Abstract:
In an aspect, in general, a spooling apparatus includes a filament feeding mechanism for deploying and retracting filament from the spooling apparatus to an aerial vehicle, an exit geometry sensor for sensing an exit geometry of the filament from the spooling apparatus, and a controller for controlling the feeding mechanism to feed and retract the filament based on the exit geometry.

Description:
BACKGROUND 
       [0001]    This invention relates to a spooler for use in an unmanned aerial vehicle system. 
         [0002]    Unmanned aerial vehicles (UAVs) are vehicles that are controlled autonomously by onboard or remote computer, remotely by a human operator, or a mixture of the two. Use of such vehicles is becoming increasingly common in both military and civilian airspaces. 
       SUMMARY 
       [0003]    In an aspect, in general, a spooling apparatus includes a filament feeding mechanism for deploying and retracting filament from the spooling apparatus to an aerial vehicle, an exit geometry sensor for sensing an exit geometry of the filament from the spooling apparatus, and a controller for controlling the feeding mechanism to feed and retract the filament based on the exit geometry. 
         [0004]    Aspects may include one or more of the following features. 
         [0005]    The spooling apparatus may include a spool of filament. The spooling apparatus my include a tension sensing and mitigation mechanism for sensing tension present on the filament and causing the controller to adjust an amount of deployed filament based on the sensed tension. The tension sensing and mitigation mechanism may be further configured to mitigate an amount of slack in the filament within the spooling apparatus. The exit geometry sensor may be configured to sense an angle of departure of the filament from the spooling apparatus. The exit geometry sensor may be configured to sense a location of the filament at an exit of the spooling apparatus. 
         [0006]    The spooling apparatus may include a power source for providing power to the aerial vehicle over the filament. The spooling apparatus may include a control station configured to communicate with the aerial vehicle over the filament. The data communicated between the aerial vehicle and the control station may include one or more of network data, point to point serial data, sensor data, video data, still camera data, payload control data, vehicle control data, and vehicle status data. 
         [0007]    The filament may be configured to act as a tether for limiting a range of the aerial vehicle. The exit geometry sensor may be configured to determine the angle of departure of the filament by measuring a value that characterizes the angle. The spool may include perforations and the spooling apparatus may include a cooling apparatus for cooling the first portion of filament by forcing cooled air through perforations in the spool and over the first portion of filament. The controller may be configured to maintain the exit geometry at an exit geometry setpoint. The controller may be configured to allow the exit geometry to deviate by a predefined amount from the setpoint without taking corrective action. 
         [0008]    In another aspect, in general, a method for managing a filament coupling an aerial vehicle to a spooling apparatus includes sensing an exit geometry of the filament from the spooling apparatus and feeding filament from the spooling apparatus according to the exit geometry including controlling a length of filament deployed from the spooling apparatus based on the exit geometry. 
         [0009]    Aspects may include one or more of the following features. 
         [0010]    Sensing the exit geometry of the filament from the spooling apparatus may include sensing an angle of departure of the filament from the spooling apparatus to the aerial vehicle. Sensing the exit geometry of the filament from the spooling apparatus may include sensing a location of the filament at an exit of the spooling apparatus. The method may further include providing power to the aerial vehicle via the filament. The method may further include establishing a communication channel between the aerial vehicle and a control station via the filament. The method may further include transmitting data over the communication channel including transmitting one or more of network data, point to point serial data, sensor data, video data, still camera data, payload control data, vehicle control data, and vehicle status data. 
         [0011]    The method may further include tethering the aerial vehicle to limit a range of the aerial vehicle. The method may further include sensing an angle of departure of the filament including sensing a value that characterizes the angle. The method may further include cooling the first portion of filament, the cooling including forcing cooled air through perforations in the spool and over the first portion of filament. Controlling a length of a portion the filament wound on a spool of the spooling apparatus based on the exit geometry may include maintaining the exit geometry of the filament at an exit geometry setpoint. Maintaining the exit geometry at the exit geometry setpoint may include allowing the exit geometry of the filament to deviate by a predefined amount from the setpoint without taking corrective action. 
