JP2004264184A - Ultrasonic air data sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airspeed measurement device for an aircraft which can perform the measurement from a low velocity region to a relatively high speed region, and can deal with a wide airflow angle; and to provide an ultrasonic air data sensor probe having no mobile parts which can realize a wind direction/velocity and air temperature measurement device for a meteorological observation at high measurement precision without requiring components at high manufacture precision. <P>SOLUTION: When the value of wind velocity to be measured greatly varies discontinuously, the ultrasonic air data sensor probe subtracts an integral multiple of one period of the ultrasonic wave used for the detection value, and performs the correction to the error estimation value nearest to the previous detection value. Further, by providing the combination of an ultrasonic wave transmitter and a receiver for calculating the wind velocity with redundancy, the wind velocity is calculated without using a signal most intensively influenced by inner and outer noises or a signal by the failed ultrasonic transmitter and the receiver. A support part is arranged so that a level difference is not generated between it and the surface of the ultrasonic receiver. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic air data sensor for measuring airspeed, wind direction, wind temperature, and air temperature, and particularly to a method suitable for low-speed aircraft in airspeed measurement. The airspeed indicates the direction and speed of movement of a three-dimensional object with respect to the airflow, and the response of the airspeed measurement is not so important in the measurement for steering, but the airspeed is used. Responsivity is important for turbulence measurement. In addition, in this specification, a low-speed aircraft refers to a short-range take-off and landing aircraft, a vertical take-off and landing aircraft, a rotary wing aircraft, a glider, an airship, a balloon, and the like.
[0002]
[Prior art]
Normally, a pitot tube used in an aircraft measures the total pressure and static pressure of air, and calculates the airspeed from the dynamic pressure of the difference, and the airflow direction is measured by an arrow blade or the like. . By the way, since the dynamic pressure measured by the pitot tube is proportional to the square of the airspeed, the measurement error increases at low speeds, and the pitot tube is suitable for low-speed speed measurement. Absent. The area where the pitot tube can be used is usually 30 to 40 m / s or more. If the speed is lower than that, or if the airflow direction is significantly different from the body axis, the speed measurement itself becomes impossible. And since the arrow blade for measuring the airflow direction has a movable part, there is a problem that the response is lowered or the vibration is caused by the mass of the arrow blade. Therefore, in a general aircraft equipped with a single pit tube as an airspeed sensor, a measurement error of an airspeed measured in a low speed range is large or cannot be measured. Since the Pitot tube cannot measure the airflow in the low-speed region as described above, it is naturally not suitable as an anemometer for weather observation.
[0003]
On the other hand, the ultrasonic anemometer used for weather observations utilizes the fact that the propagation time of ultrasonic waves propagating in a certain section changes under the influence of wind, and at predetermined intervals in all directions. A plurality of (usually six) ultrasonic transmitters / receivers arranged can measure wind in all directions on a plane. For example, Patent Document 1 corresponds to this. However, due to the aerodynamic interference between the ultrasonic transceivers, it is difficult to measure in strong winds. Measurements of 20 m / s or less for aircraft that can be mounted on an aircraft, and 60 m / s or less for large equipment for ground installation. It is a possible area. In this measurable region, the measurement range on the high-speed side is not sufficient for use in an aircraft, and an ultrasonic anemometer for weather observation is not suitable for an airspeed measuring device mounted on an aircraft. Even when an ultrasonic anemometer is used for weather observation, aerodynamic interference between ultrasonic transmitters and receivers affects the airflow, which causes deterioration in the measurement accuracy of the wind direction in particular.
[0004]
The most common wind turbine type anemometer for weather observation has a movable part and a large mass, so when installed on an aircraft boom as an airspeed indicator, the rigidity of the boom is reduced to avoid the possibility of vibration. Must be higher. The boom needs to be long in order to make it less susceptible to the disturbance of the airflow by the aircraft itself, and it is difficult to increase the rigidity. Since the responsiveness of airflow measurement is not very good, it is not suitable for an airspeed measuring device mounted on an aircraft. When used for weather observation, it is very practical, but it is necessary to manufacture propellers and tails with high accuracy in order to measure with high accuracy, and there are many mechanical parts due to the presence of moving parts. It is difficult to reduce manufacturing costs. Although this is not a problem in ordinary weather observation, it is difficult to measure the vertical wind and the wind direction and wind speed with a very weak wind for special purposes.
