Detection device and moving object

Abstract

The invention provides a detection device and a moving object. The detection device can improve object detection performance while reducing calculation load. In the detection device (40), the detection angle of an (n + 1)-th sensor (45) (first sensor) is smaller than the detection angle of an n-th sensor (second sensor). The angular range of the (n + 1)-th sensor (45) may be smaller than the angular range of the n-th sensor. And on the other hand, detection can be carried out at a short-distance position with a relatively low angular resolution, but detection needs to be carried out at a long-distance position with a relatively high angular resolution. The (n + 1) th sensor (45) can obtain a higher angular resolution than the nth sensor because the pitch of each antenna is wide. For a long-distance position, the detection device (40) obtains a high angular resolution by the (n + 1) th sensor (45) to improve detection performance, and at the same time, due to a small angular range, detection can be performed with a low calculation load. As a result, the detection device (40) can perform detection with a low calculation load by suppressing the angular resolution while ensuring a wide angular range by the nth sensor (45) for a close-range position.

Description

[0001] This application claims priority from Japanese Patent Application No. 2024-115823 filed on July 19, 2024. The entire contents of the Japanese application are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to a detection device and a mobile body. BACKGROUND

[0003] Patent Document 1 describes an RTG crane that travels on a travel path in a container yard. The RTG crane travels on the travel path and carries a container disposed at an arbitrary position in the container yard.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2004-123367

[0005] Here, in the RTG crane described above, in a case where an object exists within the travel path or the like, in order to suppress contact of the object with the RTG crane, a MIMO (Multi Input Multi Output) radar is sometimes provided as a detection device that detects a distance and an angle to the object. The MIMO radar can adjust the angle resolution by adjusting the interval of a plurality of receiving antennas arranged in a state of being separated from each other. However, in a case where a higher angle resolution is desired in a wider angle range, there is a problem that the number of receiving antennas increases and the computational load becomes large. SUMMARY

[0006] An object of the present application is to provide a detection device and a mobile body that can improve object detection performance while reducing computational load.

[0007] The detection device according to an aspect of the present application includes a first sensor and a second sensor that detect a distance to an object by radio waves, the first sensor and the second sensor each having a plurality of transmitting antennas that transmit radio waves and a plurality of receiving antennas that receive reflected radio waves, the detection angle of the second sensor being smaller than the detection angle of the first sensor, the interval of the transmitting antennas in the second sensor being wider than the interval of the transmitting antennas in the first sensor, and the interval of the receiving antennas in the second sensor being wider than the interval of the receiving antennas in the first sensor.

[0008] In the detection device, the second sensor has a smaller detection angle than the first sensor. The second sensor is able to detect a far distance position within a smaller angle range. On the other hand, a near distance position can be detected even with a lower angle resolution, but a higher angle resolution is required for the far distance position. In this regard, the interval of the transmission antennas in the second sensor is wider than the interval of the transmission antennas in the first sensor. Also, the interval of the reception antennas in the second sensor is wider than the interval of the reception antennas in the first sensor. The second sensor is able to obtain a higher angle resolution than the first sensor due to the wider interval of the antennas. Therefore, for the far distance position, the detection device improves the detection performance by obtaining a high angle resolution with the second sensor, while being able to detect with a lower computational load due to the smaller angle range. For the near distance position, the detection device ensures a wider angle range with the first sensor, while being able to detect with a lower computational load by suppressing the angle resolution. Thus, the object detection performance can be improved while reducing the computational load.

[0009] The detection device further includes an angle resolution processing section that acquires the detection results of the first sensor and the second sensor and performs angle resolution processing. The angle resolution processing section can determine a ghost from the second waveform detected by the second sensor based on the first waveform detected by the first sensor, and perform correction that deletes the second waveform determined as a ghost. At this time, the angle resolution processing section is able to delete the waveform of the ghost generated by the aliasing phenomenon from the second waveform even without performing a complex calculation.

[0010] The detection device further includes an angle resolution processing section that acquires the detection results of the first sensor and the second sensor and performs angle resolution processing. The angle resolution processing section can determine a ghost from the second waveform detected by the second sensor based on the first waveform detected by the first sensor, and perform correction that deletes the second waveform determined as a ghost. At this time, the angle resolution processing section is able to delete the waveform of the ghost generated by the aliasing phenomenon from the second waveform even without performing a complex calculation.

[0011] The detection device further includes an angle resolution processing section that acquires the detection results of the first sensor and the second sensor and performs angle resolution processing. The angle resolution processing section can determine a ghost from the second waveform detected by the second sensor based on the first waveform detected by the first sensor, and perform correction that deletes the second waveform determined as a ghost. At this time, the angle resolution processing section is able to delete the waveform of the ghost generated by the aliasing phenomenon from the second waveform even without performing a complex calculation.

[0012] The detection device further includes an angle resolution processing section that acquires the detection results of the first sensor and the second sensor and performs angle resolution processing. The angle resolution processing section can determine a ghost from the second waveform detected by the second sensor based on the first waveform detected by the first sensor, and perform correction that deletes the second waveform determined as a ghost. At this time, the angle resolution processing section is able to delete the waveform of the ghost generated by the aliasing phenomenon from the second waveform even without performing a complex calculation.

[0013] An aspect of the present application relates to a mobile body provided with a detection device and traveling on a travel path, the detection device being provided with a first sensor and a second sensor that detect a distance from an object by radio waves, the first sensor and the second sensor each having a plurality of transmission antennas that transmit radio waves and a plurality of reception antennas that receive reflected radio waves, the detection angle of the second sensor being smaller than the detection angle of the first sensor, the interval of the transmission antennas in the second sensor being wider than the interval of the transmission antennas in the first sensor, and the interval of the reception antennas in the second sensor being wider than the interval of the reception antennas in the first sensor.

[0014] According to the mobile body, the same effects and advantages as the detection device described above can be achieved.

[0015] Effects of the Invention

[0016] According to the present application, the object detection performance can be improved while reducing the computational load. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a plan view showing an exemplary container terminal of an RTG crane to which the embodiments are applied.

[0018] Figure 2 is a perspective view showing an example of a group of containers to be handled and an adjacent group of containers arranged along the travel direction of the transport trolley.

[0019] Figure 3 is a perspective view showing an RTG crane to which the embodiments are applied.

[0020] Figure 4 is a schematic plan view for explaining the relationship between the RTG crane and the travel path of the RTG crane.

[0021] Figure 5 is a view showing the detection device to which the present embodiment is applied.

[0022] Figure 6 is a view showing the first sensor.

