Radio rangefinder, unmanned rotary-wing aircraft, vehicle, and robot

Abstract

To provide a radio rangefinder capable of measuring short distances.SOLUTION: A radio rangefinder 100 disclosed herein comprises a low-shelf filter 55 instead of a high-pass filter, and is configured to attenuate a low-frequency band component of a beat signal including a leakage frequency by using the low-shelf filter 55.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a radio rangefinder that uses a frequency-swept continuous wave, and more particularly to a radio rangefinder that can measure short distances, and further to an unmanned rotorcraft equipped with the radio rangefinder, a vehicle equipped with the radio rangefinder, and a robot equipped with the radio rangefinder. [Background technology]

[0002] Radio rangefinders that use frequency sweep continuous wave (FS-CW) to measure the distance between the radio rangefinder and a tangible object are known. Frequency sweep continuous wave is obtained by continuously changing the frequency of a continuous wave within a bandwidth included in the radio frequency band. Frequency sweep continuous wave is also called "frequency modulated continuous wave (FM-CW)," "chirp signal," or "sweep signal." "Radio rangefinders" are also called "radar (radio detecting and ranging)." Hereinafter, radio rangefinders that use frequency sweep continuous wave will be referred to as "FSCW radio rangefinders."

[0003] An FSCW radio wave rangefinder includes a transmitting system that generates a frequency swept continuous wave (which is a radio wave) and emits it into space, and a receiving system that receives a reflected wave (which is a radio wave) from a tangible object that reflects the frequency swept continuous wave as a received wave and generates a beat signal by frequency mixing the frequency swept continuous wave and the received wave. Generally, the transmitting system includes a transmitting wave generator that generates the frequency swept continuous wave and a transmitting antenna that emits the frequency swept continuous wave into space, and the receiving system includes a receiving antenna that receives the reflected wave as a received wave and a mixer that generates a beat signal by frequency mixing the frequency swept continuous wave and the received wave.

[0004] If the isolation between the transmitting and receiving systems is insufficient, a leakage phenomenon occurs in which the swept frequency continuous wave is mixed into the received wave without being reflected by a tangible object other than the FSCW radio rangefinder (e.g., the target of the distance measurement). The leakage phenomenon occurs, for example, when the receiving antenna directly receives the swept frequency continuous wave emitted from the transmitting antenna, or when a portion of the swept frequency continuous wave generated by the transmitting wave generator leaks into components of the receiving system (e.g., the mixer or transmission line). Due to the measurement principles of FSCW radio rangefinders (which are well known and therefore not explained here), the effect of the leakage phenomenon generally appears as a frequency component close to the DC component (i.e., the 0 Hz component) in the power spectrum obtained by Fourier transforming the beat signal (see Figure 1). Hereinafter, this frequency is referred to as the leakage frequency. In contrast, the effect of the reflected wave from a target sufficiently far away from the FSCW radio rangefinder (e.g., more than several meters) appears as a frequency component far from the DC component in the power spectrum of the beat signal (see Figure 1). Hereinafter, the frequency corresponding to the reflected wave will be referred to as the reflected frequency. Due to the effects of attenuation due to radio wave propagation through space and attenuation due to reflection, the power of the reflected frequency component is generally smaller than the power of the leaked frequency component (see Figure 1). Therefore, the FSCW radio wave rangefinder will erroneously detect the distance between the tangible object and the FSCW radio wave rangefinder, as if the tangible object were located close to the FSCW radio wave rangefinder.

[0005] Possible technical measures to increase the isolation between the transmitting and receiving systems to prevent leakage include, for example, placing the transmitting and receiving antennas farther apart, or improving the shielding performance between the transmitting and receiving systems inside the FSCW radio rangefinder. However, the former hinders the miniaturization of the FSCW radio rangefinder, and the latter increases the manufacturing cost of the FSCW radio rangefinder.

[0006] Therefore, as a countermeasure against the leak phenomenon, most FSCW radio wave range finders include a high-pass filter that removes components of a frequency band that includes and is close to the leak frequency.

[0007] For a prior art FSCW radio range finder that includes a high-pass filter, see, for example, US Pat. No. 6,299,649. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2018-124066 Summary of the Invention [Problem to be solved by the invention]

[0009] By including a high-pass filter in an FSCW radio wave rangefinder, false detections due to leakage are suppressed, but at the same time, the FSCW radio wave rangefinder cannot measure the distance to a tangible object that is actually located close to the FSCW radio wave rangefinder. This is because the reflection frequency corresponding to the reflected wave from a tangible object that is actually located close to the FSCW radio wave rangefinder is close to the leakage frequency (see Figure 2(a)), and the component of this reflection frequency is removed by the high-pass filter (see Figure 2(b)). Although it depends on the leakage frequency and the cutoff frequency of the high-pass filter, prior art FSCW radio wave rangefinders cannot measure the distance to a tangible object that is located closer than approximately 1 m from the FSCW radio wave rangefinder.

