light <NUM> reflected by the flying object <NUM> incidents into the first beam splitter <NUM>. The first beam splitter <NUM> is configured to reflect the incident reflection light <NUM> toward the second beam splitter <NUM>. The second beam splitter <NUM> is configured to reflect the reflection light <NUM> reflected by the first beam splitter <NUM> toward the light reception device <NUM>.

In addition, the first beam splitter <NUM> is configured to reflect a part of the output-light <NUM> toward the mirror <NUM> as standard light <NUM>. The standard light <NUM> reflected by the first beam splitter <NUM> is reflected toward the mirror <NUM> and incidents the second beam splitter <NUM>. The second beam splitter <NUM> reflects the incident standard light <NUM> toward the light reception device <NUM>.

The second beam splitter <NUM> transmits the reference light <NUM>. The transmitted reference light <NUM> incidents the light reception device <NUM>.

As described above, the first beam splitter <NUM> and the second beam splitter <NUM> are configured to irradiate the flying object <NUM> with the output-light <NUM> that the first light output device <NUM> outputs and irradiate the light reception device <NUM> with the reflection light <NUM> that the flying object <NUM> reflects. In addition, the first beam splitter <NUM>, the mirror <NUM>, and the second beam splitter <NUM> are configured to irradiate the light reception device <NUM> with the output-light <NUM> as the standard light <NUM> that the first light output device <NUM> outputs. Furthermore, the second beam splitter <NUM> is configured to irradiate the light reception device <NUM> with the reference light <NUM> that the second light output device <NUM> outputs.

The light reception device <NUM> receives the combination light that is the combination of the reflection light <NUM> from the flying object <NUM>, the standard light <NUM> outputted from the first light output device <NUM>, and the reference light <NUM> outputted from the second light output device <NUM>. The light reception device <NUM> measures the distance from the ranging device <NUM> to the flying object <NUM> based on the received combination light.

More specifically, the light reception device <NUM> measures the distance to the rotor wing <NUM> of the flying object <NUM>. Herein, with reference to the change of the optical intensity over time, the standard light <NUM> is similar to the pulse light with a period Tr1, and the reference light <NUM> is similar to the pulse light with a period Tr2, as shown in <FIG>. In addition, the period Tr2 of the reference light <NUM> approximates the period Tr1 of the standard light <NUM> so that an optical beat is generated when the reference light <NUM> and the standard light <NUM> are combined.

For this reason, the optical intensity of the combination light in which the reflection light <NUM>, the standard light <NUM>, and the reference light <NUM> are combined repeats a relatively high state and a relatively low state. For example, in the first state <NUM> in <FIG>, the optical intensity of the combination light in which the reference light <NUM> and the standard light <NUM> are combined becomes relatively high. However, as the period Tr2 of the reference light <NUM> is different from the period Tr1 of the standard light <NUM>, the more time passes, the waveform of the reference light <NUM> shifts from the waveform of the standard light <NUM>, and the optical intensity of the combination light becomes relatively low. As more time passes, in the second state <NUM>, the waveform of the reference light <NUM> and the waveform of the reflection light <NUM> overlap and the optical intensity of the combination light becomes relatively high. As more time passes, the waveform of the reference light <NUM> shifts from the waveform of the reflection light <NUM> and the optical intensity of the combination light becomes relatively low. As more time passes, the waveform of the reference light <NUM> and the waveform of the standard light <NUM> overlap as in the third state <NUM> and the optical intensity of the combination light becomes relatively high.

The light reception device <NUM> measures the distance from the ranging device <NUM> and the flying object <NUM> based on a time from when the waveform of the reflection light <NUM> and the waveform of the reference light <NUM> overlap until when the waveform of the standard light <NUM> and the waveform of the reference light <NUM> overlap. For example, the light reception device <NUM> calculates a time of the first state <NUM> shown in <FIG> from when the optical intensity of the combination light in which the reflection light <NUM>, the standard light <NUM>, and the reference light <NUM> are combined becomes relatively high to a time of the second state <NUM> when the optical intensity becomes relatively high subsequently. The light reception device <NUM> measures the distance based on the calculated time. The calculated time represents a time in which time difference between the reflection light <NUM> and the standard light <NUM> is increased. As a result, the light reception device <NUM> can measure the distance with a higher accuracy than measuring the distance based on a time from when the output-light <NUM> is outputted until when the reflection light <NUM> is received.