         [0012]    In another aspect, in general, an unmanned aerial vehicle system includes an aerial vehicle and a spooling apparatus. The spooling apparatus is configured to sense an exit geometry of a filament from the spooling apparatus and feed filament from the spooling apparatus according to the exit geometry including controlling a length filament deployed from the spooling apparatus based on the exit geometry. 
         [0013]    Aspects may include one or more of the following features. 
         [0014]    The aerial vehicle may be collapsible. The system may be configured to be mounted to a mobile vehicle. The system may be configured to be collapsed and stowed in a human portable container. The system may be configured to be collapsed and stowed in a ruggedized container. 
         [0015]    Other features and advantages of the invention are apparent from the following description, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a ground powered unmanned aerial vehicle system. 
           [0017]      FIG. 2  is a spooling apparatus. 
           [0018]      FIG. 3  illustrates a number of operational scenarios of the ground powered or non-ground powered tethered unmanned aerial vehicle system. 
           [0019]      FIG. 4  illustrates an exit angle dead zone. 
           [0020]      FIG. 5  is a perforated spool. 
           [0021]      FIG. 6  is a feeder/tension sensor. 
           [0022]      FIG. 7  is a tethering version of the ground powered or non-ground powered tethered unmanned aerial vehicle system. 
           [0023]      FIG. 8  is a collapsible aerial vehicle. 
           [0024]      FIG. 9  is a ruggedized container for transporting the ground powered unmanned aerial vehicle system. 
           [0025]      FIG. 10  is a backpack for transporting the ground powered unmanned aerial vehicle system. 
           [0026]      FIG. 11  is a vehicle mountable version of the ground powered or non-ground powered tethered unmanned aerial vehicle system. 
       
    
    
     DESCRIPTION 
     1 System Overview 
       [0027]    Referring to  FIG. 1 , in one embodiment, a ground powered unmanned aerial vehicle system  100  includes an unmanned aerial vehicle  102  which is powered by and in communication with a base station  104  over an electrically conductive filament  106 . 
         [0028]    The base station  104  includes a power source  108  (e.g., a generator, battery, or power grid), a control station  110  (e.g., a laptop computer), and a spooling apparatus  112 . The power source  108  provides power to the aerial vehicle  102  over the filament  106 . The control station  110  communicates with the aerial vehicle  102  by, for example, establishing a network connection (e.g., an Ethernet connection) between itself and the aerial vehicle  102  over the filament  106 . In various embodiments, different types of information can be communicated between the control station  110  and the aerial vehicle  102 . For example, the control station  110  can send control information such as flight control information (e.g., GPS coordinates, flight speed, etc.), payload control information, and sensor (e.g., camera) control information to the aerial vehicle  102 . The aerial vehicle  102  can send information such as vehicle status information (e.g., current GPS coordinates, current payload status, etc.) and sensor data (e.g., video streams acquired by on-vehicle cameras) back to the control station  110 . In some examples, the filament  106  is the same or similar to the filaments described in U.S. Pat. No. 7,510,142 titled “AERIAL ROBOT,” U.S. Pat. No. 7,631,834 titled “AERIAL ROBOT WITH DISPENSABLE CONDUCTIVE FILAMENT,” and U.S. Patent Publication 2007/0200027 A1 titled “AERIAL ROBOT” which are incorporated herein by reference. Note that in the above patents and patent applications described above generally include a spool of filament in the aerial vehicle. However, as is described in greater detail below, the filament can similarly be spooled in the base station  104  on the ground. 
         [0029]    In some embodiments in which the vehicle  102  provides sensor data, a user  114  can interact with the control station  110  to view sensor data and flight status information from the aerial vehicle  102  and/or to specify commands for controlling the aerial vehicle  102 . 
         [0030]    One common application for the ground powered unmanned aerial vehicle system  100  is to survey (e.g., video monitoring) a geographical area. For example, the user  114  of the system  100  may use the control station  110  to issue a command to the aerial vehicle  102 , causing the aerial vehicle  102  to hover at a given GPS coordinate (i.e., a latitude, longitude, and altitude). The user  114  may monitor sensor data (e.g., a 720p video stream) from the aerial vehicle  102  to, for example, ensure that no unauthorized parties are approaching the user&#39;s position. 