[0010] The present disclosure discloses a radio rangefinder capable of measuring short distances, an unmanned rotorcraft equipped with the radio rangefinder, a vehicle equipped with the radio rangefinder, and a robot equipped with the radio rangefinder. [Means for solving the problem]

[0011] The technical matters described herein are not intended to explicitly or implicitly limit the invention described in the claims, nor to enable anyone other than those who benefit from the invention (e.g., the applicant and the right holder) to limit the invention described in the claims, but are provided simply to facilitate understanding of the gist of the invention. The outline of the invention from other perspectives can be understood, for example, from the claims at the time of filing of this patent application. The radio wave distance meter of the present disclosure includes a low-shelf filter instead of a high-pass filter, and uses the low-shelf filter to attenuate low-frequency band components of the beat signal, including the leakage frequency. Each of the unmanned rotorcraft, vehicles, and robots disclosed herein is equipped with a radio range finder disclosed herein. [Effects of the Invention]

[0012] Since the low-shelf filter is used to attenuate the low-frequency band components of the beat signal, including the leak frequency, the reflected frequency close to the leak frequency is not removed, and therefore the radio wave range finder can measure short distances. [Brief explanation of the drawings]

[0013] [Figure 1] An example of a power spectrum showing the leak frequency. [Figure 2] Examples of power spectra. (a) Power spectrum of the beat signal before passing through the high-pass filter. (b) Power spectrum of the beat signal after passing through the high-pass filter. [Figure 3] 3 shows an example of a functional configuration of a radio rangefinder according to an embodiment. [Figure 4] Examples of power spectra. (a) Power spectrum of the beat signal before passing through the low-shelf filter. (b) Power spectrum of the beat signal after passing through the low-shelf filter. [Figure 5] 10 shows an example of the functional configuration of a radio rangefinder according to a modified example. [Figure 6] FIG. 2 is a front view of the unmanned rotorcraft of the embodiment. [Figure 7]Bottom view of the unmanned rotary-wing aircraft of the embodiment. [Figure 8] Plan view of the vehicle of the embodiment. [Figure 9] Side view of the robot of the embodiment.

Mode for Carrying Out the Invention

[0014] The embodiments will be described with reference to the drawings. From the viewpoint of clarifying the gist of the embodiments, illustrations and descriptions of components (such as a power supply device, a directional coupler, an intermediate amplifier, etc.) that are considered non-essential in the embodiments although they are actually necessary or may become necessary are omitted. In each figure, for the sake of simplicity, reference numerals and the like of some components may be omitted.

[0015] <FMCW radar rangefinder> [[ID=二十]]The FMCW radar rangefinder 100 of the embodiment is, as described above, a radar rangefinder that uses a frequency-swept continuous wave, and includes a transmission wave generator 10, a transmission antenna 20, a reception antenna 30, a mixer 40, and a signal processor 50 (see FIG. 3).

[0016] The transmission wave generator 10 generates a frequency-swept continuous wave in accordance with the control of a controller (not shown). The frequency-swept continuous wave is obtained, as described above, by continuously changing the frequency of the continuous wave with a bandwidth included in the frequency band of the radio wave. "Radio wave" is defined in the Radio Law (Law No. 131 of 1950) in Japan as "an electromagnetic wave with a frequency of 3 million megahertz or less". "Frequency band of the radio wave" is, for example, the frequency band of millimeter waves. "Bandwidth included in the frequency band of the radio wave" is, for example, a bandwidth of several GHz including a center frequency of several tens of GHz. If necessary, the frequency-swept continuous wave is power-amplified. The transmission antenna 20 radiates the frequency-swept continuous wave into space.

[0017] The receiving antenna 30 receives, as a received wave, a reflected wave from a tangible object 90 that reflects the frequency swept continuous wave. The number of tangible objects 90 is not necessarily one. It is assumed that the FSCW radio wave rangefinder 100 does not have sufficient isolation between the transmitting system (which includes the transmitting wave generator 10 and the transmitting antenna 20) and the receiving system (which includes the receiving antenna 30 and the mixer 40). Therefore, as described above, a leakage phenomenon occurs in which the frequency swept continuous wave is mixed into the received wave without being reflected by a tangible object 90 other than the FSCW radio wave rangefinder 100 (e.g., a target object for distance measurement). In other words, the received wave includes reflected waves from one or more tangible objects 90 and the frequency swept continuous wave mixed in due to the leakage phenomenon.

[0018] The mixer 40 generates a beat signal having a beat frequency by frequency-mixing the frequency-swept continuous wave from the transmission wave generator 10 (actually, from a directional coupler that distributes the frequency-swept continuous wave from the transmission wave generator 10) with the received wave from the receiving antenna 30. This principle is well known as the heterodyne principle, so its explanation will be omitted.

[0019] The signal processor 50 uses the filter 55 to attenuate components of a predetermined frequency band B (see FIG. 4) of the beat signal from the mixer 40, and further calculates the distance between the FSCW radio wave rangefinder 100 and the tangible object 90 from the beat frequency of the beat signal in which the components of the frequency band B have been attenuated. The frequency band B is a continuous low frequency band that typically includes a frequency of 0 Hz and includes the beat frequency (i.e., the leakage frequency) of a signal obtained by frequency mixing the frequency swept continuous wave from the transmitted wave generator 10 with a frequency swept continuous wave contained in the received wave that is not due to reflection from tangible objects 90 other than the FSCW radio wave rangefinder 100.

