`US 20090157233A1
`
`119) United States
`112) Patent Application Publication
`Kokkeby et al.
`
`110) Pub. No. : US 2009/0157233 A1
`Jun. 18, 2009
`(43) Pub. Date:
`
`154) SYSTEM AND METHODS FOR
`AUTONOMOUS TRACKING AND
`SURVEILLANCE
`
`176)
`
`Inventors:
`
`Kristen L. Kokkeby, Corona, CA
`1US); Robert P. Lutter, Tacoma,
`WA (US); Michael L. Munoz,
`Tacoma, WA (US); Frederick W.
`Cathey, Seattle, WA (US); David J.
`Hilliard, Shoreline, WA 1US);
`Trevor L. Olson, Seattle, WA 1US)
`
`Correspondence Address:
`KLEIN, O' NEILL 4 SINGH, LLP
`43 CORPORATE PARK, SUITE 204
`IRVINE, CA 92606 (US)
`
`121) Appl. No. :
`
`11/956, 711
`
`122) Filed:
`
`Dec. 14, 2007
`
`Publication Classification
`
`151) Int. Cl.
`G05D 1/00
`
`12006. 01)
`
`. 701/3
`
`ABSTRACT
`
`152) U. S. Cl. .
`157)
`A system and methods for autonomously
`tracking and simul-
`taneously providing surveillance of a target from air vehicles.
`In one embodiment
`the system receives inputs from outside
`sources, creates tracks, identifies
`the targets and generates
`flight plans for unmanned
`air vehicles 1UAVs) and camera
`controls for surveillance of the targets. The system uses pre-
`dictive algorithms and aircraft control laws. The system com-
`prises a plurality of modules configured to accomplish these
`tasks. One embodiment comprises an automatic target recog-
`to receive video informa-
`nition 1ATR) module configured
`tion, process the video information, and produce ATR infor-
`mation including target information. The embodiment
`further
`comprises a multi-sensor
`integrator 1MSI) module configured
`to receive the ATR information, an air vehicle state input and
`track
`a target state input, process
`the inputs and produce
`information for the target. The embodiment
`further comprises
`to receive the track information,
`a target module configured
`process the track information, and produce predicted future
`state target information. The embodiment
`further comprises
`to receive the track informa-
`an ownship module configured
`tion, process the track information,
`and produce predicted
`future state air vehicle information. The embodiment
`further
`to receive the pre-
`comprises a planner module configured
`dicted future state target information and the predicted future
`travel path infor-
`state air vehicle information and generate
`for
`flight and camera steering commands
`mation
`including
`the air vehicle.
`
`RECEIVE AIRCRAFT VIDEOS
`S118
`
`RECEIVE AIRCRAFT STATE
`AND TARGET STATE
`S120
`
`INTEGRATE TARGET AND
`AIRCRAFT DATA
`S122
`
`GENERATE TARGET FILE
`S124
`
`PREDICT UAV AND TARGET
`POSITIONS
`8126
`
`PREDICT FUTURE UAV STATES AND
`REVISE UAV PLAN, WHEN NEEDED
`S'I 28
`
`VERIFY PLAN VALIDITY
`S130
`
`GENERATE CAMERA CONTROL AND
`UAV NAVIGATION COMMANDS
`S132
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`Yuneec Exhibit 1017 Page 1
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`Loiter Circle
`
`Statlonag
`Tat get
`
`Weave Plan
`
`I
`
`Moving Target
`72
`80---
`
`FIG. 3
`
`Chase Plan
`
`Fast Moving Target
`72
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`-8000
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`-6000
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`I
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`'2500
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`-5000
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`-10000
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`-12500
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`r
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`US 2009/0157233 A1
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`Jun. 18, 2009
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`SYSTEM AND METHODS FOR
`AUTONOMOUS TRACKING AND
`SURVEILLANCE
`
`BACKGROUND
`[0001] 1. Technical Field
`to control of
`[0002] The present
`disclosure
`relates
`air vehicles (UAVs), tracking of moving
`unmanned
`targets
`and surveillance of areas, stationary
`targets and moving tar-
`gets.