         [0031]    The aerial vehicle  102  includes control systems that continuously attempt to maintain the vehicle  102  at the commanded GPS coordinate (note that in some embodiments, the control system may be located in the base station  104 . However, due to environmental conditions such as wind, the aerial vehicle  102  is rarely able to maintain its position exactly at the commanded GPS coordinate. Furthermore, at times, wind can cause the aerial vehicle  102  to significantly deviate from the commanded GPS coordinate. Without mitigation, such a deviation can cause the amount of slack on the filament  106  to vary, possibly damaging the very thin, lightweight, and fragile filament  106 . For example, wind may blow the vehicle  102  in a direction away from the base station  104 , causing the amount of slack on the filament  106  to decrease, potentially placing excess tension on the filament  106  or at the very least placing a lateral force on the aerial vehicle  102  which the aerial vehicle  102  must compensate for. Without mitigation, such excess tension may result in the filament  106  breaking Conversely, wind may blow the vehicle  102  in a direction toward the base station  104 , causing the amount of slack on the filament  106  to increase. Without mitigation, the filament  106  with excess slack can potentially fall toward the ground and become tangled with ground based objects. 
         [0032]    The term ‘slack’ as is used above refers to a degree of tautness in the filament  106 . For example, if the filament  106  were to be held perfectly taut between the spooling apparatus  112  and the aerial vehicle  102 , then there would be no slack on the filament  106 . As the tautness of the filament  106  between the aerial vehicle  102  and the spooling apparatus  112  decreases, the amount of slack on the filament  106  increases. In some examples, the amount of slack on the filament can be characterized in a length of an excess of deployed filament  106  or a length of a shortage of deployed filament  106 . 
       2 Spooling Apparatus 
       [0033]    Referring to  FIG. 2 , the spooling apparatus  112  is configured to mitigate the risks described above by controlling the amount of filament  106  that is deployed such that the amount of slack on the filament  106  is optimized. In some examples, the desired amount of slack minimizes (or generally reduces or limits) the amount of horizontal force between the base station  104  and the aerial vehicle  102  while maintaining a safe distance between the ground the filament  106 . 
         [0034]    Optimizing of the amount of slack on the filament  106  reduces the risk of breaking the filament  106  due to excess tension on the filament  106  and reduces the risk of having the filament  106  become entangled with objects close to the ground due to excess slack on the paid out filament  106 . 
         [0035]    Before describing the specific functionality of the spooling apparatus  112 , it is important to note that to optimize the amount of slack on the filament  106 , the spooling apparatus  112  utilizes a relationship that exists between the amount of slack on the filament  106  and an exit angle, θ E    214  of the filament  106  from the spooling apparatus  112 . In particular, it is known that as the distance between the aerial vehicle  102  and the spooling apparatus  112  increases, the filament  106  is pulled taut, causing the filament  106  to become less slack. As the filament  106  becomes less slack, the exit angle, θ E    214  of the filament  106  from the spooling apparatus  112  increases. Conversely, as the distance between the spooling apparatus  112  and the aerial vehicle  102  decreases, the filament  106  becomes less taut, causing the amount of slack on the filament  106  to increase. As the amount of slack on the filament  106  increases, the exit angle, θ E    214  of the filament  106  from the spooling apparatus  112  decreases. 
         [0036]    Thus, the spooling apparatus  112  is configured to control the amount of filament  106  that is deployed according to a desired exit angle or set-point, θ O    220  of the filament  106  from the spooling apparatus  112 , for example to maintain the set-point, θ O    220 . Furthermore, the spooling apparatus  112  also prevents tension in the filament  106  from exceeding a predefined maximum tension. 
         [0037]    In general, the set-point, θ O    220  is defined by the user  114  on a case-by-case basis. In many situations the best choice for the set-point is simply 0° (i.e., extending along a line that is parallel to the ground). However, in some examples, an obstacle near the base station  104  may necessitate that the set-point, θ O    220  is a positive angle (relative to a line extending parallel to the ground) to ensure that the filament  106  does not become entangled with the obstacle. In other examples, the terrain may allow for a set-point, θ O    220  that is negative (relative to a line extending parallel to the ground). For example, the base station  104  may be on the top of a mountain and a filament  106  with significant slack will not likely encounter any obstacles due to the sloping sides of the mountain. 