[0020] The signal processor 50 in this example includes an ADC (analog-digital converter) 51, a band-pass filter 53, a filter 55, and a calculator 57 (see FIG. 3). The ADC 51 converts the analog beat signal from the mixer 40 into a digital beat signal. The band-pass filter 53 removes DC components and unnecessary high-frequency components from the digital beat signal (see FIG. 4(a) , which is the same as FIG. 2(a) ). The digital filter 55 attenuates the frequency band B components of the beat signal from the band-pass filter 53 (see FIG. 4(b) ). The attenuation of the filter 55 in frequency band B is smaller than the attenuation of a filter (corresponding to a high-pass filter included in a prior-art FSCW radio rangefinder) that removes leakage frequency components from the beat signal. Preferably, the attenuation of the filter 55 in frequency band B is constant. Such a filter 55 is known as a low-shelf filter. The low-shelf filter used as the filter 55 has the characteristic of attenuating components below a specified frequency. The calculator 57 performs a Fourier transform on the beat signal from the filter 55 and further attenuates the frequency f of the component with the strongest power in the power spectrum. t The distance R [m] between the FSCW radio wave rangefinder 100 and the tangible object 90 is calculated from the frequency [Hz]. According to the basic principle of the FSCW radio wave rangefinder 100, the distance R is given by formula (1). In formula (1), c is the speed of light [m / s], T is the transmission time [s] of the frequency sweep continuous wave, and W is the above-mentioned "bandwidth included in the frequency band of the radio wave" [Hz].

number

[0021] In the FSCW radio-controlled rangefinder 100, the attenuation of the filter 55 in frequency band B is not significant, so the leak frequency component is not removed from the beat signal. However, in the power spectrum of the beat signal from the filter 55, the beat frequency (i.e., the reflected frequency) component corresponding to the reflected wave from the tangible object 90 actually located close to the FSCW radio-controlled rangefinder 100 is not removed either (see FIG. 4(b)). Furthermore, the power of the reflected frequency component corresponding to the reflected wave from the tangible object 90 actually located close to the FSCW radio-controlled rangefinder 100 is usually much greater than the power of the leak frequency component (see FIG. 4(a)). Therefore, the FSCW radio-controlled rangefinder 100 can measure short distances by using the beat signal from the filter 55. According to experiments conducted by the inventors, the FSCW radio-controlled rangefinder 100 of the embodiment was able to accurately measure distances of 10 cm, which was not possible with prior art FSCW radio-controlled rangefinders.

[0022] As described above, the FSCW radio wave rangefinder 100 does not remove leakage frequency components, so if there is no tangible object 90 close to the FSCW radio wave rangefinder 100, it may not be able to detect the reflected frequency corresponding to the reflected wave from the tangible object 90 located far from the FSCW radio wave rangefinder 100. Therefore, it is desirable that the attenuation of the filter 55 in frequency band B satisfy the following condition. (conditions) The power of the leak frequency component contained in the beat signal in which the frequency band B components have been attenuated by the filter 55 is smaller than the power of the beat frequency component corresponding to the reflected wave from the tangible object 90 located at the longest distance that can be measured by the FSCW radio wave rangefinder 100, which is contained in the beat signal in which the frequency band B components have been attenuated by the filter 55.

[0023] <Modification> The filter 55 may be an analog filter. In this case, the signal processor 50 includes a band-pass filter 53a that removes DC components and unnecessary high-frequency components from the beat signal of the analog signal from the mixer 40, a filter 55a (a specific example is a low-shelf filter) that is an analog filter that attenuates components in frequency band B of the beat signal from the band-pass filter 53, an ADC 51a that converts the beat signal of the analog signal from the filter 55a into a beat signal of a digital signal, and a Fourier transform of the beat signal from the ADC 51a and further converts the frequency f t The FSCW radio wave range finder 100 includes a calculator 57 that calculates the distance R between the FSCW radio wave range finder 100 and the tangible object based on the above (see FIG. 5).

[0024] <Unmanned aircraft> The unmanned aerial vehicle of the embodiment is an unmanned aerial vehicle equipped with the FSCW radio rangefinder disclosed herein. An unmanned aerial vehicle is an aircraft without a human on board. Here, the term "aircraft" refers to a mechanical structure capable of flying through the atmosphere, including an airplane, which accelerates forward using forward thrust and can lift and glide using its forward movement and the lift generated by its wings; a rotorcraft, which can fly by obtaining lift and thrust from rotors; a glider, which can only glide; an airship, which is an aircraft that floats using an air envelope containing a gas with a density less than that of air and is equipped with wings for propulsion and steering; a ship-like aircraft structure that can glide while floating on the water surface; and a seaplane designed to take off and land on water by having floats or float-like equipment. Hereinafter, an unmanned rotorcraft will be used as an example of an unmanned aerial vehicle. The unmanned rotorcraft 200 of the embodiment (see Figures 6 and 7) is an unmanned rotorcraft that does not have fixed wings and is capable of vertical takeoff and landing. Well-known unmanned rotorcraft that do not have fixed wings and are capable of vertical takeoff and landing include so-called drones and multicopters.

[0025] The unmanned rotorcraft 200 includes a plurality of rotors 210, a plurality of electric motors 220 for driving the rotors 210, a battery 230 for supplying electrical energy to each of the plurality of electric motors 220, a flight controller 240 for controlling the flight of the unmanned rotorcraft 200, an airframe 250 equipped with the plurality of electric motors 220, the battery 230, and the flight controller 240, and movable or stationary landing gear 260 attached to the airframe 250. The number of rotors 210 is preferably three or more, and since the unmanned rotorcraft 200 is a quadcopter, the number of rotors 210 is four. The number of wing-like objects included in the rotors 210 is often two, but is not limited to this. The electric motors 220 are, for example, brushless direct current motors. The battery 230 is, for example, a lithium-ion polymer secondary battery. The flight controller 240 has a configuration in which various sensors (e.g., acceleration sensors, angular velocity sensors, geomagnetic sensors, obstacle detection sensors, and GPS (Global Positioning System) sensors) and a processor are integrated, and controls the attitude and speed of the aircraft 250 by controlling an ESC (Electric Speed ​​Controller; not shown), which controls the rotation speed of the electric motor 220. The processor is hardware for controlling external devices by performing calculations using data from the various sensors, and includes an arithmetic unit, registers, peripheral circuits, and, if necessary, cache memory. In this example, the aircraft 250 has a rectangular parallelepiped main body and four arms 251 extending from the main body in all directions, but this is not limited to this. In the example shown in each figure, one electric motor 220 is attached to the tip of each of the four arms 251. The landing legs 260 include a ground contact portion 261 for contacting the ground and a frame portion 263 connecting the ground contact portion 261 to the aircraft 250. The ground contact portion 261 may be a ferrule, a skid, or a float.