`[0003] 2. Description of Related Art
`[0004] Aerial surveillance and tracking includes the use of
`unmanned air vehicles. Currently human operators remotely
`control UAVs. The operators must steer both the UAV and the
`in order to maintain
`camera/surveillance
`tracking
`payload
`and positive identification of a moving target. Positive iden-
`or obstructions
`tification may require no interruptions
`in
`visual observation of the target. This practice is labor inten-
`sive, and therefore expensive. Usually two operators track a
`single target, enabling one operator to control flight and the
`focus, zoom, etc.
`other operator to control camera pointing,
`And in military applications
`involving hill value targets, such
`two UAVs are dedicated
`to the
`terrorists, usually
`as known
`four operators. Remotely controlling
`target,
`thus requiring
`is also prone to loss of positive
`UAVs with human operators
`identification due to bad vehicle position or bad camera angle.
`Current methods also do not adequately
`support real time
`collection of target attribute data. In addition,
`the operators
`must pay special attention to no fly zones, restricted airspace
`and obstructions, further increasing the difficulty o f maintain-
`track.
`ing an uninterrupted
`
`SUMMARY
`
`[0005] The embodiments of the present system and meth-
`ods for autonomous
`tracking and surveillance have several
`features, no single one of which is solely responsible for their
`desirable attributes. Without limiting the scope of the present
`as expressed by the claims that follow, their
`embodiments
`features now will be discussed briefly. After
`more prominent
`this discussion, and particularly after reading the
`considering
`section entitled "Detailed Description", one will understand
`how the features of the present embodiments provide advan-
`in the number of human
`include a reduction
`tages, which
`operators needed to operate the system, which in turn trans-
`lates into cost savings, a reduction
`in the likelihood
`that
`tracked targets will be lost, a decrease in the risk that UAVs
`will be lost due to crashes/collisions,
`and a decrease in the risk
`that UAVs will enter no fly zones.
`[0006] One aspect of the present system and methods for
`the realiza-
`includes
`tracking and surveillance
`autonomous
`tion that current systems for tracking and surveillance
`are
`heavily dependent upon human operators. This dependence
`is costly, and subject to losses of target/track
`upon humans
`data due to bad vehicle position or bad camera angle. Human
`to blame for these losses. Accordingly, a
`error is frequently
`for automating
`system and methods
`surveillance,
`targeting
`and tracking functions would save costs and reduce errors.
`[0007] One embodiment of the present system for autono-
`tracking a target from an air vehicle comprises an
`mously
`to
`target recognition
`automatic
`(ATR) module configured
`receive video information, process the video information, and
`produce ATR information
`target information. The
`including
`further comprises a multi-sensor
`(MSI)
`integrator
`system
`
`to receive the ATR information,
`an air
`module configured
`vehicle state input and a target state input, process the inputs
`for the target. The system
`track information
`and produce
`to receive the
`further comprises a target module configured
`track information, process the track information, and produce
`predicted future state target information. The system further
`comprises an ownship module configured to receive the track
`information, process the track information, and produce pre-
`dicted future state air vehicle information. The system further
`to receive the pre-
`comprises a planner module configured
`dicted future state target information and the predicted future
`travel path infor-
`state air vehicle information and generate
`mation including fight and camera steering commands for the
`air vehicle.
`[000S] One embodiment of the present methods of autono-
`mously tracking a target from an airborne vehicle comprises
`the steps of receiving video information
`input to an automatic
`target recognition (ATR) module, processing the video infor-
`mation, and producing ATR information. The method further
`the steps of receiving
`the ATR information,
`air
`comprises
`vehicle state
`as
`information
`information
`and target state
`to a multi-sensor
`the
`(MSI), processing
`integrator
`inputs
`track information. The method further
`inputs and producing
`the steps of receiving the track information as an
`comprises
`the track information,
`input to a target module, processing
`predicting a future state of the target and producing
`target
`the steps of
`information. The method
`further comprises
`to an ownship
`the track information
`receiving
`as an input
`module, processing the track information, predicting a future
`state of the air vehicle and producing ownship
`information.
`The method further comprises the steps of receiving the target
`information as inputs to a plan-
`information and the ownship
`ner module and generating a travel path for the air vehicle.
