Patent Publication Number: US-2019198985-A1

Title: Unmanned vehicle radar system

Description:
TECHNICAL FIELD 
     This embodiments described herein generally relate to unmanned vehicles, and in particular, the use of radar systems for guiding unmanned vehicles. 
     BACKGROUND 
     Unmanned vehicles are used in a variety of applications. For example, unmanned aerial vehicles (commonly referred to as “drones”) are increasingly used in a variety of recreational activities. Unmanned aerial vehicles are also used for a variety of commercial activities, including professional photography, mapping and delivery. Unmanned land vehicles are likewise increasingly used for cleaning, delivery and manufacturing. 
     One continuing issue with unmanned vehicles is the need for avoiding obstacles while moving. For example, unmanned aerial drones may need to avoid collisions with other flying objects, and may need to avoid stationary hazards such as trees, buildings and powerlines. Likewise, unmanned land vehicles may need to maneuver around both stationary and moving objects, including people. These unmanned land vehicles may also need to navigate through crowded buildings. In each case there is a need for the unmanned vehicle to locate and avoid potential obstacles while moving. 
     Furthermore, in many applications there is a need to provide such functionality without requiring excessive weight or power consumption. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an unmanned vehicle in accordance with an example embodiment; 
         FIG. 2  is a side view of a radar system in accordance with an example embodiment; 
         FIG. 3  is a cross-sectional side view of a radar system in accordance with an example embodiment; 
         FIG. 4  is a cross-sectional side view of a radar system in accordance with an example embodiment; 
         FIG. 5  is a side view of an unmanned aerial vehicle in accordance with an example embodiment; and 
         FIG. 6  is a side view of an unmanned aerial vehicle in accordance with an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments described herein provide radar systems for use on unmanned vehicles. The radar systems can be applied to a wide variety of unmanned vehicles, including unmanned aerial vehicles and unmanned land vehicles. For example, the radar systems can be applied to aerial vehicles commonly referred to as drones or multi-copters. The radar systems can also be applied to a variety of unmanned land vehicles, including ground based recreational or commercial vehicles. For example, the radar systems can be applied to automated delivery or cleaning devices. 
     In general, the unmanned vehicle includes a housing having at least one propulsion motor, a radar processing unit coupled to the body, and an antenna. In accordance with the embodiments described herein, the antenna includes an antenna body defining at least one transmitting waveguide and at least one receiving waveguide coupled to the radar processing unit. The antenna body is formed from plastic and includes metalized surface. In one embodiment, the antenna body is formed from 3-dimensional (3D) plastic printing. The metalized coating can then be applied to the surface of the antenna body, including the surfaces of the waveguides. 
     Turning now to  FIG. 1 , a schematic view of an unmanned vehicle  100  is illustrated. The unmanned vehicle  100  includes a vehicle housing  102 , a motor  104 , a radar processing unit  106 , and an antenna  108 . 
     The unmanned vehicle  100  can be any type of unmanned vehicle, including various types of unmanned aerial vehicles and unmanned land vehicles. Likewise, the housing  102  can be any type of suitable housing for the unmanned vehicle  100 . The motor  104  can be any type of suitable motor that can provide propulsion to the unmanned vehicle  100 . For example, the housing  102  and motor  104  can include a housing body and motor suitable for a multi-copter. In other examples, the housing  102  and motor  104  can include a housing body and motor suitable for a wheeled delivery drone. It should be noted that in many applications the unmanned vehicle  100  can include multiple motors  104 . Additionally, the unmanned vehicle  100  can include a variety of other features, including batteries, cameras, etc. 
     In accordance with the embodiments described herein, the unmanned vehicle  100  includes the radar processing unit  106  and the antenna  108 . In general, the antenna  108  includes an antenna body defining at least one transmitting waveguide and at least one receiving waveguide coupled to the radar processing unit  106 . Thus, during operation the radar processing unit  106  transmits and receives radar signals through the transmitting and receiving waveguides. The antenna  108  and its included waveguides thus define the field of view for the radar system. In one embodiment the antenna body is formed using 3-dimensional (3D) printing of plastic. In other embodiments the antenna body is molded using any suitable molding technique. Both 3D printing and molding can thus be used to define an antenna body with the waveguide structures needed for the desired radar field of view. When so constructed the radar processing unit  106  and antenna  108  can transmit and receive radar signals through the waveguides and use those signals to provide for navigation and obstacle avoidance in the unmanned vehicle  100 . 
