Patent Publication Number: US-7586514-B1

Title: Compact remote tactical imagery relay system

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to military aircraft imagery systems. More particularly, the present invention relates to an imagery system that transfers digital imagery of a target from a military aircraft to a ground station or other aircraft and returns an updated image to the aircraft for pursuit and destruction of the target. 
   2. Description of the Prior Art 
   Currently multiple military platforms, including the F/A-18 aircraft, use a PhotoTelesis Fast Tactical Imagery device to capture frames of digital video from an aircraft&#39;s sensors. The images are compressed by an aircraft&#39;s electronics systems and sent to a ground station for review and additional processing. Upon receiving the compressed images, ground troops can confirm that the pilot is observing an actual enemy target and transmit bombing coordinates to the pilot. Further, the ground troops can determine if the target is actually friendly troops thereby preventing a “blue-on-blue” or friendly fire incident. 
   The Fast Tactical Imagery device includes two weapon replaceable assemblies. The first assembly is a PRISM device, which is located in the avionics bay of the aircraft. The PRISM device performs the compression-decompression of the image and interfaces with the aircraft radios. The second assembly is the Remote Control Unit (RCU), which is mounted in the aircraft cockpit. The aircraft&#39;s pilot uses the RCU to control the PRISM device. 
   There is currently a need to deploy the PhotoTelesis Fast Tactical Imagery device on board the AV-8B Harrier aircraft. To install the Fast Tactical Imagery device on board the Harrier aircraft for use with the RCU would require installing approximately 23 new wires between the aircraft&#39;s cockpit and the aft avionics bay for the aircraft. This installation requires removal of an aircraft wing and engine, which would be an arduous task for one aircraft. For the entire fleet of Harrier aircraft the cost of outfitting each aircraft is prohibitive task. 
   Accordingly, there is a need to develop a system that uses existing aircraft cockpit displays and controls to operate the PRISM device. 
   SUMMARY OF THE INVENTION 
   The present invention overcomes some of the difficulties of the past including those mentioned above in that it comprises a highly effective compact remote tactical imagery relay system which utilizes existing serial data links and avionics on board the AV-8B harrier aircraft to capture still images from weapons video and then transmit the still images to a ground station for processing. The images can be annotated at the ground station and retransmitted to the aircraft for viewing by the pilot. 
   The compact remote tactical imagery transfer system comprising the present invention uses a Fast Tactical Imagery Processor, which is a digital image processor, to capture still images from weapons video supplied by a Litening pod or other weapons video source on board the AV-8B Harrier aircraft. The Fast Tactical Image Processor also provides for data compression, transmission, reception and display in the cockpit. An Integrated Remote Control Unit (IRCU) interfaces with the existing aircraft cockpit controls allowing the aircraft&#39;s pilot to control the operation of the Fast Tactical Imagery System and select still images for transfer to the ground station. The aircraft&#39;s on board encryption unit encrypts the still images and the onboard radio then transmits the still images to a ground station. 
   Observers at the ground station analyze the images using a laptop computer. The observers confirm the targets and coordinates are embedded in the still images, which are transmitted back to the aircraft for display to the pilot by display computer. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram illustrating the Compact Remote Tactical Imagery Relay System components; 
       FIG. 2  is a block diagram illustrating the integration of the Compact Remote Tactical Imagery Relay System into the AV-8B Aircraft&#39;s existing serial data links; 
       FIG. 3  is a pictorial representation of the Compact Remote Tactical Imagery Relay System in an operational environment; 
       FIGS. 4A ,  4 B,  4 C,  4 D,  5  and  6  are software charts illustrating the computer software program for the Integrated Remote Control Unit component of the Compact Remote Tactical Imagery Relay System of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 ,  2  and  3 , there is shown in  FIG. 2  the integration of Compact Remote Tactical Imagery Relay System  20  into the AV-8B Harrier aircraft  61 . Connected to data bus  22  is an ARC-210 radio  24 , which is a jam resistant two-way voice and data communications link to a ground station. Radio  24  includes an antenna  25  for transmitting image data to and receiving image data from the ground station or other military aircraft. Connected to the ARC-210 radio  24  is a KY-58 voice security device/encryption unit  26 , which provides for secure communication between the aircraft and the ground station by encrypting image data transmitted to a ground station and decrypting image data received from the ground station. 