`embodiment of the present
`for
`[0009] Another
`system
`tracking a target from an air vehicle comprises
`autonomously
`means for receiving video information, processing the video
`recognition
`automatic
`information,
`target
`and producing
`target information. The system
`(ATR) information
`including
`further comprises means for receiving the ATR information,
`an air vehicle state input and a target state input, processing
`track information for the target. The
`the inputs and producing
`system further comprises means for receiving the track infor-
`mation, processing the track information, and producing pre-
`information. The system
`dicted future state target
`further
`comprises means for receiving
`the track information, pro-
`cessing the track information, and producing predicted future
`state air vehicle information. The system further comprises
`means for receiving the predicted future state target informa-
`tion and the predicted future state air vehicle information and
`flight and cam-
`travel path information
`including
`generating
`for the air vehicle.
`era steering commands
`and advantages of the
`[0010] The features,
`functions,
`in vari-
`present embodiments can be achieved independently
`ous embodiments, or may be combined
`in yet other embodi-
`ments.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0011] The embodiments of the present system and meth-
`tracking and surveillance now will be
`ods for autonomous
`in detail with an emphasis on highlighting
`discussed
`the
`features. These embodiments depict the novel
`advantageous
`system and methods shown in the accom-
`and non-obvious
`
`Yuneec Exhibit 1017 Page 8
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`panying drawings, which are for illustrative purposes only.
`These drawings
`include the following figures, in which like
`indicate like parts:
`numerals
`[0012] FIG. 1 is a functional block diagram of one embodi-
`ment of the present system and methods
`for autonomous
`tracking and surveillance;
`[0013] FIG. 2 is a schematic view of a loiter circle accord-
`ing to one embodiment of the present system and methods for
`tracking and surveillance;
`autonomous
`[0014] FIG. 3 is a schematic view of a weave plan accord-
`ing to one embodiment of the present system and methods for
`tracking and surveillance;
`autonomous
`[0015] FIG. 4 is a schematic view of a chase plan according
`to one embodiment of the present system and methods
`for
`tracking and surveillance;
`autonomous
`[0016] FIG. 5 is a schematic view of a method of smoothing
`noisy tracking data according to one embodiment;
`[0017] FIG. 6 is a schematic view of a systematic search
`in which the UAV remains on one side of a border
`pattern
`while capturing visual images across the border according to
`one embodiment;
`[001S] FIG. 7 is a process flow diagram for autonomously
`tracking a target using a UAV according to one embodiment;
`and
`[0019] FIG. S is a schematic view of one embodiment of the
`present system including a UAV and a ground station.
`
`DETAILED DESCRIPTION
`[0020] Embodiments of the present system andmethods
`for
`to
`are configured
`and surveillance
`autonomous
`tracking
`to
`air vehicle
`enable an unmanned
`(UAV) continuously
`observe stationary and track moving
`targets while maintain-
`ing a low risk that the surveillance asset will be discovered.
`The targets may be ground-based,
`airborne and/or seaborne.
`The targets may be fixed structures,
`such as buildings, and
`may even be subsurface. The automated UAVs may also
`conduct general surveillance of an area, such as for defense of
`a base or fleet, and for monitoring
`roadsides for improvised
`explosive devices (IEDs) to protect ground-based
`convoys.
`The present system may be applied
`in both military and
`civilian environments. For example, the military may use the
`system to surveil or observe hostile areas in search of military
`targets, or a police department may use the system to track
`fleeing suspects.
`[0021] The system accepts target data and UAV data (and
`may accept other data, such as obstruction data and/or "blue
`force" data from the UAV or a ground station). The system
`route to maintain an
`the best navigation
`then determines
`slant range to the target for high quality camera
`advantageous
`imaging and a low probability of intercept (LPOI). The sys-
`tem then computes trajectories/flight paths to reduce the like-
`lihood of discovery of the UAV (also referred to herein as
`"ownship"). The system may incorporate numerous
`tracking
`including weaves, orbits, escapes,
`and maneuver
`techniques,
`and lead/lag pursuit course estimations. The system also con-
`trols the camera aboard the UAV to maintain uninterrupted
`visual contact with the target. The system is adapted to control
`both navigation and camera functions simultaneously.