[0023] Figure 7 is a view for explaining the distance relationship of the transmission antennas and the reception antennas.

[0024] Figure 8 is a cross-sectional view along the line VIII-VIII shown in Figure 6

[0025] Figure 9 is a schematic view showing each detection area of the detection device.

[0026] Figure 10 is an enlarged view of Figure 9 .​

[0027] Figure 11 is a schematic diagram for explaining object detection.

[0028] Figure 12 is a schematic diagram for explaining the processing content of the processing section.

[0029] Figure 13 is a detection device involved in a modification example.

[0030] In the figure: 10 - RTG crane (moving body), 40 - detection device, 41 - transmission antenna, 42 - reception antenna, 46 - angle resolution processing section, 60 - wave-absorbing wall (restriction mechanism). DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment of the present application will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference symbols, and repetitive explanation will be appropriately omitted. Also, for the convenience of explanation, in the drawings, a part is sometimes simplified or enlarged, and the dimensional ratio and the like are not limited to the content described in the drawings.

[0032] Figure 1 is a plan view showing an exemplary container terminal 1 to which the present application is applied. As shown in Figure 1 , the container terminal 1 is provided with: a container yard 2 for arranging containers C; a plurality of gantry cranes 3 for transferring the containers C with respect to a berthed container ship; a plurality of RTG cranes 10 (moving bodies) arranged in the container yard 2 and performing loading and unloading of the containers C; and a remote operation room 5 capable of remotely operating the plurality of RTG cranes 10.

[0033] Figure 2 is a perspective view showing the containers C in the container yard 2 and an exemplary transport trolley 20. The transport trolley 20 is, for example, a truck, a wagon, a trailer, or an AGV (Automated Guide Vehicle), and the like. As shown in Figure 1 and Figure 2 , a storage area for storing a plurality of containers and a travel path (truck lane) for the transport trolley 20 to travel are laid out on the container yard 2. The RTG crane 10 takes the container C from the transport trolley 20 stopped at a prescribed position and places the container C at a prescribed number position of the container yard 2. Also, the RTG crane 10 takes the container C arranged in the container yard 2 and transfers the container C to the transport trolley 20, and the container C is carried out by the transport trolley 20.

[0034] As an example, the container C is an ISO standard container. The container C is a long cuboid shape in a length direction, for example, the length of the container C in the length direction is 20 feet or more and 45 feet or less. For example, the height of the container C is 8.5 feet or more and 9.5 feet or less. The container C is stacked one or more layers on the container yard 2. The number of layers in which the container C is arranged is sometimes referred to as a tier.

[0035] As shown in Figure 1 , the container yard 2 is provided with a plurality of lanes L in which the container C is arranged, and a plurality of RTG cranes 10 are arranged. For example, the RTG crane 10 is arranged in each lane L. The number of RTG cranes 10 arranged in the lane L can be one or a plurality.

[0036] As shown in Figure 2 , the container C is stacked one or more layers on the container yard 2 to form a plurality of rows R. In each row R, the length direction of the container C constituting the row R (i.e., the container C placed in the row R) is parallel to the length direction of the container C constituting other rows R.

[0037] If the length direction of the container C arranged in the entire row on the container yard 2 is set as the X direction, the width direction of the container C is set as the Y direction, and the height direction of the container C is set as the Z direction, the container yard 2 extends in the XY plane, for example, the container C is stacked in the Z direction at a certain position in the XY plane. The X direction coincides with the traveling direction of the RTG crane 10 in the lane L. The Y direction coincides with the transverse direction of the RTG crane 10 in the lane L.

[0038] The containers C are arranged in the Y direction and stacked in the Z direction to constitute a plurality of container groups, which are referred to as bays B. A plurality of bays B are arranged in the X direction on the container yard 2. For example, the bay B includes a handling object bay (i.e., a handling object container group B1) that is a handling object of the container C and adjacent container groups B2 located on both sides of the handling object container group B1 in the X direction.

[0039] Figure 3 is a perspective view showing an example of the RTG crane 10 according to the embodiment involved in the present embodiment arranged in the container yard 2. As shown in Figure 3 , the RTG crane 10 is a container handling crane that handles the container C. The RTG crane 10 is a crane of a type called a Rubber Tired Gantry Crane (RTG crane). For example, the RTG crane 10 performs automated handling work on the container C arranged in the container yard 2 in the container terminal 1.

[0040] For example, the RTG crane 10 is provided with a pair of leg portions 11, a crane girder 12 that links the upper ends of the pair of leg portions 11, a crane trolley 13 that is able to traverse on the crane girder 12, a spreader 14 that loads and unloads a container C, and a pair of traveling portions 15A, 15B that have wheels 23. The pair of leg portions 11 and the crane girder 12 are in a door shape. For example, the RTG crane 10 is provided with two sets of the pair of leg portions 11 and the crane girder 12 in a door shape, and the two sets are arranged side by side in the X direction.

[0041] For example, the crane trolley 13 traverses in the Y direction by driving of a traverse motor. In the present embodiment, the Y direction coincides with the direction of traversal of the crane trolley 13. As an example, the crane trolley 13 has a winding driving portion 16 that includes a drum that is driven in forward and reverse rotation by a drum driving motor, and the spreader 14 is suspended via a suspension member 18 that includes a wire rope. The suspension member 18 extends from two positions of the crane trolley 13 that are arranged in the X direction, and the spreader 14 is hoisted by the suspension member 18 at the two positions that are arranged side by side in the X direction.

[0042] The spreader 14 is a hoisting device for suspending the container C. For example, the spreader 14 is in a rectangular shape that extends in the X direction. The spreader 14 is able to lock the container C from above, and loads and unloads the container C by locking and hoisting the container C. For example, the operation of the spreader 14 is controlled by driving of the traverse motor and the drum driving motor described above, which is controlled by the crane control system 100.

[0043] The traveling portions 15A, 15B are mechanisms that travel on a straight traveling path of the RTG crane 10. The RTG crane 10 is provided with a pair of traveling portions 15A, 15B that are disposed below each of the leg portions 11 at both end sides in the Y direction. Each of the traveling portions 15A, 15B is provided with a connection member 21 that connects the leg portions 11 that are separated from each other in the X direction, and a plurality of wheel units 22 that are disposed on the lower side of the connection member 21. One wheel unit 22 is provided at each of both ends of the connection member 21 in the X direction. The wheel unit 22 is provided with a plurality of wheels 23 and a wheel support portion 24 that supports the wheels 23. The wheel support portion 24 supports a pair of wheels 23 that are arranged in the Y direction, and supports the pair of wheels 23 in two sets in a state of being arranged in the X direction. In addition, the number of wheels 23 that one wheel unit 22 has and the number of wheel units 22 that the traveling portion 15A, 15B has are not particularly limited.