[0026] The unmanned rotorcraft 200 is equipped with the above-described FSCW radio rangefinder 100. Hereinafter, this FSCW radio rangefinder 100 will be referred to as the first FSCW radio rangefinder 100A. For technical details of the first FSCW radio rangefinder 100A, please refer to the above description of the FSCW radio rangefinder 100. By this reference, the description of the FSCW radio rangefinder 100 is expressly incorporated into the description of the unmanned rotorcraft 200. Hereinafter, unless otherwise specified, when referring to the names of components, etc. of the first FSCW radio rangefinder 100A, the names of the components, etc. of the above-described FSCW radio rangefinder 100 will be referred to with the word "first" added. For example, the transmitting antenna 20 of the first FSCW radio rangefinder 100A will be referred to as the first transmitting antenna 20.

[0027] In unmanned rotary-wing aircraft 200, first FSCW radio-wave rangefinder 100A is attached to the bottom of airframe 250. When unmanned rotary-wing aircraft 200 has landed on the ground or on water, first transmitting antenna 20 and first receiving antenna 30 of first FSCW radio-wave rangefinder 100A each face the ground or water surface. Therefore, the distance measured by first signal processor 50 of first FSCW radio-wave rangefinder 100A is an absolute altitude. First FSCW radio-wave rangefinder 100A may be fixed to ground portion 261 or to a portion of frame portion 263 located near ground portion 261.

[0028] Because first FSCW radio wave rangefinder 100A is mounted on unmanned rotary-wing vehicle 200, there is a possibility that frequency components corresponding to reflected waves from components of unmanned rotary-wing vehicle 200 (e.g., landing gear 260) or tangible objects mounted on unmanned rotary-wing vehicle 200 (e.g., cargo (not shown)) may appear near the DC component in the power spectrum of the beat signal. Therefore, in first FSCW radio wave rangefinder 100A, first frequency band B preferably includes the beat frequency of a signal obtained by frequency mixing a first frequency swept continuous wave included in the first received wave that is not due to reflection from tangible object 90 (excluding unmanned rotary-wing vehicle 200 and tangible objects mounted on unmanned rotary-wing vehicle 200) with the first frequency swept continuous wave from first transmitted wave generator 10.

[0029] The unmanned rotary-wing aircraft 200 preferably carries one or more FSCW radio-controlled rangefinders 100 in addition to the first FSCW radio-controlled rangefinder 100A. Hereinafter, each of the one or more additional FSCW radio-controlled rangefinders 100 will be referred to as a second FSCW radio-controlled rangefinder 100B. The unmanned rotary-wing aircraft 200 of this embodiment is equipped with four second FSCW radio-controlled rangefinders 100B. For technical details of the second FSCW radio-controlled rangefinder 100B, please refer to the above description of the FSCW radio-controlled rangefinder 100. Hereinafter, unless otherwise specified, when referring to the names of components of the second FSCW radio-controlled rangefinder 100B, the names will be the names of the components of the above-mentioned FSCW radio-controlled rangefinder 100 with "second" added. For example, the transmitting antenna 20 of the second FSCW radio-controlled rangefinder 100B will be referred to as the second transmitting antenna 20.

[0030] In unmanned rotary-wing aircraft 200, second FSCW radio wave rangefinder 100B is attached near the tip of arm 251. When unmanned rotary-wing aircraft 200 is on the ground or on water, second transmitting antenna 20 and second receiving antenna 30 of second FSCW radio wave rangefinder 100B are each oriented in the same direction in the horizontal plane and in the opposite direction to body 250 of unmanned rotary-wing aircraft 200.

[0031] Because second FSCW radio wave rangefinder 100B is mounted on unmanned rotary-wing vehicle 200, there is a possibility that frequency components corresponding to reflected waves from components of unmanned rotary-wing vehicle 200 (e.g., rotor 210) or tangible objects mounted on unmanned rotary-wing vehicle 200 (e.g., cargo (not shown)) may appear near the DC component in the power spectrum of the beat signal. Therefore, in second FSCW radio wave rangefinder 100B, second frequency band B preferably includes the beat frequency of a signal obtained by frequency mixing the second frequency swept continuous wave contained in the second received wave that is not due to reflection from tangible object 90 (excluding unmanned rotary-wing vehicle 200 and tangible objects mounted on unmanned rotary-wing vehicle 200) with the second frequency swept continuous wave from second transmitted wave generator 10.

[0032] From the viewpoint of preventing interference, it is desirable that the "bandwidth included in the frequency band of radio waves" in the first FSCW radio wave rangefinder 100A and the "bandwidth included in the frequency band of radio waves" in the second FSCW radio wave rangefinder 100B do not overlap with each other.

