Abstract:
A system and method for dynamic electronic surveillance comprising an imaging system having an angular measurement device, such as a seeker, in combination with a GPS receiver and a microprocessor which are used to compute a latitude and longitude of a remotely sensed position after it has been surveyed from a plurality of known measuring positions.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to electronic surveillance, and more particularly relates to use of directional image sensors in electronic surveillance, and even more particularly relates to methods and systems for dynamic surveillance of a remote object using directional sensors. 
     BACKGROUND OF THE INVENTION 
     In recent years, military mission planners typically have utilized a tremendous amount of intelligence information in carrying out their duties. Modern satellite imagery has proven to be an invaluable component of this intelligence information. However, it is often difficult, dangerous, and/or expensive to obtain very current and detailed information regarding dynamic rear enemy positions. Surveillance aircraft can be used, but at the risk of human life. Drones or other un-piloted surveillance aircraft have been used, but at great expense. 
     Missile-launched directional image sensors have gained widespread acceptance. One common usage of such directional image sensors has been in conjunction with seekers used for missile guidance. Typically, in these systems, an electronic sensor is manipulated to sense an area in front of a missile; the system is used to survey the area and to lock on and track a target. The target may be stationary or mobile, such as an enemy tank, mobile missile launcher, etc. In such systems, some information is often provided, via a telemetry data link, to a remotely located weapons officer who uses the information to guide the missile. 
     While these missile-launched seeker systems have proven utility in the battlefield, they do have some drawbacks. First of all, they are often used for very limited purposes. For example, seeker systems are widely used with glide bombs and other missiles to provide precision guidance only in areas very near the ultimate target. Another example is where a single seeker system is used to point a single gun or group of linked guns to lock on a mobile target, such as an enemy tank in tank-to-tank warfare. Secondly, these seeker systems typically do not generate surveillance information for use other than the targeting of the missile or other mobile munitions co-located with the seeker system. 
     Consequently, there exists a need for improved methods and systems for assisting mission planners and others with dynamic surveillance in an efficient manner. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a system and method for dynamic surveillance in an efficient manner. 
     It is a feature of the present invention to utilize a GPS receiver in conjunction with a seeker to dynamically determine a location of a remotely surveyed position. 
     It is another feature of the present invention to include a system and software to compute a latitude and longitude coordinate for a remotely surveyed position. 
     It is an advantage of the present invention to achieve improved efficiency in electronic surveillance of dynamic targets. 
     It is another feature of the present invention to utilize an optical sighting device having angular measurement capabilities. 
     It is another advantage of the present invention to provide the ability to use human sight-aided equipment which is capable of generating position information of a remote location. 
     The present invention is an apparatus and method for dynamic surveillance designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out in a “wasted utility-less” manner in a sense that the lack of use of additional inherent utility of seekers and GPS receivers in mobile military applications has been greatly reduced. 
     Accordingly, the present invention is a system and method for dynamic surveillance, which uses a GPS receiver and an angularly adjustable image system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be more fully understood by reading the following description of the preferred embodiments of the invention, in conjunction with the appended drawings wherein: 
     FIG. 1 is a simplified schematic depiction of a process of the present invention. 
     FIG. 2 is a simplified block diagram of the apparatus of the present invention. 
     FIG. 3 is a simplified block diagram view of the prior art. 