As shown in <FIG>, the controller <NUM> is provided with an input output device <NUM>, a communication device <NUM>, a storage device <NUM>, and a processor <NUM>. For example, the controller <NUM> is a computer. The input output device <NUM> receives information for the processor <NUM> to execute processes. In addition, the input output device <NUM> outputs result of the processes that the processor <NUM> executed. The input output device <NUM> includes various input devices and output devices, and includes for example a keyboard, a mouse, a microphone, a display, a speaker, a touch panel, or the like. The input output device <NUM> may be omitted.

The communication device <NUM> performs communication with other devices such as the observation device <NUM>, the ranging devices <NUM>, or the like. The communication device <NUM> transfers information received from the observation device <NUM> and the ranging devices <NUM> to the processor <NUM>. In addition, the communication device <NUM> transfers control signals that the processor <NUM> generates to the ranging devices <NUM>. The communication device <NUM> includes various interfaces such as a network interface card (NIC), universal serial bus (USB), or the like.

The storage device <NUM> stores various data for predicting the movement of the flying object <NUM> such as a movement prediction program <NUM>. The storage device <NUM> is used as a non-transitory tangible storage medium that memorize the movement prediction program <NUM>. The movement prediction program <NUM> may be provided as a computer program product that is computer-readably stored in a storage medium <NUM> or may be provided as a computer program product that is downloadable from a server.

The processor <NUM> performs various data processes for predicting the movement of the flying object <NUM>. The processor <NUM> reads out from the storage device <NUM> and executes the movement prediction program <NUM>, and generates control signals for controlling the ranging devices <NUM>. For example, the processor <NUM> includes a central processing unit (CPU) or the like.

As shown in <FIG>, the processor <NUM> realizes a rotor wing detection section <NUM>, a rotation measurement section <NUM>, and the movement prediction section <NUM> by executing the movement prediction program <NUM>. The rotor wing detection section <NUM> detects a position where a rotor wing <NUM> of a flying object <NUM> exists. The rotation measurement section <NUM> outputs output-light <NUM> to the detected position of the rotor wing <NUM> and measures a rotation amount that represents a rotational speed of the rotor wing <NUM> of the flying object <NUM>. The movement prediction section <NUM> predicts a movement of the flying object <NUM> based on the measured rotation amount.

(Operation of the movement prediction apparatus) When a flying object <NUM> approaches the movement prediction apparatus <NUM>, the observation device <NUM> detects the flying object <NUM>. The observation device <NUM> transmits position information of the detected flying object <NUM> to the processor <NUM> of the movement prediction apparatus <NUM>. When the processor <NUM> receives the position information of the flying object <NUM>, the processor <NUM> executes a process of the movement prediction method shown in <FIG> by executing the movement prediction program <NUM>.

In the step S110, the rotor wing detection section <NUM> that is realized by the processor <NUM> searches for a position of a rotor wing <NUM> of a flying object <NUM>. Specifically, the rotor wing detection section <NUM> transmits a control signal for outputting seed light <NUM> to the optical oscillator <NUM>. The optical oscillator <NUM> outputs seed light <NUM> based on the control signal from the rotor wing detection section <NUM>. In addition, the rotor wing detection section <NUM> generates a first light output signal for outputting output-light <NUM> and a second light output signal for outputting reference light <NUM>. The first light output device <NUM> outputs output-light <NUM> based on the first light output signal. In addition, the second light output device <NUM> outputs reference light <NUM> based on the second light output signal.

