Abstract:
A surveillance system includes a multi-propeller aircraft having a main propeller and a plurality of wing unit propellers; a housing that houses the main propeller and the wing unit propellers; an ultra-wideband (UWB) radar imaging system; a control system for controlling flight of the multi-propeller aircraft from a remote location; and a telemetry system for providing information from the ultra-wideband (UWB) radar imaging system to the remote location. A method includes: remotely controlling flight of the aircraft using a main propeller and a plurality of wing unit propellers with airflow from the main propeller to the wing unit propellers for lift and propulsion; operating an ultra-wideband (UWB) radar imaging system from the aircraft; and transmitting information from the UWB radar imaging system to a display at a location remote from the aircraft.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/309,379, filed Mar. 1, 2010, which is incorporated by reference. In addition, this application is related to the following co-pending applications, which are incorporated by reference: U.S. patent application Ser. No. 12/852,440, filed Aug. 6, 2010; U.S. patent application Ser. No. 12/732,163, filed Mar. 25, 2010; and U.S. patent application Ser. No. 12/649,268, filed Dec. 29, 2009. 
    
    
     BACKGROUND 
     The present disclosure generally relates to radio frequency (RF) detection and ranging (RADAR) and, more particularly, to providing surveillance information to an operator at a safe distance from hostile armed individuals who may have weapons, for example, or dangerous objects such as unexploded ordnance (UXO). 
     Portable, hand-held radars have been used for detection of hidden objects, e.g., objects such as weapons hidden behind a wall of a building. Such technology may be useful in situations where surveillance of an inhabitable area from behind a building wall may be desired, for example, for detecting illegal activities such as smuggling or illegal border crossings or, for example, detecting the presence of hostile individuals in a war zone or terrorist situation. 
     In some situations, e.g., police work, military combat scenarios, or fire and rescue situations, it may be desirable to be able to detect living individuals, and various objects that may be in their possession using a portable, hand-held radar system from outside a building, for example, occupied by the individuals. In other situations, such as the well-known problem of disposing of hidden landmines left over from past conflicts, it may be desirable to be able to detect unexploded ordnance. Many such situations, however, can expose the operator of a portable, hand-held radar system to grave danger and unacceptably high risks. 
     SUMMARY 
     According to one embodiment, a system includes: a multi-propeller aircraft having a main propeller and a plurality of wing unit propellers; a housing that houses the main propeller and the wing unit propellers; an ultra-wideband (UWB) radar imaging system housed in the housing; a control system, housed in the housing, for controlling flight of the multi-propeller aircraft from a remote location; and a telemetry system, housed in the housing, for providing information from the ultra-wideband (UWB) radar imaging system to the remote location. 
     According to another embodiment, a method includes: remotely controlling flight of an aircraft using a main propeller and a plurality of wing unit propellers for lift and propulsion; operating an ultra-wideband (UWB) radar imaging system from the aircraft; and transmitting information from the UWB radar imaging system to a display at a location remote from the aircraft. 
     According to a further embodiment, an unmanned aerial vehicle includes: a ground plate; a plurality of wing propeller units attached to the ground plate; a housing attached to the ground plate; a main propeller unit connected, directly or indirectly, to the ground plate and disposed to provide a portion of airflow to the wing propeller units; and a control system in communication with the main propeller unit and the wing propeller units and providing flight control by adjustment of the speed and thrust from all of the propeller units concurrently. 