[0005]
An ultrasonic airspeed sensor for an aircraft (Patent Document 2), which has been developed by the inventor first and has already filed a patent application, is for solving the above-mentioned drawbacks of the conventional device, and is mounted on a low-speed aircraft. It can be used for low speed flight. However, the airspeed sensor increases the measurement noise component in the region where the airspeed is 50 m / s or more, and may not be able to measure at a lower speed depending on the airflow angle. The former is caused by a step formed between the surface of the ultrasonic transceiver and the support part due to the ultrasonic transceiver being attached to the surface of the support part at an angle, and the structurally high speed In the area, it was found that the noise was generated by the turbulence of the airflow. In addition, the latter cause is that, due to the positional relationship between the support portions, the presence of an airflow angle at which a part of the ultrasonic transceiver enters the downstream region of the upstream ultrasonic transceiver support portion, the downstream side. It was found that the effect was due to the turbulence of the ultrasonic transceiver.
[0006]
[Patent Document 1]
JP-A-5-307087 "Ultrasonic wind direction and wind speed temperature measuring device"
Released on November 19, 1993
[Patent Document 2]
Japanese Patent Application Laid-Open No. 2001-278196, "Aircraft Ultrasonic Airspeed Sensor"
Released on October 10, 2001
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, that is, an airspeed measuring device for an aircraft capable of measuring a relatively high speed region from a low speed region and capable of coping with a wide airflow angle, and a high airspeed measurement device. It is an object of the present invention to provide an ultrasonic air data sensor / probe which does not require any parts which require high manufacturing accuracy and which does not have a movable part capable of realizing a wind direction / wind speed / temperature measuring device for weather observation with high measurement accuracy.
[0008]
[Means for Solving the Problems]
The ultrasonic air data correction method of the present invention is used for a system in which a pair of ultrasonic transmitters / receivers intermittently measures wind speed intermittently when a detected value changes discontinuously. This is to subtract an integral multiple of one period of the ultrasonic wave and correct the error estimation value to the error estimation value closest to the previous detection value.
The ultrasonic air data sensor of the present invention has a transmission / reception surface of an ultrasonic transmitter / receiver that is smoothly continuous with the surface of its support portion and has no irregularities in order to reduce the occurrence of turbulence and increase the stability of measurement. At the same time, the support portions are arranged in front and rear with respect to the main wind direction. Also, a plurality of opposing ultrasonic transceivers are arranged and combined in different directions of the propagation path, and the number is set to be more redundant than the minimum required number and the arrangement wind speed is increased. By making the combination of ultrasonic transceivers for calculation redundant, the wind speed can be calculated without using the signal that is most affected by internal and external noise or the signal from the failed ultrasonic transceiver. I made it.
When mounted on an aircraft as an airspeed indicator, the support rod for fixing the ultrasonic transceiver is attached to the base so that the ultrasonic transceiver support does not fall off even if the joint between the support rod and the base is broken. Through the structure.
An ultrasonic air data sensor for ground installation in which a pair of ultrasonic propagation paths is formed between an ultrasonic transceiver installed on a base and an ultrasonic transceiver arranged concentrically around the base, In order to reduce the influence of the wake of the base, the ultrasonic transceivers arranged concentrically are mounted at a lower position than the ultrasonic transceiver installed on the base.
The wide-area meteorological observation system of the present invention is for ground installation in which a pair of ultrasonic propagation paths is formed between an ultrasonic transceiver installed on a base and an ultrasonic transceiver arranged concentrically around the base. A large number of ultrasonic air data sensors were connected to a weather data management center via a public communication line, and terminals in various places were connected to a weather data management center via a public communication line.
The aircraft measurement system according to the present invention corrects and calculates the equivalent airspeed from the ultrasonic air data sensor, the atmospheric pressure sensor, and the true airspeed to obtain the same equivalent airspeed measurement value as the pitot tube. Means.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram showing the principle of an ultrasonic anemometer. When the ultrasonic wave propagates in the air, when the ultrasonic wave propagates in the forward direction with the wind, the propagation speed increases by the wind speed, and when the ultrasonic wave propagates in the reverse direction, the propagation speed decreases by the wind speed. Accordingly, the relationship between the propagation time of the ultrasonic wave and the wind speed, which are obtained by dividing the distance by the speed, is as follows.
W = D / 2 × (t₂-T₁) / (T₁× t₂) ‥‥ (1)
However,
W: Wind speed
D: Spacing between ultrasonic transmitter and receiver
t₁: Propagation time of ultrasonic wave in forward direction to wind speed
t₂: Propagation time of ultrasonic wave in the direction opposite to wind speed
At the same time, utilizing the fact that the propagation speed of the ultrasonic wave changes with the temperature, the temperature can be obtained by the following equation.
