Patent Publication Number: US-2022230354-A1

Title: Navigation system and method

Description:
The present application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 63/138,578 filed on Jan. 18, 2021, the entire disclosure of which is incorporated by reference herein. 
    
    
     INTRODUCTION 
     This disclosure relates generally to systems and methods of navigation for one or more vehicles located within a control volume. 
     Global positioning systems (GPS) may be used for navigation and geo-location in a wide variety of applications, including aircraft, surface watercraft, automotive vehicles and personal cell phones. However, GPS signals are not available or reliable in some environments, such as the “urban canyon” environments of large cities where tall buildings may obstruct GPS signals. GPS can also be electronically jammed, may not work reliably at high latitudes, and occasionally suffers drop-outs and periods of interrupted service. 
     Some alternatives to GPS systems are available, such as on-board radar, infrared camera systems and the like, but such alternatives tend to be heavy and expensive. 
     SUMMARY 
     According to one embodiment, a navigation system for one or more vehicles located within a control volume includes: a first camera configured to observe the one or more vehicles and first, second and third reference points within a first field of view, wherein the first, second and third reference points have first, second and third known spatial positions, respectively, the first camera being further configured to produce a first output signal from observation of the observed vehicles and reference points; a second camera configured to observe the one or more vehicles and the first, second and third reference points within a second field of view, the second camera being further configured to produce a second output signal from observation of the observed vehicles and reference points; and a processor operatively connected with the first and second cameras and configured to determine a respective spatial position for each of the one or more vehicles from the first and second output signals. 
     Each of the first, second and third known spatial positions may be a respective set of x, y and z coordinates, and each of the first, second and third known spatial positions may be known with respect to an origin located within the control volume. Additionally, each of the first and second cameras may be configured to detect at least one of visible light, infrared light and ultraviolet light, and may be disposed such that their respective fields of view are generally orthogonal with each other. Further, each of the first, second and third reference points may be (i) a respective point on a respective physical object disposed within the control volume and/or (ii) a respective focal point of a respective reference point beacon disposed within the control volume. 
     The first output signal may be representative of a first two-dimensional image of the control volume as viewed from the first camera, and the second output signal may be representative of a second two-dimensional image of the control volume as viewed from the second camera. 
     The navigation system may further include: (i) a transmitter operatively connected with the processor and configured to transmit one or more messages into the control volume, wherein the one or more messages contain a respective set of three-dimensional spatial coordinates for each of the one or more vehicles; (ii) a first real-time tracking system operatively connected with the first camera for determining respective first two-dimensional coordinates of each of the one or more vehicles using the first output signal and the first, second and third known spatial positions, and a second real-time tracking system operatively connected with the second camera for determining respective second two-dimensional coordinates of each of the one or more vehicles using the second output signal and the first, second and third known spatial positions; and/or (iii) a respective vehicle beacon configured to be carried aboard each of the one or more vehicles, wherein each vehicle beacon is configured to transmit a respective vehicle identification. 
     The one or more vehicles and the control volume may be, respectively: one or more aircraft and a landing zone including a first airspace above the landing zone; one or more ground vehicles and an area of terrain including a second airspace above the terrain; one or more surface watercraft and a region of open water including a third airspace above the open water; one or more submersible watercraft and a volume of navigable water; or one or more spacecraft and a volume of navigable space. 
     According to another embodiment, a navigation system for one or more vehicles located within a control volume includes: (i) a first camera configured to observe the one or more vehicles and first, second and third reference points within a first field of view, wherein the first, second and third reference points have first, second and third known spatial positions, respectively, and wherein each of the first, second and third known spatial positions is known with respect to an origin located within the control volume, the first camera being further configured to produce a first output signal from observation of the observed vehicles and reference points, wherein the first output signal is representative of a first two-dimensional image of the control volume as viewed from the first camera; (ii) a second camera configured to observe the one or more vehicles and the first, second and third reference points within a second field of view, the second camera being further configured to produce a second output signal from observation of the observed vehicles and reference points, wherein the second output signal is representative of a second two-dimensional image of the control volume as viewed from the second camera; (iii) a processor operatively connected with the first and second cameras and configured to determine a respective spatial position for each of the one or more vehicles from the first and second output signals; and (iv) a transmitter operatively connected with the processor and configured to transmit one or more messages into the control volume, wherein the one or more messages contain a respective set of three-dimensional spatial coordinates for each of the one or more vehicles. 
     Each of the first, second and third known spatial positions may be a respective set of x, y and z coordinates, and the first and second cameras may be disposed such that their respective fields of view are generally orthogonal with each other. Each of the first, second and third reference points may be (i) a respective point on a respective physical object disposed within the control volume and/or (ii) a respective focal point of a respective reference point beacon disposed within the control volume. 
     The navigation system may further include a respective vehicle beacon configured to be carried aboard each of the one or more vehicles, wherein each vehicle beacon is configured to transmit a respective vehicle identification. Additionally, the navigation system may further include: a first real-time tracking system operatively connected with the first camera for determining respective first two-dimensional coordinates of each of the one or more vehicles using the first output signal and the first, second and third known spatial positions; and a second real-time tracking system operatively connected with the second camera for determining respective second two-dimensional coordinates of each of the one or more vehicles using the second output signal and the first, second and third known spatial positions. 