[0033] When unmanned rotary-wing aircraft 200 is equipped with second FSCW radio rangefinder 100B, second FSCW radio rangefinder 100B has high performance that can accurately measure distances of 10 cm, so unmanned rotary-wing aircraft 200 can get closer to an object during flight than unmanned rotary-wing aircraft of the prior art. Therefore, unmanned rotary-wing aircraft 200 is useful for inspecting tall structures such as high-rise buildings, steel towers, and bridges, for example.

[0034] <Vehicle> The vehicle 300 of the embodiment is a vehicle with wheels or tracks, i.e., a wheeled vehicle or a tracked vehicle. The vehicle 300 shown in FIG. 8 is a wheeled vehicle. The vehicle 300 is preferably driven by a prime mover. The prime mover is typically, but not limited to, a thermal engine (examples of which include a gasoline engine and a diesel engine) or an electric motor (examples of which include a permanent magnet synchronous motor and a DC commutator motor). The vehicle 300 may be a vehicle for traveling on roads (e.g., an automobile (including four-wheeled vehicles and two-wheeled vehicles), a trolleybus), a vehicle for transporting loads and loads (e.g., a forklift, a hand truck, a towing vehicle, a straddle carrier, etc.), a vehicle for civil engineering or construction work (e.g., a dump truck, a road roller, a bulldozer, a shovel, a wheel loader), a vehicle for agricultural work (e.g., a tractor, a cultivator), or a military vehicle (e.g., a tank, an armored vehicle, a self-propelled artillery). Vehicle 300 may be a vehicle intended to carry passengers or a vehicle intended not to carry passengers. Vehicle 300 may also be a vehicle capable of autonomous travel with or without passengers on board.

[0035] The vehicle 300 is equipped with the above-described FSCW radio wave distance meter 100. For technical details of the FSCW radio wave distance meter 100, please refer to the above description of the FSCW radio wave distance meter 100. By this reference, the description of the FSCW radio wave distance meter 100 is expressly incorporated into the description of the vehicle 300.

[0036] In vehicle 300, FSCW radio wave rangefinders 100 are attached, for example, to each of the front and rear ends of vehicle 300. The transmitting antenna 20 and receiving antenna 30 of FSCW radio wave rangefinder 100 are each oriented in the same direction in the horizontal plane and facing away from vehicle 300. Furthermore, although not shown, FSCW radio wave rangefinders 100 may be attached to each of the right and left sides of vehicle 300, or to each of the front right corner, front left corner, rear right corner, and rear left corner of vehicle 300.

[0037] Since the FSCW radio wave rangefinder 100 is mounted on the vehicle 300, there is a possibility that frequency components corresponding to reflected waves from components of the vehicle 300 (e.g., bumper, diffuser, license plate) or tangible objects (e.g., cargo) mounted on the vehicle 300 may appear near the DC component in the power spectrum of the beat signal. Therefore, in the FSCW radio wave rangefinder 100, it is preferable that the frequency band B includes the beat frequency of a signal obtained by frequency mixing the frequency swept continuous wave contained in the received wave that is not due to reflection from the tangible objects 90 (excluding the vehicle 300 and tangible objects mounted on the vehicle 300) with the frequency swept continuous wave from the transmitted wave generator 10.

[0038] <Ship> A vessel (not shown) according to an embodiment of the present invention is a vessel equipped with the FSCW radio wave rangefinder of the present disclosure. Here, a vessel is a structure that satisfies at least two requirements: it must be able to float on water and move. There is no limitation on the carrying capacity of the vessel; therefore, the vessel may be a vessel designed to carry people, a vessel designed to carry goods, or a vessel designed to carry neither people nor goods. Furthermore, the vessel may be a vessel capable of autonomous navigation, with or without people on board. There is no limitation on the means for obtaining buoyancy; therefore, the vessel may be a displacement vessel, a planing vessel, a hydrofoil vessel, a hovercraft, or a ground-effect vehicle. There is no limitation on the power source for movement; therefore, the vessel may be a rowboat, a sailboat, a motor-sailboat, or a powerboat (powered by a gasoline engine, a diesel engine, a gas turbine engine, a nuclear reactor, a diesel-electric engine, or a turboelectric engine). There are no limitations on the type of vessel, and thus vessels include monohulls, catamarans, trimarans, wave piercers, hydrofoils, hovercrafts, ground effect aircraft, and personal watercraft. There are no limitations on the use, and thus vessels include merchant ships, passenger ships, cargo-passenger ships, container ships, tankers, bulk carriers, refrigerated and frozen carriers, ferries, railroad car ferries, RO-RO ships, fishing boats, warships, patrol boats, rescue ships, training ships, oceanographic research vessels, meteorological research vessels, work vessels, icebreakers, ice-laying ships, dredgers, offshore resource drilling ships, crane ships, tugboats, pilot boats, lightboats, firefighting boats, quarantine boats, radio relay boats, lighthouse supply ships, lighthouse patrol boats, hospital ships, water ships, and fuel ships.

[0039] The vessel of the embodiment is equipped with the above-described FSCW radio wave rangefinder 100. For technical details of the FSCW radio wave rangefinder 100, please refer to the above description of the FSCW radio wave rangefinder 100. By this reference, the description of the FSCW radio wave rangefinder 100 is expressly incorporated into the description of the vessel of the embodiment.