T = T₀× (a / a₀)²× (1 + W_v ²/ A²) ‥‥ (2)
a = D / 2 × (t₁+ T₂) / (T₁× t₂) ‥‥ (3)
However,
T: Temperature
T₀: Standard temperature
a: Sound speed
a₀: Sound speed at standard temperature
W_v: Wind velocity component perpendicular to the ultrasonic wave propagation direction
[0010]
In order to measure the propagation time of the ultrasonic wave, a pulsed ultrasonic wave is transmitted from the transceiver, received by the opposing transceiver, and its timing is measured. At this time, if the signal level at the time of reception decreases due to some influence such as airflow or noise, the head of the pulse signal cannot be recognized, and a measurement time delay corresponding to an integral multiple of the wavelength of the ultrasonic wave occurs. Sometimes. Even if a circuit for automatically increasing the gain is provided, the delay is not always completely eliminated because the noise level becomes relatively high. Since a large discontinuity occurs in the measurement signal due to this delay, a correct measurement value can be obtained by subtracting an integer multiple of τ obtained by the following equation from the propagation time measurement value according to the magnitude of the discontinuity. it can.
τ = 1 / f ‥‥ (4)
However,
τ: time for one wavelength
f: Frequency of ultrasonic wave used
[0011]
The discontinuous amount changes according to the wind speed, and can be estimated by the following equation. If the received signal on the leeward side is delayed by one wavelength,
dW = W−D / 2 × [(t₂-T₁−τ) / ｛(t₁+ Τ) × t₂｝] ‥‥ (5)
If the received signal on the windward side is delayed by one wavelength,
dW = W−D / 2 × [(t₂-T₁+ Τ) / ｛t₁× (t₂+ Τ)｝] ‥‥ (6)
If both received signals are delayed by one wavelength,
dW = W−D / 2 × [(t₂-T₁) / ｛(T₁+ Τ) × (t₂+ Τ)｝] ‥‥ (7)
However,
dW: Discontinuous amount estimation value
W: Wind speed
D: Spacing between ultrasonic transmitter and receiver
t₁: Propagation time of ultrasonic wave in forward direction to wind speed
t₂: Propagation time of ultrasonic wave in the direction opposite to wind speed
τ: time for one wavelength
[0012]
A threshold value for determining the discontinuous amount is set in advance, and when the measured value changes discontinuously, an integer multiple of the separately stated discontinuous amount estimated value closest to the discontinuous amount is subtracted from the measured value, Use that value as an accurate measurement. In practice, the discontinuity of the measured value is most often only a delay of one wavelength, that is, one time the estimated value. The correction of the measurement value based on the discontinuous amount estimation value is performed only when the reception level of the ultrasonic wave decreases. This is because the same discontinuity occurs when returning from an incorrect state to a normal state.
If the same number of wavelength delays occur in both the upwind and downwind received signals, the amount of discontinuity is small, and in practice, a clear difference from a normal measured value fluctuation cannot be recognized. However, in general, the received signal on the leeward side is more susceptible to the turbulence of the airflow, so that it is likely to be overwhelmingly discontinuous. What happens is very rarely stochastic.
[0013]
Conventionally, ultrasonic anemometers for meteorological observations need to detect wind speeds in all directions with the same accuracy. Therefore, six ultrasonic transceivers are mounted on six support rods, which complicates the shape and causes aerodynamic turbulence. Streams and acoustic noise were likely to occur. However, aircraft generally fly at high speeds in only one direction and cannot fly in other directions or fly at very low speeds. Therefore, as an airspeed sensor for an aircraft, it is not necessary to be able to measure airflow in all directions in the same way, and only a single direction can be measured in a relatively high speed range. Therefore, the arrangement of the ultrasonic transceiver necessary for the ultrasonic anemometer is devised from the viewpoint of emphasizing the measurement of the airflow in one direction, the overall shape of the device is simplified, and the aerodynamic noise and the turbulence of the airflow are reduced. I thought that. In particular, if there is an object upstream of the ultrasonic transmitter / receiver, it is easily affected by the turbulence of the airflow. Therefore, a structure that causes turbulence of the airflow is arranged upstream of the ultrasonic transmitter / receiver, placing importance on the airflow in one direction. It is important not to do so. In Patent Document 2 “Aircraft ultrasonic airspeed sensor”, which was the inventor's earlier invention, the above object was able to be achieved to some extent. Due to the inclined mounting, a step was formed between the surface of the ultrasonic transceiver and the separately-supported portion, and in a high-speed region, the airflow was disturbed and noise was generated. In the present invention, the entire configuration is devised so that the transmission / reception axis of the ultrasonic wave is perpendicular to the surface of the support, so that the surface of the ultrasonic transceiver is smoothly connected to the surface of the support, and the turbulence of airflow Can now be minimized. This shape is also effective when used as an anemometer for weather observation.