The rotor wing detection section <NUM> outputs output-light <NUM> based on the position information of the flying object <NUM> in order to search for the position where the flying object <NUM> exists, and searches for the position of the rotor wing <NUM> of the flying object <NUM>. Specifically, the rotor wing detection section <NUM> uses a ranging device <NUM> and measures a distance to a predetermined position of an object in a direction in which the output-light <NUM> is outputted, such as the flying object <NUM>. The rotor wing detection section <NUM> detects a position of which the distance that the light reception device <NUM> measures changes rapidly, continuously, and periodically, as the position of the rotor wing <NUM>.

A distance from a ranging device <NUM> to a rotor wing <NUM> of a flying object <NUM> changes rapidly, continuously, and periodically over time. For example, as shown in <FIG>, a ranging device <NUM> measures a distance to a first wing <NUM>-<NUM> of a rotor wing <NUM> irradiated with output-light <NUM>. The rotor wing <NUM> rotates for example in a counterclockwise direction shown in the arrow <NUM>. As shown in <FIG>, when the rotor wing <NUM> rotates, the first wing <NUM>-<NUM> moves out from the radiation line of output-light <NUM> and the output-light <NUM> irradiates a second wing <NUM>-<NUM>. For this reason, in a state of <FIG>, the distance that the ranging device <NUM> measures becomes longer than in the state of <FIG>. As shown in <FIG>, when the rotor wing <NUM> rotates furthermore, the second wing <NUM>-<NUM> approaches the ranging device <NUM>. As a result, the distance that the ranging device <NUM> measures becomes shorter. As shown in <FIG>, when the rotor wing <NUM> rotates furthermore, the second wing <NUM>-<NUM> approaches the ranging device <NUM> and the distance that the ranging device <NUM> measures becomes shorter. As shown in <FIG>, when the rotor wing <NUM> rotates to a predetermined position, the output-light <NUM> irradiates the tip of the second wing <NUM>-<NUM>. When the rotor wing <NUM> rotates furthermore, the second wing <NUM>-<NUM> move out from the irradiation line of the output-light <NUM>. For this reason, the output-light <NUM> irradiates a third wing <NUM>-<NUM>. As described above, when the output-light <NUM> irradiates the rotor wing <NUM>, the distance that the ranging device <NUM> measures periodically changes.

In the step S120, the rotor wing detection section <NUM> determines whether a predetermined number or more of rotor wings <NUM> has been detected. For example, the rotor wing detection section <NUM> determines whether three or more rotor wings <NUM> has been detected. When the rotor wing detection section <NUM> detected a predetermined number, for example three or more, of rotor wings <NUM>, the process of the step S130 is executed to predict a movement of the flying object <NUM>. When the rotor wing detection section <NUM> does not detect a predetermined number or more of rotor wings <NUM>, the process of the step S170 is executed, by determining that the flying object <NUM> is not controlling a fine movement such as an ascent, a descent, or a turning by the rotor wing <NUM>.

In the step S130, the rotation measurement section <NUM> determines an irradiation position to irradiate with the output-light <NUM>. Specifically, the rotation measurement section <NUM> determines a predetermined position in each region of regions of the plurality of detected rotor wings <NUM> as an irradiation position. For example, in the region of the detected rotor wing <NUM>, a position at a predetermined distance from the center thereof is determined as the irradiation position. The predetermined distance may be determined based on a width size that is the longest length in the region of the rotor wing <NUM>, for example. The predetermined distance may be <NUM>% of the width size that is the longest length in the region of the rotor wing <NUM>, for example. It should be noted that the width size of the region of the rotor wing <NUM> represents a length of a line segment connecting two edges of the region, for example.

