Abstract:
Systems and methods for mapping a surface of a celestial body containing objects and terrain are provided. One system includes a Synthetic Aperture RADAR (SAR) module configured to capture a high-resolution image of the terrain of at least a portion of the surface and a map module configured to store map data representing the portion of the surface. The system also includes a fusion module configured to combine the high-resolution image and the map data to generate a high-resolution map of the portion of the surface. A method includes orbiting the celestial body, capturing, via the SAR module, a high-resolution image during each orbit, and fusing the captured high-resolution image with a low-resolution map of the surface to generate a high-resolution map of the surface. A computer-readable medium for storing instructions that cause a processor to perform the above method is also provided.

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to mapping, and more particularly relates to mapping the surface of a celestial body. 
       BACKGROUND 
       [0002]    On Jul. 20, 1969, Neil Armstrong and Edwin E. “Buzz” Aldrin landed the Apollo 11 Eagle Lunar Module on the Moon. Just prior to the lunar landing, Neil Armstrong noticed that the lunar module autopilot was going to land the lunar module in a boulder field. In response thereto, Neil Armstrong switched OFF the autopilot and manually landed the lunar module in a safer area only seconds before the lunar module ran out of fuel. The reason the autopilot was headed for the boulder field was due to the fact that the surface of the Moon had only been mapped using equipment (i.e., telescopes) located on Earth or located on spacecraft orbiting the Moon during earlier Apollo missions, and did not contain sufficiently detailed lunar surface information. 
         [0003]    Presently, maps of the Moon&#39;s surface are still relatively primitive in that they are limited to the maps used during the Apollo Space Program and to maps generated using modern equipment located on Earth and/or in man-made satellites orbiting Earth. In other words, current lunar surface maps still do not include detailed enough information to enable an autopilot to safely choose and land a lunar module on the Moon. Furthermore, the surface of the Moon is not being monitored in order to record any changes in the surface of the Moon, and specifically, the change in location of natural objects (e.g., rocks) and made-made objects. These changes may need to be tracked in real-time during, for example, manned or unmanned missions to the Moon, which are scheduled to begin starting in the year 2020. 
         [0004]    The lack of detailed surface information is even more problematic with Mars. That is, because 1) the Earth is considerably farther away from Mars than from the Moon; 2) there have been relatively few unmanned missions to Mars; and 3) there have not been any previous manned missions to Mars, the surface maps of Mars are even less detailed than the maps of the Moon. This is problematic because manned missions to Mars are scheduled to begin in the year 2030, and there is an obvious goal of being able to accurately locate a safe place to land a space module on Mars&#39; surface. 
         [0005]    Accordingly, it is desirable to provide systems and methods for accurately mapping the surface of a celestial body. In addition, it is desirable to provide systems and methods for mapping changes in position of objects and terrain on the surface of the celestial body in real-time. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention. 
       BRIEF SUMMARY 
       [0006]    Various embodiments provide systems for mapping a surface of a celestial body containing objects and terrain. One exemplary system comprises a Synthetic Aperture RADAR (SAR) module configured to capture a high-resolution image of the terrain of at least a portion of the surface and a map module configured to store map data representing the portion of the surface. The system also comprises a fusion module in communication with the SAR module and the map module, wherein the fusion module is configured to receive the high-resolution image and the map data, and combine the high-resolution image and the map data to generate a high-resolution map of the portion of the surface. 
         [0007]    Methods for mapping a surface of a celestial body containing terrain and an object are also provided. An exemplary method comprises the steps of orbiting the celestial body and capturing, via a SAR module, a high-resolution image of the terrain during each orbit. The method also comprises the step of fusing the captured high-resolution image with a low-resolution map of the surface to generate a high-resolution map of the surface. 
         [0008]    Various embodiments also provide a computer-readable medium storing instructions that, when read by a processor, cause the processor to perform a method comprising the step of capturing, via a SAR module, a high-resolution image of a terrain of at least a portion of a surface a celestial body during a plurality of orbits around the celestial body. The computer-readable medium also stores instructions that cause the processor to perform the step of fusing the captured high-resolution image with map data representing the portion of the surface to generate a high-resolution map of the surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
           [0010]      FIG. 1  is a block diagram of one exemplary embodiment of a system for mapping a surface of a celestial body; and 
           [0011]      FIG. 2  is a diagram illustrating the operation of the system of  FIG. 1  in accordance with one exemplary embodiment of the invention; 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
         [0013]    Various embodiments of the invention provide systems and methods for mapping the surface of a celestial body (e.g., a planet (not the Earth), a moon, or other similar celestial bodies). Other embodiments provide systems and methods for mapping real-time changes in position of objects and terrain on the surface of the celestial body. 