[0014]
No matter how the ultrasonic transceiver is arranged, there is always an airflow direction that is affected by turbulence when dealing with airflow in all directions. For this reason, in the present invention, redundancy is provided by arranging the combination of the ultrasonic transceivers more than the minimum required three sets, and the utilization rate and the measurement accuracy are improved by not using incorrect data. I did it. This configuration also ensures a function that operates effectively even when a part of the ultrasonic transceiver fails.
[0015]
The basic principle of the present invention will be described with reference to FIGS. FIG. 2 shows a probe shape, in which A is a front view from the front, and B is a side view. Four support rods 11, 12, 13, and 14 are planted on the base body 1 such that the ends of the shafts are parallel to each other and the axes of the shafts are located at the vertices of a quadrangle. It is a transceiver support. This probe shape is designed to minimize the turbulence in the airflow, where the direction of flow velocity, which is the main detection component of the aircraft, coincides with the axial direction from the front of the fuselage from the viewpoint of ensuring the stability of ultrasonic measurement. It was devised. When the present invention is applied to the measurement of the airspeed of an aircraft, as described above, the main component in the direction of flow velocity from the front to the rear of the aircraft is mainly. Therefore, in order to detect the component, the ultrasonic transceiver must be arranged in a different position in the front-rear direction, and the surface of the ultrasonic transceiver is perpendicular to the X axis in order to be installed in accordance with the transmission / reception axis. Will be inclined. For this reason, the arrangement of the ultrasonic transceiver was considered such that the tip of the support rod was formed in a streamline shape, and the surface thereof was parallel and smoothly connected to the surface of the ultrasonic transceiver. Then, a plurality of propagation paths for transmitting and receiving ultrasonic waves are formed, and the flow velocity component of the fluid is measured as three-dimensional information based on the propagation time information on which the flow velocity component of the fluid is superimposed. Specifically, three sets of six ultrasonic transceivers of a conventional ultrasonic anemometer are provided as four sets and eight sets, and the base 1 and the support rods 11, as shown in FIG. An ultrasonic transceiver is fixed to the fuselage so that the axial directions of 12, 13, and 14 face the front of the aircraft, and an ultrasonic transceiver is attached to the base 1 and the support rods 11, 12, 13, and 14, and an ultrasonic transmission and reception path is formed. I did it. Since the ultrasonic transmission / reception path is formed between the ultrasonic transmission / reception devices arranged at different positions in the longitudinal direction of the body, the flow velocity of the component in the longitudinal direction of the body can be detected. Moreover, since the probe base 1 and the support rods 11, 12, 13, and 14 have the least resistance to the airflow in this direction, the flow state is stable and accurate measurement can be performed. In addition, as shown in FIG. 4, by providing the axes of the support rods 11, 12, 13, and 14 with a slight opening angle toward the front, the length of the support rods can be shortened, so that the rigidity is increased. Weight can be reduced.
[0016]
When the present invention is applied to and used in an anemometer for weather observation on the ground, the front when mounted on an aircraft is used vertically upward. In this case, it is necessary to cope with airflow from all directions in the horizontal direction, but the shape according to the present invention is not necessarily suitable for airflow from all directions. However, in the case of meteorological observation, it is sufficient to measure a wind speed of 60 m / s at the maximum, and it is not necessary to measure an airflow as high as an airspeed of an aircraft. Furthermore, due to the redundancy described later, the signal from the ultrasonic transmitter / receiver on the leeward side is not used, so that the wind direction and wind speed can be measured with high accuracy by always using the optimal signal for the airflow in all directions. it can. In the case of ground-based meteorological observation, since the weight limit is not as strict as that for aircraft, it is possible to improve the strong wind measurement performance by making it larger than for aircraft.
[0017]
With the arrangement configuration of the ultrasonic transceiver as described above, a three-dimensional airspeed or wind direction can be obtained. This arrangement places the most importance on the measurement of the flow velocity in the direction indicated by the arrow. As shown in FIG. 3, an X-axis is defined in the front-rear direction of the aircraft, a Y-axis is defined in the left-right direction, and a rectangular coordinate system of the Z-axis is defined in the up-and-down direction. The velocity component Wn of the airflow in the ultrasonic wave propagation direction between each pair of ultrasonic transceivers is expressed by the following equation.