`[0022] Because the present system is automated
`it drasti-
`cally reduces the workload of any operator(s) monitoring
`the
`system. The system thus enables tracking of high value mov-
`ing targets while reducing the likelihood of a loss of positive
`identification
`in target viewing) during
`target
`(interruption
`tracking. The operator can "fly the camera. " because he or she
`
`is relieved of the dual duty of navigating
`the UAV and main-
`the desired pointing of the camera. The operator is
`taining
`thus able to focus on stalking targets, scanning borders, look-
`ing for IEDs, etc. The system also enables a single operator to
`track multiple moving targets simultaneously,
`the
`increasing
`probability of engaging a high value target after an external
`incident. Because one operator
`attack or a base intrusion
`working at a single location, such as an Insitu Multiple UAV
`(IMUSE) station, may track multiple
`Software Environment
`the logistical footprint
`the present system reduces
`targets,
`necessary for target tracking. The present system also allows
`tar-
`an operator to control multiple UAVs to track maritime
`gets. It can establish a visual identification area around deep
`track and identify small or
`sea and littoral fleets to monitor,
`large moving objects.
`[0023]
`In one embodiment, a system (also referredto herein
`as a "Stalker system") and associated methods provide auto-
`matic generation of UAV and camera steering controls for
`itself may be imple-
`target following. The Stalker system
`mented as software executable code, specialized application
`specific integrated circuits (AS ICs), or a combination
`thereof,
`in hardware and oth-
`where some functions are implemented
`ers in executable code. In a high-level
`sense, the Stalker
`system can operate as a finite state machine where the states
`are steps in a plan to achieve a certain desired trajectory. The
`Stalker system accepts target and UAV state updates, and
`when engaged may be queried for UAV and camera com-
`mands. FIG. 1, which is described in detail below, illustrates
`this process. Each UAV command query checks for a plan-
`ning state transition and may output a new UAV steering
`command depending upon the selected mode.
`[0024] Embodiments of the Stalker system support at least
`four main functions. One function
`is generating UAV and
`for stalking a cooperative
`camera positions and orientations
`target. A cooperative moving
`is one that
`target
`moving
`its own geodetic position, as is typical of
`actively publishes
`friendly forces. Another function is generating UAV and cam-
`for stalking a non-
`era position and orientation commands
`is autono-
`cooperative moving
`the tracking
`target, whether
`mous, or by an operator using a camera joystick. A non-
`is one whose position must be
`cooperative moving
`target
`the use of electronic sensors and operator
`observed through
`inputs, as is typical of hostile forces. Another
`is
`function
`generating UAV and camera position and orientation com-
`for automatic
`to
`camera and position calibration
`mands
`reduce target location errors. Another function
`is generating
`for
`UAV and camera position and orientation
`commands
`subse-
`stalking a roadside or a search area, and generating
`to revisit targets if targets of interest are
`quent commands
`detected in those specified areas.
`[0025] One goal of the Stalker system is to establish and
`maintain a range to target between preset minimum and maxi-
`mum values. These values are specified to provide a large
`number of pixels on the target, while maintaining noise and
`that the target is not likely to detect. Another
`visual signatures
`goal of the Stalker system is to maintain an uninterrupted
`line
`of sight to the target, taking care to avoid obstructing viewing
`angles with the wing and fuselage.
`In embodiments of the present system, a UAV (not
`[0026]
`shown) includes at least one video camera, which may be a
`form of camera
`digital camera. For simplicity
`the singular
`those of ordinary skill in
`will be used throughout,
`although
`that the UAV may include more than
`the art will appreciate
`one camera. The UAV further includes a plurality of sensors.
`
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`A first subset of the sensors detects various states of the UAV,
`while a second subset of the sensors detects various states of
`the target. The detected states may include, but are not limited
`speed, acceleration and
`to position, orientation,
`heading,
`other kinematic states, size, type and/or class of the target, and
`other states. A video signal generated by the camera and
`to hardware
`signals generated by the sensors are transmitted
`to visualize and track the
`that use the signals
`components
`target. FIG. 1 illustrates some of these components. Some or
`all of the components
`in FIG. 1 could be located on
`illustrated
`the UAV or they could be located at one or more ground
`could also be split between
`stations. The components
`the
`UAV and one or more ground stations. FIG. S illustrates an
`example embodiment of the present system including a UAV
`74 and a ground station 134.
