JP2008203123A - Water surface and ground surface observation device for aircraft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device capable of observing a water surface wave or a ground surface state in a wide and necessary area, and a flow velocity of a water surface, and an on-water alighting or landing support device for an aircraft using the device. <P>SOLUTION: The water surface or ground surface observation device for the aircraft is mounted with a laser beam transceiver on the aircraft, the laser beam transceiver includes a means equipped with a mechanism capable of setting a transceiving direction to a downward direction, a front-downward direction and a lateral-downward direction, with respect to an airframe, and for accumulating angle information thereof and data of the transceived laser beams, and a means for processing the data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for observing the state of water surface waves and flow velocity or ground undulation from an aircraft flying in the sky, and a landing support device for a surface aircraft or landing and emergency landing support for a land aircraft using the method. It relates to the device. An aircraft generally indicates an airplane, a rotorcraft, an airship, or a hot air balloon, but the present invention can be applied in principle to any flying object such as an artificial satellite or a parachute. The surface aircraft is a surface aircraft, a flying boat, a rotorcraft capable of landing, an amphibious aircraft, and the like. The water surface includes a lake surface, a sea surface, a river surface, and the like.

  Usually, water level and wave height observation for disaster prevention etc. are carried out by wave height meter installed on the coast or in the sea, up and down movement of buoy floating on the water surface or visual observation of waves. Therefore, observation information of only the installation location or visible range of the wave height meter or buoy can be obtained. There are ultrasonic wave type, radio wave type, laser type, etc., all of which have an effective range of several tens of meters or less. Since the flow velocity on the water surface is also observed visually, such as the movement of suspended matter, it may not be observable depending on the presence or absence of suspended matter and the state of light.

  The state of the waves on the surface of the water when a surface aircraft or a land aircraft in an emergency lands is visually confirmed by the pilot. Therefore, it is difficult to judge when the light beam state is bad or when the wave height is near the limit value. In the case of weather information by advance forecast or wireless communication, the range and time cannot be specified in detail, so accuracy and reliability are low. The Shin-Maywa US-1 type flying boat developed in Japan is equipped with the world's only wave height meter for airborne applications, but it is an application of a radio altimeter and has functions for wave height and wavelength analysis. There is no function to observe the wave propagation velocity or flow velocity. It is not preferable to install other devices for detecting these information because it increases capital investment. Increased redundancy by replacing or multiplexing with other devices capable of observing wave conditions and flow velocities or ground undulations is effective for cost reduction or increased reliability.

  When a land aircraft lands other than a paved runway, the state of the ground is grasped by radio notification from a ground observer. However, when there is no observer on the ground in an emergency, etc., the pilot is observing visually, and there are cases where sufficient confirmation cannot be made. For example, in the case of the Dornier 228 aircraft, it is said that it can safely land on a riverbank composed of gravel less than 1 inch, but it is extremely difficult for the operator to check it during flight. .

Regarding the measurement of flight altitude, the barometric altimeter and the radio altimeter are used properly according to the altitude, and these are used without any problem. However, the increase in redundancy due to replacement or multiplexing by other devices is costly. Effective for reducing or improving reliability. Patent Document 1 presents a laser altimeter. SUMMARY OF THE INVENTION An object of the present invention is to provide a device capable of aeronautical surveying that can flexibly and quickly collect topographic information without placing a map root on the ground surface. The GPS measures the position of the surveying device without placing the figure root on the ground surface, and the laser altimeter controller reflects the laser beam from the laser beam irradiator and then reflects it on the target. Measure the distance to the target from the time it takes to return. From these measurement results, the topographical information of the target is calculated by the central computer, while the mirror that reflects the laser beam rotates about a certain axis. This type of laser altimeter has already been put into practical use, but it has only a single function for altitude measurement and no function for observing the state of the water surface or ground. Since the measurement accuracy of the radio altimeter is several tens of centimeters, the accuracy is insufficient to determine whether or not the aircraft can land on the ground.
Japanese Patent Laid-Open No. 10-89958 “Aeronautical Surveying Device” released on April 10, 1998

  An object of the present invention is to solve the above-mentioned problems, that is, a device capable of observing water surface waves or ground conditions in a wide area and a necessary region and a water surface velocity, and landing of an aircraft using the device. Another object is to provide a landing support device.