W_n= Vxsinθn + (Vysinφn + Vzcosφn) × cosθn (8)
However,
Vx: X direction component of airspeed
Vy: Y-direction component of airspeed
Vz: Z component of airspeed
W_n: Velocity component of the airflow in the direction of the ultrasonic transceiver (path n)
θn: YZ plane and W_nAngle with
φn: Z axis and W in YZ plane_nAngle with
Here, assuming that the arrangement of each sensor is a right angle as shown in FIG. 3, that is, φ1 is 90 degrees, φ2 is 180 degrees, and φ3 is 270 degrees.
W₁= Vxsin θ1 + Vycos θl (9)
W₂= Vxsin θ2-Vycos θ2 (10)
W₃= Vxsin θ3-Vycos θ3 (11)
Then, if θ1 = θ2 = θ3 = θ, then
Vx = (W₁+ W₃) / 2 sin θ ‥‥ (12)
Vy = (W₁-W₃) / 2cosθ ‥‥ (13)
Vz = (W₁+ W₃-2 x W₃) / 2cosθ ‥‥ (14)
Thus, the airspeed can be obtained from this equation.
[0018]
When the velocity component of the airflow in the ultrasonic wave propagation direction obtained by each set of ultrasonic transceivers changes discontinuously, it is measured by subtracting an integer multiple of the discontinuous estimated value closest to the discontinuity. Errors can be reduced. Assuming that an integer multiple of that time is N, the value of N is 0 when a normal measurement is being performed, but the value increases to N when a discontinuous change occurs in the measured value due to a turbulence in the airflow or a failure. I do. By constantly monitoring the value of N of each ultrasonic transceiver set and not using the measured value of the ultrasonic transceiver set having the largest value of N, the airflow finally obtained by the above equation can be obtained. Speed reliability and measurement accuracy are improved.
[0019]
Further, even when the measured value of the ultrasonic propagation time becomes 0 or a value exceeding the threshold value, the measured value of the corresponding ultrasonic transceiver set is not used. This is because such a state may be a failure of the ultrasonic transceiver, or an unmeasurable state due to airflow turbulence or noise.
[0020]
When mounting an object exposed to the outside of the aircraft, it is natural to confirm that the object is strong enough by strength calculation or strength test, but it is also necessary to consider deterioration due to aging and corrosion . In the present invention, since the support rods 11, 12, 13, and 14 are configured to penetrate the base 1, in the event that the joint between the base and the support rod is broken by welding or the like, the support rod is There is no fear of falling off even if it shifts or rotates.
[0021]
Aircraft usually display the equivalent airspeed obtained by a pitot tube on a flight control instrument, which the pilot uses to fly. This is because the influence of the airflow on the airframe is related not only to the speed of the airflow but also to the density of the atmosphere. Since the airspeed obtained by the ultrasonic sensor is a true airspeed, by combining with an atmospheric pressure sensor, the equivalent airspeed is calculated by the following correction formula, and a measurement value equivalent to that of a conventional pitot tube is obtained. A measurement system can be constructed.
VEAS = VTAS {P / (ρoRT)}^0.5 ‥‥ (15)
However,
VEAS: equivalent airspeed
VTAS: true airspeed
P: Atmospheric pressure
R: gas constant
T: Atmospheric temperature
ρo: standard atmospheric density
[0022]
【Example】
Hereinafter, an example manufactured for measuring airspeed in a rotary wing aircraft is shown in FIG. 4, and the present embodiment will be described. In a general rotary wing aircraft, the maximum airspeed in the forward direction is about 80 m / s, and the speed when flying in other directions, for example, up, down, left, and right is extremely low. By applying the present invention, it is expected that the airspeed can be measured in almost the entire flight speed range of the rotary wing aircraft. In this embodiment, the axes of the four support rods 11, 12, 13, and 14 are not parallel to the axis of the base 1, but have a slight opening angle β (10 degrees in this embodiment) as shown in the figure. It is held and attached. This is because high-speed conditions, that is, strong airflow in a rotary wing aircraft, are limited only in the forward direction, so it is necessary to have a structure that is rigid and low in weight, and it is structurally disturbing the airflow. The turbulence of the air flow at the time is generated as a wake, and thus has been considered in view of the fact that the ultrasonic wave propagation path is not affected. Incidentally, in this embodiment, the propagation path length between the ultrasonic transceivers was 50 mm, the θ angle was 20 degrees, and the wavelength of the ultrasonic wave used was 200 kHz. Further, an anti-ice heater for preventing icing is built in the base 1 and the tip of each support rod. In addition, since the ultrasonic waves are caused to flow on the leeward side according to the airspeed of the airframe, the ultrasonic transceivers are not linearly opposed to each other, but are installed on the windward side with an α angle as shown in FIG. I did it. As a result, the propagation path of the ultrasonic wave has a bow shape bulging to the windward side as shown in the figure. The transmitting / receiving surface of the ultrasonic transceiver is formed as a smooth continuous surface with the surface of the support rod so as not to have an uneven shape. Since the directivity of the ultrasonic transceiver used in this embodiment is 15 degrees on one side, if α is 10 degrees and the sound speed is 340 m / s, the ultrasonic wave is transmitted when the airspeed of the aircraft is 60 m / s. Transmission and reception are performed at the center point of the covered area, and a range from about 150 m / s forward to about 30 m / s backward is a measurement range based on directivity.