         [0014]    Turning now to the figures,  FIG. 1  is a block diagram of a system  100  for mapping the surface of a celestial body. System  100  comprises a Synthetic Aperture RADAR (SAR) module  110 , a radio frequency identification (RFID) module  120 , a sensor module  130 , a map module  140 , and a synthetic vision module  150 , all in communication with a fusion module  160  via a network  170  (e.g., a local area network LAN) that is wireless, although portions of network  170  may couple one or more components of system  100  via wired communication technology. 
         [0015]    SAR module  110  may include any combination of device(s), software, and hardware component(s) capable of using electromagnetic waves to generate/capture a high-resolution image of a geographic area from a moving platform (e.g., a spacecraft, a space station, a satellite, etc.). SAR technology is known in the art and the particulars of SAR technology will not be discussed herein in detail; however, the application of SAR technology in accordance with various embodiments of SAR module  110  is discussed below. 
         [0016]    In one embodiment, SAR module  110  is configured to generate a two-dimensional (2-D) image of a pre-determined geographic area on, for example, the Moon, Mars, or other celestial body. One dimension in the generated image is called range (or cross track) and is a measure of the “line-of-sight” distance from the RADAR to the geographic area. Range measurement and resolution are achieved in Synthetic Aperture RADAR in a manner similar to other RADAR technologies. That is, range is determined by precisely measuring the time from transmission of an electromagnetic pulse to receiving the echo from various terrain features (e.g., mountains, valleys, hills, canyons, plains, etc.) in the geographic area and object(s) (e.g., structures, vehicles, etc.) located within the geographic area. The range resolution is determined by the transmitted pulse width, meaning that narrow pulses yield high range resolution and wide pulses yield low range resolution. Various embodiments of SAR module  110  may use any pulse width depending on the particular application of system  100 , although SAR module  110  preferably utilizes a narrow pulse width for surface mapping of the Moon or Mars. 
         [0017]    The other dimension in the generated image is called azimuth, which is perpendicular to the range. To obtain fine azimuth resolution, in one embodiment, SAR module  110  includes a physically large antenna  1110  configured to focus the transmitted and received energy into a sharp beam (see  FIG. 2 ), although SAR module  110  may include more than one antenna  1110 . Each antenna  1110  preferably includes a diameter less than about ⅓ meters and a height less than about ⅕ meters. Since the sharpness of the beam defines the azimuth resolution, SAR module  110  may utilize an antenna having any diameter and/or height appropriate for a particular application of system  100 . Specifically, SAR module  110  may include one or more antennas  1110  that are larger than the above-identified diameters and heights. 
         [0018]    Achieving fine azimuth resolution may also be described from a Doppler processing viewpoint. That is, the position of the geographic area along the flight path or orbit determines the Doppler frequency of its echoes. Geographic area ahead of the moving platform produces a positive Doppler offset, while geographic area behind the moving platform produces a negative offset. As the moving platform flies a distance (i.e., the synthetic aperture), echoes are resolved into a number of Doppler frequencies. The Doppler frequency of the various terrain features of the geographic area and/or objects located within the geographic area determines the azimuth position of each terrain feature or object. 
         [0019]    Further to the general discussion above, it is noted that because the range to each terrain feature and object on the synthetic aperture changes along the synthetic aperture, the energy reflected from the terrain features and objects should be “mathematically focused” to compensate for the range dependence across the aperture prior to image formation. Additionally, in fine-resolution applications of SAR module  110 , the range and azimuth processing is dependent upon one another, which also increases the amount of computational processing needed to accurately generate/capture a high-resolution image of the geographic area. 
         [0020]    RFID module  120  may be any system, device, hardware, software, or combination thereof configured to identify the location of an object or asset. This capability keeps track of objects/assets that change position faster than the mapping capabilities provided by SAR module  110  discussed above. As will be discussed in more detail below, such objects or assets may be located on the surface of a celestial body that is being mapped. RFID module  120  may utilize one or more RF technologies (e.g., 802.11 specifications, RFID specifications, ultra wideband (UWB) specifications, WiFi specifications, WiMAX specifications, and the like RF technologies) in identifying such locations. 