     In one embodiment the antenna body has an exterior shape configured to provide semispherical field of view for radar signals generated by the radar processing unit and transmitted by the antenna body. In another embodiment the antenna body has an exterior shape configured to provide full spherical field of view. For example, the antenna body can have a semispherical or hemispherical shape exterior shape to provide such a partial or full field of view. In other embodiments the antenna body can have a partial or modified polyhedron shape to provide such a partial or full field of view. 
     In some applications multiple antennas  108  can be used on one unmanned vehicle  100 . For example, multiple antennas  108  with a semispherical field of view scan can be implemented together on the vehicle  100  and configured to provide a spherical field of view or 360 degree circular field of view around the unmanned vehicle  100 . 
     In one embodiment, a first antenna  108  is positioned on the top side of the housing  102 , while a second antenna  108  is positioned on the bottom side of housing  102 . Such a configuration can provide a full up and down view for an unmanned aerial vehicle. In another embodiment, a first antenna  108  is positioned on the left side of the housing  102 , while a second antenna  108  is positioned on the right side of housing  102 . Such a configuration can provide a full or nearly full 360 degree view for an unmanned land vehicle. 
     In one embodiment, the antenna body is formed together with other elements of the unmanned vehicle  100 . For example, the antenna body can be formed with or as part of the housing  102 . In this example, the antenna body, including the exterior shape and the transmitting and receiving waveguides can be formed with the same processes used to form the housing  102 . As one specific example, the housing  102  and the antenna body can be formed together using 3D printing. As another specific example, the housing  102  and the antenna body can be formed together using injection molding. In both cases the plastics used to define the exterior shape and the transmitting and receiving waveguides can be defined with the same processes used to define the shapes structures of the unmanned vehicle  100 . 
     Turning now to  FIG. 2 , a side view of an exemplary radar system  200  is illustrated. The radar system  200  includes a radar processing unit  206  and an antenna  208 . The radar system  200  is exemplary of the type of radar system that can be implemented on an unmanned vehicle, including pilotless aerial vehicles such as multi-copters. 
     The antenna  208  includes an antenna body  210  and a metalized surface  212 . The antenna body  210  defines a plurality of transmitting waveguides and a plurality of receiving waveguides coupled to the radar processing unit  206 . The transmitting waveguides are coupled to transmitting outputs (TX) and the receiving waveguides are coupled to receiving inputs (RX). The configuration of the waveguides and the distribution of the transmitting outputs (TX) and the receiving inputs (RX) determine the define the field of view of the radar system. The metalized surface  212  provides the conductivity needed for transmitting electromagnetic waves from the antenna  208 . 
     Again, the antenna body  210  can be 3D printed from any suitable plastic material. Likewise, the metalized surface  212  of the antenna body  210  can be metalized using suitable metallic materials and any suitable deposition or coating process. In other embodiments the antenna body is injection molded. The use of a plastic antenna body  210  having a metalized surface  212  and defining transmitting and receiving waveguides can provide the antenna  208  with a very low relative weight. Such a low weight is particularly important in unmanned aerial vehicles such as multi-copters and other types of drones. 
     Furthermore, the use of a 3D printed or injection molded plastic antenna body can provide an antenna body with the waveguide structures needed for the desired radar field of view. In the embodiment of  FIG. 2  the antenna body  210  has a partial polyhedron shape. This shape allows the different transmitting ports (TX) to transmit the radar signals in different directions. Likewise, the different receiving ports (RX) can receive the reflected radar signals from different directions. Taken together, the partial polyhedron shape can provide semispherical field of view for radar signals generated by the radar processing unit  206  and transmitted out the transmitting ports (TX) and received by the receiving ports (RX). 