[0023]
FIG. 5 shows the discontinuous change estimated value of the measured value. Since the maximum speed of the rotary wing aircraft is usually 70 m / s or less, the airflow component in the ultrasonic path direction rarely exceeds 30 m / s. In addition, when the same number of wavelength delays occur in the received signals on both the windward and leeward sides, the amount of discontinuity is small as shown in FIG. In consideration of these, the threshold value for determining the discontinuity amount is set to ± 3 m / s, and when the measured value changes discontinuously beyond ± 3 m / s, the discontinuity closest to the discontinuity amount is set. An integer multiple of the continuous amount estimate is subtracted from the measured value, and the value is used as an accurate measured value. In practice, the discontinuity of the measured value is most often only a delay of one wavelength, that is, one time the estimated value. The data update period is 50 ms, and it is not considered as a normal physical phenomenon that a flow velocity change of ± 3 m / s or more actually occurs during this period. Absent.
[0024]
FIG. 6 shows an example in which the sensor according to the present embodiment is installed and mounted on a rotary wing machine. The rotary wing machine has a phenomenon in which the forward speed is remarkably large in other directions, and the main rotor R is blown down. Therefore, in order to avoid the influence on the airspeed measurement, the sensor S is attached to the front end of the long rod-shaped base body 1 that coincides with the forward direction of the fuselage so that the support rods 11 and 12 are located forward of the front end of the main rotor R. , 13, and 14 are mounted. The airspeed measured by the ultrasonic anemometer is a true airspeed. However, by installing the barometer B at the same time and correcting it with the measured value, the airspeed is measured in the same manner as a pitot tube used in a normal aircraft. An equivalent airspeed can be obtained.
[0025]
FIG. 7 shows an example in which the present invention is applied to a ground anemometer for weather observation. There is no problem with the same form as that for the rotary wing machine, but when it is not necessary to measure the airflow in the vertical direction, the support rods are three as shown in the figure and the axis of the support rod when viewed from above is triangular. It is planted so as to be located at each vertex. By arranging the ultrasonic transceiver mounted on the base 1 and the ultrasonic transceiver mounted on the support rods 11, 12, and 13 at positions vertically displaced as shown in the figure, the turbulence of the airflow based on the wake is obtained. Can be reduced. In the case of installation on the ground, the risk of dropping the support rod is not as high as that at the time of mounting, so that it is not necessary to penetrate the support rod through the base. The measurement of the temperature is obtained by measuring the propagation time of the ultrasonic wave reciprocating between the constant and known ultrasonic wave propagation paths, and the air temperature can be directly measured. As described above, a system for measuring the wind direction and the wind speed and the air temperature is configured.
[0026]
Ultrasonic anemometers are used in places where maintenance is difficult, such as in tunnels, because they have few failures and do not require regular maintenance. FIG. 8 shows an example of application to a wide area weather observation system in which a number of ultrasonic air data sensors according to the present invention are connected by a public communication line by taking advantage of this advantage. Numerous observation points including unmanned observation points that are difficult to maintain are located in various places, and ultrasonic air data sensors are installed at each observation point and connected to a weather data management center via a public communication line. An administrator server system is installed in the center to provide a center function, and users in each region are equipped with terminals capable of receiving and analyzing data. The user can receive the observation data including the data of other areas as well as the sensors installed by the user at the terminal, and the analysis processing can be performed by installing and preinstalling common software. It can also be performed on a terminal. The administrator manages the communication server and monitors the failure of the sensor. The signal processor does not need to calculate the wind direction, the wind speed, and the temperature, but simply sends the measurement signal to the public communication line. The calculation is performed by a user installing software operating on a general-purpose computer in his / her analysis system. This reduces the hardware cost of the signal processor and makes it easier to respond to software improvements.