In the step S140, the rotation measurement section <NUM> starts a measurement of a rotation amount that represents a rotational speed of each rotor wing <NUM> based on a change amount of the distance that is measured by irradiating each determined irradiation position with the output-light <NUM>. In a region of a rotor wing <NUM>, the distance that the ranging device <NUM> measures periodically changes within a predetermined range like the curved line <NUM> in <FIG>. The first state shown in <FIG> represents the state of <FIG> and represents a state immediately before the first wing <NUM>-<NUM> moves out from the irradiation line of the output-light <NUM>. When the output-light <NUM> irradiates the first wing <NUM>-<NUM>, the measured distance shows the lower limit value; and at the moment when the output-light <NUM> leaves the first wing <NUM>-<NUM>, the measured distance rapidly increases. The second state shown in <FIG> represents the state in <FIG>: as the second wing <NUM>-<NUM> that is irradiated with the output-light <NUM> approaches the ranging device <NUM>, the measured distance becomes shorter. The third state shown in <FIG> represents the state in <FIG> and the fourth state shown in <FIG> represents the state in <FIG>. The fifth state shown in <FIG> represents the state in <FIG>: when the output-light <NUM> irradiates the second wing <NUM>-<NUM>, the measured distance shows the lower limit. At the moment when the output-light <NUM> leaves the second wing <NUM>-<NUM>, the measured distance rapidly increases. As described above, the wing irradiated with the output-light <NUM> changes to the first wing <NUM>-<NUM>, the second wing <NUM>-<NUM>, the third wing <NUM>-<NUM>, and the fourth wing <NUM>-<NUM> in order. In accordance with this change, the measured distance periodically changes.

The rotation measurement section <NUM> measures a rotation amount based on changes of the measured distance. For example, when the rotor wing <NUM> has four wings, as each of the first wing <NUM>-<NUM> to the fourth wing <NUM>-<NUM> are irradiated with the output-light <NUM> during one rotation of the rotor wing <NUM>, the measured distance periodically changes four times. When the rotational speed of the rotor wing <NUM> increases, the time during which the change of the measured distance is repeated four times becomes shorter. As described above, the rotation measurement section <NUM> measures the rotation amount based on the amount of time required for the change of the measured distance to be repeated a predetermined count of times. It should be noted that the count of times, which the change of the measured distance is repeated, does not depend on the number of wings that the rotor wing <NUM> has. For example, even if the rotor wing <NUM> has five wings, the rotation amount may be measured based on the amount of time required for the change of the measured distance to be repeated four times.

For example, the rotation measurement section <NUM> measures the rotation amount based on an amount of time required for a count of times, that the measured distance becomes smaller than a threshold value, to reach a predetermined count of times. This threshold value is determined based on a difference between the lower limit value and the average value of the measured distance, as shown in <FIG>. For example, the threshold value is a value which the average value subtracted with <NUM>% of the difference between the lower limit value and the average value of the measured distance. The rotation measurement section <NUM> counts the times that the measured distance becomes smaller than the threshold value, and measures the amount of time until the count of times reaches a predetermined value, which is four, for example. The rotation measurement section <NUM> calculates an inverse number of the measured amount of time as the rotation amount. It should be noted that the average value of the measured distance represents the average value of the distance that is measured during a predetermined period, and the lower limit value represents the shortest distance that is measured during a predetermined period.

In addition, the rotation measurement section <NUM> determines a rotation direction of the rotor wing <NUM> based on the change amount of the measured distance. Specifically, the rotation measurement section <NUM> determines the rotation direction of the rotor wing <NUM> based on the irradiation position of the output-light <NUM> in the region of the rotor wing <NUM> and the change amount of the measured distance. As shown in <FIG>, when the irradiation position is in left side of the region of the rotor wing <NUM> and the rotor wing <NUM> is rotating in a counterclockwise direction when viewed from above, the measured distance repeats a first state of rapid increase and the second to fourth states of gradual decrease, as shown in <FIG>. On the other hand, when the rotor wing <NUM> is rotating in a clockwise direction, the measured distance repeats a state of rapid decrease and states of gradual increase. In addition, when the irradiation position is in right side of the region of the rotor wing <NUM> and the rotor wing <NUM> is rotating in a counterclockwise direction when viewed from above, the measured distance repeats a state of rapid decrease and states of gradual increase. When the rotor wing <NUM> rotates in clockwise direction, the measured distance repeats a state of rapid increase and states of gradual decrease. As described above, the rotation measurement section <NUM> determines the rotation direction of the rotor wing <NUM> by determining whether the irradiation position of the output-light <NUM> is in left side or right side of the region of the rotor wing <NUM> and whether an increase or a decrease in the distance that is periodically measured changes relatively rapidly.