         [0021]    As illustrated in  FIG. 1 , RFID module  120  includes one or more tags  1210 , one or more tag readers  1220 , one or more access points  1230 , and/or other components that may be included within an RFID system. Tag(s)  1210  may be any type of tag (e.g., active RFID tags, passive RFID tags, semi-active RFID tags, etc.) implementing one or more of the above RF technologies. As such, tag reader(s)  1220 ) access point(s)  1230 , and any other component included within RFID module  120  communicates with one another and/or with RFID tag reader, a WiFi tag reader, a WiMAX tag reader, a UWB tag reader, a 802.11 tag reader, a Zigbee tag reader, and the like tag reader, and access point(s)  1230  are configured to enable RFID module  120  to communicate with one or more external computing devices (e.g., processor  1610 , discussed below). 
         [0022]    Sensor module  130  may include any system, device, hardware, software, or combinations thereof capable of detecting the location of an object on the surface of a celestial body that is being mapped. For example, sensor module  130  may utilize digital video image capturing techniques (e.g., light capturing devices, cameras, charge-coupled devices with a range from ultraviolet to infrared, etc.), RADAR, LIDAR, and the like sensors that are capable of visually, acoustically, or otherwise detecting the present location of an object (e.g., a structure, vehicle, and/or other man-made or natural objects). 
         [0023]    Map module  140  may be any device, hardware, software, or combination thereof capable of storing map data  1410  representing a particular geographic area. In one embodiment, map data  1410  is a digital map of the surface of a celestial body, and particularly, a low-resolution map of the surface of the Moon. In accordance with one aspect of the invention, the low-resolution map of the surface of the Moon is generated from one or more maps of the Moon&#39;s surface generated during the Apollo Space Program, one or more maps of the Moon&#39;s surface generated from the Earth (e.g., via a telescope, RADAR, digital imagery, etc.), one or more maps of the Moon&#39;s surface generated from a satellite, space station, or probe orbiting the Earth, and/or the like low-resolution maps of the Moon&#39;s surface, including combinations thereof. 
         [0024]    In another embodiment, map data  1410  is a low-resolution digital map of the surface of Mars. In accordance with one aspect of the invention, the digital map of the surface of the Mars is generated from one or more maps of Mars&#39; surface generated from the Earth (e.g., via a telescope, RADAR, digital imagery, etc.), one or more maps of Mars&#39; surface generated from a satellite, space station, or probe orbiting the Earth, and/or the like low-resolution maps of Mars&#39; surface, including combinations thereof. 
         [0025]    Synthetic vision module  150  may be any system, device, hardware, software, or combinations thereof capable of using terrain data, object data, and/or other data to provide situational awareness to the flight crew of, for example, a spacecraft. In one embodiment, Synthetic vision module  150  is a synthetic vision system manufactured by Honeywell International, Inc. of Morristown, N.J., although other embodiments may include other synthetic vision systems. Synthetic vision systems are generally known in the art and will not be discussed in detail herein; however, the operation of various embodiments of synthetic vision module  150  incorporating a synthetic vision system is discussed below. 
         [0026]    Synthetic vision module  150 , in one embodiment, includes a display  1510 , one or more terrain databases  1520 , and Global Positioning System (GPS)  1530  that show spacecraft flight crews where they are located with respect to the terrain/objects, and the direction in which the spacecraft is oriented. Synthetic vision module  150  further includes an integrity-monitoring system (IMS)  1540  that ensures that the information display  1510  is displaying corresponds to where the spacecraft actually is located. 
         [0027]    In one embodiment, synthetic vision module  150  is configured to show, via display  1510 , terrain, an object, an approach path, a landing site, and the like in a photorealistic display. That is, synthetic vision module  150  is configured to fuse three-dimensional (3-D) data into display  1510  such that synthetic vision module  150  is able to provide situational awareness to the flight crew. 
         [0028]    Fusion module  160  may be any device, hardware, software, firmware, or combination thereof capable of obtaining and integrating data from SAR module  110 , RFID module  120 , sensor module  130 , and map module  140 . In one embodiment, fusion module  160  comprises a processor  1610  configured to integrate the data from SAR module  110 , RFID module  120 , sensor module  130 , and map module  140  using information fusion techniques. Information fusion is known in the art and various embodiments of fusion module  160  may include one or more algorithms  1620  capable of fusing the data obtained from two or more of SAR module  110 , RFID module  120 , sensor module,  130 , and map module  140 . 
         [0029]    In one embodiment, the one or more algorithms  1620  are configured to fuse imagery data generated/captured by SAR module  110  and digital map data from map module  140 . That is, algorithm(s)  1620  may be configured to receive one or more captured images of a portion of the surface of the Moon (or Mars) and fuse (e.g., overlay) the captured images on a low-resolution digital map representation of the portion. For example, a low-resolution map generated by the Apollo Space Program, an Earth-orbiting satellite, a telescope, RADAR located on Earth, and/or the like may be fused (i.e., modified) with the high-resolution image captured/generated by SAR module  110  to generate a high-resolution digital map of the surface of the Moon (or Mars). 