     The radar processing unit  206  can include any suitable type of radar processing unit. Specifically, the radar processing unit  206  can include one or more packaged integrated circuits configured to generate and receive radar signals. In a typical embodiment the radar processing unit  206  can be configured to include multiple transmission channels and multiple receiver channels, and can thus facilitate multiple-input multiple-output (MIMO) radar operation. 
     As one specific example, the radar processing unit  206  can be implemented to provide a frequency-modulated continuous-wave (FMCW) radar. Such a radar can use an exemplary frequency band of 70-90 GHz and a chirp bandwidth of up to 2 GHz. Again, this is just one example and other implementations can also be used. 
     The radar processing unit  206  can include a variety of different circuits and devices to facilitate radar operation. For example, the radar processing unit  206  can include a variety of filters, analog-to-digital converters (ADCs), monitoring circuits, etc. In most applications it will be desirable to use a radar processing unit  206  with relatively low power requirements. 
     In typical embodiment the radar processing unit  206  will be implemented as a packaged integrated circuit. Such a packaged integrated circuit can use a variety of package lead technologies, including various types of pins, wire leads and ball grid arrays (BGAs). In such an example the package leads would provide the input and output interfaces for coupling to other devices on the unmanned vehicle. Additionally, the package leads can provide the interface between the antenna  208  and each of the transmission and receiver channels on the radar processing unit  206 . 
     As one specific example, the interface between the radar processing unit  206  and the antenna  208  can be realized as a chip-package-waveguide transition. As another example, the interface between the radar processing unit  206  and the antenna  208  can be realized as a chip-package-PCB-waveguide transition. In each of these examples the leads of the packaged radar processing unit  206  are coupled to the transmitting and receiving waveguides of the antenna  208 . This connection can be direct, or it can be implemented through intermediate features such as PCB&#39;s and other waveguides. 
     Turning now to  FIG. 3 , a cross-sectional side view of the radar system  200  is illustrated. This cross-sectional side view shows the plurality of transmitting waveguides  214  and receiving waveguides  216  that are defined in the antenna body  210 . In this example, there are an equal number of transmitting waveguides  214  and receiving waveguides  216 . However, that is just one example implementation. 
     Each of the transmitting waveguides  214  and receiving waveguides  216  provides a connection to the corresponding transmitting and receiving I/O on the radar processing unit  206 . As one example, each of the waveguides  214  and  216  can be connected to the radar processing unit  206  through a chip-package-waveguide transition structure. 
     Again, the antenna body  210  includes a metalized surface  212 . As can be seen in  FIG. 3 , the interior walls of the transmitting waveguides  214  and receiving waveguides  216  include the metalized surface  212 . This metalized surface  212  on the walls of the transmitting waveguides  214  and the receiving waveguides  216  provides the conductivity needed for transmitting electromagnetic waves from the radar processing unit  206  to the transmitting outputs (TX) and from the receiving inputs (RX) to the radar processing unit  206 . 
     Turning now to  FIG. 4 , a second cross-sectional side view of the radar system  200  is illustrated. Like  FIG. 3 , this cross-sectional view shows the plurality of transmitting waveguides  214  and receiving waveguides  216  that are defined in the antenna body  210 . However, in this example several of the transmitting waveguides  214  and the receiving waveguides  216  are shared. Specifically, multiple transmitting waveguides  214  are connected to one transmitting output of the radar processing unit  206 . Likewise, multiple receiving waveguides  216  are connected to one receiving input of the radar processing unit  206 . Thus, in this implementation some of the input and output channels of the radar processing unit  206  are split into multiple antenna outputs and inputs. Such an embodiment can thus be used where the transmitting and receiving channels are limited, or where simply more transmitting ports (TX) and receiving ports (RX) are needed to provide the fully desired field of view for the radar system  200 . 
     As was described above, the radar systems described herein can be applied to a wide variety of unmanned vehicles, including various types of pilotless drones. Turning now to  FIG. 5 , a simplified side view of an exemplary unmanned aerial vehicle  500  is illustrated. The aerial vehicle  500  includes a vehicle housing  502  and propulsion motors  504 . In this example, the aerial vehicle  500  is a multi-copter type drone device that has multiple propellers  506  driven by the propulsion motors  504 . 