     The scope of the invention is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a cross sectional diagram, taken along line A-A′ in  FIG. 1B , of a standoff surveillance system apparatus in accordance with one embodiment; 
         FIG. 1B  is a plan view diagram of a standoff surveillance system apparatus in accordance with one embodiment; 
         FIG. 2  is a side view diagram of system components of a standoff surveillance system apparatus in accordance with an embodiment; 
         FIG. 3  is a side sectional view toward an interior of a housing for a standoff surveillance system apparatus in accordance with an embodiment; 
         FIG. 4  is a side view of an exterior of a housing for a standoff surveillance system apparatus in accordance with an embodiment; 
         FIG. 5  is a system diagram illustrating one example of a system architecture for a standoff surveillance system in accordance with an embodiment; 
         FIG. 6  is a system diagram illustrating the wing propeller units shown in  FIG. 5  in more detail, in accordance with one embodiment; and 
         FIG. 7  is a system diagram illustrating one example of a system architecture for a system interface and remote control for a standoff surveillance system in accordance with one embodiment. 
     
    
    
     Embodiments and their advantages are best understood by referring to the detailed description that follows. Like reference numerals are used to identify like elements illustrated in one or more of the figures. 
     DETAILED DESCRIPTION 
     In accordance with one or more embodiments of the present invention, systems and methods disclosed herein provide means for standoff detection of inanimate objects of interest, e.g., unexploded ordnance (UXO), and living individuals—as well as means for discriminating between the two—using a sensing apparatus, e.g., unmanned aerial vehicle (UAV), that can be remotely controlled to keep the operator out of danger, e.g., from explosives or hostile individuals, to which an operator using a portable, hand-held surveillance unit would be exposed. The term “standoff” is used to indicate use of a surveillance sensing apparatus that can, for example, be flown by an operator at a safe distance from the operator to place the surveillance system sensing apparatus in a position that would otherwise be dangerous or inaccessible to the operator for detecting objects and individuals of interest. In one or more embodiments, the surveillance system sensing apparatus may include multiple sensors, such as a combination of a 5 Giga Hertz (GHz) ultra-wideband (UWB) radar imaging system, a very high frequency, e.g., 60 GHz ultra-wideband radar imaging system, and off-the-shelf optical zooming devices where optical zooming is switchable and the video image is fused to the RF image using 60 GHz radar zooming by applying a very narrow RF beam. The radiated power of an RF imager in one embodiment may be less than 100 microwatts (uW). Dimensions for a circular UAV of one embodiments may be within a 1 foot to 2 foot radius, depending on the payload and weight excluding the electronics may less than 3 pounds (lb). A number of multi-sensor and compact radar systems are disclosed in co-pending U.S. patent applications, including: U.S. patent application Ser. No. 12/852,440, filed Aug. 6, 2010; U.S. patent application Ser. No. 12/732,163, filed Mar. 25, 2010; and U.S. patent application Ser. No. 12/649,268, filed Dec. 29, 2009, all of which are herein incorporated by reference. 
     In one or more embodiments, a multi-propeller system may accomplish easy, noiseless take-off and landing of embedded ultra-wideband radar imaging systems for covert monitoring of the existence of living individuals and other objects on a premises, or survey of a building for its layout from outside of the premises. For example, the system may address problems of quiet take off and landing on a roof or a sloped area and may be controlled remotely by a wireless radio system. The surveillance system apparatus can also enable detection of highly reflective material such as metallic cased UXO, or detection of intrusion underground such as tunneling. Embodiments may be used to identify objects, such as a weapon or UXO, identify and differentiate multiple individuals, track the individuals&#39; motion and display the tracking in real time to a remote operator using telemetry. 
     Embodiments may be useful, for example, to persons outside a building (e.g., fire, rescue workers, military, police, border patrol, or others) requiring surveillance or intelligence data (e.g., detection of living persons and various objects that may be in their possession) regarding individuals occupying a building when entering the building is not practical, permissible, or safe—such as for rescue workers trying to locate earthquake victims trapped inside damaged buildings. Embodiments may be useful in such situations particularly when close approach to the area of interest is unsafe, e.g., in the case of identifying UXO, or inaccessible, e.g., in the case of collapsed buildings or buildings guarded by hostile individuals. 