         [0038]    The spooling apparatus  112  of  FIG. 2  includes a communications input port  216 , a power input port  218 , and a set-point input port  221 . The spooling apparatus  112  also includes a filament interface  223 , a spool  224 , a feeder/tension sensor  226 , a position sensor  227 , and a control system  228 . 
         [0039]    The filament interface  223  receives the communications and power inputs and couples them to the filament  106 . The filament  106  extends from the filament interface  223  to the spool  224 . In general, the spool  224  is a cylindrical member onto which the filament  106  that is not deployed from the spooling apparatus  112  is wound. In some examples, the spool  224  is driven by a motor which can be controlled (e.g., by the control system as is described below) to cause the spool  224  to rotate in a first direction to deploy filament  106  and in a second direction to re-spool filament  106 . The motor is also controllable to vary the speed of rotation of the spool  224 . 
         [0040]    After being deployed from the spool  224 , the filament  106  is fed into a feeder/tension sensor  226 . In general, the feeder/tension sensor  226  serves two functions:
       quickly feeding the filament  106  from the spooler  224  through the spooling apparatus  112 , and   measuring the tension, T  229  that is present on the filament  106 .       
 
         [0043]    A signal representing the tension, T  229  measured by the feeder/tension sensor  226  is passed to the control system  228 . The filament  106  is fed through the feeder/tension sensor  226  to the position sensor  227 . A more detailed description of the feeder/tension sensor  226  is presented below. 
         [0044]    The position sensor  227  measures an exit geometry (e.g., a position) of the filament  106  at the point where the filament  106  exits the spooling apparatus  112 . The measured position of the filament  106  is then used to determine the exit angle, θ E    214  of the filament  106 . The exit angle, θ E    214  is passed from the position sensor  227  to the control system  228 . 
         [0045]    In some examples, the position sensor  227  includes a straw-like tube  230  which coaxially surrounds a portion of the filament  106  at the point where the filament  106  exits the spooling apparatus  112 . The straw like tube  230  is coupled to, for example, a high precision potentiometer, which outputs a signal indicative of the exit angle, θ E    214  of the filament  106 . In other examples, various types of position sensors such as optical, mechanical, or magnetic rotary encoders are used to sense θ E    214  of the straw. In other examples, different types of sensors such as inductive position sensors can be used to sense θ E    214 . 
         [0046]    In some examples, the control system receives the exit angle, θ E    214 , the set-point, θ O    220 , and the measured tension, T  229  as inputs and applies a control algorithm to the inputs to determine a control signal output, Cmd  232 . The control signal output, Cmd  232  is passed to the spool  224  and/or to the feeder/tension sensor  226  and actuates the spool  224  and/or the feeder/tension sensor  226  to maintain the exit angle, θ E    214  of the filament  106  at the set-point, θ O    220 . In some examples, a filament feeding mechanism (e.g. pinch rollers) in the feeder/tension sensor  226  receives the Cmd  232  input and which causes the filament feeding mechanism to vary a speed and direction of filament feeding based on the exit angle, θ E    214 . For example, if the sensed exit angle, θ E    214  is below the setpoint, θ O    220  the filament feeding mechanism receives a value of Cmd  232  which causes the filament feeding mechanism to re-spool filament at a commanded speed. Conversely, if the sensed exit angle, θ E    214  is above the setpoint, θ O    220  the filament feeding mechanism receives a value of Cmd  232  which causes the filament feeding mechanism to deploy filament at a commanded speed. 
         [0047]    In some examples, speed and direction of operation of the filament feeding mechanism (which is based on the sensed exit angle θ E    214 ) indirectly controls the speed and direction of rotation of the spool  224 . For example, a dancer mechanism within the feeder/tension sensor  226  may sense a decrease in slack or tension in the filament within the feeder/tension sensor  226  and subsequently command the spool  224  to alter its speed and direction of rotation. In other examples, the Cmd  232  signal from the control system  228  directly controls both the filament feeding mechanism and the spool  224 . In this way, the control system  228  causes the spool  224  and feeder/tension sensor  226  to deploy or re-spool filament  106  such that the set-point, θ O    220  is maintained. 