`the terms "component",
`[0027] As used in this disclosure,
`"module", "system. " and the like are intended
`to refer to a
`entity, either hardware, a combination of
`computer-related
`hardware and software, software, or software
`in execution.
`For example, a component may be, but is not limited to being,
`a process running on a processor, a processor, a hardware
`component, an object, an executable, a thread of execution, a
`program, and/or a computing system. Also, these components
`can execute from various computer readable media having
`various data structures stored thereon. Computer executable
`(or code) can be stored, for example, on com-
`components
`puter readable media including, but not limited to, an ASIC
`(application specific integrated circuit), CD (compact disc),
`DVD (digital video disk), ROM (read only memory), floppy
`disk, hard disk, EEPROM (electrically erasable program-
`mable read only memory) and memory stick in accordance
`with the claimed subject matter.
`to FIG. 1, one embodiment of the
`[002S] With reference
`present system 20 includes an automatic
`target recognition
`integration (MSI) mod-
`(ATR) module 22 and a multi-sensor
`ule 24. As used herein,
`the term module may include any
`combination of hardware,
`firmware, and software to imple-
`ment the functions described. The ATR module 22 receives a
`video signal 26 from the UAV (not shown). The ATR module
`22 includes
`the video signal 26 and
`to analyze
`instructions
`generates an output 2S that it sends to the MSI module 24. In
`to the ATR output 2S, the MSI module 24 also
`addition
`receives a UAV state signal 30 and a target state signal 32. The
`signals 30, 32 are generated by the sensors described above,
`and may also be generated by other sources observing
`the
`UAV and/or the target, such as ground-based observers, radar,
`satellites, etc. All of these signals include information about
`the states of the UAV and the target, which may include
`speed, acceleration
`position, orientation,
`heading,
`and/or
`other kinematic states, size, type and/or class of the target, and
`other states.
`inputs 2S, 30, 32
`[0029] The MSI module 24 receives
`described above and processes the data therein to produce an
`output 34. The MSI module output 34 is referred to herein as
`track information or a track file. The track file 34 includes not
`the kinematics o f the UAV and the
`only information regarding
`target, but also estimates of the accuracy of the data in the
`track file 34, and also target identification data, such as the
`type of the target, whether
`the target is
`size, class, and/or
`cooperative or non-cooperative, etc. Those o f ordinary skill in
`that the track file may or may not be
`the art will appreciate
`retrieval. The word "file" is
`stored in memory for subsequent
`
`used broadly herein and does not imply that the process of
`step of
`the track file 34 includes an additional
`producing
`storing the file in memory.
`[0030] The MSI module 24 sends the track file 34 to a target
`module 36 and an ownship module 3S. The target module 36
`processes the data in the track file 34 relating to the current
`state of the target, and compares (Gates) this data to previous
`the current state o f the target. The
`predictions made regarding
`target module 36 uses all available data and comparisons
`between past predictions and current states, and makes fur-
`ther predictions about future states of the target. Gating
`in
`target module 36 produces an output 40 that it sends to a
`planner module 42.
`[0031] Ownship module 3S processes the data in the track
`file 34 relating to the current state of the UAV, and compares
`(Gates) this data to previous predictions
`(not shown) made
`the current state of the UAV. Discrepancies
`in the
`regarding
`predicted state of the UAV versus its current state may be due
`the UAV off its intended
`to, for example, winds blowing
`course. The ownship module 3S uses all available data and
`comparisons between past predictions and current states, and
`about future states of the UAV.
`makes further predictions
`Gating in ownship module 3S then produces an output 44 that
`it sends to the planner module 42.