The aircraft water surface and ground observation apparatus of the present invention includes a laser beam transmitter and a receiver mounted on an aircraft, and the laser beam transmitter / receiver sets a transmission / reception direction to the aircraft at least in a downward direction, a downward front direction, and a downward direction. A mechanism capable of storing the angle information and transmission / reception laser beam data and a data processing unit are provided.
One method of using the aircraft water surface and ground observation apparatus of the present invention is to attach a laser beam transmitter and receiver having a distance measuring function to the lower part of the aircraft, and to direct the laser beam downward for a predetermined time during flight. Transmitting and receiving waves, and observing the flight altitude or water level from the average value of the distance data detected based on the transmitted and received signal, and observing the wave height value of the water surface or the undulation of the ground from the amount of change.
Another method of using the aircraft water surface and ground observation apparatus of the present invention is to transmit a laser beam at a known time interval during flight in a diagonally downward front direction and a diagonally downward direction, and a change amount of a reception pulse interval. Based on the above, the propagation speed and propagation direction of waves on the water surface are observed during flight. Also, one method of data processing of transmission / reception signals is to observe the flow velocity on the water surface based on the Doppler effect.
One mode of use of the aircraft water surface and ground observation apparatus of the present invention is to use observation data obtained by the above method for landing or landing support of an aircraft.

  The effect of the present invention is that by mounting a laser range finder on an aircraft, the aircraft observes the wave height of the lower water surface, the undulation of the ground and the flight altitude during the flight, And an apparatus for observing the propagation direction and flow velocity. The observation apparatus according to the present invention can be mounted on an aircraft and used for observation of tsunamis, topography, and the like. In addition, it can be used to predict the movement of drifters and driftwood at the time of a maritime accident by observing the propagation velocity, propagation direction and flow velocity of waves on the sea surface. Furthermore, when this apparatus is mounted on a surface aircraft, the pilot can know the state of the water surface that is scheduled to land in real time, so it is easy to determine whether or not to land, and safety is improved. In the case of landing of a land aircraft or emergency landing, safety is similarly improved. Further, when this apparatus is used instead of a radio altimeter, the procurement cost of the radio altimeter and the maintenance cost of the radio station can be reduced. When used in addition to a radio altimeter, the reliability of altitude measurement is improved because a multiplex system is configured.

ただし、
Ｄ：航空機と水面との鉛直方向の距離
ｄ：レーザ式測距器の距離計測値
θ：航空機の姿勢角
Ｈ：航空機の平均飛行高度
ｈ：最大波高
ｔ：計測単位時間(数秒間) FIG. 1 is a diagram schematically showing the principle of measuring the flight altitude and observing the wave height of the water surface from above using a laser range finder 2 mounted on the aircraft 1.
When the laser range finder 2 is mounted face down and the distance to the water surface is measured while the aircraft 1 is flying horizontally, the distance measurement value (d) of the laser range finder 2 as shown in Equation [1]. ) Multiplied by cos θ, the moving average value for t seconds (D) represents the average flight altitude (H) of the aircraft 1, and the amount of change in D for t seconds represents the maximum wave height (h). Even when the aircraft 1 moves, the wave height can be observed similarly even when the aircraft 1 stops in the air and the waves move. The attitude angle (θ) of the aircraft 1 can be obtained from a general navigation device mounted on the aircraft 1. The water level can also be calculated by comparing the altitude on the earth fixed coordinates using GPS or the like with the average flight altitude H. In addition, when used over land, it is possible to measure the average flight height and observe land undulations in the same way. As a method for performing distance measurement, there are a method of measuring the time until the transmitted laser beam is received, and a method of using “beat” based on the phase difference between the transmitted beam and the received beam (heterodyne method). These are all known techniques.