         [0048]    In the examples described above, the filament feeding mechanism is described as being included in the feeder/tension sensor  226  (e.g., as pinch rollers). In other examples, the filament feeding mechanism is included at the exit of the spooling apparatus, for example, in the position sensor  227 . 
         [0049]    In some examples, the control system is a cascaded control system with an inner loop which controls a torque output of the spool motor and one or more output loops that implement position, velocity, tension, and angle based control. 
         [0050]    A variety of suitable feedback control system algorithms can be implemented by the control system  228 . Some examples of suitable feedback control systems are proportional controllers, PID controllers, state space controllers, etc. 
         [0051]    In some examples, the control system  228  is also configured to monitor the measure of tension, T  229  to determine if a dangerous amount of tension is present on the filament  106 . If the control system  228  determines that the tension, T  229  on the filament  106  is greater than a predetermined limit, the control system  228  causes the spool  224  to deploy filament  106  until the tension on the filament  106  is reduced to a safe level (e.g., the tension on the filament is below the predetermined limit). 
       3 Example 
       [0052]    Referring to  FIG. 3 , the ground powered unmanned aerial vehicle system  100  is shown with the filament  106  in three different scenarios. In the first scenario, a sufficiently deployed filament  334  has a sufficient amount of filament deployed, causing the actual exit angle, θ E    214  measured by the position sensor  227  to be substantially the same as the desired exit angle, θ O    220  (in this example, 0°). In this case, the spooling apparatus  112  does not need to take any action to correct the exit angle, θ E    214  of the filament. 
         [0053]    In the second scenario, an overly taut filament  336  has too little filament deployed, causing the actual exit angle, θ E    214  measured by the position sensor  227  to be greater than the desired exit angle, θ O    220 . As is noted above, such a scenario may occur if the aerial vehicle  102  is blown in a direction away from the base station  104 . In this case, the spooling apparatus  112  acts to deploy additional filament in order to provide slack to the deployed filament. In particular, the control system  228  determines that the actual exit angle, θ E    214  is greater than the desired exit angle, θ O    220  and sends a control signal, Cmd  232  to the spool  224 , commanding the spool  224  to adjust the amount of deployed filament until the actual exit angle, θ E    214  and the desired exit angle, θ O    220  are substantially the same. 
         [0054]    In the third scenario, an overly slack filament  338  has too much filament deployed, causing the actual exit angle, θ E    214  measured by the position sensor  227  to be less than the desired exit angle, θ O    220 . As is noted above, such a scenario can occur if the aerial vehicle  102  is blown in a direction toward the base station  104 . In this case, the spooling apparatus  112  acts to re-spool the deployed filament in order to reduce the amount of slack on the deployed filament. In particular, the control system  228  determines that the actual exit angle, θ E    214  is less than the desired exit angle, θ O    220  and sends a control signal, Cmd  232  to the spool  224 , commanding the spool  224  to adjust the amount of deployed filament until the actual exit angle, θ E    214  and the desired exit angle, θ O    220  are substantially the same. 
       4 Additional Features 
     4.1 Sensor Dead Zone 
       [0055]    Referring to  FIG. 4 , in some examples, the control system  228  allows for a “dead zone”  440  around the desired exit angle, θ O    220 . In general, the dead zone  440  is a range of angles surrounding the desired exit angle, θ O    220 . If the exit angle, θ E    214  measured by the position sensor  227  falls within the dead zone  440 , the control system  228  takes no action to adjust the length of the filament  106 . Once the exit angle, θ E    214  measured by the position sensor  227  exceeds the boundaries of the dead zone  440 , the control system  228  re-spools or deploys filament  106  as described above. 
       4.2 Cooling and Cross Ratio 
       [0056]    In some examples, the filament  106  is required to carry a substantial amount of power to the aerial vehicle  102  and resistive losses in the filament  106  cause heating of the filament  106 . In general, the deployed filament  106  is cooled as it drifts through the air. However, the spooled (i.e., un-deployed) filament  106  can become overheated, possibly damaging the filament. Referring to  FIG. 5 , to address heating of the filament  106 , the spool  224  is hollow and includes a plurality of perforations  544 . Air is forced into the hollow spool  224 , creating a positive pressure within the spool  224  which causes the air to flow out of the spool  224  through the perforations  544 . The air flowing through the perforations  544  acts to cool the filament  106  which is wound on the spool  224 . In some examples, the filament  106  is wound onto the spool  224  in a predetermined pattern such that the amount of surface area of the filament  106  that comes into contact with the air flowing through the perforations  544  is maximized while not inhibiting the airflow. In some examples, the predetermined winding pattern also minimizes cross-talk between individual windings of the filament  106 . 