   There is also an Automatic Target Handoff System (ATHS)  28  connected to the Military Standard 1553 data bus  22 . The Automatic Target Handoff System  28  is an integral component of the target acquisition data transmission capabilities of the AV-8B Harrier Aircraft  61 . Target information is transferred using short data burst rather than voice communications to minimize the possibility of jamming and lessen the probability of detection, while increasing the transfer of very accurate target information. 
   The Radar Display Computer (DC)  30  is connected to the Military Standard 1553 data bus  22 . The display computer  30  is also connected to a weapons video source  31 . The AV-8B Harrier aircraft&#39;s video source utilized by the Compact Remote Tactical Imagery System  20  is a Litening pod  31  which is a targeting pod integrated into the aircraft&#39;s avionics and mounted externally to the aircraft. The target pod  31  contains a high resolution, forward looking infrared sensor that displays an infrared image of the target to the aircrew. The Litening pod  31  also contains a charged coupled device camera used to obtain target imagery in the visible portion of the electromagnetic spectrum. 
   An Up Front Control Set (UFCS)  32  located in the aircraft&#39;s cockpit is also connected to the radar display computer  30 . The Compact Remote Tactical Imagery Relay System  20  includes a splitter cable  34  to interrupt the radar display computer  30  serial data connection/serial data line  40  to the Up Front Control Set  32 , and a splitter cable  36  to interrupt the radar display computer  30  video connection/video data line  42  from Litening pod  31  which provides the weapons video to display computer  30 . The Compact Remote Tactical Imagery Relay System  20  also has a splitter cable  38  to interrupt serial data connection  44  from the automatic target handoff system  28  which provides digital data and push to talk signals to the encryption unit  26 . 
   As shown in  FIG. 1 , the Compact Remote Tactical Imagery Relay System  20  comprises a PhotoTelesis Fast Tactical Imagery IIa (FTI IIa) processor  46 , which is a digital image processor providing for image capture from the weapons video supplied by the Litening pod  31 . The FTI IIa processor  46  also provides for data compression, transmission, reception and display in the cockpit. In a reconnaissance scenario, the FTI IIa processor  46  supplies to the pilot time critical image strike information that allows the pilot to view a battlefield at extended ranges thru still frames. Bomb damage assessment can also be transmitted immediately after an air strike to the pilot. 
   Fast Track Imagery IIa processor  46  also has a compact flash memory card which is removable. The compact flash memory card provides a capability to upload and download target images before and after a mission. Small text messages may also be attached to and transmitted with the images, which are then displayed on a cockpit display via the display computer  30 . 
   Compact Remote Tactical Imagery Relay System  20  also contains an Integrated Remote Control Unit (I-RCU)  48  which replaces a Remote Control Unit (RCU) normally used to control the operation of the Fast Tactical Imagery IIa processor  46 . Integrated Remote Control Unit  48  monitors the Up Front Control Set  32  to Remote Display Computer serial bus by tapping connection  40  between display computer  30  and control set  32  to detect a switchover request. When a switchover request is detected by the Integrated Remote Control Unit  48 , unit  48  replaces the display computer  30  for UFCS/display commands entered by the pilot. This allows for control of the digital image processor  46  by the pilot for digital imaging purposes. 
   When the Integrated Remote Control Unit  48  gains control of the Up Front Control Set  32 , display computer  30  is disconnected from up front control set  32  and commands sent from push buttons on control set  32  are routed to the Integrated Remote Control Unit  48  for processing. 
   When image capture and transmission is not selected by the pilot, the Integrated Remote Control Unit  34  is in an unintrusive monitoring state. Further, removal of power from the Integrated Remote Control Unit  48  will result in normal communications between the remote display computer  30  and the up front control set  32 . 
   Integrated remote control unit  48  comprises a commercially available PC104 processor board  52  and its associated I/O modules and power board  54  are stacked and then placed inside of the FTI IIa enclosure  56 . The Integrated Remote Control Unit  48  and the FTI IIa enclosure  56  are mounted on a pallet  58  adjacent one another. A cable  60  connects the PC104 processor board  52  and its associated I/O modules and power board  54  to the FTI IIa processor  46 . 