However,
D: Vertical distance between aircraft and water surface d: Distance measurement value of laser range finder θ: Attitude angle of aircraft H: Average flight altitude of aircraft h: Maximum wave height t: Measurement unit time (several seconds)

FIG. 2 is a diagram schematically showing the basic principle of observing the wave propagation speed according to the present invention. In order to observe the propagation velocity of the wave, a laser beam is emitted obliquely downward (α angle) from the transmitter 3 mounted on the aircraft 1 that is flying horizontally or hovering at a horizontal inertia velocity V, and the wave surface on the water surface The irregularly reflected laser light is received by the receiver 4 mounted on the aircraft. When the relative velocity between the wave in the laser axis direction and the aircraft 1 is U, the horizontal component (W) of the laser beam radiation azimuth of the wave propagation velocity on the water surface can be obtained by the following equation [2]. The vertical movement of the water surface can be ignored because it is offset by long-term observation.
W = U / sin (α + θ) −V [2]
However,
α: Angle between the aircraft's downward direction and the laser beam radiation direction θ: Aircraft attitude angle U: Relative velocity between the laser axis direction wave and the aircraft V: Aircraft horizontal inertia velocity W: Water surface wave propagation velocity Horizontal component of laser beam radiation

FIG. 3 is a diagram showing a method for obtaining the relative velocity (U) between the wave in the laser axis direction and the aircraft 1. The pulsed laser light transmitted from the transmitter 3 on the machine at equal intervals (τ _T ) is irregularly reflected on the water surface, and the scattered light is received by the receiver 4 mounted at the same location as the transmitter 3. The If the propagation speed of light is C and the distance between the position where the i-th pulse is reflected on the water surface and the aircraft 1 is represented by d _i , the time for the first transmitted pulsed light to reciprocate as described above is 2d ₁ / C, where the time for which the pulsed light transmitted after time (τ _T ) travels back and forth is 2d ₂ / C, d ₁ -d ₂ is the amount of change δ between the wave and the aircraft 1 at time (τ _T ). The pulse interval of the received pulsed light is shortened by δ when the laser light reciprocates. Considering the following pulse light in the same way, the pulse interval of the received light can be expressed by τ _R in the following equation [3].
τ _R = τ _T -2δ / C [3]
However,
τ _T : Transmitted light pulse interval τ _R : Received light pulse interval δ: Change in distance between wave and aircraft at time τ _T C: Light propagation speed

example graph of the time variation of tau _T is 4 (A). Since the actual pulse rate is assumed to be about 1 kHz to 100 kHz, such a continuous signal can be obtained. Note that the absolute value of δ decreases as the radiation rate increases, so the measurement accuracy per pulse decreases. However, the number of samples that can be integrated per unit time increases. Becomes higher. Further, when a wave irradiated with laser light shifts to an adjacent wave, the distance between the wave and the aircraft 1 instantaneously increases, so that τ _R pulsates as shown in the figure. Since this pulsation part becomes a measurement error factor, it can be removed by a low-pass filter. However, for the more complete removal, the following method is used in the present invention.

First, FIG. 4 (a) is a graph showing the time variation of Δ obtained as Δ = τ _T −τ _R. Then rectified by including rectifying circuit △, obtained by removing most of the pulsation, a △ _R of FIG. 4 (c). Furthermore, when obtaining the envelope due smoothing circuit, the △ _E of FIG. 4 (d) is obtained. Thus, △ _E is the maximum value of △, i.e. it can be a laser beam to obtain a measurement signal of the condition to be irradiated at right angles to the surface of the waves. In principle, the rectification of (c) can be omitted, but it is an effective means for performing smoothing efficiently.

Obtained in the previous section △ _E means a time which the laser beam reciprocates distance [delta]. Since the distance between the wave in the laser axis direction and the aircraft 1 changes by time (τ _T ) by δ (the amount of change in the distance between the wave and the aircraft 1 at time τ _T) , the wave in the laser axis direction and the aircraft 1 Relative velocity U can be obtained by equation [4].
_{U = C × △ E / 2τ} T ‥‥ [4]
However,
U: Relative speed between wave in laser axis direction and aircraft τ _T : Transmitted light pulse interval Δ _E : Time for laser light to reciprocate at δ distance C: Light propagation speed

  By the above method, a measurement signal can be obtained under the condition that the laser beam is irradiated at right angles to the wave surface. However, the irradiation angle is in the range of ± 30 degrees because the wave shape is extremely unique. In this case, the maximum measurement error of the relative velocity U between the wave in the laser axis direction and the aircraft 1 is ± 33%. However, since the wave shapes are generally diverse and change over time, this error is averaged and much smaller.