         [0057]    In general, deploying or re-spooling of filament  106  on the spool  224  is at least in part accomplished by rotating the spool  224  while laterally moving a level winder (see the level winder of  FIG. 6 ) back and forth from one end of the spool  224  to the other. A spooling pattern is defined by an amount of lateral movement of the level winder relative to the number of rotations of the spool and is referred to as the “cross ratio.” Different cross ratios may be chosen for different applications. For example, certain cross ratios may be advantageous for applications where heating of the spooled microfilament is a problem. Such cross ratios may, for example, maximize airflow through the perforations  544 . Other cross ratios may be advantageous for applications where cross-talk between individual windings is a problem. 
         [0058]    The cross ratio for a given application must be taken into account when winding new spools of microfilament. Furthermore, the firmware of the spooling apparatus must also be configured to maintain the desired cross ratio as the microfilament is deployed and re-spooled from the spooling apparatus. 
       4.3 Feeder/Tension Sensor 
       [0059]    Referring to  FIG. 6 , one example of the feeder/tension sensor  226  is configured to safely and quickly deploy and re-spool microfilament from the spooling apparatus. The feeder/tension sensor  226  includes a level winder  680 , a dancer mechanism  682 , a pinch roller mechanism  684 , and a tension sensor  686 . The level winder  680  maintains a proper cross ratio of the spooled microfilament  106 , the dancer mechanism  682  mitigates microfilament slack within the spooling apparatus, the pinch roller mechanism  684  maintains a desired microfilament tension within the spooling apparatus, and the tension sensor monitors the amount of tension on the microfilament. 
       4.4 Full or Partial Tethering 
       [0060]    Referring to  FIG. 7 , another example of the ground powered unmanned aerial vehicle system  100  is configured to constrain a range of motion of the aerial vehicle  102  within a boundary  742 . In some examples, the boundary  742  is three dimensional. For example, the boundary  742  shown in  FIG. 7  (which is circular when viewed from above) may have, for example, a three dimensional dome shape. In some examples, the boundary  742  can take on other shapes, including user-defined and possibly irregular shapes. 
         [0061]    In some examples, the boundary  742  may be maintained by providing the spooling apparatus  112  of the base station  104  with a limited amount of filament  106  such that, as the aerial vehicle  102  approaches the boundary  742 , the spooling apparatus  112  is unable to deploy any more filament  106 . In other examples, the boundary  742  may be maintained by providing the spooling apparatus  112  with a specification of the boundary  742  and configuring the spooling apparatus  112  to refuse to deploy additional filament  106  when the aerial vehicle  102  is at the edge of the boundary  742 . 
         [0062]    In some examples, the filament  106  is stronger than the communications and power transmission filament described above in order to resist breaking when tension is applied to the filament  106  at the edge of the boundary  742 . 
         [0063]    In some examples, the aerial vehicle  102  is self powered (e.g., a battery powered aerial vehicle) and the filament is used only as a tether to constrain the aerial vehicle  102 . 
       5 Deployment Configurations 
       [0064]    Referring to  FIG. 8 , in some examples, the airframe of the aerial vehicle is collapsible such that the vehicle can be easily and safely stowed in a compact container. For example, the airframe of the aerial vehicle can operate in an expanded state  886  and collapse to a collapsed state  888  when no longer operating. In this way, the aerial vehicle can easily be stowed and transported without being unduly cumbersome and with reduced risk of being damaged. 
         [0065]    Referring to  FIG. 9 , in some examples, the elements described above can be packaged into a ruggedized container  990  for safe deployment. The ruggedized container can include a number of compartments  992  for safely and securely storing different components of the aerial vehicle system such as the aerial vehicle (or parts thereof), the spooler apparatus, additional spools of microfilament, and so on. 