[0044] The RTG crane 10 is provided with a travel position detection unit 26 to enable straight travel on the travel path. The travel position detection unit 26 detects the travel position of the RTG crane 10 in the Y direction with respect to the travel path. The travel position detection unit 26 is provided on the lower surface side of the travel unit 15A to detect a guide line 27 provided on the ground of the travel path in a straight line shape along the X direction. For example, the guide line 27 is configured to include a magnet, and the travel position detection unit 26 is configured by a sensor that detects the magnetic force. For example, when the travel unit 15A travels straight in the X direction without deviation in the Y direction with respect to the travel path, the magnetic force detected by the travel position detection unit 26 is constant. In contrast, in the case where the travel unit 15A deviates in the Y direction with respect to the travel path, or the travel direction is inclined with respect to the travel path, or the like, the magnetic force detected by the travel position detection unit 26 varies. Thus, the deviation of the travel position of the RTG crane 10 can be detected from the detection result of the travel position detection unit 26.

[0045] Figure 4 is a schematic plan view for illustrating the relationship between the RTG crane 10 and the travel paths RDA, RDB of the RTG crane 10. As shown in Figure 4 , the travel unit 15A on one side in the Y direction travels on the travel path RDA. The travel unit 15B on the other side in the Y direction travels on the travel path RDB. Thus, by the travel unit 15A traveling straight on the travel path RDA and the travel unit 15B traveling straight on the travel path RDB, the RTG crane 10 travels in a direction parallel to the X direction. In the following description, the directions in the absolute coordinates based on the travel paths RDA, RDB are described using the X direction and the Y direction, and sometimes the direction in which the RTG crane 10 travels is referred to as the "travel direction D1". Also, sometimes the horizontal direction orthogonal to the travel direction D1 is referred to as the "lateral direction D2" of the RTG crane 10. Also, sometimes the direction orthogonal to the travel direction D1 and the lateral direction D2 is referred to as the "vertical direction D3".

[0046] The travel path RDA extends straight in the X direction on one end portion side in the Y direction of the RTG crane 10 and at a position adjacent to one side in the Y direction of the bay B of the container C. The travel path RDB extends straight in the X direction on the other end portion side in the Y direction of the RTG crane 10 and at a position adjacent to the other side in the Y direction of the bay B of the container C. A truck lane can be arranged on the other side in the Y direction of the bay B of the container C. Each of the travel paths RDA, RDB is set to be slightly wider than the size of the lateral direction D2 of the travel units 15A, 15B. Among them, as Figure 4As shown, the side in the travel direction D1 is set as "toward A1", and the other side is set as "toward A2". At this time, the travel sections 15A, 15B are able to travel toward the toward A1. At this time, the toward A1 corresponds to the advancing side in the travel direction D1 of the travel sections 15A, 15B. Also, the travel sections 15A, 15B are able to travel toward the toward A2. At this time, the toward A2 corresponds to the advancing side in the travel direction D1 of the travel sections 15A, 15B.

[0047] The RTG crane 10 is provided with detection sections 30 installed to the RTG crane 10. The detection sections 30 detect an object present on the advancing side in the travel direction of the RTG crane 10. In the present embodiment, the detection sections 30 are composed of detection sections 30A, 30B, 30C, 30D provided at four positions. When the travel sections 15A, 15B travel with the toward A1 as the advancing side, the detection sections 30A, 30B detect an object present on the advancing side of the travel sections 15A, 15B in the travel direction D1. The detection sections 30A, 30B are installed to the toward A1 side of the travel sections 15A, 15B with respect to the crane main girder 12. The detection sections 30A, 30B detect an object present within detection target regions DEA, DEB extending along the advancing side (toward A1 side) in the travel direction D1. The detection target regions DEA, DEB are set so as to be able to detect an object present at a place where the travel sections 15A, 15B are scheduled to pass (i.e., on the travel paths RDA, RDB within a prescribed distance range on the toward A1 side as viewed from the travel sections 15A, 15B).

[0048] When the travel sections 15A, 15B travel with the toward A2 as the advancing side, the detection sections 30C, 30D detect an object present on the advancing side of the travel sections 15A, 15B in the travel direction D1. The detection sections 30C, 30D are installed to the toward A2 side of the travel sections 15A, 15B with respect to the crane main girder 12. The detection sections 30C, 30D detect an object present within detection target regions DEC, DED extending along the advancing side (toward A2 side) in the travel direction D1. The detection target regions DEC, DED are set so as to be able to detect an object present at a place where the travel sections 15A, 15B are scheduled to pass (i.e., on the travel paths RDA, RDB within a prescribed distance range on the toward A2 side as viewed from the travel sections 15A, 15B).

[0049] Each of the detection sections 30A, 30B, 30C, 30D has a detection device 40. The number of detection devices 40 possessed by each of the detection sections 30A, 30B, 30C, 30D is not particularly limited. However, the detection device 40 involved in the present embodiment is able to ensure a high angular resolution without using triangulation using two radar devices or the like. Therefore, each of the detection sections 30A, 30B, 30C, 30D can have one detection device 40.

[0050] Next, the configuration of the detection device 40 will be described with reference to Figure 5 The configuration of the detection device 40 will be described. In the present embodiment, the detection device will be described taking a radar device that detects a distance to an object by an electric wave as an example. Figure 5 is a view that shows the detection device 40 according to the present embodiment. As shown in Figure 5 The detection device 40 is configured by providing elements or wiring on a substrate 50. Figure 5 is a view of the detection device 40 as viewed from the outside of the running portion 15 in the running direction D1. The detection device 40 according to the present embodiment is a MIMO (Multiple Input Multiple Output) radar that employs a MIMO technology using a plurality of antennas on the transmission side and the reception side. The detection device 40 is provided with a first sensor 45A, a second sensor 45B, a third sensor 45C, a fourth sensor 45D, and an angle resolution processing portion 46. Note that the "first sensor" in the claims indicates a sensor that detects a larger angle than the "second sensor", and the "second sensor" indicates a sensor that detects a smaller angle than the "first sensor". Therefore, the "first sensor" in the claims does not mean only the first sensor 45A of the embodiment, and the "second sensor" in the claims does not mean only the second sensor 45B of the embodiment. For example, if the first sensor 45A is regarded as the "first sensor", the sensors 45B, 45C, and 45D all correspond to the "second sensor". In the case where the second sensor 45B is regarded as the "first sensor", the sensors 45C and 45D both correspond to the "second sensor".