Next, by substituting U (relative velocity between the wave in the laser axis direction and the aircraft) obtained by Equation [4] into Equation [2], W (Laser Light Radiation Direction Horizontal Component of Wave Surface Propagation Speed) ) Can be obtained as shown in Equation [5]. Here, θ and V can be obtained from a general navigation device mounted on the aircraft 1, and α is a fixed value when the device is attached.
_{W = C × △ E / {} 2τ T × sin (α + θ)} - V ‥‥ [5]
However,
α: Angle between the downward direction of the aircraft and the laser beam radiation direction θ: Aircraft attitude angle V: Aircraft horizontal inertia velocity W: Laser wave radiation velocity horizontal component of water surface wave propagation velocity τ _T : Transmission light Pulse interval Δ _E : Time required for the laser beam to reciprocate at a distance of δ C: Light propagation speed

ただし、
Ｗt：水面の波の伝搬速度
Ｗx：波の伝搬速度の機首方位成分
Ｗy：波の伝搬速度の水平面内でＷxに直角な方位の成分
ψw：航空機１との相対的な波の伝搬方位 By changing the radiation direction of the laser light to at least two directions of the aircraft head 1 obliquely below the heading direction and obliquely below the horizontal direction in the horizontal plane, at least the horizontal component of the laser light radiation direction of the wave propagation velocity on the water surface is changed. Two directions can be obtained.
FIG. 5 is a plan view of the aircraft 1 as viewed from above. When the north direction on the surface of the earth is represented by N and the west direction is represented by E, the aircraft 1 is flying with the nose directed in the direction of ψ. When the heading component of the wave propagation velocity is Wx and the component of the direction perpendicular to the horizontal plane is Wy, the wave propagation velocity (Wt) on the water surface and the relative propagation direction (ψw) with the aircraft 1 are It can be obtained from equation [6].

However,
Wt: Wave propagation velocity on the water surface Wx: Heading component of wave propagation velocity Wy: Wave propagation velocity component perpendicular to Wx in the horizontal plane ψw: Wave propagation direction relative to aircraft 1

When the wave propagation azimuth is represented by the azimuth on the earth's surface, the azimuth angle (ψ) of the aircraft obtained from general navigation equipment mounted on the aircraft is superimposed on the observation azimuth (ψw), and ψ + ψw
Based on the above principle, it is possible to observe the propagation velocity and propagation direction of waves on the water surface from an aircraft flying horizontally or hovering over the water surface.

ただし、
Ｓd： レーザ光放射軸方向の流速成分と航空機との相対速度
ν_Ｔ：送信光の振動数
ν_Ｒ：受信光の振動数
Ｃ： 光の伝搬速度
θd： Ｓdに対する測定点の移動方向の角度 Next, a method for observing the flow velocity on the water surface will be described. The water surface velocity and the wave propagation velocity are basically independent. That is, waves may exist even when the water surface is not flowing, and conversely, waves may not exist even when the water surface is flowing.
As shown in FIG. 6, laser light is irradiated obliquely downward from a transmitter 3 mounted on an aircraft 1 that is flying horizontally or hovering, and laser light irregularly reflected on the water surface is received by a receiver 4 mounted on the aircraft 1. Receive. The frequency of the received laser light changes due to the Doppler effect according to the flow velocity of the water surface, so the amount of change is measured as the difference from the transmitted light, so that the relative velocity between the velocity component in the laser beam radiation axis direction and the aircraft (Sd) can be calculated. As the change in the frequency due to the Doppler effect, an equation shown in Equation [7] in consideration of the special relativity theory is known.