     According to yet another embodiment, a method of navigation for one or more vehicles located within a control volume includes: (i) observing, with a first camera, the one or more vehicles and first, second and third reference points within a first field of view, wherein the first, second and third reference points have first, second and third known spatial positions, respectively; (ii) producing, by the first camera, a first output signal from observation of the observed vehicles and reference points; (iii) observing, with a second camera, the one or more vehicles and the first, second and third reference points within a second field of view; (iv) producing, by the second camera, a second output signal from observation of the observed vehicles and reference points; and (v) determining, by a processor operatively connected with the first and second cameras, a respective spatial position for each of the one or more vehicles from the first and second output signals. 
     The method may further include one or more of: determining respective first two-dimensional coordinates of each of the one or more vehicles using the first output signal and the first, second and third known spatial positions; determining respective second two-dimensional coordinates of each of the one or more vehicles using the second output signal and the first, second and third known spatial positions; transmitting one or more messages into the control volume, wherein the one or more messages contain a respective set of three-dimensional spatial coordinates for each of the one or more vehicles; and receiving a respective vehicle identification transmitted from a respective vehicle beacon carried aboard each of the one or more vehicles. 
     The above features and advantages, and other features and advantages, of the present teachings are readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out the present teachings, as defined in the appended claims, when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective schematic view and block diagram of first and second embodiments of a navigation system. 
         FIG. 2  is a perspective schematic view of a reference point beacon, emitter or reflector. 
         FIG. 3  is an alternative front perspective schematic view and block diagram of the configuration shown in  FIG. 1 . 
         FIG. 4  is a front perspective schematic view and block diagram of third and fourth embodiments of a navigation system. 
         FIG. 5  is a front perspective schematic view and block diagram of an alternative configuration of the third and fourth embodiments. 
         FIG. 6  is another alternative front perspective schematic view and block diagram of the first configuration shown in  FIGS. 1 and 3 , illustrating message broadcast. 
         FIG. 7  is an alternative front perspective schematic view and block diagram of the third configuration shown in  FIG. 5 , illustrating message broadcast. 
         FIG. 8  is a flowchart for a method of navigation utilizing a navigation system according to first and second embodiments of the present disclosure. 
         FIG. 9  is a flowchart for a method of navigation utilizing a navigation system according to third and fourth embodiments of the present disclosure. 
         FIGS. 10A-E  are schematic perspective views of the vehicles and control volume of  FIGS. 1 and 3-7 , specifically: aircraft and a landing zone; ground vehicles and an area of terrain; surface watercraft and a region of open water; submersible watercraft and a volume of navigable water; and spacecraft and a volume of navigable space. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, wherein like numerals indicate like parts in the several views, a navigation system  20  for one or more vehicles  22  located within a control volume  24 , and a method  100 ,  200  of navigation for one or more vehicles  22  located within a control volume  24 , are shown and described herein. The navigation system  20  and method  100 ,  200  are described below in multiple embodiments, each of which is effective for determining the spatial position SP (e.g., three-dimensional spatial coordinates  69 ) of each of the one or more vehicles  22  within the control volume  24 , which may be used for navigation, collision avoidance, trajectory planning, traffic control and the like. 
     The navigation system  20  and method  100 ,  200  provide GPS-like navigation information which may be useful in environments where GPS is not available or not reliable (such as “urban canyon” environments in cities). Additionally or alternatively, the navigation system  20  and method  100 ,  200  may serve as a complementary, supplemental or redundant back-up system to GPS and other geo-location systems. 
     Note that certain reference numerals in the drawings have subscripts, such as the two vehicles  22   1  and  22   2  in  FIGS. 1 and 3-7 . Subscripts are used in the drawings and in the present description to refer to individual elements (such as the aforementioned vehicles), while the use of reference numerals without subscripts may refer to the collective group of such elements and/or to a singular but generic one of such elements. Thus, reference numeral  22   1  refers to a specific vehicle, while reference numeral  22  (without the subscript) may refer to all the vehicles, the group of vehicles, or a singular but generic vehicle (i.e., any vehicle). 
     The control volume  24  is represented in the drawings as a rectangular volume, but other volumetric shapes may also be used. Each of the vehicles  22  is represented in the drawings as a small pentagon having a center or centroid  28 , at which an optional time-modulated beacon or transponder  29  may be carried. (Such beacons  29  may also be carried at locations other than the vehicle centroid  28 , such as on the vehicle&#39;s exterior.) The vehicles  22  and control volume  24  are described herein in an exemplary manner as being, respectively, one or more aircraft (e.g., fixed-wing, rotary-wing, drones, etc.)  22   AC , and a landing zone or runway  25   LZ  including a first airspace  23   A1  above the landing zone  25   LZ  ( FIG. 10A ). However, the one or more vehicles  22  and the control volume  24  may assume various other configurations, such as: (i) one or more ground vehicles  22   GV  and an area of terrain  25   T  including a second airspace  23   A2  above the terrain  25   T  ( FIG. 10B ); (ii) one or more surface watercraft  22   SWC  and a region of open water having a surface  25   OW  and including a third airspace  23   A3  above the open water surface  25   OW  ( FIG. 10C ); (iii) one or more submersible watercraft  22   SUB  and a volume of navigable water V NW , optionally including an open water surface  25   OW , a fourth airspace  23   A4  above the water surface  25   OW , and/or a sea floor, river bed or other ground plane  25   F  beneath the volume of water V NW  ( FIG. 10D ); or (iv) one or more satellite or other spacecraft  22   SC  and a volume of navigable space V NS , optionally including one or more control surfaces  25   CS  (e.g., the outer surface of a space station, asteroid, etc.) which the spacecraft  22   SC  may be engaged with ( FIG. 10E ). Note that the drawings herein are schematic in nature and are not necessarily drawn to scale. 