[0051] Reference will be made to Figure 6 The configuration of the first sensor 45A will be described. The first sensor 45A is provided with a plurality of transmission antennas 41 and a plurality of reception antennas 42. The plurality of transmission antennas 41 are antennas that transmit an electric wave (millimeter wave) to the front. The plurality of reception antennas 42 are antennas that receive an electric wave reflected by an object. For the sake of description, the first sensor 45A has a transmission antenna 41 identified as "Tx1", a transmission antenna 41 identified as "Tx2", and a transmission antenna 41 identified as "Tx3". The first sensor 45A has a reception antenna 42 identified as "Rx1", a reception antenna 42 identified as "Rx2", a reception antenna 42 identified as "Rx3", and a reception antenna 42 identified as "Rx4".

[0052] The first sensor 45A is a sensor of a frequency continuous modulation system. The first sensor 45A is a radar that transmits an electric wave modulated in a manner such that the frequency of the transmission wave of the transmission antenna 41 is continuously changed with the passage of time, that is, a chirp. The first sensor 45A generates an intermediate frequency signal (IF signal) from the frequency difference between the transmission chirp of the transmission antenna 41 and the reception chirp (wave returned after reflection from an object), and calculates the distance to the object by measuring the frequency of the IF signal.

[0053] In the present embodiment, the transmission antenna 41 transmits a millimeter wave as an electric wave. The millimeter wave is set to an electric wave including a frequency bandwidth from the quasi-millimeter wave region to about 100 GHz. In addition, the quasi-millimeter wave is a frequency bandwidth of less than 33 GHz, and is sometimes referred to as a microwave.

[0054] The first sensor 45A has n transmission antennas 41 and m reception antennas 42. In the present embodiment, the number of transmission antennas 41 is "n = 3". The number of reception antennas 42 is "m = 4". However, the number of transmission antennas 41 and reception antennas 42 is not particularly limited. As the transmission antenna 41 and reception antenna 42, a microstrip antenna is employed. The patch type transmission antenna 41 and reception antenna 42 have an antenna element 51 composed of a flat plate pattern. In the present embodiment, the transmission antenna 41 and reception antenna 42 are arranged in the same plane. Figure 6 In the example shown in the drawing, the transmission antenna 41 has a plurality of (5) antenna elements 51 connected in series and arranged in the up-down direction D3. The reception antenna 42 has a plurality of (3) antenna elements 51 connected in series and arranged in the up-down direction D3. However, the number of antenna elements 51 of the transmission antenna 41 and reception antenna 42 is not limited, and can be one. Also, the transmission antenna 41 and reception antenna 42 are not limited to a microstrip antenna, and other types of antennas can be employed.

[0055] Here, the distance between the antennas will be described. The m reception antennas 42 are arranged at a distance d apart from each other in the lateral direction D2. The reception antennas 42 of "Rx1", "Rx2", "Rx3", and "Rx4" are arranged in this order from one side in the lateral direction D2. The n transmission antennas 41 are arranged at a distance md apart from each other in the lateral direction D2, where md is the distance d multiplied by the number of reception antennas 42 (m). In the present embodiment, m = 4, so the distance apart becomes 4d. The transmission antennas 41 are arranged at positions separated downward from the reception antennas 42. The transmission antennas 41 of "Tx1", "Tx2", and "Tx3" are arranged in this order from one side in the lateral direction D2.

[0056] Next, reference will be made to Figure 7 The relationship between the transmission antenna 41 and reception antenna 42 will be described. Figure 7 is a model diagram for explaining the relationship between the transmission antenna 41 and reception antenna 42, and is the same asFigure 6 The transmitting antenna 41 and the receiving antenna 42 are positioned differently, with the receiving antenna 42 located at a position separated from the transmitting antenna 41 by a lateral distance D2. Additionally, the first sensor 45A can be adopted as follows: Figure 7 The configuration shown. Figure 7 The upper layer represents the actual antenna configuration. However, the electromagnetic absorbing walls are omitted in the upper layer diagram. Figure 7 The lower layer represents a virtual antenna configuration. Furthermore, the m (four) receiving antennas 42 are referred to as antenna group SG1. If the transmitting antenna 41 of "Tx1" emits a radio wave, then each receiving antenna 42 of antenna group SG1 receives the reflected wave. Additionally, the combination where the transmitting antenna 41 of "Tx1" emits a radio wave and the receiving antenna 42 of "Rx1" receives the reflected wave is called "Tx1→Rx1". Similarly, if the transmitting antenna 41 of "Tx1" emits a radio wave, then the receiving antennas 42 of "Rx2", "Rx3", and "Rx4" also receive the reflected wave. Therefore, combinations of "Tx1→Rx2", "Tx1→Rx3", and "Tx1→Rx4" exist.

[0057] If the transmitting antenna 41 of “Tx2” in the upper diagram emits radio waves, then each receiving antenna 42 of antenna group SG1 receives the reflected waves. Therefore, there are combinations of “Tx2→Rx1”, “Tx2→Rx2”, “Tx2→Rx3”, and “Tx2→Rx4”. As shown in the lower diagram, a virtual antenna group SG2 with the same structure as antenna group SG1 is set to the right of antenna group SG1. The distance between the rightmost receiving antenna 42 of antenna group SG1 (“Rx4”) and the leftmost receiving antenna 42 of virtual antenna group SG2 (“Rx1”) is set as the antenna spacing d of antenna group SG1. Here, the distance 4d between the transmitting antenna 41 of “Tx1” and the transmitting antenna 41 of “Tx2” is the distance d between the receiving antennas 42 of antenna group SG1 multiplied by the distance of the number of receiving antennas 42 (four). Therefore, in the combinations of "Tx2→Rx1", "Tx2→Rx2", "Tx2→Rx3", and "Tx2→Rx4", the receiving angle of the receiving antenna 42 of antenna group SG1 receiving the reflected wave is the same as the receiving angle of the transmitting antenna 41 of "Tx1" in the combinations of "Tx1→Rx1", "Tx1→Rx2", "Tx1→Rx3", and "Tx1→Rx4" of the virtual antenna group SG2. Therefore, the combination of the transmitting antenna 41 of "Tx2" and antenna group SG1 is equivalent to the combination of the transmitting antenna 41 of "Tx1" and the virtual antenna group SG2.