         [0030]    In another embodiment, the one or more algorithms  1620  are further configured to fuse the high-resolution digital map data modified by SAR module  110  with object location data obtained from RFID module  120  and/or object location data obtained from sensor module  130 . That is, algorithm(s)  1620  may be configured to fuse (e.g., overlay) the location of objects associated with an RFID tag  1210  and/or detected by sensor module  130  with the high-resolution digital map in real-time. For example, the present location of a structure, vehicle, and/or the like object may be fused on to the high-resolution digital map of the surface of the Moon (or Mars or other celestial body) and displayed to the flight crew (via display  1510 ) such that the flight crew is able to locate a suitable place to land a spacecraft. That is, the high-resolution map provides the terrain features of the surface of the Moon, while the data obtained from RFID module  120  and/or sensor module  130  provides real-time location information for any objects that may be present on the surface of the Moon or other celestial body. The following discussion relating to the operation of system  100  may be beneficial in understanding the spirit and scope of the various embodiments of system  100 . 
         [0031]      FIG. 2  is a diagram illustrating one example of the operation of one embodiment of system  100 . This example does not limit the scope of system  100 , but rather, is intended to provide one skilled in the art with a better understanding of how various embodiments of system  100  may be implemented. 
         [0032]    As illustrated in the embodiment shown in  FIG. 2 , SAR module  110  is implemented on a crew exploration vehicle (CEV)  210  orbiting the Moon  220  (or Mars or other celestial body); however, SAR module  110  may be included as a portion of a satellite, space station, or other spacecraft orbiting a celestial body  220 . Also illustrated in  FIG. 2  are a variety of objects, and specifically, a space station  230 , a plurality of vehicles  240 , a landing module  250 , and a plurality of communication antennas  260 . 
         [0033]    In one embodiment, system  100  operates by SAR module  110  capturing one or more high-resolution images of a pre-determined geographic area  275  of the celestial body&#39;s surface during each orbit of CEV  210  around the celestial body. Map module  140  also stores a low-resolution map  1410  of area  275 . Fusion module  160  then updates/modifies low-resolution map  1410  with the image(s) captured by SAR module  110  after each orbit or after a pre-determined number of orbits (e.g., 2, 3, 4, or 5 orbits) to generate a high-resolution map (not shown) of the surface of area  275 . The high-resolution map may then be stored in map module  140  and/or displayed on one or more displays  1510  included within CEV  210 , space station  230 , landing module  250 , and/or on the Earth. 
         [0034]    After the high-resolution map is generated, the high-resolution map may be populated in real-time with the present location of space station  230 , vehicles  240 , and communication antennas  260  obtained from RFID module  120  and/or sensor module  130 . This may be done while landing module  250  is landing so that the flight crew of landing module  250  is able to locate a landing site that does not include any obstructions (i.e., terrain features and/or objects). Once landing module  250  has landed, the high-resolution map may be further constantly, substantially constantly, or periodically populated/updated in real-time to include the location of landing module  250  obtained from RFID module  120  and/or sensor module  130 . 
         [0035]    To obtain the location of space station  230 , vehicles  240 , landing module  250 , and communication antennas  260  from RFID module  120 , space station  230 , vehicles  240 , landing module  250 , and communication antennas  260  each have a respective RFID tag  1210  attached to it. Likewise, sensor module  130  may constantly, substantially constantly, or periodically monitor area  275  to detect the present location of space station  230 , vehicles  240 , landing module  250 , and communication antennas  260 . 
         [0036]    Although  FIG. 2  does not specifically illustrate where the various components of system  100  are located, one skilled in the art will appreciate that the various components of system  100  may be located in any one or more of space station  230 , vehicles  240 , landing module  250 , and on the Earth, provided that the various components of system  100  are capable of communicating with one another. That is, SAR module  110 , RFID module  120 , sensor module  130 , map module  140 , synthetic vision module  150 , and fusion module  160  may each be located on space station  230 , vehicles  240 , landing module  250 , or on the Earth, or portions of SAR module  110 , RFID module  120 , sensor module  130 , map module  140 , synthetic vision module  150 , and fusion module  160  may be located in different ones of space station  230 , vehicles  240 , landing module  250 , and on the Earth, except that landing module  250  will preferably include at least one display  1510  displaying the high-resolution map, with or without object location data obtained from RFID module  120  and/or sensor module  130  fused therein during landing. 
         [0037]    While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.