However,
Sd: Relative velocity between the velocity component in the laser beam emission axis direction and the aircraft ν _T : Frequency of transmitted light ν _R : Frequency of received light C: Light propagation velocity θd: Angle of measurement point moving direction with respect to Sd

In Expression [7], (Sd / C) ² is extremely small with respect to 1, and is ignored here. Then, Sd can be obtained from equation [8] by modifying equation [7].
Sd = C (ν _R −ν _T ) / ν _R cos (θd) [8]
However,
Sd: Relative velocity between the velocity component in the laser beam emission axis direction and the aircraft 1 ν _T : Frequency of transmitted light ν _R : Frequency of received light C: Speed of light propagation θd: Angle of moving direction of measurement point with respect to Sd

The flow velocity component (Ss) in the direction along the water surface relative to the aircraft 1 can be obtained by the equation [9] as can be seen from the geometric analysis diagram shown in FIG. 7, and the horizontal flow velocity component (Sh) is It can obtain | require by Formula [10].
Ss = Sd / cos (θd) [9]
However,
Sd: Flow velocity component in the direction of the laser beam emission axis and the relative velocity between the aircraft Ss: Flow velocity component in the direction along the water surface relative to the aircraft θd: Angle of movement direction of the measurement point with respect to Sd Sh = Ss × cos (θw) − V [10]
However,
Sh: horizontal velocity component Ss: velocity component along the water surface relative to the aircraft θw: inclination angle of the water surface V: horizontal inertia velocity of the aircraft

ただし、
Ｓd： レーザ光放射軸方向の流速成分と航空機との相対速度
ν_Ｔ：送信光の振動数
ν_Ｒ：受信光の振動数
Ｃ： 光の伝搬速度
θd： Ｓdに対する測定点の移動方向の角度
Ｖ： 航空機の水平方向慣性速度
Ｓs： 航空機に相対的な水面に沿う方向の流速成分
Ｓh： 水平方向の流速成分
θw： 水面の傾斜角
α： 機体の下向きとレーザ光の放射方向とのなす角
θ： 航空機の姿勢角 As can be seen from FIG. 7, there is a relationship of θd = θw + 90 ° −α−θ, and Sh (horizontal flow velocity component) can be expressed by equation [11] from equations [8], [9], and [10].

However,
Sd: Relative velocity between the flow velocity component in the laser beam emission axis direction and the aircraft ν _T : Frequency of transmitted light ν _R : Frequency of received light C: Light propagation velocity θd: Angle of movement of measurement point relative to Sd V : Horizontal inertial velocity of the aircraft Ss: Flow velocity component along the water surface relative to the aircraft Sh: Horizontal flow velocity component θw: Angle of inclination of the water surface α: Angle between the downward direction of the aircraft and the radiation direction of the laser beam θ : Aircraft attitude angle

In addition, the flow velocity on the water surface does not change in a short time, and what is required for use is an average value for a long time of about several minutes or more. If the average for a long time is taken, the tilt angle (θw) due to the wave is canceled out to zero. Therefore, Expression [11] is simplified as Expression [12].
Sh = C (ν _R −ν _T ) / ν _R sin ² (α + θ) −V [12]
However,
Sh: Horizontal flow velocity component relative to the aircraft V: Horizontal inertia velocity of the aircraft ν _T : Frequency of transmitted light ν _R : Frequency of received light C: Light propagation speed α: Aircraft downward and laser light The angle formed by the direction of radiation θ: Aircraft attitude angle

In the above description, the vertical movement of the water surface is not mentioned, but if this is also taken for an average over a long period of time, it can be neglected because it is offset to zero.
By changing the radiation direction of the laser beam to at least two directions, that is, the heading direction of the aircraft 1 obliquely below and the direction perpendicular to the right angle within the horizontal plane, the horizontal component of the laser beam radiation direction horizontal direction at least two directions can be obtained. It is done.

ただし、
Ｓht：水面の流速
Ｓhx：水面の流速の機首方位成分
Ｓhy：水面の流速の水平面内でＳhxに直角な方位の成分
ψs： 航空機との相対的な水流方位 FIG. 8 is a plan view of the aircraft 1 as viewed from above. When the north direction on the surface of the earth is represented by N and the west direction is represented by E, the aircraft 1 is flying with the nose directed in the direction of ψ. Assuming that the heading direction component of the water surface velocity is Shx and the component in the direction perpendicular to the horizontal surface is Shy, the water surface velocity (Sht) and the relative water flow direction (ψs) with the aircraft 1 are expressed by the equation [13]. It can ask for.