[0058] To the right of the virtual antenna group SG2, a virtual antenna group SG3 is also set up. In this case, in the combinations of "Tx3→Rx1", "Tx3→Rx2", "Tx3→Rx3", and "Tx3→Rx4", the receiving angle of the receiving antenna 42 of antenna group SG1 receiving the reflected wave is the same as the receiving angle of the transmitting antenna 41 of "Tx1" and the virtual antenna group SG3 in the combinations of "Tx1→Rx1", "Tx1→Rx2", "Tx1→Rx3", and "Tx1→Rx4". Therefore, the combination of the transmitting antenna 41 of "Tx3" and antenna group SG1 is equivalent to the combination of the transmitting antenna 41 of "Tx1" and virtual antenna group SG3. Thus, by setting the antenna spacing as shown in the upper diagram, as shown in the lower diagram, it is possible to obtain performance equivalent to receiving radio waves from the transmitting antenna 41 of "Tx1" by "n×m" (here, 12) receiving antennas 42. That is, by using "n+m" antennas, it is possible to achieve the same performance as using "1+n×m" antennas. Even in Figure 6 In the configuration shown, the distances between the four receiving antennas 42 corresponding to the transmitting antenna 41 of "Tx1", the distances between the four receiving antennas 42 corresponding to the transmitting antenna 41 of "Tx2", and the distances between the four receiving antennas 42 corresponding to the transmitting antenna 41 of "Tx3" are different from each other. Therefore, equivalent performance to that obtained when receiving with "n×m" (12 in this case) receiving antennas 42 can be achieved.

[0059] like Figure 8 As shown, in the first sensor 45A, an electromagnetic wave absorbing wall 60 (limiting mechanism) for absorbing electromagnetic waves is provided on the transmitting antenna 41. The electromagnetic wave absorbing wall 60 functions as a limiting member that limits the emission range of electromagnetic waves. In this embodiment, the electromagnetic wave absorbing wall 60 has a first portion 62A relative to the transmitting antenna 41 "Tx1", a second portion 62B relative to the transmitting antenna 41 "Tx2", and a third portion 62C relative to the transmitting antenna 41 "Tx3". Each portion 62A, 62B, and 62C of the electromagnetic wave absorbing wall 60 has an opening 61 that allows electromagnetic waves emitted from the antenna element 51 of the transmitting antenna 41 to be emitted. The openings 61 of each portion 62A, 62B, and 62C are shown in the front view ( Figure 6 In the view shown, multiple antenna elements 51 of each transmitting antenna 41 are surrounded together. Since multiple antenna elements 51 are arranged in the vertical direction D3, the opening 61 has a shape that has a length direction along the vertical direction D3.

[0060] like Figure 8As shown, each of the portions 62A, 62B, 62C of the electric wave absorbing wall 60 has a side wall portion 64 protruding from the substrate 50 toward the traveling direction Dl, and an end wall portion 66 separated from the substrate 50 toward the traveling direction Dl and facing the substrate 50. A reference line SL2 orthogonal to the substrate 50 is set with respect to the central position of the antenna element 51 of the transmission antenna 41. A pair of side wall portions 64 is provided on both sides in the lateral direction D2 of the reference line SL2. The end wall portion 66 is provided so as to extend from the front end portions of the pair of side wall portions 64 toward the lateral direction D2. In the present embodiment, the end wall portion 66 is inclined from the front end portions of the side wall portions 64 in a manner to move away from the antenna element 51 in the traveling direction Dl as it approaches the reference line SL2. In the end wall portion 66, the opening 61 is formed in the vicinity of the reference line SL2. The electric wave W from the antenna element 51 is restricted by the end wall portion 66 at portions other than the opening 61, and is emitted to the outside only from the opening 61. The boundaries LMl, LM2 of the electric wave emission range are defined by lines passing through the both side edge portions of the opening 61 from the central position of the antenna element 51. The boundaries LMl, LM2 are inclined with respect to the reference line SL2 in a manner to expand along the lateral direction D2 as they move away from the antenna element 51. Further, in the present embodiment, the side wall portions 64, the end wall portion 66, and the opening 61 have a left-right symmetrical structure with the reference line SL2 as a reference. Further, the material of the electric wave absorbing wall 60 is not particularly limited as long as it can absorb electric waves, and for example, the electric wave absorbing wall 60 can be configured by adhering an electric wave absorbing sheet to the outside of a resin material. Meanwhile or instead, the electric wave absorbing wall 60 can have a shell-like structure, and can accommodate a liquid that absorbs electric waves in the inside. As the liquid, water or the like can be used. Further, the electric wave absorbing wall 60 can have a solid and solid structure.

[0061] As described above, the electric wave emission angle range of the transmission antenna 41 can be restricted to a range "Qlimit = arcsin (A / (2d))" or less, at which the aliasing phenomenon does not occur, by the electric wave absorbing wall 60. Further, "d" is the antenna interval of the reception antenna 42 (refer to FIG. 2). Figure 6 By making the antenna interval d larger than A / 2, the first sensor 45A can have an angle resolution that exceeds the angle resolution Qres = 2 / N (N: number of antennas) when the antenna interval d is A / 2.

[0062] Returning to Figure 5The structure of the detection device 40 will be described in more detail. The detection device 40 has the first sensor 45A, the second sensor 45B, the third sensor 45C, and the fourth sensor 45D in this order from the lower side. The centers of the respective sensors 45A, 45B, 45C, and 45D in the lateral direction D2 are aligned with each other. However, the centers can not be completely coincident, and can be offset in the lateral direction D2. Also, the first sensor 45A, the second sensor 45B, the third sensor 45C, and the fourth sensor 45D can be arranged in this order from the upper side. The substrates 50 of the respective sensors 45A, 45B, 45C, and 45D are separate independent bodies from each other. However, all or a part of the respective sensors 45A, 45B, 45C, and 45D can use a common substrate 50.