       FIG. 1  illustrates a standoff surveillance system  100  including a UAV  102  (also referred to as multi-propeller aircraft  102 ) that may be used to fly electronics  106  for surveillance system  100  to remote locations according to one or more embodiments. Standoff surveillance system  100  may include a housing  112  that may house the electronics  106  for an RF imaging and flight control system  130  (see  FIG. 5 ) and other system components such as main propeller  104 , wing unit propellers  105 , main motor shaft  108 , and ground plate  119 . In one implementation, the wing unit propellers  105  may be a pair of coaxial propellers with counter spinning capability to double the air flow and neutralize the torque. In another implementation, every other wing unit propeller  105  may be spinning opposite to the previous one in sequence around the periphery of ground plate  119  to neutralize the torque. In a third implementation, the main propeller  104  may be balanced by the wing unit propellers  105 . Housing  112  may include a light weight protective cover  125  (see  FIGS. 3 and 4 ) encasing its outer surface  111 . The surface of the cover  125  may be tiled with solar cells, which may be connected to an internal rechargeable battery for prolonged operations. The outer edge of the ground plate  119  may be buffered with a soft plastic bumper  114 , which may be attached to housing  112  for smooth landing of the aircraft  102 . Housing  112  may also have an inner surface  113  which may be shaped to direct an airflow  122  (see  FIG. 2 ) from the main propeller  104  into wing unit propellers  105 . Housing  112  may also include one or more stabilizer feedback tubes  110  for directing airflow between the main propeller  104  and the wing unit propellers  105 . For example, the air flow may be through the main large propeller  104  and a portion of outflow air may be fed back to the smaller propellers  105  through a narrow tube  110  for stability. Direction of rotation (indicated be arrows  107  and  109 ) and rate of rotation of each propeller may be controlled for stable take-off and landing. As indicated by arrows  107  and  109  some of the propellers may be counter rotating with respect to each other for control of the overall net torque and rotational inertia for all of the propellers. 
       FIG. 2  is a side view diagram of system components that may be housed in a housing  112  of a standoff surveillance system  100 .  FIG. 2  shows a general layout of components on a supporting ground plate  119 , to which the components may be attached and to which the housing  112  may also be connected, either directly or indirectly, for support of the housing  112 . In an alternative embodiment, the housing  112  may provide support for components that are attached to it and held, for example, by ground plate  119 . As seen in  FIG. 2 , the supported components may include sensor arrays  132  (see also  FIG. 5 ) which may include, for example, UWB radar scanners, video and audio inputs such as cameras and microphones, night vision cameras, global positioning system (GPS) units, altimeters, and gyro systems. The supported components may include sensing, flight control, and telemetry system  130  (also referred to as “sensor signal processing unit” or “RF scanner and control system” as in  FIG. 5 ).  FIG. 2  also shows more clearly airflow  120  through the propellers  104  and  105 , comprising entry airflow  121 , stabilizing airflows  122 , and exit airflows  123 . As may be seen from  FIG. 2 , most of the components are mounted near the ground plate, so that the center of gravity is very close to the ground plate, which is low in the UAV  102 , for stability. 
       FIG. 3  shows an interior of a UAV  102  and  FIG. 4  shows an exterior of a UAV  102  for a standoff surveillance system  100 .  FIGS. 3 and 4  show wind suppression hollow tubes  124  that open through the protective cover  125  to the outer surface  111  of UAV  102 . Protective cover  125  may provide impact protection for UAV  102  and may rendered porous—for example, with regard to cross winds—and lighter in weight by the openings of hollow tubes  124 . In one implementation the tubes  124  may be formed to collect the wind (large area inlet) and spray jet (smaller cross section outlet) back the air to resist the wind. The number of tubes  124  may be very large, while the weight of each tube may be ultra light. In another implementation, the tubes  124  may form a large honeycomb type structure that passes the air through and provides almost no resisting surface to the wind, while mechanically supporting the UAV  102  against shock. 