     As illustrated in  FIGS. 1, 3-5 and 10A -E, the control volume  24  may have a surface  25  therein, such as the ground (in the case of an airspace), the surface above a body of water, or a sea floor, river bed or the like beneath a volume of water. This surface  25  may be flat and smooth, or uneven and undulating. The control volume  24  may also contain an origin or zero point  26  from which position coordinates may be measured for vehicles  22  and other objects within the control volume  24 . The origin or zero point  26  may correspond to a physical landmark or other physical object within the control volume  24 , or it may be an arbitrarily assigned point in space within the control volume  24 . From this origin or zero point  26 , the respective x, y and z coordinates of other objects within the control volume  24  (e.g., vehicles  22  and reference points  30 ) may be determined. For example, as illustrated in  FIG. 1 , the origin  26  may be defined at the front lower left corner of the control volume  24 , with the x, y and z coordinates of a first vehicle  22   1  being (x 1 , y 1 , z 1 ) and of a second vehicle  22   2  being (x 2 , y 2 , z 2 ). As other examples, the origin  26  may be a landing point on the ground, a landing point on a building or other structure, a landing point on a vehicle  22 , a docking point or dock in a port, and the like. Thus, the origin  26  may be the intended destination or landing/docking point for one or more vehicles  22 , and the x, y and z axes and coordinates may be defined as extending from the origin  26 . Note that prior to implementation of the navigation system  20  and method  100 ,  200 , the x, y and z coordinates of the one or more of the vehicles  22 —and perhaps of all of the vehicles  22 —are not known, but may be determined by use of the navigation system  20  and method  100 ,  200 . 
     The control volume  24  may also contain first and second reference points  30   A ,  30   B , and optionally a third reference point  30   C . (Alternatively, one or more of these reference points  30  may be disposed outside of the control volume  24 , as further discussed below.) Each of these reference points  30   A ,  30   B ,  30   C  has a respective known spatial position SP A , SP B , SP C , each of which may be represented by a respective set of x, y and z coordinates (e.g., as measured from or defined with respect to the origin  26 ). Each of the first, second and third known spatial positions SP A , SP B , SP C  may be known, measured or defined with respect to the origin  26 , which may be located within the control volume  24  or outside the control volume  24 . For example, as shown in  FIG. 1 , the first and second reference points  30   A ,  30   B  may be located at the two back lower corners of the control volume  24 , and the third reference point  30   C  may be located in the middle of the front lower edge of the control volume  24 , with all three reference points  30   A ,  30   B ,  30   C  being elevated just slightly above the surface or ground  25 . Each of the reference points  30   A ,  30   B ,  30   C  may be (i) a respective point  31  on a respective physical object  39  disposed within the control volume  24 , and/or (ii) a respective focal point  38  of a respective reference point beacon  32  disposed within the control volume  24 . The known spatial positions SP A , SP B , SP C  of the reference points  30   A ,  30   B ,  30   C  may be known, measured or defined relative to an Earth-oriented inertial reference frame, or to any arbitrary inertial reference frame, which may be stationary with respect to the Earth (such as a helipad on the roof of a building) or moving (such as a helipad on a boat floating/moving on the surface of a body of water). 
       FIG. 2  shows a perspective schematic view of a reference point beacon, emitter or reflector  32  (hereinafter referred to as a “beacon/reflector”) which may be used for each reference point  30 . The beacon/reflector  32  includes body portion  33  carried atop a stand  34  which is fixed in the ground or surface  25 , thus disposing the body portion  33  at a certain height above the surface  25 . (Alternatively, the beacon/reflector  32  may not include a stand  34 , and the body portion  33  may be disposed upon or flush with the ground surface  25 .) The beacon/reflector  32  may be an “active” device which includes a lens or emitter portion  35  on the body portion  33  from which a collection of beams or rays of electromagnetic (EM) energy  36  may be directed (such as visible light, microwave energy, etc.). In the case of an active beacon/reflector  32 , the EM energy  36  may be emanating continuously or in pulses. On the other hand, the beacon/reflector  32  may be a “passive” device which includes a mirror or reflector portion  35  on the body portion  33  which easily reflects EM energy  36 . The lens/emitter portion/mirror/reflector portion  35  may be configured such that the rays of emanated or reflected EM energy  36  may be characterized by a central axis, beam or ray  37  extending from a focal point  38  centrally located on the lens/emitter portion/mirror/reflector portion  35 . Alternatively, the beacon/reflector  32  may be an ordinary physical object  39  (e.g., a boulder, sign or landmark) which is disposed within (or even outside of) the control volume  24  and which may serve as a convenient reference point  30 . In any case, a particular point  31  on the beacon/reflector  32  may be used as the specific and precise location of the reference point  30 . 
       FIG. 1  illustrates a first embodiment of the navigation system  20  for one or more vehicles  22  located within a control volume  24 . The navigation system  20  includes a first camera or receiver  40  configured to observe the one or more vehicles  22  and the first, second and third reference points  30   A ,  30   B ,  30   C  within a first field of view  45 , wherein the first, second and third reference points  30   A ,  30   B ,  30   C  have first, second and third known spatial positions SP A , SP B , SP C , respectively. The first camera  40  is further configured to produce a first output signal  44  from observation of the observed vehicles  22  and reference points  30 . The navigation system  20  also includes a second camera or receiver  50  configured to observe the vehicles  22  and reference points  30  within a second field of view  55 , with the second camera  50  being further configured to produce a second output signal  54  from observation of the observed vehicles  22  and reference points  30 . (For example, the first and second output signals  44 ,  54  may comprise video signals, a stream of still images, or the like.) Additionally, the navigation system  20  includes a processor  60  operatively connected with the first and second cameras  40 ,  50  and configured to determine a respective spatial position SP for each of the one or more vehicles  22  from the first and second output signals  44 ,  54 . Thus, for example, if there are two vehicles  22   1 ,  22   2  being viewed by the first and second cameras  40 ,  50 , then the processor  60  will determine respective spatial positions SP 1 , SP 2  for the vehicles  22   1 ,  22   2 . Each of these spatial positions SP 1 , SP 2  may be represented by a respective set of three-dimensional coordinates  69   1 ,  69   2  such as x, y and z (or other) coordinates (e.g., as measured from the origin  26 ). 