   The computer software program  53  for processor board  52  is written C++ and uses the Linux operating system. 
   Referring to  FIGS. 1 ,  2  and  3 , a pilot in an AV-8B Harrier aircraft  61  uses the Litening-II targeting pod  31  to observe ground target areas including specific targets such enemy troops, radar installation, and/or missile sites. The pilot of aircraft  61  snaps one or more images from the video stream he is watching via the radar display computer  30 . The still images selected by the pilot are transmitted to a ground station via the aircraft&#39;s radio  24  as RF signals  62  which include compressed and encrypted video images. 
   At the ground station, a PRC-117 radio  64  with a built-in encryption unit receives the RF signals including the video images. The video images are decrypted and transmitted to a portable laptop computer  68  via a serial data link  66 . Laptop computer  68  uses PhotoTelesis ICE software to process the video images for display at the ground station. ICE software is an integrated software application that provides capabilities to capture, display, compress, send and receive digital imagery on Windows computers. In addition, ICE software allows a user to manage, manipulate, annotate and print the still images. PhotoTelesis Corporation of San Antonio, Tex. manufactures the ICE software and the Fast Track Imagery IIa processor  46 . 
   A PRC-113 radio with a KY-57 encryption unit can also be used at the ground station to receive and transmit video images to aircraft  61 . 
   At the ground station, observers analyze the images using laptop computer  68 . The observers confirm the targets and coordinates are embedded in the images that are transmitted back to the aircraft for display to the pilot by display computer  30 . Image transfer time is approximately twenty seconds at nominal compression ratios. 
   Since the Compact Remote Tactical Imagery Relay System  20  uses existing aircraft avionics including radio  24 , airframe structural modifications and electrical modifications are not required. System  20  can be installed in an aircraft and removed from the aircraft in less than three hours. 
   The CRTIR (Compact Rapid Tactical Imagery Relay) system software is written in object-oriented C++, with threads, and implemented on the Linux operating system. 
   Software control flow is based on the cyclic executive model. The main function dynamically creates all needed controllers using the controller data structure and input from the command line. It then cycles thru each of the controllers and allows them a turn at system resources. This is necessary to mimic the timing on the serial data link between the UFCS (Up Front Control System) and DCU (Display Computer Unit), which reside on the actual plane. 
   Software data flow is provided by the use of threads and a data blackboard. Data from the FTI PRISM and the UFCS is gathered via separate threads of execution and then written to a common memory area or blackboard which makes it available to the main thread of execution. The main thread of execution is responsible for writing out updates to the blackboard which are then forwarded to the UFCS and the FTI PRISM. 
   Integration of the PC 104 watchdog timer routines ( FIG. 4 ) in the embedded software ensures program malfunction does not lock up the entire system. 
     FIGS. 4A ,  4 B,  4 C,  4 D,  5  and  6  are software charts illustrating the computer software program for the integrated remote control unit  46  of the Compact Remote Tactical Imagery Relay System  20  of  FIG. 1 . 
     FIGS. 4A ,  4 B,  4 C and  4 D is a top level view of the software elements grouped by function. The Controller software elements of  FIG. 4A  comprise Controller, BIT_Controller, Debug_Controller, FTI_Controller and Relay_Controller. The Executive software elements of  FIG. 4B  comprise Controller Factory, Executive and Watchdog. There is also an RCU_Exception element. The Memory Structures software elements of  FIG. 4C  comprise Shared_Memory and Shared_Receive_Buffer. The System Connections Software elements of  FIG. 4D  Comprise Prism_Model, Serial_Port, and UFCS_Interface. 
     FIG. 5  depicts the relationship between various software object classes and the data contained in each class. 
     FIG. 6  depicts a more detailed view of the derived objects within the software system. 
   From the foregoing, it is readily apparent that the present invention comprises a new, unique, and exceedingly useful compact remote tactical imagery relay system for processing video images generated by an aircraft&#39;s weapons video source which constitutes a considerable improvement over the known prior art. Many modifications and variations of the present invention are possible in light of the above teachings. It is to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.