       FIG. 5  illustrates one example of a system architecture for a standoff surveillance system  100  for a sensing, flight control, and telemetry system  130 . Sensing, flight control, and telemetry system  130  may include an RF imaging section  131  and a flight control section  141 , which may communicate wirelessly via a remote controller unit included in control system  160  (see also  FIG. 7 ). Wireless control system  160  may conform, for example, to any of the open standards or may be a proprietary control system. Wireless network connectivity may be provided by a wireless control system  160 . 
     RF imaging section  131  may include one or more UWB RF scanners (e.g., sensor array  132 ) such as, for example, the 5 GHz or 60 GHz systems referenced above. The UWB RF scanner (sensor array unit  132 ) may be connected to a digital signal processing (DSP) unit  134 , which may access a memory unit  136  comprising, for example, a random access memory (RAM). The DSP unit  134  may communicate, as shown in  FIG. 5 , with flight control section  141 . 
     Flight control section  141  may include a micro-controller  140 . Micro-controller  140  may integrate all sensory and control inputs from the components of flight control section  141  and may provide control and telemetry outputs for UAV  102 . As shown in  FIG. 5 , micro-controller  140  may receive inputs from wireless link  142 , which may provide operator control inputs from an operator at a remote location using, for example, a wifi or RF remote controller unit of wireless control system  160 . Micro-controller  140  may receive additional control and stabilizing inputs, for example, from gyro system  144  and altimeter system  146 . Micro-controller  140  may receive position or location data from GPS system  148 . For example, inputs from GPS system  148  may enable UAV  102  to report its position via telemetry and to be monitored over Google® maps, for example, using GPS. 
     Micro-controller  140  may provide control outputs and receive feedback inputs from master rotor unit  145  and wing propeller units  150 . Master rotor unit  145  may include the main propeller  104 , a main motor and motor shaft  108 , and an electronic speed control (ESC) for driving the motor. Similarly, as shown in  FIG. 6 , each wing propeller unit  155  of the plurality of wing propeller units  150  may include a wing unit propeller  105 , a DC motor  151  and an ESC (not shown) for driving the motor. Each wing propeller unit  155  may include a local controller and a micro-electro mechanical (MEM) based gyro or accelerometer (not shown). 
     Flight control section  141  may also include a power manager unit  147  for providing and regulating electrical power to any of the systems of UAV  102 . 
       FIG. 7  illustrates one example of a multi-link wireless control system  160  for standoff surveillance system  100 . Multi-link wireless control system  160  may include a system interface display (e.g., devices  163 ,  165 ) for providing surveillance information to a user from an RF imaging system or other surveillance systems (e.g., video, audio) on UAV  102 . Control system  160  may provide a system interface for one or more operators using display and input devices  163  and  165  to communicate with and control UAV  102  at a location remote from UAV  102 . The remote controller may be a laptop or hand-held system as illustrated by devices  163 ,  165  shown in  FIG. 7 , or a device that provides joy stick controls, for example, for the rate of rotation for each of propellers  104 ,  105 . For example, flight control may be provided by adjustment of the speed and thrust from all of the propeller units concurrently under direction of micro-controller  140 , which may interpret signals from the joysticks to co-ordinate the adjustments. 
     Multi-link wireless control system  160  may provide links, as shown, for a UWB radar RF sensor unit  168 , gimbal video camera and stabilization unit  166 , night vision camera  169 , flight control unit  162 , and line-of-sight (LOS) to non-line-of-sight (NLOS) router link  164 . Each of these units may, for example, process telemetry data or interface control inputs to a corresponding unit on UAV  102 . Interface display  163 , for example, may provide first person view (FPV) control and direct visual flight control for UAV  102  as well as display telemetry data such as RF imaging from the UWB radar sensors on board the UAV  102 . Interface display  165  may provide an LOS to NLOS router link for UAV  102 . 
     Embodiments described herein illustrate but do not limit the disclosure. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present disclosure. Accordingly, the scope of the disclosure is best defined only by the following claims.