     Each of the first and second cameras/receivers  40 ,  50  may be configured to detect or receive visible light, infrared light and/or ultraviolet light, as well as other wavelengths of EM energy  26  (e.g., microwaves). The first camera  40  is configured to detect first EM signals  42  within a first collection volume or field of view  45  having a first central ray or path  46 , and the second camera  50  is configured to detect second EM signals  52  within a second collection volume or field of view  55  having a second central ray or path  56 . The first collection volume or field of view  45  may have opposed first and second lateral edges  47 ,  48  and a distal extent or edge  49 , which may be envisioned as somewhat of a wedge or cone shape. Likewise, the second collection volume or field of view  55  may have opposed first and second lateral edges  57 ,  58  and a distal extent or edge  59 , which may also be envisioned as somewhat of a wedge or cone shape. However, these shapes are merely illustrative, as the first and second fields of view  45 ,  55  may also assume other shapes. 
     Each of the first and second cameras/receivers  40 ,  50  is configured and/or positioned to view the control volume  24  within its respective field of view  45 ,  55 , as well as the first, second and third reference points  30   A ,  30   B ,  30   C . While the drawings illustrate the first, second and third reference points  30   A ,  30   B ,  30   C  as being inside of or at the outer boundary of the control volume  24 , one or more of these reference points  30  may be disposed outside of the control volume  24 . For example, the third reference point  30   C  may be disposed near the location illustrated in  FIGS. 1 and 3-7 , but slightly outside the control volume  24  and slightly closer to the cameras  40 ,  50  than is illustrated in the aforementioned drawings. (I.e., the third reference point  30   C  would be disposed slightly “in front of” the control volume  24 .) In this example, the third reference point  30   C  would still be seen within each of the two fields of view  45 ,  55 . Likewise, one or both of the first and second reference points  30   A ,  30   B  may be disposed near their respective locations illustrated in  FIGS. 1 and 3-7 , but slightly outside of and “behind” the control volume  24 , and in this case, too, the first and second reference points  30   A ,  30   B  would still be visible within each of the two fields of view  45 ,  55 . 
     Note that the word “receiver”, as used herein, includes any device configured to receive EM energy  26  from the control volume  24  and produce an electrical signal (e.g., output signals  44  and  54 ) that is representative of or provides spatial/locational information about objects disposed within the control volume  24 . Thus, “receiver” include devices such as (i) cameras and imagers which are configured to form images of the objects within the control volume  24  (whether using visible light or EM energy  26  of other wavelengths), as well as (ii) rangefinders and the like which are configured to measure the distance to objects by transmitting or directing EM energy  26  (or other energy, such as sonar) at each object and receiving EM energy  26  (or other energy) in the form of a return signal back from each object. In the first and second embodiments, two cameras  40 ,  50  are utilized, which may provide, simulate or enable a binocular or stereoscopic view of the control volume  24 . 
     As illustrated in  FIGS. 1, 3 and 6 , the first and second cameras  40 ,  50  may be disposed such that their respective collection volumes or fields of view  45 ,  55  are generally orthogonal with each other, with the first and second central rays  46 ,  56  meeting at a convergence point  27  and with an angle θ defined between the first and second central rays  46 ,  56  of approximately 90 degrees. The first EM signals  42  (which are detected by the first camera  40 ) are illustrated in  FIGS. 1 and 3-7  as signals  42   1 ,  42   2  coming from the first and second vehicles  22   1 ,  22   2 , and signals  42   A ,  42   B ,  42   C  coming from the first, second and third reference points or beacon/emitters  30   A ,  30   B ,  30   C . Similarly, the second EM signals  52  (which are detected by the second camera  50 ) are illustrated as signals  52   1 ,  52   2  coming from the first and second vehicles  22   1 ,  22   2 , and signals  52   A ,  52   B ,  52   C  coming from the first, second and third reference points or beacon/emitters  30   A ,  30   B ,  30   C . Note that while the first and second cameras  40 ,  50  and reference points  30  are depicted in the drawings as being fixed, one or more of these elements may be gimbaled for rotation about one or more axes, and/or configured for translation or other motions. 
     The first output signal  44  may be representative of a first two-dimensional image  66  of the control volume  24  as viewed from the first camera  40 , and the second output signal  54  may be representative of a second two-dimensional image  68  of the control volume  24  as viewed from the second camera  50 . These images  66 ,  68  may be viewed together or separately on one or more monitors or other display devices, which may be connected to the processor  60 , the cameras  40 ,  50 , or the real-time tracking systems  62 ,  64  described below. 
     The navigation system  20  may further include (i) a first real-time tracking system  62  operatively connected with the first camera  40  for determining respective first two-dimensional coordinates  61  for each of the one or more vehicles  22  using the first output signal  44  and the first, second and third known spatial positions SP A , SP B , SP C , and (ii) a second real-time tracking system  64  operatively connected with the second camera  50  for determining respective second two-dimensional coordinates  63  for each of the one or more vehicles  22  using the second output signal  54  and the first, second and third known spatial positions SP A , SP B , SP C . Note that while the processor  60  and the real-time tracking systems  62 ,  64  are shown in  FIGS. 1, 3-4 and 6  as being separate modules or elements, the functionality of the real-time tracking systems  62 ,  64  may be included as part of the processor  60 , as illustrated in  FIGS. 5 and 7 . 
     The navigation system  20  may further include a respective vehicle beacon or transponder  29  configured to be carried aboard each of the one or more vehicles  22 . Each vehicle beacon  29  may be configured to transmit or broadcast a respective vehicle identification  21 , utilizing the same range of EM energy  26  which the first and second cameras  40 ,  50  are configured to receive. For example, a vehicle beacon  29   1  carried aboard a first vehicle  22   1  (e.g., at the first vehicle&#39;s centroid  28   1 , outer surface, etc.) may emit a first vehicle identification  21   1  as a series of long and short intermittent pulses of light which serve to identify the first vehicle  22   1 , while a vehicle beacon  29   2  carried aboard a second vehicle  22   2  (e.g., at the second vehicle&#39;s centroid  28   2 , outer surface, etc.) may emit a second vehicle identification  21   2  that is different from the first vehicle identification  21   1  (and is unique to the second vehicle  22   2 ) in order to identify the second vehicle  22   2 . (These pulses may be in Morse code, binary code or other format.) Optionally, the pulses of the vehicle beacon  29  may be at a wavelength just outside the visible spectrum (e.g., infrared or ultraviolet), and the cameras  40 ,  50  may be configured to detect this wavelength in addition to the visible spectrum. 