[0063] The detection device 40 uses the sensor 45 having a wider detection angle at a close distance, and uses a sensor having a smaller detection angle but a better angle resolution than the sensor 45 at a far distance (refer to FIG. 6). Figure 9 The adjustment of the angle resolution is made in accordance with the distance between the virtual receiving antennas, and the sensor 45 having a higher angle resolution at the far distance side makes the antenna pitch longer. The detection angle of the n+1 sensor 45 is smaller than the detection angle of the n sensor 45. Also, the pitch of the transmission antennas 41 in the n+1 sensor 45 is wider than the pitch of the transmission antennas 41 in the n sensor 45. The pitch of the receiving antennas 42 in the n+1 sensor 45 is wider than the pitch of the receiving antennas 42 in the n sensor 45. Specifically, the detection angle of the second sensor 45B is smaller than the detection angle of the first sensor 45A. Also, the pitch of the transmission antennas 41 in the second sensor 45B is wider than the pitch of the transmission antennas 41 in the first sensor 45A. The pitch of the receiving antennas 42 in the second sensor 45B is wider than the pitch of the receiving antennas 42 in the first sensor 45A. The detection angle of the third sensor 45C is smaller than the detection angle of the second sensor 45B. Also, the pitch of the transmission antennas 41 in the third sensor 45C is wider than the pitch of the transmission antennas 41 in the second sensor 45B. The pitch of the receiving antennas 42 in the third sensor 45C is wider than the pitch of the receiving antennas 42 in the second sensor 45B. The detection angle of the fourth sensor 45D is smaller than the detection angle of the third sensor 45C. Also, the pitch of the transmission antennas 41 in the fourth sensor 45D is wider than the pitch of the transmission antennas 41 in the third sensor 45C. The pitch of the receiving antennas 42 in the fourth sensor 45D is wider than the pitch of the receiving antennas 42 in the third sensor 45C. In addition, the structures of the sensors 45B, 45C, and 45D are the same as those of the first sensor 45A described in Figure 6 the first embodiment, except for the difference in the pitch of the transmission antennas 41 and the pitch of the receiving antennas 42. Here, the pitch indicates the distance between the antennas in the lateral direction D2.

[0064] The angle decomposition processing unit 46 acquires the detection results of each sensor 45A, 45B, 45C, and 45D and performs angle decomposition processing. The angle decomposition processing unit 46 uses each sensor 45A, 45B, 45C, and 45D separately according to the distance from the detection device 40. For example... Figure 9 As shown, the angle resolution processing unit 46 defines a range of a predetermined distance and a predetermined width in front of the detection device 40 as the detection target area DE. Furthermore, the angle resolution processing unit 46 defines a range of a predetermined distance in front of the detection device 40 and a predetermined width wider than the detection target area DE as the non-detection target area NDE. Specifically, the detection target area DE is, for example, defined as a range of 30m from the detection device 40 and ±1m in width. The non-detection target area NDE is the outer region of 30m from the detection device 40 and ±1.3m in width. When the angle resolution processing unit 46 detects an object within the detection target area DE, it determines "detected"; when it detects an object within the non-detection target area NDE, or when it does not detect an object, it determines "not detected".

[0065] like Figure 9 As shown, the first sensor 45A has a detection object area AE1. The second sensor 45B has a detection object area AE2. The third sensor 45C has a detection object area AE3. The fourth sensor 45D has a detection object area AE4.

[0066] like Figure 10 As shown, when the maximum detection angle of the first sensor 45A in the horizontal direction is less than ±90 degrees, a blind spot (marked by the shaded line) occurs within the detection target area AE1, extending beyond (90 degrees - maximum detection angle) degrees to the left and right of the first sensor 45A. The maximum detection angle θ of the first sensor 45A is set with this blind spot as the allowable range. With the allowable distance for the blind spot set to 1.42m, the relationship between the maximum detection angle θ and the allowable distance is "tanθ = 1 / 1.42", therefore, the maximum detection angle θ of the first sensor 45A becomes 0.613 (rad) (35.1 degrees). Since the relationship between the antenna spacing d (the distance between the receiving antennas 42) and the maximum detection angle θmax is "θmax = sinθmax", the maximum detection angle θmax is determined by the relationship between the antenna spacing d (the distance between the receiving antennas 42) and the maximum detection angle θmax. -1 (λ / 2d)”, therefore, when the maximum detection angle θmax is 35.1 degrees, the antenna spacing d is “d=λ / 2×sin(θmax)=λ / 1.15”.

[0067] The relationship between the number of antennas, antenna spacing d, and angular resolution θres of the first sensor 45A is "θres=λ / Nd". Here, when the number of virtual receiving antennas for the first sensor 45A (d=λ / 1.15) is set to 16, the angular resolution becomes "θres=λ / (16×λ / 1.15)=0.0719(rad)=4.12 degrees". For example... Figure 9 As shown, with an angular resolution of 4.12 degrees, the detection distance limit is approximately 3.8 meters when identifying objects at 1m and 1.3m along the horizontal axis D2. The angular resolution is determined by "the angle θ2 of the object at 1m along the horizontal axis D2 - the angle θ1 of the object at 1.3m along the horizontal axis D2". Therefore, the angular resolution of the first sensor 45A is "atan(1 / 3.8) - atan(1.3 / 3.8) = 4.14 degrees".

[0068] To identify objects at a detection distance exceeding 3.8m from the first sensor 45A, the second sensor 45B requires a higher angular resolution than the first sensor 45A. Therefore, a second sensor 45B with an angular resolution approximately twice that of the first sensor 45A is prepared. When the antenna spacing d of the second sensor 45B is set to λ / 0.6, the angular resolution becomes "θres = λ / (16 × λ / 0.6) = 0.0375 (rad) = 2.15 degrees". At this angular resolution of 2.15 degrees, the detection distance limit for identifying objects at 1m and 1.3m along the horizontal direction D2 is approximately 7.8m.

[0069] To identify objects at a detection distance exceeding 7.8m of the second sensor 45B, the third sensor 45C requires a higher angular resolution than the second sensor 45B. Therefore, a third sensor 45C with an angular resolution approximately twice that of the second sensor 45B is prepared. When the antenna spacing d of the third sensor 45C is set to λ / 0.3, the angular resolution is "θres=λ / (16×λ / 0.3)=0.0188(rad)=1.07 degrees". At an angular resolution of 1.07 degrees, the detection distance limit for identifying objects at 1m and 1.3m along the horizontal direction D2 is approximately 15.9m.

[0070] To identify objects at a detection distance exceeding 15.9m of the third sensor 45C, the fourth sensor 45D requires a higher angular resolution than the third sensor 45C. Therefore, a fourth sensor 45D with an angular resolution approximately twice that of the third sensor 45C is prepared. When the antenna spacing d of the fourth sensor 45D is set to λ / 0.15, the angular resolution becomes "θres = λ / (16 × λ / 0.15) = 0.0938 (rad) = 0.54 degrees". With an angular resolution of 0.54 degrees, objects at a distance of approximately 31.7m and at a distance of 1m and 1.3m along the horizontal axis D2 can be identified.