    
    
     DETAILED DESCRIPTION 
     Now referring to the drawings wherein like numerals refer to like matter throughout, and more specifically referring to FIG. 1, there is shown a simplified graphic depiction of components of a method of the present invention, generally designated  100 . There is shown a flight path  102 , which can represent a flight path line of a missile (cruise or ballistic), or a general path of travel for any mobile object, including a foot soldier. The details of each point on the flight path  102  are not important except that it has at least two points: first angular measurement location  110 , and second angular measurement location  112  therein which are known. Flight path  102  begins at missile launch site  104  and ends at missile target  106 . Of course, when the present invention is employed on a mobile platform other than a missile, other descriptive terms would be more suitable. Flight path  102  is shown in relation to compass rose reference lines  108 . Flight path  102  is also shown to include first angular measurement location  110  and second angular measurement location  112 . These locations are known because they represent positions or locations where measurements are taken and GPS data is obtained. Since the GPS derived latitude and longitude coordinates of first angular measurement location  110  and second angular measurement location  112  are known, the separation distance “d” can be calculated. At first angular measurement location  110 , a first angle  116  is determined via use of angular measurement instrument  206  (FIG.  2 ); the angular measurement is taken as extending from the flight path  102 . However, it should be understood that other points, lines, etc. of reference could be used as well. Often, the angle between the flight path  102  and a North reference line would be expressed as the heading of the missile. The first angular measurement location-bearing angle  122  of the surveyed target at first angular measurement location  110  would be the angle between the North reference line and first bearing line  126 . First angle  116  could be expressed as bearing minus heading or first angular measurement location bearing angle  122  minus missile heading  120 . Other reference lines could be used as well; it is believed that compass rose reference lines  108  are preferred. Similarly, second angle  118  could be expressed as second angular measurement location bearing angle  124  minus missile heading  120 . A triangle is created by first bearing line  126 , second bearing line  128 , and known leg  130 . Using well-known techniques of Euclidean geometry, lengths of either first bearing line  126  or second bearing line  128  can be calculated. Once either of these lengths is known, and the locations of first angular measurement location  110  and second angular measurement location  112  are determined by the GPS receiver  202  (FIG.  2 ), a latitude and longitude coordinate can be determined for surveyed target  114 . It should be understood that latitude and longitude may be expressed in various units of measure. It should also be understood that any other geo-reference systems could be used instead of latitude and longitude, which is believed now to be preferred. 
     A more detailed understanding of the present invention can be achieved by now referring to FIG. 2, which shows a mobile platform, generally designated  200 , including a GPS receiver  202 , which could be any type of position system, such as Glonass, Loran, or others. Mobile platform  200  can be any mobile platform. When it is a missile, it will be coupled to a propulsion system (not shown, but well known in the art) to carry the missile to its intended target. Microprocessor  204  is shown to represent a computing platform upon which the remote position determining software of the present invention would run. It should be understood that microprocessor  204  need not be a separate, independent, or distinct microprocessor. In fact, microprocessor  204  could be a shared processor with GPS receiver  202  or angular measurement instrument  206  or sensor system  208 . Microprocessor  204  is coupled to a data or program storage location  205 , which, among other things, stores the remote position-determining software of the present invention. This remote position-determining software may be written in any appropriate software language which is suitable for use with the microprocessor  204 . With the aid of this description and common knowledge of programming techniques, a person skilled in the art would be able to generate software to perform the functions shown and described in FIG.  1 . Angular measurement instrument  206  can be any instrument which is capable of generating an angular measurement signal which relates to an angular orientation of surveyed target  114  with respect to the flight path  102  or mobile platform  200 . Where the present invention is deployed on a missile, the angular measurement instrument  206  could be part of a seeker (similar to well-known prior art seekers) used to track targets, etc. or other sensor system  208 . Additionally, when the present invention is deployed in a missile application, it would be necessary to include data link  210 , which could be used to transmit back to a weapons officer or mission planner the location of enemy targets surveyed by the missile. In prior art remotely guided missile systems, such as shown in FIG. 3, it has been well known to provide real-time video images to a weapons officer station  226 , which is coupled via radio  224  and antenna  222  to the antenna  211 . Once the missile is very near the target, the weapons officer uses the video to guide the missile or glide bomb to its exact target location. FIG. 3 shows much the same apparatus as FIG. 2, the present invention. One salient difference is the microprocessor  304  is not functioning the same as microprocessor  204  of FIG. 2, and it does not operate on the same software. Microprocessor  304  does not perform the calculation as described and shown in FIG. 1, and consequently, it also does not assist in the delivery of lat/lon location tagged images as is done by the apparatus of FIG.  2 . Storage  305  does not contain the remote position-determining software of the present invention. 