     Additionally, the navigation system  20  may further include a transmitter  70  operatively connected with the processor  60  and configured to transmit or broadcast one or more messages  72  into the control volume  24 , wherein the one or more messages  72  contain a respective spatial position SP or set of three-dimensional spatial coordinates  69  for each of the vehicles  22  that are within the control volume  24 . Thus, the transmitter  70  is configured to broadcast the exact spatial location of each and every vehicle  22  within the control volume  24 . (This information may then be received and used by each vehicle  22 , and/or by a traffic control function, in order to assist in navigation, collision avoidance, trajectory planning, traffic control and the like.) These spatial positions SP or three-dimensional spatial coordinates  69  may be expressed as x, y and z coordinates, polar coordinates, or other coordinates, and may utilize the origin  26  or other point as the coordinate origin. 
     In addition to including the spatial positions SP or three-dimensional spatial coordinates  69  of all the vehicles  22  within the control volume  24 , the one or more messages  72  may also include the vehicle identifications  21  for all the vehicles  22 . The one or more messages  72  may be sequenced and/or structured such that each vehicle identification  21  may be readily associated with its corresponding vehicle&#39;s spatial position SP or three-dimensional spatial coordinates  69 . (Note that as used herein, spatial position SP and three-dimensional spatial coordinates  69  may be used interchangeably.) For example, either or both of the first and second cameras  40 ,  50  may receive a first vehicle identification  21   1  from a first vehicle  22   1 , a second vehicle identification  21   2  from a second vehicle  22   2 , and so forth, and the transmitter  70  may transmit one or more messages  72  collectively containing all the vehicle identifications ( 21   1 ,  21   2 , etc.) and all the vehicles&#39; spatial locations (SP 1 , SP 2 , etc.) or three-dimensional spatial coordinates ( 69   1 ,  69   2 , etc.) in a manner in which the unique spatial locations SP or three-dimensional spatial coordinates  69  are appropriately associated with their respective vehicle identifications  21 . 
     According to another configuration, a navigation system  20  for one or more vehicles  22  located within a control volume  24  includes: (i) a first camera  40  configured to observe the one or more vehicles  22  and first, second and third reference points  30   A ,  30   B ,  30   C  within a first field of view  45 , wherein the first, second and third reference points  30   A ,  30   B ,  30   C  have first, second and third known spatial positions SP A , SP B , SP C , respectively, and wherein each of the first, second and third known spatial positions  30   A ,  30   B ,  30   C  is known with respect to an origin  26  located within the control volume  24 , the first camera  40  being further configured to produce a first output signal  44  from the observed vehicles  22  and reference points  30 , wherein the first output signal  44  is representative of a first two-dimensional image  66  of the control volume  24  as viewed from the first camera  40 ; (ii) a second camera  50  configured to observe the one or more vehicles  22  and the first, second and third reference points,  30   A ,  30   B ,  30   C  within a second field of view  55 , the second camera  50  being further configured to produce a second output signal  54  from the observed vehicles  22  and reference points  30 , wherein the second output signal  54  is representative of a second two-dimensional image  68  of the control volume  24  as viewed from the second camera  50 ; (iii) a processor  60  operatively connected with the first and second cameras  40 ,  50  and configured to determine a respective spatial position SP for each of the one or more vehicles  22  from the first and second output signals  44 ,  54 ; and (iv) a transmitter  70  operatively connected with the processor  60  and configured to transmit one or more messages  72  into the control volume  24 , wherein the one or more messages  72  contain a respective set of three-dimensional spatial coordinates  69  for each of the one or more vehicles  22 . 
     As illustrated by the flowchart of  FIG. 8 , a method  100  of navigation for one or more vehicles  22  located within a control volume  24  is also provided. At step  110 , the one or more vehicles  22  are observed with a first camera  40 , along with first, second and third reference points  30   A ,  30   B ,  30   C , within a first field of view  45 , wherein the first, second and third reference points  30   A ,  30   B ,  30   C  have first, second and third known spatial positions SP A , SP B , SP C , respectively. At step  120 , a first output signal  44  is produced by the first camera  40  from the observed vehicles  22  and reference points  30 . At step  130 , the one or more vehicles  22  and the first, second and third reference points  30   A ,  30   B ,  30   C  are observed within a second field of view  55  with a second camera  50 . At step  140 , a second output signal  54  from the observed vehicles  22  and reference points  30  is produced by the second camera  50 . And at step  170 , a respective three-dimensional spatial position SP for each vehicle  22  is determined, from the first and second output signals  44 ,  54 , by a processor  60  operatively connected with the first and second cameras  40 ,  50 . 
     The method  100  of navigation may further include one or more additional steps. For example, at step  150 , respective first two-dimensional coordinates  61  may be determined for each of the one or more vehicles  22  using the first output signal  44  and the first, second and third known spatial positions SP A , SP B , SP C , and similarly at step  160 , respective second two-dimensional coordinates  63  may be determined for each vehicle  22  using the second output signal  54  and the first, second and third known spatial positions SP A , SP B , SP C . At step  180 , one or more messages  72  may be transmitted into the control volume  24 , wherein the one or more messages  72  contain a respective set of three-dimensional spatial coordinates  69  for each vehicle  22 . And at step  190 , a respective vehicle identification  21  may be received (e.g., by the first and/or second camera  40 ,  50 ), which is transmitted from a respective vehicle beacon or transponder  29  carried aboard each of the one or more vehicles  22 . 
     In addition to the first embodiment illustrated in  FIGS. 1, 3 and 6  in which two cameras  40 ,  50  and three reference points  30   A ,  30   B ,  30   C  having known spatial positions SP A , SP B , SP C  are used, the navigation system  20  and method  100  may also include three other different but related embodiments. These include: (i) a second embodiment in which two cameras  40 ,  50  and two reference points  30   A ,  30   B  having known spatial positions SP A , SP B  are used, along with known first and second spatial positions SP 40 , SP 50  for the cameras  40 ,  50 ; (ii) a third embodiment in which one camera  40 , one transceiver  51  and three reference points  30   A ,  30   B ,  30   C  having known spatial positions SP A , SP B , SP C  are used; and (iii) a fourth embodiment in which one camera  40 , one transceiver  51  and two reference points  30   A ,  30   B  having known spatial positions SP A , SP B  are used, along with known first and second spatial positions SP 40 , SP 51  for the camera  40  and transceiver  51 . These four embodiments are summarized below in TABLE 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Comparison of Embodiments 
               
