Abstract:
Systems and methods to determine and ascertain the occurrence of an event are provided. The event can manifest its presence through transient signatures that alter short or long term background sensor registered signals. The system can include multiple sensors, one or more data recorders and data reporting devices. Event data from each sensor is collected, recorded and reported. Data from the various sensors is correlated to triangulate or otherwise localize the occurrence of an event. The sensors can be incorporated on a single device or can be a distributed set of independent sensors on separate devices that share their information with the data collection system.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to event detection. More particularly, the present invention relates to systems and methods to determine and ascertain the occurrence of an event that manifests its presence through transient signatures that alter short term and long term background sensor registered signals. 
     (2) Description of the Prior Art 
     Currently, a number of event detection methods rely on human observation. As an illustrative example, current minesweeping systems are towed by a manned platform, such as a helicopter or surface ship. Since there is some level of human situational awareness, direct observation is used to recognize if the sweep system being employed has indeed swept a mine or not. Accordingly, tactical memorandums and concept of operation documents for these systems explicitly state that those manning the platform shall watch for a plume or explosion when sweeping or neutralizing mines. 
     The fundamental concept of mine hunting and sweeping is shifting from this perspective to an entirely unmanned operation. Larger countermeasure ships and helicopters are slated to be retired in favor of smaller unmanned systems. For mine hunting systems, detailed methods of data collection and post mission analysis (PMA) are prescribed. A human operator downloads and reviews every sonar image or other data that the system collects. 
     For mine sweeping, however, PMA has been neglected due to the use of manned platforms and human observations, as described previously. Current unmanned sweep systems record when the system is energized and where it is. However, there are no provisions for recording whether or not a mine firing has occurred. Further, if a mine firing has occurred, there are no provisions for recording where the mine firing occurred. 
     Accordingly, the judgment as to whether an area has been cleared of naval sea mines to an acceptable level has to rely on vague position and status data. Such vague data is inadequate for deciding whether to risk lives and assets in moving them through an area that may or may not be sufficiently cleared. Thus, if an unmanned sweeping capability is desired, there is a need for a multi-sensor data collection system that can detect, localize, and report mine firings that have been actuated by an unmanned sweep system. 
     SUMMARY OF THE INVENTION 
     It is therefore a general purpose and primary object of the present invention to provide systems and methods to determine and ascertain the occurrence of an event that manifests its presence through transient signatures that alter short or long term background sensor registered signals. The system can include multiple sensors, one or more data recorders and data reporting devices. 
     Event data from each sensor are collected, recorded and reported. Data from the various sensors is correlated to triangulate or otherwise localize the occurrence of an event. The sensors can be incorporated on a single device or can be a distributed set of independent sensors on separate devices that share their information with the data collection system. 
     In one embodiment, a method for detecting an event manifesting a plurality of characteristic transient signatures includes detecting one or more of the characteristic transient signatures, correlating each of the detected signatures to confirm an occurrence of the event and correlating timing and location information of the detected signatures to determine a timing and location of the occurrence. Further, the method can include displaying the occurrence and the timing and location of the occurrence. 
     The method can include correlating the detected signatures with historical event data to characterize the event and the method can also display the characterization of the occurrence. In detecting the signatures, the method can include deploying one or more sensors attuned to detect one or more of the characteristic transient signatures. The method can also include the sensors transmitting the detected signatures to a processor for correlation. 
     In deploying the sensors, the method can include conducting a sweep of an area of interest and forcing at least one occurrence of the event by said sweep. The method can also display an area where further occurrences of the event have been mitigated by the sweep. The sweep can be conducted by an unmanned mine sweeping platform, wherein the event is the detonation of a mine. 
     In one embodiment, a method of conducting a mine sweeping operation includes deploying an unmanned mine sweeping platform, detecting a plurality of mine explosion characteristics, correlating the detected mine explosion characteristics to confirm an occurrence of a mine explosion and determining a time and location of the mine explosion based on timing and location information associated with each of the detected mine explosion characteristics. 