[0040] In the ship of the embodiment, the FSCW radio wave rangefinder 100 is attached to, for example, the front, rear, left, and right sides of the ship of the embodiment. The transmitting antenna 20 and the receiving antenna 30 of the FSCW radio wave rangefinder 100 are each oriented in the same direction in the horizontal plane and facing away from the ship of the embodiment.

[0041] Since the FSCW radio wave rangefinder 100 is mounted on the ship of the embodiment, there is a possibility that frequency components corresponding to reflected waves from components of the ship of the embodiment (e.g., an anchor) or tangible objects (e.g., cargo) mounted on the ship of the embodiment may appear near the DC component in the power spectrum of the beat signal. Therefore, in the FSCW radio wave rangefinder 100, it is preferable that the frequency band B includes the beat frequency of a signal obtained by frequency mixing the frequency swept continuous wave contained in the received wave not due to reflection from a tangible object 90 (excluding the ship of the embodiment and tangible objects mounted on the ship of the embodiment) with the frequency swept continuous wave from the transmitted wave generator 10.

[0042] Unlike laser rangefinders, FSCW radio wave rangefinders can measure distances even in dense fog environments, and therefore the FSCW radio wave rangefinders disclosed herein improve the safety of ships equipped with the FSCW radio wave rangefinders disclosed herein.

[0043] <Robot> The robot 400 of the embodiment is a mobile robot that can move using wheels or caterpillars. The robot 400 includes, for example, a wheelchair robot, a self-reliance assistance robot, a welfare robot, a cleaning robot, a delivery robot, a food distribution robot, a guide robot, a security robot, and a military robot. The robot 400 shown in Fig. 9 is a cleaning robot that cleans the surface of a road or the like.

[0044] The robot 400 is equipped with the above-described FSCW radio wave distance meter 100. For technical details of the FSCW radio wave distance meter 100, please refer to the above description of the FSCW radio wave distance meter 100. By this reference, the description of the FSCW radio wave distance meter 100 is expressly incorporated into the description of the robot 400.

[0045] In the robot 400, the FSCW radio wave range finder 100 is attached, for example, to each of the front, rear, left, and right sides of the robot 400. The transmitting antenna 20 and the receiving antenna 30 of the FSCW radio wave range finder 100 face in the same direction in the horizontal plane and in the opposite direction to the robot 400.

[0046] Since the FSCW radio wave rangefinder 100 is mounted on the robot 400, there is a possibility that frequency components corresponding to reflected waves from components of the robot 400 (for example, a movable arm if the robot 400 is a humanoid robot) or from tangible objects (for example, cargo) mounted on the robot 400 may appear near the DC component in the power spectrum of the beat signal. Therefore, in the FSCW radio wave rangefinder 100, it is preferable that the frequency band B includes the beat frequency of a signal obtained by frequency mixing the frequency swept continuous wave contained in the received wave that is not due to reflection from the tangible object 90 (excluding the robot 400 and tangible objects mounted on the robot 400) with the frequency swept continuous wave from the transmitted wave generator 10.

[0047] <Addendum> The technical features disclosed in the various embodiments and their modifications described above are not necessarily mutually exclusive, and technical features of one embodiment or its modifications may be applied to technical features of another embodiment or its modifications, provided that there is no contradiction from a technical viewpoint.

[0048] The claims as of the filing of this application do not necessarily exhaustively claim all inventions disclosed in this specification. In this regard, this should not be understood or construed as meaning that the applicant has pre-filing waived any right to a patent for any invention not claimed at the time of filing this application. To the extent permitted by the laws, regulations, or treaties of any country or region where this application is filed, the applicant reserves the right to a patent for any invention not claimed in this application, the right to file a divisional application for such invention, the right to claim such invention by amendment, and any other rights, unless the applicant expressly and conclusively expresses a contrary intention.

[0049] While the present invention has been described with reference to exemplary embodiments, those skilled in the art will recognize that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the invention. Furthermore, many modifications can be made to adapt a particular system, device, or component thereof to the teachings of the present invention without departing from the essential scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed for carrying out this invention, but rather that the invention will include all embodiments falling within the scope of the appended claims.

[0050] Furthermore, the use of terms such as "first," "second," etc., when used in this specification and / or the appended claims, does not denote any order or importance, and terms such as "first," "second," etc., are used to distinguish between elements. The terms used herein are for the purpose of describing embodiments and are not intended to limit the invention in any way. The term "comprises" and its conjugations, when used in this specification and / or the appended claims, reveal the presence of referenced features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The term "and / or" includes any and all combinations of one or more of the associated listed elements, if any. In the claims and the specification, unless otherwise specified, the use of words such as "connected," "coupled," "joined," "connected," or synonyms thereof, and all word forms thereof, does not necessarily negate the presence of one or more intermediate elements between two elements, e.g., "connected" or "coupled" to each other or "connected" to each other. In the claims and the specification, the term "any," if any, should be understood as a term that has the same meaning as the universal symbol ∀, unless otherwise specified. For example, the phrase "for any X" has the same meaning as "for all X" or "for each X." A phrase such as "at least one of A, B, and C" (e.g., "at least one of A, B, and C," "at least one of A, B, or C," "at least one of A, B, and / or C"), if any, should be understood as a term that has the same meaning as the universal symbol ∀, unless otherwise specified. S This means that we arbitrarily select one element from the set P excluding the empty set φ. In this example, S={A,B,C},2 S={φ,{A},{B},{C},{A,B},{A,C},{B,C},{A,B,C}},P={{A},{B},{C},{A,B},{A,C},{B,C},{A,B,C}}, which means that one element (e.g., {A,C}) is arbitrarily selected from the set P.