[0027]
【The invention's effect】
The ultrasonic air data correction method of the present invention is used for a system in which a pair of ultrasonic transmitters / receivers intermittently measures wind speed intermittently when a detected value changes discontinuously. Since an integral multiple of one cycle of the ultrasonic wave is subtracted and corrected to an error estimation value closest to the previous detection value, a measurement error due to the influence of internal and external noise can be effectively reduced.
[0028]
Also, the ultrasonic air data sensor of the present invention is a combination of a plurality of opposed ultrasonic transmitters / receivers arranged in different directions of the propagation path, and the transmitting / receiving surface of the ultrasonic transmitter / receiver is By adopting a configuration in which the shape of the support is smoothly continuous with the surface of the support and has no irregularities, and the support is arranged back and forth in the main wind direction, the occurrence of turbulence is reduced and the measurement is stabilized. I raised the character.
[0029]
The ultrasonic air data sensor according to the present invention is a combination of a plurality of opposed ultrasonic transceivers arranged in different directions of the propagation paths, and the number is extra than the minimum required number. By adopting a configuration that has a wind speed vector calculation means that is arranged with redundancy and does not use the measured value of the leeward side ultrasonic transceiver based on the detected wind direction information, the effect of the wake generated by the device itself The accuracy of the measurement was improved by excluding the detection values of the ultrasonic transceiver receiving the above. In addition, when a criterion that uses the magnitude of the error estimation value as a criterion that does not use the measurement value of the ultrasonic transceiver on the leeward side has no influence, the detection value of the ultrasonic transceiver can be effectively captured when there is no influence.
[0030]
A plurality of opposing ultrasonic transceivers are arranged and combined with different directions of propagation paths, and the number thereof is arranged with extra redundancy than the minimum required number. The ultrasonic air data sensor according to the present invention, which employs a configuration including means for detecting that the ultrasonic transceiver has failed or is in a measurement-disabled state, is such that a part of the ultrasonic transceiver is in a failure or measurement-disabled state. In this case, a stable measurement can be performed by measuring the wind speed while excluding the detection value of the ultrasonic transceiver.
[0031]
A support for fixing the ultrasonic transceiver, wherein a pair of ultrasonic propagation paths are formed between the ultrasonic transceiver installed on the base and the ultrasonic transceiver arranged concentrically around the base. In the ultrasonic air data sensor of the present invention having a structure in which a rod penetrates through the base, the ultrasonic transceiver supporting portion does not fall off even when the joint between the support rod and the base is broken.
[0032]
An ultrasonic transmitter / receiver installed on a base and an ultrasonic transmitter / receiver arranged concentrically around the base, wherein a pair of ultrasonic transmission paths are formed on the ground, and the ultrasonic transmitter / receiver is arranged concentrically. The ultrasonic air data sensor of the present invention, which employs a configuration in which the ultrasonic transmitter / receiver is mounted at a position lower than the ultrasonic transmitter / receiver installed on the base body, is a sensor having a smaller size than a conventional ultrasonic anemometer for weather observation. Since it is less susceptible to the turbulence of the airflow generated by the support rod, the accuracy is high with respect to the omnidirectional airflow, and the measurement ability in strong winds is also improved. In addition, this sensor has no moving parts and can perform highly accurate measurement as an ultrasonic anemometer that does not require a high degree of manufacturing accuracy. In addition, the temperature can be measured at the same time, and the entire observation system can be miniaturized because a one hundred box is not required.
[0033]
Numerous ultrasonic air data sensors for ground installation, wherein a pair of ultrasonic propagation paths are formed between an ultrasonic transceiver installed on a base and an ultrasonic transceiver arranged concentrically around the base. Is connected to a weather data management center via a public communication line, and a wide-area weather observation system that connects terminals in various places to a weather data management center via a public communication line does not require extensive hardware, Information can be easily collected, and the weather information of each place processed at the center can be easily used at each terminal.
[0034]
The aircraft measurement system of the present invention including the ultrasonic air data sensor according to the present invention, an atmospheric pressure sensor, and a unit that corrects and calculates an equivalent airspeed from a true airspeed is provided by the same equivalent pair as the pitot tube. The air speed measurement value can be obtained, and as a result, the speed display at low speed flight becomes more accurate than before, and the flight safety of the aircraft can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the principle of a general ultrasonic anemometer.