However,
Sht: Flow velocity on the surface of the water Shx: Nose direction component of the velocity of the surface of the water Shhy: Component of the direction of the flow velocity of the water surface in the direction perpendicular to the Shx ψs: Flow direction relative to the aircraft

In the case where the water current direction is expressed in the direction on the earth's surface, the azimuth angle (ψ) of the airframe obtained from a general navigation device mounted on the aircraft 1 is superimposed on the observation direction (ψs) and is expressed as ψ + ψs. That's fine.
Based on the above principle, the velocity and direction of the water surface can be observed from an aircraft flying horizontally or hovering over the water surface.

  Hereinafter, an example in which the apparatus according to the present invention is mounted on a flying boat is shown in FIG. 9, and this embodiment will be described. A laser transceiver 2 (3) and a display 4 including a signal processing circuit are installed in the aircraft so that the pilot can monitor observation information. In the case of a flying boat, water lands from the fuselage, so the optical unit 5 exposed to the outside is attached to the lower surface of the main wing to avoid damage. At this time, since the change of θ is 10 degrees or less in a normal flight state, the optical characteristics are taken into consideration in consideration of specifications at the time of landing so that the average value of the difference between the vertical line and the optical center line is minimized in advance. If the part is attached, there is no problem even if cos θ is 1. If the difference between the horizontal inertia velocity of the aircraft and the wave propagation velocity is 100 m / s and the pulse period of the laser light is 10 kHz, the wave height can be observed with a resolution of 1 cm horizontally. The sea level is calculated by comparison with altitude information using GPS. As specific means for obtaining the average value and change amount of the signal, it is easy to use a low-pass filter and a low-cut filter by an electronic circuit.

  FIG. 10 is a conceptual diagram in the case of observing the propagation direction, propagation speed, and flow velocity on the water surface. A is observed by irradiating the laser beam obliquely downward in the traveling direction of the aircraft and B is obliquely inclined downward in the lateral direction. It is possible to observe the wave propagation speed and water surface velocity in the aircraft traveling direction, and the wave propagation speed and water surface velocity in the transverse direction. At this time, the bank angle is used as the posture angle during lateral observation. When the wave propagation direction and the water current direction are expressed in the east, west, north, and south directions on the earth's surface, the heading data of the navigation gyro mounted on the aircraft may be superimposed on the observation direction.

  FIG. 11 shows a mounting example for observing the flight altitude, the wave height of the water surface, the wave propagation direction, the propagation velocity, and the water surface flow velocity with a single device. In this apparatus, the laser transmitter / receiver 2 (3) and the optical unit 5 are connected by an optical fiber 6, and the degree of freedom of mounting of the optical unit 5 is high. A rotating prism 7 for deflecting laser light is attached to the front surface of the optical unit, and the prism is rotated by a prism rotator 8 having a built-in servo motor. Can be scanned. When the angle β is 39.23 degrees, and the mounting angle of the apparatus is 30 degrees when viewed from the front and the side with respect to the downward direction of the aircraft as shown in FIG. Each observation can be performed with the optical axis being stopped in the respective directions. Note that the laser beam scanning plane shown in the figure does not depict the intersection with the horizontal plane, but represents the intersection with the plane perpendicular to the prism rotation axis. From 60 degrees are equally spaced.

If the device is installed as in the previous section, when the laser beam irradiates directly under the aircraft, the flight altitude and the wave height of the water surface are observed, and when the laser beam irradiates 60 degrees forward and 60 degrees laterally of the aircraft, Wave propagation direction, propagation velocity and water surface velocity can be observed.
There are known methods for measuring the distance using laser light, such as a method of measuring the round-trip time of pulsed light and a method of using “beat” based on the phase difference between transmitted light and received light. This is a technique that can be incorporated into the apparatus according to the present invention.
As for the horizontal inertia velocity, attitude angle, bank angle, and azimuth angle of an aircraft, signals from an inertial navigation device or the like normally mounted on the aircraft are used.

  The safety of laser light for the human body is similar to that of surveying rangefinders. However, even when a high-power laser is used to increase the distance, one point is determined by the movement of the aircraft and scanning of the laser light. It is not oriented and can be said to be extremely safe. In particular, a 1.5 μm band laser beam is called an eye safety laser and is highly practical because it is used in optical communications.