     In accordance with the embodiments described herein, the aerial vehicle  500  also includes two radar systems  510 . Each of the radar systems  510  includes an antenna body  512 . These antenna bodies  512  each define at least one transmitting waveguide and at least one receiving waveguide. These waveguides are coupled to one or more radar processing units (not shown in  FIG. 5 ). Thus, during operation, the radar systems  510  each transmit and receive radar signals through the transmitting and receiving waveguides of the antenna bodies  512 . The antenna bodies  512  their included waveguides thus define the field of views for the radar systems  510 . 
     In this embodiment each of the radar systems  510  defines a substantially semispherical field of view. With one antenna body  512  mounted at the top of the vehicle housing  502  and the other antenna body  512  mounted at the bottom of the vehicle housing  502 , the two antenna bodies  512  together can provide near full spherical view as represented by the dashed line  514 . 
     Again, because the antenna bodies  512  can be implemented in plastic with a conductive metallic coating, such antenna systems  510  can provided with relatively little weight. Thus, the radar systems  510  can provide improved vehicle navigation and obstacle detection without excessive weight added to the vehicle  500 . 
     In one embodiment, the antenna bodies  512  are formed separately and attached the vehicle housing  502 . For example, the antenna bodies  512  can be separately formed and then attached to the vehicle using adhesive or any suitable fastener. 
     In other embodiments the antenna bodies  512  are formed together with the vehicle housing  502 . In this example, the antenna bodies  512 , including the exterior shape and the transmitting and receiving waveguides can be defined with the same processes used to form the vehicle housing  502 . Stated another way, the exterior shape waveguides can be implemented as part of the vehicle housing  502 . As one specific example, the vehicle housing  502  and the antenna bodies  512  can be formed as part of the same 3D printing process. As another specific example, the vehicle housing  502  and the antenna bodies  512  can be formed together as part of the same plastic molding process. These embodiments can simplify manufacturing of the unmanned vehicle  500  by not requiring the use of separate procedures and fasteners to affix the antenna bodies  512  to the vehicle housing  502 . Furthermore, not requiring adhesives or other fasteners can further reduce the weight of the overall unmanned vehicle  500 . 
     Turning now to  FIG. 6 , a simplified side view of an exemplary unmanned land vehicle  600  is illustrated. The land vehicle  600  includes vehicle housing  502  and propulsion motors (not shown in  FIG. 6 ). In this example, the land vehicle  600  is a wheeled device that has multiple wheels  606 . 
     In accordance with the embodiments described herein, the land vehicle  600  also includes two radar systems  610 . Each of the radar systems  610  includes an antenna body  612 . These antenna bodies  612  each define at least one transmitting waveguide and at least one receiving waveguide. These waveguides are coupled to one or more radar processing units (not shown in  FIG. 6 ). Thus, during operation, the radar systems  610  each transmit and receive radar signals through the transmitting and receiving waveguides of the antenna bodies  612 . The antenna bodies  612  their included waveguides thus define the field of views for the radar systems  610 . 
     In this embodiment each of the radar systems  610  defines a semi spherical field of view. With one antenna body  612  mounted at one side of the vehicle housing  602  and the other antenna body  612  mounted at the opposite side of the vehicle housing  602 , the two antenna bodies  612  together can provide near 360 degree view as represented by the dashed line  614 . 
     Again, in one embodiment, the antenna bodies  612  are formed separately and attached the vehicle housing  602 . In other embodiments, the antenna bodies  512  are formed together with the vehicle housing  502 , using the same processes and materials. 
     Again, because the antenna bodies  612  can be implemented in plastic, with a conductive coating, such antenna systems  610  can provided with relatively little weight. Thus, the radar systems  610  can again provide improved vehicle navigation and obstacle detection without excessive weight added to the land vehicle  600 . 