            
           
           
               
               
               
            
               
                   
                 Known Spatial Positions 
                 Related Drawings 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 First 
                 Second 
                 Reference 
                   
                 Navigation 
                 Method 
               
               
                 Embodiment 
                 Receiver 
                 Receiver 
                 Points 
                 Receivers 
                 System 20 
                 100, 200 
               
               
                   
               
               
                 First 
                 Camera 40 
                 Camera 50 
                 SP A , SP B , SP C   
                 — 
                 FIGS. 1, 3, 6 
                 FIG. 8 
               
               
                 Second 
                 Camera 40 
                 Camera 50 
                 SP A , SP B   
                 SP 40 , SP 50   
                 FIGS. 1, 3, 6 
                 FIG. 8 
               
               
                 Third 
                 Camera 40 
                 Transceiver 51 
                 SP A , SP B , SP C   
                 — 
                 FIGS. 4, 5, 7 
                 FIG. 9 
               
               
                 Fourth 
                 Camera 40 
                 Transceiver 51 
                 SP A , SP B   
                 SP 40 , SP 51   
                 FIGS. 4, 5, 7 
                 FIG. 9 
               
               
                   
               
            
           
         
       
     
     As used herein, a transceiver  51  is configured to both (i) transmit EM/rangefinding energy  53   TX  and (ii) receive EM/rangefinding energy  53   RX  in the form of a return signal reflected or evinced from other objects in the control volume  24  (such as vehicles  22 ). For example, the transceiver  51  and the transmitted EM/rangefinding energy  53   RX  may be, respectively: a distance measuring equipment (DME) device and radio waves, a radar device and radar waves, a sonar device and sonar waves, or a laser rangefinder and coherent laser light. Note that the received EM energy/return signal  53   RX  may have the same wavelength as the transmitted EM energy  53   RX , or it may have a different wavelength. In the third and fourth embodiments, the transceiver  51  may be manually or automatedly directed at each vehicle  22  within the control volume  24  in order to determine or “range find” a distance M from the transceiver  51  to each vehicle  22 . For example, M 1  and M 2  are shown in the drawings to represent the respective distances from the transceiver  51  to the first and second vehicles  22   1 ,  22   2 . A first beam of EM energy  53   RX1  may be directed at a first vehicle  22   1  and a return signal of EM energy  52   RX1  received back from the vehicle  22   1  by the transceiver  51 ; then, a second beam of EM energy  53   TX2  may be directed at a second vehicle  22   2  and a return signal of EM energy  52   RX2  received back from the vehicle  22   2  by the transceiver  51 . 
     Note that the transceiver  51  does not necessarily have to transmit and receive EM energy  53   TX ,  53   RX  from the very same device, but may include a transmitting portion and a receiving portion that are partially or entirely separate from each other, but which together comprise a transceiver  51 . The transceiver  51  may be configured to use the transmitted and received EM energy  53   TX ,  53   RX  to determine the distance M from the transceiver  51  to targeted objects (such as each vehicle  22 ), or the transceiver  51  may communicate with another device external to the transceiver  51 , such as a distance determination system or device  65 , which utilizes signals from the transceiver  51  to calculate or determine the distance M. 
     In the second embodiment, two cameras  40 ,  50  and two reference points  30   A ,  30   B  having known spatial positions SP A , SP B  are used, along with known first and second spatial positions SP 40 , SP 50  for the cameras  40 ,  50 . In this embodiment, as illustrated in  FIGS. 1, 3 and 6 , a navigation system  20  for one or more vehicles  22  located within a control volume  24  includes: a first camera  40  configured to observe the one or more vehicles  22  and first and second reference points  30   A ,  30   B  within a first field of view  45 , wherein the first and second reference points  30   A ,  30   B  have first and second known spatial positions SP A , SP B , respectively, the first camera  40  having a known first camera spatial position SP 40  and being further configured to produce a first output signal  44  from the observed vehicles  22  and reference points  30 ; a second camera  50  configured to observe the one or more vehicles  22  and the first and second reference points  30   A ,  30   B  within a second field of view  55 , the second camera  50  having a known second camera spatial position SP 50  and being further configured to produce a second output signal  54  from the observed vehicles  22  and reference points  30 ; and a processor  60  operatively connected with the first and second cameras  40 ,  50  and configured to determine a respective spatial position SP for each of the one or more vehicles  22  from the first and second output signals  44 ,  54  and from the known first and second camera spatial positions SP 40 , SP 50 . 
     In this second embodiment, each of the known first and second camera spatial positions SP 40 , SP 50  may be a respective set of x, y and z coordinates. The navigation system  20  may further include: (i) a first real-time tracking system  62  operatively connected with the first camera  40  for determining respective first two-dimensional coordinates  61  of each of the one or more vehicles  22  using the first output signal  44 , the first and second known spatial positions SP A , SP B , and the known first camera spatial position SP 40 ; and (ii) a second real-time tracking system  64  operatively connected with the second camera  50  for determining respective second two-dimensional coordinates  63  of each of the one or more vehicles  22  using the second output signal  54 , the first and second known spatial positions SP A , SP B , and the known second camera spatial position SP 50 . This second embodiment may also include any of the relevant subject matter of dependent claims  2 - 7  and  9 - 10  as originally filed. 
     As illustrated in  FIG. 8 , in this second embodiment, a method  100  of navigation for one or more vehicles  22  located within the control volume  24  includes: (i) at step  110 , observing, with a first camera  40  having a known first camera spatial position SP 40 , the one or more vehicles  22  and first and second reference points  30   A ,  30   B  within the first field of view  45 , wherein the first and second reference points  30   A ,  30   B  have first and second known spatial positions SP A , SP B , respectively; (ii) at step  120 , producing, by the first camera  40 , a first output signal  44  from the observed vehicles  22  and reference points  30 ; (iii) at step  130 , observing, with a second camera  50  having a known second camera spatial position SP 50 , the one or more vehicles  22  and the first and second reference points  30   A ,  30   B  within the second field of view  55 ; (iv) at step  140 , producing, by the second camera  50 , a second output signal  54  from the observed vehicles  22  and reference points  30 ; and (v) at step  170 , determining, by a processor  60  operatively connected with the first and second cameras  40 ,  50 , a respective spatial position SP for each of the one or more vehicles  22  from the first and second output signals  44 ,  54  and from the known first and second camera spatial positions SP 40 , SP 50 . 