[0071] like Figure 11 As shown, when attempting to detect objects A and B located further to the right of the sensor's front, at different angles at the same distance, the data processing of the angle FFT in sensors 45A, 45B, 45C, and 45D is explained. Furthermore, the angle θ of object A is... A Set the angle θ of object B to 5 degrees. B The angle is set to 22 degrees. As a general method of angle FFT, the angle decomposition processing unit 46 first determines whether objects A and B are located on the right or left based on the polarity of the imaginary part of the angle FFT result in each sensor 45A, 45B, 45C, and 45D. Here, since objects A and B are only located on the right, the explanation of this signal processing method is omitted.

[0072] Here, the angle decomposition processing unit 46 determines a virtual image from the (n+1)th waveform detected by the (n+1)th sensor 45 based on the nth waveform detected by the nth sensor 45, and performs correction by deleting the (n+1)th waveform determined to be a virtual image. Specifically, when the detection device 40 measures the above... Figure 11 In the case of objects A and B shown, such as Figure 12 As shown, the angle decomposition processing unit 46 obtains the angle FFT results of the first sensor 45A and the second sensor 45B. In the first sensor 45A, within an angle range smaller than ±35.1 degrees corresponding to the Nyquist frequency, a waveform WA corresponding to object A is generated at a position of 5 degrees, and a waveform WB corresponding to object B is generated at a position of 22 degrees. In the first sensor 45A, the emission is limited by the electromagnetic wave absorption wall 60 to an angle smaller than ±35.1 degrees corresponding to the Nyquist frequency. Therefore, aliasing does not occur.

[0073] On the other hand, in the measurement result of the second sensor 45B, the wave form WA corresponding to the object A is generated at a position of 5 degrees in an angle range smaller than ±17.5 degrees corresponding to the Nyquist frequency. In an angle range larger than ±17.5 degrees corresponding to the Nyquist frequency, an aliasing phenomenon caused by the wave form WB corresponding to the object B is generated at a position of 22 degrees. The signal processing target range PA of the second sensor 45B is a range of ±17.5 degrees or less than the Nyquist frequency. Since the angle of the object B is 22 degrees (17.5 + 4.5 degrees), the wave form FWB of the virtual image corresponding to the object B is generated at a position of -13 degrees (-17.5 + 4.5 degrees).

[0074] In this regard, the angle resolution processing section 46 refers to the angle FFT of the measurement result of the first sensor 45A and grasps that no object is detected in the vicinity of the position of -13 degrees. Therefore, the angle resolution processing section 46 judges that the wave form FWB around -13 degrees in the angle FFT of the measurement result of the second sensor 45B is a virtual image, deletes the data of the corresponding wave form FWB, and acquires the angle FFT relating to the signal processing result of the second sensor 45B. In the processed angle FFT, only the wave form WA is shown in an angle range of ±17.5 degrees. Thus, the angle resolution processing section 46 can detect the object A by the second sensor 45B.

[0075] Further, in the measurement result of the third sensor 45C, the wave form WA corresponding to the object A is generated at a position of 5 degrees in an angle range smaller than ±8.75 degrees corresponding to the Nyquist frequency. Since the position of 22 degrees is limited by the wave absorbing wall 60, the wave form WB corresponding to the object B is not generated. The signal processing target range PA of the third sensor 45C is a range of ±8.75 degrees or less than the Nyquist frequency. Since the angle of the object A is 5 degrees (8.75 - 3.75 degrees), the wave form FWA of the virtual image corresponding to the object A is generated at a position of -12.5 degrees (-8.75 - 3.75 degrees).

[0076] In this case, the angle resolution processing section 46 refers to the angle FFT of the measurement result of the second sensor 45B and grasps that no object is detected in the vicinity of -12.5 degrees. Therefore, the angle resolution processing section 46 judges that the waveform FWA around -12.5 degrees in the angle FFT of the measurement result of the third sensor 45C is a virtual image, deletes the data of the corresponding waveform FWA, and acquires the angle FFT related to the signal processing result of the second sensor 45B. In the angle FFT after the processing, only the angle range of ±8.75 degrees and the waveform WA are shown. Thus, the angle resolution processing section 46 can detect the object A by the third sensor 45C. Even in the case where the signal processing result of the fourth sensor 45D is obtained, the angle resolution processing section 46 performs the same processing with reference to the angle FFT of the measurement result of the third sensor 45C.

[0077] Here, in each of the sensors 45B, 45C, 45D other than the first sensor 45A on the close distance side, it is necessary to physically limit the emission by the wave-absorbing wall 60 in a range of twice or more the Nyquist frequency (refer to the range of RG of Figure 12 In addition to this, as shown by the second sensor 45B of Figure 12 , the wave-absorbing wall 60 can limit the emission range to a range of twice or less the Nyquist frequency and more the Nyquist frequency in the angle FFT of the second sensor 45B (refer to the range of RGX of Figure 12 ).

[0078] The nth sensor 45 can perform the output limitation so that the arrival distance of the electric wave becomes the detection distance of the (n+1)th sensor. The detection distance is the distance from the detection device 40 to the front end of the detection target region AE1, AE2, AE3, AE4. The arrival distance of the electric wave is the distance up to which the electric wave of the nth sensor 45 can arrive. The arrival distance is longer than the detection distance. Specifically, the measurement result of the first sensor 45A is used for the detection in the detection target region AE1 (up to 3.8 m) of the first sensor 45A and the comparison with the measurement result of the second sensor 45B. Therefore, the electric wave of the first sensor 45A does not need to arrive at the detection distance of the detection target region AE3 of the third sensor 45C. Therefore, the first sensor 45A can limit the output of the arrival distance of the electric wave to the detection distance of the second sensor 45B. Similarly, the second sensor 45B can limit the output of the arrival distance of the electric wave to the detection distance of the third sensor 45C. The third sensor 45C can limit the output of the arrival distance of the electric wave to the detection distance of the fourth sensor 45D.

[0079] Next, the effects of the RTG crane 10 and the detection device 40 according to the present embodiment will be described.

[0080] First, the detection device according to the comparative example will be described. In the detection device according to the comparative example, a single sensor is used, and the antenna interval is set to λ / 2 to enable reception of reflected waves from a range of -90 degrees to +90 degrees. For example, if a sensor with an antenna interval of λ / 2 is used to obtain an angle resolution of 0.54 degrees (0.0094 rad), it is possible to calculate that 214 receiving antennas are required according to "θres = 2 / N (θres: angle resolution, N: number of antennas)". Thus, the required calculation resources for signal processing become very large. Also, in applications using a millimeter wave radar, even in a case where the detection range of an obstacle is a narrow angular range in front, since an electric wave is emitted over a wide range of -90 degrees to +90 degrees, in a case where an object with a large reflectance such as a container exists outside the detection range, it is sometimes difficult to detect an object with a small reflectance in the detection range due to the influence of the object with a large reflectance.