In the step S150, the movement prediction section <NUM> predicts the movement of the flying object <NUM> based on the measured rotation amount of each rotor wing <NUM>. The movement prediction section <NUM> determines based on changes of the rotation amount that a force according to the change of the rotation amount is working at the position of the corresponding rotor wing <NUM>. For example, when the rotation amount is increasing, the movement prediction section <NUM> determines that an upward force is increasing at the position of the corresponding rotor wing <NUM>. In addition, when the rotation amount is decreasing, the movement prediction section <NUM> determines that a downward force is increasing at the position of the corresponding rotor wing <NUM>.

The movement prediction section <NUM> determines forces generated at the position where each rotor wing <NUM> is arranged and predicts the movement of the flying object <NUM>. For example, when a rotation amount of a rotor wing <NUM> of a plurality of rotor wings <NUM> that is in relatively right direction is increasing compared to a rotation amount of a rotor wing <NUM> that is in relatively left direction, the movement prediction section <NUM> predicts that the flying object <NUM> will move to left direction. In addition, when the rotation amount of all rotor wings <NUM> is increasing, the movement prediction section <NUM> predicts that the flying object <NUM> will ascend. Furthermore, when the rotational speed of a rotor wing <NUM> that is rotating in counterclockwise direction when viewed from above is increasing compared to the rotational speed of a rotor wing <NUM> that is rotating in clockwise direction, the movement prediction section <NUM> predicts that the flying object <NUM> will turn in counterclockwise direction. When the rotational speed of a rotor wing <NUM> that is rotating in clockwise direction when viewed from above is increasing compared to the rotational speed of a rotor wing <NUM> that is rotating in counterclockwise direction, the movement prediction section <NUM> predicts that the flying object <NUM> will turn in clockwise direction.

The movement prediction section <NUM> may determine an attitude of the flying object <NUM> based on the position of the rotor wing <NUM> that the ranging section <NUM> has measured. The movement prediction section <NUM> determines a position in a direction in which the output-light <NUM> is radiated from the ranging device <NUM> and at the measured distance as the position of each rotor wing <NUM>. The movement prediction section <NUM> determines an attitude such as an inclination of the flying object <NUM> based on the position of each rotor wing <NUM>. For example, when the position of a rotor wing <NUM> among a plurality of rotor wings <NUM> that is in relatively right direction is lower than the position of a rotor wing <NUM> that is in relatively left direction, the movement prediction section <NUM> determines that the flying object <NUM> is tilted so that right side is lower than left side. The movement prediction section <NUM> may predict the movement of the flying object <NUM> based on the determined attitude of the flying object <NUM> and the rotation amount of each rotor wing <NUM>.

In the step S160, the movement prediction section <NUM> determines whether the movement prediction section <NUM> is detecting a flying object <NUM>. When the movement prediction section <NUM> is detecting a flying object <NUM>, the process of the step S150 will be executed and the process will be repeated. At that time, the rotation measurement section <NUM> changes the position to irradiate with the output-light <NUM> in accordance with the movement of the flying object <NUM> that the movement prediction section <NUM> has predicted. For example, when it is predicted that the flying object <NUM> will move to left, the rotation measurement section <NUM> moves the position to irradiate with the output-light <NUM> to left. As described above, the rotation measurement section <NUM> moves the position to irradiate with the output-light <NUM> depending on the movement of the flying object <NUM> and carries on measuring the rotation amount of each rotor wing <NUM>.