     The method  100  of the second embodiment may further include one or more of: (vi) at step  150 , determining respective first two-dimensional coordinates  61  of each of the one or more vehicles  22  using the first output signal  44 , the first and second known spatial positions SP A , SP B , and the known first camera spatial position SP 40 ; (vii) at step  160 , determining respective second two-dimensional coordinates  63  of each of the one or more vehicles  22  using the second output signal  54 , the first and second known spatial positions SP A , SP B , and the known second camera spatial position SP 50 ; (viii) at step  180 , transmitting one or more messages  72  into the control volume  24 , wherein the one or more messages  72  contain a respective set of three-dimensional spatial coordinates  69  for each of the one or more vehicles  22 ; and (ix) at step  190 , receiving a respective vehicle identification  21  transmitted from a respective vehicle beacon  29  carried aboard each of the one or more vehicles  22 . 
     In the third embodiment, one camera  40 , one transceiver  51  and three reference points  30   A ,  30   B ,  30   C  having known spatial positions SP A , SP B , SP C  are used. In this embodiment, as illustrated in  FIGS. 4, 5 and 7 , a navigation system  20  for one or more vehicles  22  located within a control volume  24  includes: a camera  40  configured to observe the one or more vehicles  22  and first, second and third reference points  30   A ,  30   B ,  30   C  within a first field of view  45 , wherein the first, second and third reference points  30   A ,  30   B ,  30   C  have first, second and third known spatial positions SP A , SP B , SP C , respectively, the camera  40  being further configured to produce an output signal  44  from the observed vehicles  22  and reference points  30 ; a transceiver  51  configured to transmit rangefinding energy  53   RX  into the control volume  24  and to receive a respective return signal  53   RX  from each of the one or more vehicles  22  indicative of a respective distance measurement M from the transceiver  51  to each respective vehicle  22 ; and a processor  60  operatively connected with the camera  40  and transceiver  51  and configured to determine a respective spatial position SP for each of the one or more vehicles  22  from the output signal  44  and from at least one of the respective return signal  53   RX  and the respective distance measurement M. 
     In this third embodiment, the output signal  44  may be representative of a two-dimensional image  66  of the control volume  24  as viewed from the camera  40 . As illustrated in  FIGS. 5 and 7 , the camera  40  and transceiver  51  may be disposed generally side-by-side with each other, such that a central ray  46  of the field of view  45  of the camera  40  and the one or more beams of EM energy  53   RX ,  53   RX  of the transceiver  51  are generally pointing in the same direction as each other. (Here, “side-by-side” also includes the camera  40  and transceiver  51  being at different heights from each such, such as the transceiver  51  being disposed above or below the camera  40 .) The navigation system  20  may further include: (i) a real-time tracking system  62  operatively connected with the camera  40  for determining respective first two-dimensional coordinates  61  of each of the one or more vehicles  22  using the output signal  44  and the first, second and third known spatial positions SP A , SP B , SP C ; and/or (ii) a distance determination system  65  operatively connected with the transceiver  51  for determining a respective distance M from the transceiver  51  to each of the one or more vehicles  22  using the respective return signals  53   RX  from each of the one or more vehicles  22 . This third embodiment may also include any of the relevant subject matter of dependent claims  2 ,  5 ,  7  and  9 - 10  as originally filed. 
     As illustrated in  FIG. 9 , in this third embodiment, a method  200  of navigation for one or more vehicles  22  located within the control volume  24  includes: (i) at step  210 , observing, with a camera  40 , the one or more vehicles  22  and first, second and third reference points  30   A ,  30   B ,  30   C  within a first field of view, wherein the first, second and third reference points  30   A ,  30   B ,  30   C  have first, second and third known spatial positions SP A , SP B , SP C , respectively; (ii) at step  220 , producing, by the camera  40 , an output signal  44  from the observed vehicles  22  and reference points  30 ; (iii) at step  230 , transmitting, by a transceiver  51 , rangefinding energy  53   TX  into the control volume  24  (e.g., at each of the one or more vehicles  22 ); (iv) at step  240 , receiving, by the transceiver  51 , a respective return signal  53   RX  from each of the one or more vehicles  22  indicative of a respective distance measurement M from the transceiver  51  to each respective vehicle  22 ; and; (v) at step  270 , determining, by a processor  60  operatively connected with the camera  40  and transceiver  51 , a respective spatial position SP for each of the one or more vehicles  22  from the output signal  44  and from at least one of the respective return signal  53   RX  and the respective distance measurement M. 
     The method  200  of the third embodiment may further include one or more of: (vi) at step  250 , determining respective first two-dimensional coordinates  61  of each of the one or more vehicles  22  using the output signal  44  and the first, second and third known spatial positions SP A , SP B , SP C ; (vii) at step  260 , determining a distance measurement M from the transceiver  51  to each of the one or more vehicles  22  using the respective return signals  53   RX ; (viii) at step  280 , transmitting one or more messages  72  into the control volume  24 , wherein the one or more messages  72  contain a respective set of three-dimensional spatial coordinates  69  for each of the one or more vehicles  22 ; and (ix) at step  290 , receiving a respective vehicle identification  21  transmitted from a respective vehicle beacon  29  carried aboard each of the one or more vehicles  22 . 
     In the fourth embodiment, one camera  40 , one transceiver  51  and two reference points  30   A ,  30   B  having known spatial positions SP A , SP B  are used, along with known first and second spatial positions SP 40 , SP 51  for the camera  40  and transceiver  51 . In this embodiment, as illustrated in  FIGS. 4, 5 and 7 , a navigation system  20  for one or more vehicles  22  located within a control volume  24  includes: a camera  40  configured to observe the one or more vehicles  22  and first and second reference points  30   A ,  30   B  within a first field of view  45 , wherein the first and second reference points  30   A ,  30   B  have first and second known spatial positions, SP A , SP B , respectively, the camera  40  having a known camera spatial position SP 40  and being further configured to produce an output signal  44  from the observed vehicles  22  and reference points  30 ; a transceiver  51  having a known transceiver spatial position SP 51  and being configured to transmit rangefinding energy  53   TX  into the control volume  24  and to receive a respective return signal  53   RX  from each of the one or more vehicles  22  indicative of a respective distance measurement M from the transceiver  51  to each respective vehicle  22 ; and a processor  60  operatively connected with the camera  40  and transceiver  51  and configured to determine a respective spatial position SP for each of the one or more vehicles  22  from (i) the output signal  44 , (ii) at least one of the respective return signal  53   RX  and the respective distance measurement M, and (iii) the known camera and transceiver spatial positions SP 40 , SP 51 . 