[0081] In contrast, in the detection device 40 according to the present embodiment, the detection angle of the (n+1)th sensor 45 (first sensor) is smaller than the detection angle of the nth sensor (second sensor). A distant position can be detected in a small angular range. Thus, the angular range of the (n+1)th sensor 45 can be smaller than the angular range of the nth sensor. On the other hand, a close position can be detected using a low angle resolution, but a distant position needs to be detected with a high angle resolution. In contrast, the interval of the transmission antennas 41 in the (n+1)th sensor 45 is wider than the interval of the transmission antennas 41 in the nth sensor. Also, the interval of the reception antennas 42 in the (n+1)th sensor is wider than the interval of the reception antennas 42 in the nth sensor. The (n+1)th sensor 45 can obtain a higher angle resolution than the nth sensor due to the wide interval of the antennas. Thus, for a distant position, the detection device 40 improves the detection performance by obtaining a higher angle resolution with the (n+1)th sensor 45, and can detect with a low calculation load since the angular range is small. For a close position, the detection device 40 can detect with a low calculation load by ensuring a wide angular range with the nth sensor 45 while suppressing the angle resolution. Thus, the object detection performance can be improved while reducing the calculation load.

[0082] The detection device 40 also has an angle resolution processing section 46 that performs angle resolution processing on the detection results of the nth sensor 45 and the (n+1)th sensor 45. The angle resolution processing section 46 can determine a ghost image that is generated by aliasing from the 2nd waveform detected by the (n+1)th sensor 45 based on the 1st waveform detected by the nth sensor 45, and perform correction that deletes the 2nd waveform determined to be a ghost image generated by aliasing. At this time, the angle resolution processing section 46 can delete the waveform of the ghost image from the 2nd waveform even without performing complex calculations.

[0083] The transmission antenna 41 of the nth sensor 45 and the (n+1)th sensor 45 can also have a restriction mechanism that restricts the range of emission of the electric wave. At this time, the range of emission of the electric wave of the transmission antenna 41 can be easily adjusted by the restriction mechanism.

[0084] The restriction mechanism can restrict the range of emission to be twice or less the Nyquist frequency and the Nyquist frequency or more in the angle FFT of the (n+1)th sensor 45. At this time, by suppressing the transmission of the electric wave in an unnecessary wide range, unnecessary reflection caused by containers and the like on both sides of the travel path can be suppressed.

[0085] The nth sensor 45 can perform output restriction so that the distance of arrival of the electric wave is the detection distance of the (n+1)th sensor 45. In this way, by suppressing the distance of arrival of the electric wave of the nth sensor 45 to the required distance, unnecessary reflection caused by containers and the like on both sides of the travel path can be suppressed.

[0086] The RTG crane 10 according to the present embodiment is a mobile body that has the detection device 40 and travels on a travel path, and the detection device 40 has the above-described structure. According to the RTG crane 10, the same effects and advantages as the detection device 40 described above can be achieved.

[0087] The present application is not limited to the above-described embodiments.

[0088] In the above-described embodiments, the RTG crane is exemplified as the mobile body, but the present application is not limited thereto. For example, the mobile body can be a crane other than the RTG crane, or a shovel, a forklift, a transport trolley, or the like.

[0089] In the above-described embodiments, the electric wave absorbing wall is exemplified as the restriction member that restricts the range of emission of the electric wave, but the present application is not limited thereto. For example, the restriction member can be a waveguide antenna that restricts the range of emission of the electric wave (for example, refer to Figure 13 ).

[0090] In the above-described embodiments, a plurality of sensors 45 can be provided on one substrate 50 instead of one sensor 45 provided on one substrate 50. For example, as shown in FIG. 9, a plurality of sensors 45 can be provided on one substrate 50.Figure 13 The third sensor 45C shown in (a) is provided on the substrate 50 alone. Figure 13 The fourth sensor 45D shown in (b) is provided on the substrate 50 alone. Figure 13 The circuit of the third sensor 45C and the circuit of the fourth sensor 45D are provided on the substrate 50 shown in (c) at the same time. Figure 13 On the substrate shown in (c), the antenna of the third sensor 45C and the antenna of the fourth sensor 45D are arranged at positions shifted from each other so as not to interfere with each other. Figure 13 In the present embodiment, a structure in which the emission range is limited by the waveguide antenna is exemplified, but the sensor shown in (b) can be mounted on one substrate 50 together with the sensor shown in (a). Figure 5 In the present embodiment, a structure in which the emission range is limited by the waveguide antenna is exemplified, but the sensor shown in (b) can be mounted on one substrate 50 together with the sensor shown in (a).

Claims

1. A detection device, wherein a first sensor and a second sensor that detect a distance to an object by radio waves are provided, the first sensor and the second sensor each have a plurality of transmission antennas that transmit the radio waves and a plurality of reception antennas that receive reflected radio waves, a detection angle of the second sensor is smaller than a detection angle of the first sensor, a pitch of the transmission antennas in the second sensor is wider than a pitch of the transmission antennas in the first sensor, a pitch of the reception antennas in the second sensor is wider than a pitch of the reception antennas in the first sensor.

2. The detection device according to claim 1, wherein an angle resolution processing section that acquires detection results of the first sensor and the second sensor and performs angle resolution processing is further provided, the angle resolution processing section determines a virtual image from a first waveform detected by the first sensor from a second waveform detected by the second sensor, and performs correction that deletes the second waveform determined as the virtual image.

3. The detection device according to claim 1, wherein a restriction mechanism that restricts an emission range of the radio waves is further provided in the transmission antennas of the first sensor and the second sensor.

4. The detection device according to claim 3, wherein the restriction mechanism restricts the emission range to be not lower than a Nyquist frequency and twice or less the Nyquist frequency in an angle FFT of the second sensor.

5. The detection device according to claim 1, wherein the first sensor limits an output so that a distance of arrival of the radio waves becomes a detection distance of the second sensor.

6. A mobile body that travels on a travel path and is provided with a detection device, wherein the detection device is provided with a first sensor and a second sensor that detect a distance to an object by radio waves, the first sensor and the second sensor each have a plurality of transmission antennas that transmit the radio waves and a plurality of reception antennas that receive reflected radio waves, a detection angle of the second sensor is smaller than a detection angle of the first sensor, a pitch of the transmission antennas in the second sensor is wider than a pitch of the transmission antennas in the first sensor, a pitch of the reception antennas in the second sensor is wider than a pitch of the reception antennas in the first sensor.

Images