It is principle explanatory drawing which measures the flight height by this invention, and observes a wave height. It is principle explanatory drawing which observes the propagation velocity of the wave by this invention. It is a figure which shows the system which calculates | requires the relative velocity (U) of the wave of the laser axis direction and the aircraft 1 by this invention. It is a figure which shows the system which calculates | requires the propagation velocity of the wave by this invention. It is a figure explaining the system which calculates | requires the propagation speed and propagation direction of the wave by this invention. It is principle explanatory drawing which observes the flow velocity of the water surface by this invention. It is a figure which shows the system which calculates | requires the flow velocity of the water surface by this invention. It is a figure explaining the system which calculates | requires the flow velocity and water flow direction of a water surface by this invention. It is a figure which shows the example which mounted the water surface and ground observation apparatus by this invention in the flying boat. It is a conceptual diagram which shows the example of an observation system at the time of mounting the water surface and ground observation apparatus by this invention on an aircraft. It is a figure which shows the example at the time of mounting the water surface and ground observation apparatus by this invention on an aircraft as a single apparatus. It is a figure which shows the example of the mounting direction of the optical part at the time of mounting the water surface and ground observation apparatus by this invention on an aircraft.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aircraft 2 Laser transmitter 3 Laser receiver 4 Indicator 5 Optical part 6 Optical fiber 7 Deflection prism 8 Prism rotator α Angle formed by the downward direction of the machine and the radiation direction of the laser beam β Deflection angle of the laser beam δ Time τ _T Amount of change in distance between wave and aircraft at θ θ Attitude angle of aircraft θd Angle of movement direction of measurement point with respect to Sd θw Tilt angle of water surface τ _T Pulse interval of transmitted light τ _R Pulse interval of received light τ _Rn nth τ _R
ψ Aircraft heading ψs Water flow direction relative to aircraft ψw Wave propagation direction relative to aircraft △ τ _T −τ _R
△ _R rectified △ _E δ Time for laser light to reciprocate at δ C Light propagation speed D Distance in vertical direction between aircraft and water surface H Average flight altitude of aircraft U Waves in laser axis direction and aircraft 1 Relative velocity of aircraft V Inertial velocity of aircraft in the horizontal direction Sh Flow velocity in the horizontal direction Ss Flow velocity component in the direction along the water surface relative to the aircraft W Laser wave radiation direction horizontal component of wave propagation velocity on the water surface d Laser range finder Distance measurement value h Maximum wave height t Measurement unit time (several seconds) Wt Wave propagation velocity Wx Wave propagation velocity heading component Wy Wave propagation velocity component in a direction perpendicular to Wx in the horizontal plane Sht Water surface velocity Shx Nose direction component of the water surface velocity Shy Component of the azimuth direction perpendicular to Shx within the horizontal surface velocity of the water surface

Claims (5)

  A laser beam transmitter and receiver are mounted on an aircraft, and the laser beam transmitter / receiver has a mechanism capable of setting a transmission / reception direction at least in a downward direction, a downward front direction, and a downward direction with respect to the aircraft, and transmits and receives angle information thereof An aircraft water surface and ground observation apparatus comprising means for storing and storing laser light data and means for processing data.   A laser beam transmitter and receiver equipped with a distance measuring function are attached to the lower part of the aircraft, the laser beam is transmitted and received for a predetermined time during flight, and the average of the distance data detected based on the transmitted and received signal The method of using an aircraft water surface and ground observation device according to claim 1, wherein the flight altitude is observed from the value, the crest value of the water surface from the amount of change, or the undulation of the ground.   A laser beam is transmitted in a forward and downward direction at known time intervals during flight, and the propagation velocity and propagation direction of waves on the water surface are observed during flight based on the amount of change in the interval between received pulses. The method of using the aircraft water surface and ground observation device according to claim 1.   4. The method of using an aircraft water surface observation apparatus according to claim 3, wherein the data processing is to observe the flow velocity of the water surface based on the Doppler effect.   The method for using the aircraft water surface and ground observation device according to claim 1, wherein the observation data obtained by the method according to any one of claims 2 to 4 is used for landing or landing support of an aircraft.

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