When the movement prediction section <NUM> is not detecting any flying object <NUM>, the process of predicting the movement of the flying object <NUM> that the observation device <NUM> detected ends. The rotation measurement section <NUM> stops the output of the output-light <NUM> when the process ends.

In the step S120, when the rotor wing detection section <NUM> does not detect a predetermined number or more of rotor wings <NUM>, the processor <NUM> executes the step S170. In the step S170, the processor <NUM> carries on measuring the distance from the ranging device <NUM> to the flying object <NUM>. By measuring the distance to the flying object <NUM> by use of the ranging device <NUM>, the processor <NUM> can measure the position of the flying object <NUM> with high accuracy.

In the step S180, the processor <NUM> determines whether the processor <NUM> is detecting a flying object <NUM>. When the processor <NUM> is detecting a flying object <NUM>, the process of the step S170 will be executed and the process will be repeated. When the processor <NUM> is not detecting any flying object <NUM>, the process of predicting the movement of the flying object <NUM> that the observation device <NUM> detected ends. The processor <NUM> stops the output of the output-light <NUM> when the process ends.

As described above, the movement prediction apparatus <NUM> predicts a movement of a flying object <NUM> based on forces that the rotor wings <NUM> of the flying object <NUM> generate. As a result, the movement prediction apparatus <NUM> predicts the movement of the flying object <NUM> with high accuracy.

(Embodiment <NUM>) As shown in <FIG>, the movement prediction apparatus <NUM> may be provided with a laser oscillator <NUM> that irradiates a flying object <NUM> with a high-power laser beam <NUM>. The laser oscillator <NUM> irradiates a predetermine position of the flying object <NUM> with the laser beam <NUM> in accordance with the movement of the flying object <NUM>, that the movement prediction apparatus100 predicted, to deal with the flying object <NUM>.

The controller <NUM> controls the laser oscillator <NUM>. For example, the controller <NUM> generates a signal that indicates an irradiation position of the laser beam <NUM> that the laser oscillator <NUM> radiates such as an irradiation direction of the laser beam <NUM>, a focus distance, and the like. The laser oscillator <NUM> radiates the laser beam <NUM> based on the generated signal. As other configurations and operations of the movement prediction apparatus <NUM> is similar to the embodiment <NUM>, description thereof will be omitted.

(Embodiment <NUM>) As shown in <FIG>, the movement prediction apparatus <NUM> may be provided with an imaging device <NUM> that captures an image of the flying object <NUM>. The movement prediction section <NUM> predicts the movement of the flying object <NUM> based on a rotation amount of the rotor wing <NUM> that is measured by the ranging device <NUM>. In addition, the movement prediction section <NUM> judges the movement of the flying object <NUM> such as a movement route, a change of attitude, and the like based on an image of the flying object <NUM> that the imaging device130 captured. The movement prediction section <NUM> updates a relationship between the change of the rotation amount of each rotor wing <NUM> and a ratio of change of the predicted movement of the flying object <NUM> such as a ratio of changes of speed, acceleration, angular acceleration or the like, based on a difference between a movement of the flying object <NUM> determined from the image and a movement of the flying object <NUM> predicted from the rotation amount of the rotor wing <NUM>.

Specifically, the movement prediction section <NUM> acquires images of the flying object <NUM> that are captured before and after the prediction of the movement of the flying object <NUM>, and calculates a distance that the flying object <NUM> moved from the acquired images. The movement prediction section <NUM> updates the relationship between the change of the rotation amount of the rotor wing <NUM> and the ratio of the change of the predicted movement of the flying object <NUM>, based on a difference between the calculated movement distance of the flying object <NUM> and the predicted movement distance of the flying object <NUM>.