[0051] Unless otherwise specified, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Furthermore, terms such as those defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant art and this disclosure, and should not be interpreted ideally or excessively formally unless explicitly defined.

[0052] It will be understood that in describing the present invention, many techniques and steps are disclosed. Each of these has distinct advantages, and each can be used in combination with one or more, or in some cases all, of the other disclosed techniques. Therefore, to avoid cluttering, this specification will refrain from describing every possible combination of individual techniques or steps. Nevertheless, the specification and claims should be read with the understanding that such combinations are fully within the scope of the present invention and claims.

[0053] The corresponding structure, material, acts, and equivalents of all functional elements combined with means or steps in the following claims are intended to include the structure, material, or acts, if any, that perform the function in combination with other elements.

[0054] Although the present invention has been described above with reference to exemplary embodiments, it is not limited to these embodiments. Various modifications and variations are possible without departing from the spirit of the present invention. The selected and described embodiments are intended to illustrate the principles of the present invention and its practical application. The present invention may be used in various embodiments with various modifications or variations, which are determined according to the expected use. All such modifications and variations are intended to be included within the scope of the present invention, as defined by the appended claims, and are intended to be accorded the same protection when interpreted in accordance with the breadth that is fairly, legally, and equitably to be given. [Explanation of symbols]

[0055] 10 Transmitting Wave Generator 20 transmitting antennas 30 receiving antenna 40 Mixer 50 Signal processor 51 ADC 51a ADC 53 Bandpass Filter 53a Bandpass Filter 55 filters 55a filter 57 Arithmetic unit 90 Tangible Objects 100 Radio distance meter 100A Radio Rangefinder 100B radio distance meter 200 Unmanned Rotorcraft 210 Rotor 220 Electric motor 230 battery 240 Flight Controller 250 aircraft 251 Arm 260 landing gear 261 Grounding part 263 Frame section 300 vehicles 400 robots

Claims

1. A radio wave rangefinder that measures the distance between a radio wave rangefinder and a tangible object using a frequency sweep continuous wave obtained by continuously changing the frequency of a continuous wave within a bandwidth included in the frequency band of radio waves, a transmission wave generator that generates the frequency swept continuous wave; a transmitting antenna that emits the frequency sweep continuous wave into space; a receiving antenna that receives, as a received wave, a reflected wave from the tangible object that reflects the frequency sweep continuous wave; a mixer that mixes the frequency sweep continuous wave from the transmission wave generator with the reception wave to generate a beat signal having a beat frequency; a signal processor that attenuates components of a predetermined frequency band of the beat signal using a filter and calculates the distance from the beat frequency of the beat signal from which the components of the predetermined frequency band have been attenuated; Including, the predetermined frequency band includes a beat frequency of a signal obtained by frequency mixing the frequency swept continuous wave included in the received wave without being due to reflection from a tangible object other than the radio wave rangefinder and the frequency swept continuous wave from the transmitted wave generator, this frequency being hereinafter referred to as a leak frequency; The filter is a low-shelf filter. Radio distance meter.

2. A radio wave rangefinder that measures the distance between a radio wave rangefinder and a tangible object using a frequency sweep continuous wave obtained by continuously changing the frequency of a continuous wave within a bandwidth included in the frequency band of radio waves, a transmission wave generator that generates the frequency swept continuous wave; a transmitting antenna that emits the frequency sweep continuous wave into space; a receiving antenna that receives, as a received wave, a reflected wave from the tangible object that reflects the frequency sweep continuous wave; a mixer that mixes the frequency sweep continuous wave from the transmission wave generator with the reception wave to generate a beat signal having a beat frequency; a signal processor that attenuates components of a predetermined frequency band of the beat signal using a filter and calculates the distance from the beat frequency of the beat signal from which the components of the predetermined frequency band have been attenuated; Including, the predetermined frequency band includes a beat frequency of a signal obtained by frequency mixing the frequency swept continuous wave included in the received wave without being due to reflection from a tangible object other than the radio wave rangefinder and the frequency swept continuous wave from the transmitted wave generator, this frequency being hereinafter referred to as a leak frequency; an attenuation amount of the filter in the predetermined frequency band is smaller than an attenuation amount of a filter that removes the leak frequency component contained in the beat signal in the predetermined frequency band; Radio distance meter.

3. 3. The radio wave rangefinder according to claim 2, The attenuation of the filter is constant in the predetermined frequency band. A radio wave rangefinder characterized by:

4. 4. The radio wave rangefinder according to claim 1, The attenuation of the filter in the predetermined frequency band is the power of the leak frequency component included in the beat signal in which the components in the predetermined frequency band have been attenuated is smaller than the power of the beat frequency component included in the beat signal in which the components in the predetermined frequency band have been attenuated, the beat frequency component corresponding to the reflected wave from the tangible object located at the longest distance measurable by the radio wave rangefinder; Fulfilling A radio wave rangefinder characterized by:

5. An unmanned rotary-wing aircraft equipped with a first radio rangefinder, having no fixed wings, and capable of vertical takeoff and landing, The unmanned rotorcraft includes a plurality of rotors, a plurality of electric motors for driving the plurality of rotors, a battery for supplying electric energy to each of the plurality of electric motors, a flight controller for controlling flight of the unmanned rotorcraft, an airframe that mounts the plurality of electric motors, the battery, and the flight controller, and landing gear attached to the airframe, The first radio wave rangefinder includes: A radio wave rangefinder that measures a first distance between a first radio wave rangefinder and a first tangible object by using a first frequency swept continuous wave obtained by continuously changing the frequency of a first continuous wave within a first bandwidth included in a frequency band of radio waves, a first transmission wave generator that generates the first frequency swept continuous wave; a first transmitting antenna that emits the first frequency swept continuous wave into space; a first receiving antenna that receives, as a first received wave, a first reflected wave from the first tangible object that reflects the first frequency swept continuous wave; a first mixer that mixes the first frequency swept continuous wave from the first transmission wave generator with the first reception wave to generate a first beat signal having a first beat frequency; a first signal processor that attenuates a component of a predetermined first frequency band of the first beat signal using a first filter, and calculates the first distance from the first beat frequency of the first beat signal from which the component of the predetermined first frequency band has been attenuated; Including, the predetermined first frequency band includes a beat frequency of a signal obtained by frequency mixing the first frequency swept continuous wave included in the first received wave without being due to reflection from a tangible object, excluding the unmanned rotary-wing aircraft and a tangible object mounted on the unmanned rotary-wing aircraft, with the first frequency swept continuous wave from the first transmitted wave generator; the first filter is a low-shelf filter; When the unmanned rotary-wing aircraft is on the ground or on water, each of the first transmitting antenna and the first receiving antenna faces the ground or water surface; the first distance is an absolute altitude; Unmanned rotorcraft.

6. The unmanned rotorcraft according to claim 5, the unmanned rotorcraft further includes a second radio range finder; The second radio wave rangefinder includes: a radio wave rangefinder configured to measure a second distance between the second radio wave rangefinder and a second tangible object by using a second frequency swept continuous wave obtained by continuously changing the frequency of a second continuous wave within a second bandwidth included in a frequency band of radio waves, a second transmission wave generator that generates the second frequency swept continuous wave; a second transmitting antenna that emits the second frequency swept continuous wave into space; a second receiving antenna that receives, as a second received wave, a second reflected wave from the second tangible object that reflects the second frequency swept continuous wave; a second mixer that mixes the second frequency swept continuous wave from the second transmission wave generator with the second reception wave to generate a second beat signal having a second beat frequency; a second signal processor that attenuates a component of a predetermined second frequency band of the second beat signal using a second filter, and calculates the second distance from the second beat frequency of the second beat signal in which the component of the predetermined second frequency band has been attenuated; Including, the predetermined second frequency band includes a beat frequency of a signal obtained by frequency mixing the second frequency swept continuous wave included in the second received wave without reflection from a tangible object, excluding the unmanned rotary-wing aircraft and a tangible object mounted on the unmanned rotary-wing aircraft, with the second frequency swept continuous wave from the second transmitted wave generator; the second filter is a low-shelf filter; When the unmanned rotorcraft is in a state of landing on the ground or on water, the second transmitting antenna and the second receiving antenna are each oriented in the same direction in a horizontal plane. An unmanned rotorcraft characterized by:

7. A vehicle equipped with a radio rangefinder and having wheels or tracks, The radio wave rangefinder comprises: A radio wave rangefinder that measures the distance between a radio wave rangefinder and a tangible object using a frequency sweep continuous wave obtained by continuously changing the frequency of a continuous wave within a bandwidth included in the frequency band of radio waves, a transmission wave generator that generates the frequency swept continuous wave; a transmitting antenna that emits the frequency sweep continuous wave into space; a receiving antenna that receives, as a received wave, a reflected wave from the tangible object that reflects the frequency sweep continuous wave; a mixer that mixes the frequency sweep continuous wave from the transmission wave generator with the reception wave to generate a beat signal having a beat frequency; a signal processor that attenuates components of a predetermined frequency band of the beat signal using a filter and calculates the distance from the beat frequency of the beat signal from which the components of the predetermined frequency band have been attenuated; Including, the predetermined frequency band includes a beat frequency of a signal obtained by frequency mixing the frequency swept continuous wave included in the received wave without being due to reflection from a tangible object, excluding the vehicle and tangible objects mounted on the vehicle, with the frequency swept continuous wave from the transmitted wave generator; the filter is a low-shelf filter, The transmitting antenna and the receiving antenna are oriented in the same direction in a horizontal plane. vehicle.

8. A robot equipped with a radio rangefinder and capable of moving using wheels or tracks, The radio wave rangefinder comprises: A radio wave rangefinder that measures the distance between a radio wave rangefinder and a tangible object using a frequency sweep continuous wave obtained by continuously changing the frequency of a continuous wave within a bandwidth included in the frequency band of radio waves, a transmission wave generator that generates the frequency swept continuous wave; a transmitting antenna that emits the frequency sweep continuous wave into space; a receiving antenna that receives, as a received wave, a reflected wave from the tangible object that reflects the frequency sweep continuous wave; a mixer that mixes the frequency sweep continuous wave from the transmission wave generator with the reception wave to generate a beat signal having a beat frequency; a signal processor that attenuates components of a predetermined frequency band of the beat signal using a filter and calculates the distance from the beat frequency of the beat signal from which the components of the predetermined frequency band have been attenuated; Including, the predetermined frequency band includes a beat frequency of a signal obtained by frequency mixing the frequency swept continuous wave included in the received wave without being due to reflection from a tangible object, excluding the robot and tangible objects mounted on the robot, with the frequency swept continuous wave from the transmitted wave generator; the filter is a low-shelf filter, The transmitting antenna and the receiving antenna are oriented in the same direction in a horizontal plane. robot.

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