`[0032] The planner module 42 combines the target module
`input 44 with additional
`input 40 and the ownship module
`data provided by a legs module 46, a weave corridor module
`4S, a loiter circle module 50, a region search module 52, a
`command module 54 and a camera module 56. The functions
`of each of these modules are described in detail below. Based
`on the various inputs, the planner module 42 builds a model
`for predicting future UAV states given its current state and the
`currently active command. The planner module 42 uses the
`model to predict future UAV states at certain critical times,
`and to establish goals, which in turn produce predicted UAV
`and camera positions. The planner 42 also combines all data
`for course corrections and/or pattern
`to produce commands
`for the UAV. These adjustments
`are described
`adjustments
`below with respect to three top-level goal states for the UAV.
`The present system 20 uses all of the functions described
`in stalking both cooperative and non-co-
`above extensively
`operative targets.
`[0033] With continued reference to FIG. 1, the legs module
`46 predicts a long-term flight path for the UAV. In support of
`the legs module 46 also predicts
`the long-term predictions,
`short-term
`legs that together make up the long-term
`flight
`path. The legs module 46 communicates
`to the
`its predictions
`planner module 42 to aid the planner module 42 in creating
`to control the flight of the UAV.
`UAV commands
`to FIG. 1, in certain
`[0034] With continued
`reference
`the command module 54 includes data regard-
`embodiments
`ing the UAV mission environment. This data may include, for
`locations of interna-
`terrain maps,
`topographical
`example,
`tional borders, locations of obstructions and other data. The
`data may also include the locations and kinematics of other
`aircraft in the vicinity. By accessing the data in the command
`module 54, the present system 20 can command
`the UAV to
`track on a target while avoiding
`maintain an uninterrupted
`and crossing into no fly zones. The com-
`collisions/crashes
`mand module 54 also validates UAV commands to ensure that
`the UAV is capable of executing the commands
`to achieve the
`desired flight path. For example, if a UAV command indicates
`that the UAV should execute a very tight turn that is beyond
`
`Yuneec Exhibit 1017 Page 10
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`limits, the validity function of the com-
`the UAVs physical
`mand module 54 will reject the command as being impossible
`for the UAV to execute.
`[0035] With continued reference to FIG. 1, the present sys-
`tem 20 further comprises a camera module 56 and a camera
`commander module 5S. The camera module 56 predicts
`future camera imaging characteristics, such as pointing, focus
`and zoom. The camera module 56 communicates with the
`planner module 42 and generates outputs
`for the camera
`commander module 5S. The camera commander module 5S
`generates commands 60 for the camera, such as where to
`point and how to focus and zoom. Together the camera mod-
`ule 56 and the camera commander module 5S, in conjunction
`control camera
`with the planner module 42, automatically
`in order to obtain an uninterrupted
`functions
`and high quality
`image of the target.
`[0036]
`In certain embodiments
`the camera and/or sensors
`information beyond
`that generally
`may provide additional
`provided by traditional visual surveillance. For example, the
`camera/sensors may provide three-dimensional
`visual repre-
`sentations of the target. These three-dimensional
`views are
`enhanced by multi-aspect viewing of the target in accordance
`and chase surveillance
`the
`with
`loiter, weave,
`patterns
`described below. The camera/sensors may further provide
`informa-
`infrared signature
`information,
`signature
`thermal
`tion, color information, etc. for the target. All information
`collected by the camera/sensors may be provided to an ATR/
`Trainer module 62 (FIG. 1), described below, for use in future
`target identifications. Multiple aspect coverage of the target
`function of the
`target recognition
`enables
`the automatic
`present system 20, described below, to recognize geometric
`aspects of the target that are not available in two-dimensional
`or single aspect imagery, drastically decreasing the time nec-
`essary for the present system 20 to recognize the target.
`[0037] While in cooperative and non-cooperative
`stalking
`modes, and prior to receiving either the UAV state input 30 or
`the target state input 32, the Stalker system 20 is in a startup
`state. Once the system 20 has received both the UAV state
`input 30 and the target state input 32, the system 20 is queried
`for a steering command and/or a camera command. The sys-
`tem 20 then transitions
`from startup to a top-level goal state.
`These top-level goal states include loiter 64, weave 66, and
`chase 6S, each of which are illustrated
`in FIGS. 2-4, respec-
`tively. Those of ordinary skill in the art will appreciate
`that
`top-level goal states may be provided depending
`additional
`upon the state of the target.