     The embodiments described herein thus provide radar systems for use on unmanned vehicles. The radar systems can be applied to a wide variety of unmanned vehicles, including unmanned aerial vehicles and unmanned land vehicles. In general, the unmanned vehicle includes a housing having at least one propulsion motor, a radar processing unit coupled to the body, and an antenna. In accordance with the embodiments described herein, the antenna includes an antenna body defining at least one transmitting waveguide and at least one receiving waveguide coupled to the radar processing unit. The antenna body is formed from plastic and includes metalized surface. In one embodiment, the antenna body is formed from 3-dimensional (3D) plastic printing. 
     In one embodiment, an unmanned vehicle is provided, including: a housing, the housing including at least one propulsion motor; a radar processing unit coupled to the housing; and an antenna, the antenna having an antenna body defining at least one transmitting waveguide and at least one of receiving waveguide, the antenna body formed from plastic and having a metallized surface, the at least one of transmitting waveguide and at least one of receiving waveguide coupled to the radar processing unit. 
     In another embodiment, an unmanned vehicle is provided, including: a housing, the housing including at least one propulsion motor; a radar processing unit coupled to the housing; and an antenna, the antenna including an antenna body defining a plurality of transmitting waveguides and a plurality of receiving waveguides, the antenna body formed from plastic using a 3-dimensional (3D) printing process, the antenna body including a metallized surface, the plurality of transmitting waveguides and plurality of receiving waveguides coupled to the radar processing unit. 
     In another embodiment, a pilotless aerial drone is provided, including: a housing, the housing including at least one propulsion motor; a radar processing unit coupled to the housing; a first antenna coupled to a first surface of the housing, the first antenna including a first antenna body with a first exterior surface shape, the first antenna body defining a first plurality of transmitting waveguides and a first plurality of receiving waveguides, the first antenna body formed from plastic and having a first metallized surface, the first plurality of transmitting waveguides and first plurality of receiving waveguides coupled to the radar processing unit; a second antenna coupled to a second surface of the housing opposite the first surface, the second antenna including a second antenna body with a second exterior surface shape, the second antenna body defining a second plurality of transmitting waveguides and a second plurality of receiving waveguides, the second antenna body formed from plastic and having a second metallized surface, second first plurality of transmitting waveguides and second plurality of receiving waveguides coupled to the radar processing unit; and wherein the first exterior shape and the second exterior shape are configured to provide a combined spherical field of view for radar signals generated by the radar processing unit and transmitted by the first antenna body and the second antenna body. 
     In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the scope of the invention as set forth in the appended claims. For example, the connections may be any type of connection suitable to transfer signals from or to the respective nodes, units or devices, for example via intermediate devices. 
     Accordingly, unless implied or stated otherwise the connections may for example be direct connections or indirect connections. However, other modifications, variations and alternatives are also possible. The specifications and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense. 
     In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other elements or steps then those listed in a claim. Furthermore, the terms “a” or “an,” as used herein, are defined as one or more than one. Also, the use of introductory phrases such as “at least one” and “one or more” in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an.” 
     The terms “first,” “second,” “third,” “fourth” and the like in the description and the claims are used for distinguishing between elements and not necessarily for describing a particular structural, sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances. Furthermore, the terms “comprise,” “include,” “have” and any variations thereof, are intended to cover non-exclusive inclusions, such that a circuit, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such circuit, process, method, article, or apparatus. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical or non-electrical manner. 
     While the principles of the inventive subject matter have been described above in connection with specific systems, apparatus, and methods, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of the inventive subject matter. The various functions or processing blocks discussed herein and illustrated in the Figures may be implemented in hardware, firmware, software or any combination thereof. Further, the phraseology or terminology employed herein is for the purpose of description and not of limitation. 
     The foregoing description of specific embodiments reveals the general nature of the inventive subject matter sufficiently that others can, by applying current knowledge, readily modify and/or adapt it for various applications without departing from the general concept. Therefore, such adaptations and modifications are within the meaning and range of equivalents of the disclosed embodiments. The inventive subject matter embraces all such alternatives, modifications, equivalents, and variations as fall within the spirit and broad scope of the appended claims.