         [0066]    Referring to  FIG. 10 , in some examples, the elements described above can be packaged into a human portable container such as a backpack  1094  that can easily be carried by a human. For example, the back pack can be configured to facilitate safe and secure transportation of the collapsed aerial vehicle  1095 , the base station of the aerial vehicle system  1096 , and the spooling apparatus  1098 . In some examples, the base station  1096  and the spooling apparatus  1098  are packed first into the backpack  1094  and the collapsed aerial vehicle  1095  is packed on top of the base station  1096  and the spooling apparatus  1098 . 
         [0067]    Referring to  FIG. 11 , in some examples the elements described above can be packaged into a vehicle mountable container  1100  which can be mounted to a roof of a vehicle  1102 . In other examples, the vehicle mountable container  1100  can be mounted to a bed of a pickup truck, on a flat bed trailer, on a Humvee, or on an armored personnel carrier. In some examples, the aerial vehicle system in the vehicle mountable container  1100  is configured to draw power from the vehicle  1102 . In some examples, the vehicle mountable container  1100  can be used for mobile operation of the ground powered unmanned aerial vehicle system  100 , with the aerial vehicle  102  following the vehicle  1102 . In other examples, the vehicle mountable container can be used for stationary operation of ground powered unmanned aerial vehicle system  100 . 
       6 Alternatives 
       [0068]    The filament  106  is described above as an electrically conductive filament. However, in some examples, the filament is a fiber optic cable over which the control station  110  communicates with the aerial vehicle  102 . 
         [0069]    In some examples, the system of  FIG. 1  includes a power conversion box between the power source  108  and the spooling apparatus  112  for converting the power produced by the power source  108  into a form that is usable by the aerial vehicle  102 . 
         [0070]    While the communication between the control station  110  and the aerial vehicle  102  is described above as taking place over a network connection, various other types of communication protocols can be used. For example, the control station  110  and the aerial vehicle  102  can communicate using point-to-point serial communications, USB communications, etc. 
         [0071]    In some examples, the aerial vehicle  102  includes payload that includes a high definition visible light video camera and the video stream is a high definition digital video stream such as a 720p, 1080i, or 1080p video stream. In some examples, the aerial vehicle includes a payload including multicore cameras, TOF laser depth cameras, hyperspectral cameras, or multi-sensor gigapixel camera arrays. In some examples, the aerial vehicle  102  includes a night vision camera such as an active illumination video camera or a thermal imaging camera. In some examples, the aerial vehicle  102  includes both a visible light video camera and a night vision camera. In some examples, the aerial vehicle  102  includes a high resolution still camera. In some examples, other payloads can include sensors, emitters (e.g., lasers), or weapons systems. 
         [0072]    While the above description generally describes the position sensor  227  as being located within the spooling apparatus  112 , it is noted that the position sensor  227  does not need to be located within the spooling apparatus  112 . For example, the position sensor  227  could be located some distance from the spooling apparatus  112   
         [0073]    In some examples, the spooling apparatus  112  maintains a record of how much filament  106  is currently deployed and the control system  228  takes the record into account when controlling the speed and direction of rotation of the spool  224 . 
         [0074]    In some examples, the aerial vehicle  102  is configured to fly to a higher altitude to take up slack on the filament  106  in an emergency situation. In other examples, the aerial vehicle  102  includes an on-board supplementary spooling apparatus which can take up slack on the filament  106  in an emergency situation. 
         [0075]    In some examples, the aerial vehicle  102  includes a battery which acts as reserve power for situations where the filament  102  is severed or damaged, interrupting power from the power source  108 . The battery allows the aerial vehicle  102  to safely land. 
         [0076]    In some examples, the aerial vehicle  102  includes a configurable bay for accepting custom payloads. 
         [0077]    In some examples, the system  100 , including some or all of the aerial vehicle  102 , the spooler  112 , and control computer  110  are connected to a communications network such one or more other computers on the communications network are connected to and can interact with the system  100  to either control it or gather and analyze data. 
         [0078]    It is to be understood that the foregoing description is intended to illustrate and not to limit the scope of the invention, which is defined by the scope of the appended claims. Other embodiments are within the scope of the following claims.