FIG. 2 is a shape embodying an air data sensor / probe according to the present invention for an aircraft, wherein A is a front view from the front, and B is a side view.
FIG. 3 is a diagram illustrating an airflow measurement principle in an air data sensor according to the present invention.
FIG. 4 is a diagram showing an embodiment in which the air data sensor according to the present invention is embodied for a rotating machine.
FIG. 5 is a diagram showing a discontinuous change estimated value of a measurement value of the air data sensor according to the present invention.
FIG. 6 is a diagram showing an example in which an air data sensor according to the present invention is installed and mounted for a rotary wing aircraft.
FIGS. 7A and 7B show a shape of an air data sensor / probe according to the present invention embodied for weather observation, wherein A is a top view and B is a side view.
FIG. 8 is a diagram showing an example in which the air data sensor according to the present invention is applied to a wide-area weather observation system.
[Explanation of symbols]
W wind speed
D Ultrasonic propagation distance
V airspeed
a sound velocity
R main rotor
B Barometer
S Sensor probe
1 Substrate
11,12,13,14 Support rod

Claims (10)

In a system in which the wind speed is intermittently and continuously measured by a pair of opposed ultrasonic transceivers, when the detected value changes discontinuously, an integer multiple of one cycle of the ultrasonic wave used for the detected value is subtracted. An ultrasonic air data correction method for reducing a measurement error due to the influence of internal and external noise, wherein the correction is performed to an error estimated value closest to a detected value. A plurality of opposed ultrasonic transceivers are arranged and combined with different directions of propagation paths, and the transmitting and receiving surfaces of the ultrasonic transceivers are smoothly continuous with the surface of the supporting portion, and the irregularities are formed. An ultrasonic air data sensor characterized by having no shape and arranging the support part back and forth in the main wind direction to reduce turbulence and enhance measurement stability. A plurality of opposed ultrasonic transceivers are arranged and combined with different directions of propagation paths, and the number is arranged with redundancy more than the minimum required number and detected. By providing a wind speed vector calculating means that does not use the measured value of the leeward side ultrasonic transceiver based on the wind direction information, measurement is performed excluding the detected value of the ultrasonic transceiver which is affected by the wake generated by the device itself An ultrasonic air data sensor having improved accuracy. 4. The ultrasonic air data sensor according to claim 3, wherein the magnitude of the error estimation value is used as a criterion for not using the measurement value of the ultrasonic transceiver on the leeward side. A plurality of opposing ultrasonic transceivers are arranged and combined with different directions of propagation paths, and the number thereof is arranged with extra redundancy than the minimum required number. By providing means for detecting that the ultrasonic transceiver has failed or has become unmeasurable, when a part of the ultrasonic transceiver has failed or becomes unmeasurable, the detection value of the ultrasonic transceiver has been detected. An ultrasonic air data sensor characterized by measuring a wind speed by excluding the following. 6. The ultrasonic air data sensor according to claim 5, wherein a failure or an unmeasurable state is used as a criterion, and the fact that the ultrasonic propagation time measured value is 0 or exceeds a threshold value is used. A support for fixing the ultrasonic transceiver, wherein a pair of ultrasonic propagation paths are formed between the ultrasonic transceiver installed on the base and the ultrasonic transceiver arranged concentrically around the base. An ultrasonic air data sensor having a structure in which a rod penetrates through the base so that the ultrasonic transceiver supporting portion does not fall off even when a joint between the support rod and the base is broken. An ultrasonic transmitter / receiver installed on a base and an ultrasonic transmitter / receiver disposed concentrically around the base, wherein a pair of ultrasonic transmission paths is formed on the ground, and the ultrasonic transmitter / receiver is arranged concentrically. An ultrasonic air data sensor characterized in that the effect of the wake of the substrate is reduced by mounting the ultrasonic transmitter / receiver at a position lower than the ultrasonic transmitter / receiver installed on the base. Numerous ultrasonic air data sensors for ground installation, wherein a pair of ultrasonic propagation paths are formed between an ultrasonic transceiver installed on a base and an ultrasonic transceiver arranged concentrically around the base. A wide-area meteorological observation system that connects to a weather data management center via a public communication line and terminals in various locations to a weather data management center via a public communication line. 10. An ultrasonic air data sensor according to any one of claims 2 to 9, an atmospheric pressure sensor, and means for correcting and calculating an equivalent airspeed from a true airspeed, so that an equivalent air sensor equivalent to a pitot tube is provided. Aircraft measurement system that obtains airspeed measurements.

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