     It is also envisioned the present invention could enjoy utility with handheld surveillance equipment used by a foot soldier, hiker, hunter, or other person. A handheld device could be constructed which includes an angular measurement instrument  206  which records an orientation of the device with respect to a reference. This device would be optical in nature, so that a human eye is used to align the device with a surveyed target  114 . A GPS receiver  202  would be coupled thereto, as described and shown elsewhere in this description. An inertial reference system  214 , such as one including at least one gyroscope, an accelerometer or electronic compass, or other rotation sensor, could be included as well. (Note: a missile application may or may not have an inertial reference system  214  to augment the information from the GPS receiver  202 .) The operation of the handheld device would be similar, and it would follow the same basic reverse triangulation technique of the present invention. In one preferred embodiment, the handheld device would have a button or switch which when depressed, would initiate the process of the present invention. Assuming the device were in motion, the device would continue to its operation of making numerous calculations from differing positions (determined by GPS receiver  202 ); then, upon release of the button, the device would calculate and display, via display device  212 , the latitude and longitude of the surveyed target  114 . (Note: in missile applications, there generally would not be any need for a display on the missile.) This assumes that the device was optically aligned with the surveyed target  114  both when the button is pressed and when it is released. This creates the potential for an extremely user-friendly device, which has countless uses, such as search and rescue, forest fire spotting, law enforcement, and others. These devices could be handheld, or they could be mounted in a vehicle or an aircraft, and they may be combined with other optical equipment, such as binoculars, cameras, laser range finders, spotting scopes, etc. 
     In operation, the apparatus and method of the present invention as described in FIGS. 1-2, could function as follows: In a missile application, the missile is launched from missile launch site  104 ; its sensor system  208  is activated either immediately or once it is located over an area to be surveyed. Images of the area are transmitted back to the weapons officer station  226  via data link  210  and intermediate equipment. The images transmitted during the transit, or non-final approach phase, are preferably of enemy armor, munitions, or other facilities. Instead of sending back just raw video images, these images are now recognized, using known image recognition techniques and a database available in flight. Once an object is recognized as an object to be surveyed, then the process described in FIG. 1 is performed. A lat/lon of this remotely located object is then associated with an image of the object, and both are transmitted to the weapons officer station  226  or other mission planner. The image may be a text-augmented video image with a textual tag giving lat/lon displayed on or about the image. The lat/lon information of the object may also be transmitted by data link  210  without an image, and with some predetermined identifier or classification of the type of object. Several objects may be encountered during the transit phase of the missile flight, and each can be surveyed and reported back to the weapons officer station  226  or other mission planner. The above-described operation is carried out, at least in part, by the remote position software which is stored in storage location  205 . This remote position-determining software could include the entire software necessary to survey and fully report on several remote objects during the transit phase of the missile flight. Once the missile reaches its target area, the normal final targeting and remote guidance functions of the present invention (which are similar to those for prior art system  300 ) resume, and the missile is precisely guided to its target. Back at the weapons officer station  226 , the information from the missile is gathered, along with other similar missiles, and new targeting of future missiles is performed with the information provided by the lat/lon tagged images of the present invention. Very little new hardware or software is required to implement the new missile surveillance system of the present invention. 
     Throughout this description, reference is made to a seeker and to a microprocessor, because it is believed that the beneficial aspects of the present invention would be most readily apparent when used in connection with such devices; however, it should be understood that the present invention is not intended to be so limited and should be hereby construed to include other non-seeker and non-microprocessor devices as well. 
     It is thought that the method and apparatus of the present invention will be understood from the foregoing description and that it will be apparent that various changes may be made in the form, construct steps, and arrangement of the parts and steps thereof, without departing from the spirit and scope of the invention or sacrificing all of their material advantages. The form herein described is merely a preferred exemplary embodiment thereof.