For example, it is assumed that the flying object <NUM> moves upward. At that time, the movement prediction section <NUM> calculates a distance the flying object <NUM> moved upward from the images captured before and after the prediction of the movement of the flying object <NUM>. The movement prediction section <NUM> compares the distance of the upward movement of the flying object <NUM> that is calculated from the captured images and the distance of the upward movement of the flying object <NUM> predicted from the rotation amount of the rotor wing <NUM>. When the distance calculated from the captured images is smaller than the distance predicted from the rotation amount of the rotor wing <NUM>, the movement prediction section <NUM> updates so that the distance of the upward movement of the flying object <NUM> predicted from the rotation amount of the rotor wing <NUM> becomes smaller.

As a result, the movement prediction section <NUM> can improve the accuracy of predicting the movement in accordance with the detected flying object <NUM>. As other configurations and operations of the movement prediction apparatus <NUM> are similar to the embodiment <NUM>, descriptions thereof will be omitted.

(Variation examples) Although in each embodiment, examples that the rotation measurement section <NUM> measures a rotation amount of each detected rotor wing <NUM> have been shown, this is not limitative, and the rotation measurement section <NUM> may measure rotation amounts of two or more rotor wings <NUM> of the detected rotor wings <NUM>. The movement prediction section <NUM> predicts the movement of the flying object <NUM> based on the positions and the rotation amounts of the rotor wings <NUM> that are measured.

As long as the rotation measurement section <NUM> can measure the rotation amount of the rotor wing <NUM> based on the change amount of the distance from the ranging device <NUM> to the rotor wing <NUM>, an arbitrary method may be selected. For example, the rotation measurement section <NUM> may calculate the rotation amount based on an amount of time required for reaching a predetermined number of times that a change amount of the distance from an average value of the measured distances exceeds a threshold value. The threshold value may be determined based on a difference between a distance that represents an average value of the measured distances and a distance of the measured distances that is the furthest from the average value. In addition, the rotation measurement section <NUM> may calculate a period of the measured distance by an arbitrary method and calculate the rotation amount from the calculated period.

The imaging device <NUM> may capture a video of the flying object <NUM>. In this case, the movement prediction section <NUM> extracts each frame of the captured video as images and judges the movement of the flying object <NUM> based on the extracted images.

The embodiments and the variation examples that are described above are examples and may be modified within a range of not inhibiting the functions. In addition, the configurations described in each embodiment and variation example may be arbitrarily modified and/or arbitrarily combined within a range of not inhibiting the functions.

For example, the movement prediction apparatus <NUM> may be provided with the laser oscillator <NUM> and the imaging device <NUM>. In addition, if the light reception device <NUM> can receive the standard light <NUM>, the reflection light <NUM> and the reference light <NUM>, an arbitrary configuration may be selected as the optical system of the first beam splitter <NUM>, the mirror <NUM> and the like. In addition, if one light reception device <NUM> can receive a plurality of combinations of light and measure a distance based on each combination of light, the movement prediction apparatus <NUM> may have with one light reception device <NUM> that is common to the plurality of ranging devices <NUM>. The movement prediction apparatus <NUM> may be provided with one first light output device <NUM> that is common to the plurality of ranging devices <NUM>, split the output-light <NUM> that the one first light output device <NUM> outputs, and irradiate each rotor wing <NUM> of the flying object <NUM> with the split output-light <NUM>. One second light output device <NUM> common to the plurality of ranging devices <NUM> may be provided.

Claim 1:
A movement prediction apparatus comprising:
a first light output device configured to output output-light having a spectral component of a first optical frequency comb of which a frequency comb interval is a first interval;
a second light output device configured to output reference light having a spectral component of a second optical frequency comb of which a frequency comb interval is a second interval different from the first interval;
a light reception device configured to receive first combination light that is a combination of standard light that is a first part of the output-light, first reflection light that is a second part of the output-light reflected by a first rotor wing of an flying object having a plurality of rotor wings, and the reference light, to measure a first distance to the first rotor wing based on the first combination light; and
a processor configured to calculate a first rotation amount that represents a rotational speed of the first rotor wing based on a change amount of the measured first distance, and predict a movement of the flying object based on a change of the calculated first rotation amount.