     In this fourth embodiment (and similar to the third embodiment), the output signal  44  may be representative of a two-dimensional image  66  of the control volume  24  as viewed from the camera  40 . As illustrated in  FIGS. 5 and 7 , the camera  40  and transceiver  51  may be disposed generally side-by-side with each other, such that a central ray  46  of the field of view  45  of the camera  40  and the one or more beams of EM energy  53   TX ,  53   RX  of the transceiver  51  are generally pointing in the same direction as each other. (Here, “side-by-side” also includes the camera  40  and transceiver  51  being at different heights from each such, such as the transceiver  51  being disposed above or below the camera  40 .) The navigation system  20  may further include: (i) a real-time tracking system  62  operatively connected with the camera  40  for determining respective first two-dimensional coordinates  61  of each of the one or more vehicles  22  using the output signal  44  and the first, second and third known spatial positions SP A , SP B , SP C ; and/or (ii) a distance determination system  65  operatively connected with the transceiver  51  for determining a respective distance M from the transceiver  51  to each of the one or more vehicles  22  using the respective return signals  53   RX  from each of the one or more vehicles  22 . This fourth embodiment may also include any of the relevant subject matter of dependent claims  2 ,  5 ,  7  and  9 - 10  as originally filed. 
     As illustrated in  FIG. 9 , in this fourth embodiment, a method  200  of navigation for one or more vehicles  22  located within the control volume  24  includes: (i) at step  210 , observing, with a camera  40  having a known camera spatial position SP 40 , the one or more vehicles  22  and first and second reference points  30   A ,  30   B  within a first field of view  45 , wherein the first and second reference points  30   A ,  30   B  have first and second known spatial positions SP A , SP B , respectively; (ii) at step  220 , producing, by the camera  40 , an output signal  44  from the observed vehicles  22  and reference points  30 ; (iii) at step  230 , transmitting, by a transceiver  51  having a known transceiver spatial position SP 51 , rangefinding energy  53   TX  into the control volume  24 ; (iv) at step  240 , receiving, by the transceiver  51 , a respective return signal  53   RX  from each of the one or more vehicles  22  indicative of a respective distance measurement M from the transceiver  51  to each respective vehicle  22 ; and; (v) at step  270 , determining, by a processor  60  operatively connected with the camera  40  and transceiver  51 , a respective spatial position SP for each of the one or more vehicles  22  from (i) the output signal  44 , (ii) at least one of the respective return signal  53   RX  and the respective distance measurement M, and (iii) the known camera and transceiver spatial positions SP 40 , SP 51 . 
     The method  200  of the fourth embodiment may further include one or more of: (vi) at step  250 , determining respective first two-dimensional coordinates  61  of each of the one or more vehicles  22  using the output signal  44 , the first and second known spatial positions SP A , SP B , and the known camera spatial position SP 40 ; (vii) at step  260 , determining a distance measurement M from the transceiver  51  to each of the one or more vehicles  22  using the respective return signals  53   RX ; (viii) at step  280 , transmitting one or more messages  72  into the control volume  24 , wherein the one or more messages  72  contain a respective set of three-dimensional spatial coordinates  69  for each of the one or more vehicles  22 ; and (ix) at step  290 , receiving a respective vehicle identification  21  transmitted from a respective vehicle beacon  29  carried aboard each of the one or more vehicles  22 . 
     In the third and fourth embodiments, the transceiver  51  may produce an output signal  54  representative of or containing the distance measurement(s) M from the transceiver  51  to each vehicle  22  within the control volume  24  which has been targeted by the transceiver  51 . (Here “targeted” it is meant that rangefinding EM energy  53   TX  has been transmitted or directed at a vehicle  22  and a return signal of EM energy  53   RX  has been received back from the vehicle  22  by the transceiver  51 .) The distance measurement(s) M may be displayed, manipulated or characterized as human-readable alphanumeric information or as machine-readable information (e.g., binary code, hexadecimal code, sequences and amplitudes of varying voltages, etc.), as represented by reference numeral  67  in  FIGS. 4, 5 and 7 . 
     Note that in any of the embodiments above, each of the control volume  24 , the first, second and third reference points  30   A ,  30   B ,  30   C , the first and second cameras/receivers  40 ,  50  and the transceiver  51  may be configured to be stationary or moving (e.g., with respect to the origin  26 ). Also, over time the control volume  24  may expand and/or contract in size and may change in shape. When one or more of the control volume  24 , the reference points  30 , the cameras/receivers  40 ,  50  and the transceiver  51  is/are moving (whether translationally, rotationally or otherwise), it may be necessary to know or determine one or more vectors, motion paths (versus time) and/or other data and information relating to one or more of the moving and stationary objects in order to determine the spatial positions SP of each vehicle  22  within the control volume  24 . 
     The above description is intended to be illustrative, and not restrictive. While the dimensions and types of materials described herein are intended to be illustrative, they are by no means limiting and are exemplary embodiments. In the following claims, use of the terms “first”, “second”, “top”, “bottom”, etc. are used merely as labels, and are not intended to impose numerical or positional requirements on their objects. As used herein, an element or step recited in the singular and preceded by the word “a” or “an” should be understood as not excluding plural of such elements or steps, unless such exclusion is explicitly stated. Also, elements of some embodiments may be added to other embodiments or substituted for other elements in such other embodiments. Additionally, the phrase “at least one of A and B” and the phrase “A and/or B” should each be understood to mean “only A, only B, or both A and B”. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. And when broadly descriptive adverbs such as “substantially” and “generally” are used herein to modify an adjective, these adverbs mean “for the most part”, “to a significant extent” and/or “to a large degree”, and do not necessarily mean “perfectly”, “completely”, “strictly” or “entirely”. Additionally, the word “proximate” may be used herein to describe the location of an object or portion thereof with respect to another object or portion thereof, and/or to describe the positional relationship of two objects or their respective portions thereof with respect to each other, and may mean “near”, “adjacent”, “close to”, “close by”, “at” or the like. 
     The flowcharts and block diagrams in the drawings illustrate the architecture, functionality and/or operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment or portion of code, which includes one or more executable instructions for implementing the specified logical function(s). It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, may be implemented by hardware-based systems that perform the specified functions or acts, or combinations of hardware and computer instructions. These computer program instructions may also be stored in a computer-readable medium that can direct a controller or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions to implement the functions and/or actions specified in the flowcharts and block diagrams. 
     This written description uses examples, including the best mode, to enable those skilled in the art to make and use devices, systems and compositions of matter, and to perform methods, according to this disclosure. It is the following claims, including equivalents, which define the scope of the present disclosure.