`[003S] Each top-level goal state corresponds
`to a dynami-
`cally generated plan to attain a desired UAV trajectory for
`imaging quality while controlling visual and
`advantageous
`audio signatures of the UAV. Each top-level goal state is also
`intended to prevent over flight of the target, which could cause
`the target to detect the UAV. Consistent with these objectives,
`then, at least target speed and UAV speed detertmine
`the
`top-level goal. For example, if target speed is zero or near
`zero, the coal may be to loiter in a circle 70, as illustrated
`in
`FIG. 2. The loiter path 70 may encircle the target 72, or it may
`in the vicinity of the target 72. Further,
`be somewhere
`the
`loiter path 70 need not be a circle, but could be some other
`shape. If target speed is not near zero and is less than UAV
`speed, the goal may be to weave back and forth behind
`the
`in FIG. 3. If target speed is high, the
`target 72, as illustrated
`in FIG. 4. The
`goal may be to chase the target 72, as illustrated
`as the target 72 acceler-
`top-level goal changes dynamically
`ates, decelerates, stops and starts.
`
`[0039] Corresponding
`to each top-level goal are goal-spe-
`states, or steps to achieve the top-level goal.
`cific planning
`that are sched-
`These steps are mapped to steering commands
`uled to be sent to the UAV at specified times. Planning a UAV
`in both space and time and
`reasoning
`trajectory
`involves
`predicting how the UAV will respond to commands. There-
`fore, accurately
`a UAV
`trajectory preferably
`planning
`includes an estimate of the command
`time latency and a
`model of how the UAV will maneuver when it executes the
`command.
`[0040] When loitering, each UAV maneuver
`is executed
`to commands generated by the planner module 42 in
`pursuant
`conjunction with the loiter circle module 50 (FIG. 1). The
`loiter circle module 50 makes predictions regarding the future
`state of the UAV, which the planner module 42 uses to gen-
`for the UAV. In the case of a circular
`erate loiter commands
`loiter path 70 (FIG. 2), a loiter command has three parts: a
`turn center (a co-altitude geodetic location), a turn radius, and
`a turn direction (clockwise or counter-clockwise
`as viewed
`from above). Thus, when the system 20 determines
`that the
`the target 72 is stopped,
`loiter, as when
`the
`UAV should
`planner 42 and the loiter circle module 50 generate at least
`one loiter point for the UAV. The loiter point(s) is/are sent to
`that controls the UAV's movement along with
`the hardware
`camera pointing commands.
`if the aircraft
`[0041]
`In one embodiment,
`the
`is outside
`loiter circle 70 then it executes a loiter command
`commanded
`as follows. With reference to FIG. 2, the UAV 74 makes an
`initial turn 76 so that its direction of flight is tangential
`to the
`loiter circle 70 and is compatible with the commanded
`turn
`direction. The UAV 74 then flies straight to the tangent point
`7S. Upon reaching
`the tangent point 7S the UAV 74 flies
`around the loiter circle 70 until commanded
`to do otherwise.
`Each of these UAV maneuvers are executed pursuant
`to com-
`mands generated by the planner module 42 in conjunction
`with the loiter circle module 50 (FIG. 1).
`[0042] When the loiter path 70 encircles the target 72, the
`provides full 360' imaging of the
`loiter plan advantageously
`target 72. Images captured and other sensor readings
`taken
`from such 360' degree sweeps can advantageously
`provide
`the target 72 to the ATR module
`full geometric data regarding
`the ATR/Trainer module 6' (FIG. 1)
`22. In one embodiment
`logs the target data and attempts to identify the
`automatically
`target. If the target cannot be identified,
`then the ATR/Trainer
`module 62 classifies the target as a new entity and records the
`data. This data may be shared system wide, including con-
`to other UAVs in the field. The present
`tinuous dissemination
`system 20 thus rapidly increases its knowledge base as UAVs
`in the field gather more and more data about new targets and
`share that data with other UAVs in the field.
`to FIG. 3, when commanded
`[0043] With reference
`to
`execute a weave plan 66 the UAV 74 moves back and forth
`across the target's path of travel