     The method can include correlating the detected mine explosion characteristics with historical mine explosion data to characterize the mine explosion. Also, the method can include displaying the mine explosion, the timing and location of the mine explosion and the characterization of the mine explosion. Further, the method can display an area where a further occurrence of one such mine explosion event is mitigated by the mine sweeping operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein like reference numerals and symbols designate identical or corresponding parts throughout the several views and wherein: 
         FIG. 1  illustrates a schematic elevation view of a system for detecting a mine explosion event; 
         FIG. 2  illustrates a diagrammatic view of the known effects of an underwater mine explosion event; 
         FIG. 3  illustrates a display of the system of  FIG. 1 ; 
         FIG. 4  illustrates an input/output diagram of the system of  FIG. 1 ; and 
         FIG. 5  is a block diagram of a method for detecting an event. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     For illustration and ease of description, but not for limitation, the systems and methods are described herein relative to unmanned mine sweeping operations, wherein the event occurrence to be ascertained is a mine firing or explosion event. Referring now to  FIG. 1 , there is shown a schematic elevation view of system  100  for detecting a mine explosion event. Unmanned platform  102  is deployed at sea surface  2  and sweeps an area of sea surface  2  in order to detect and detonate mines  4  that may be located beneath surface  2 . Plume  6  illustrates the detonation of one such mine  4 . 
     Referring also to  FIG. 2 , there is shown a diagrammatic representation of the known effects of detonating a mine  4 . In addition to plume  6 , which is characterized by shock spray dome  6   a  and gas bubble plumes  6   b  above sea surface  2 , surface waves  8  and air blast wave  10  can be observed by sensors  102   a  aboard platform  102 . Further, unmanned surface vehicle (USV)  104  and unmanned air vehicle (UAV)  106  can employ respective sensors  104   a  and  106   a  to also detect at surface and above surface effects of mine  4  detonation. 
     As illustrated in  FIG. 2 , the underwater effects of mine  4  detonation include oscillating and migrating gas bubble  12 , bubble pulse  14 , shock wave  16  and respective surface  2  and bottom  18  reflected shock waves  2   a  and  18   a . Unmanned underwater vehicle (UUV)  108  can deploy sensors  108   a  to detect one or more characteristics of the underwater effects. Additionally, one or both of USV  104  and UUV  108  can deploy respective towed array sensors  104   b  and  108   b  to also detect underwater effects. Other effects can also be observed, such as possible radar signatures from parts of detonated mine  4  and temperature anomalies from the explosion. 
     For ease of reference, the various sensors  102   a ,  104   a ,  104   b ,  106   a ,  108   a  and  108   b  will be collectively referred to hereinafter as sensors  110 . In addition to detecting explosion effects, sensors  110  include known timing and global positioning system (GPS) capabilities. The data collected by sensors  110  can be transmitted to processing platform (or processor)  112 . Platform  112  correlates the data from sensors  110 , and based on the detected explosion effects from sensors  110 , determines if a mine explosion has occurred. 
     If so, processing platform  112  utilizes the timing and GPS information from sensors  110  to determine the timing and GPS location of the explosion event. Additionally, using techniques known in the art, time signal analysis of shock wave  16  and reflected shock waves  2   a  and lea can yield information regarding the depth at which mine  4  detonated. 
     Results from processing platform  112  can be displayed to a human operator. Referring now to  FIG. 3 , there is shown a schematic representation of display  114 . For illustration, but not limitation, display  114  is depicted as showing the actual track  102   b  and future track  102   c  of platform  102 . Actual track  102   b  is based on GPS information from platform  102 . 
     In addition to tracking information, display  114  can depict location and timing information for detected explosion events (illustrated by symbols  116  with associated time in  FIG. 3 ). Further information, such as the locations of sensor platforms  104 ,  106  and  108 , may also be depicted on display  114 . 
       FIG. 4  depicts an input/output diagram for processing platform  112 . In addition to data  118  from sensors  110 , historical data  120  characterizing explosion effect signatures for various mines can be input to processing platform  112 . With this information, a detected explosion event may be characterized as to the type and origin of the exploded mine. Thus, platform  112  outputs can include event confirmation  122 , timing and location information  124  and mine characterization  126 . 
     When characterization is possible, display  114  can include differing symbols for differing types of mines, as indicated by symbol  116   a  and associated time in  FIG. 3 . In addition, based on actual track  102   b  and confirmed mine explosion events ( 116 ,  116   a ), display  114  can indicate areas that have been cleared of mines to acceptable levels, as indicated by dash-dot line  128  in  FIG. 3 . Such information can aid in making the judgment as to whether or not to risk lives and assets in moving them through an area. 
       FIG. 5  depicts a block diagram of method  200  for detecting a mine explosion event. Method  200  begins by deploying sensors  110  in the environment where an event may occur (block  202 ), as described with respect to  FIG. 1 . As described previously for the case of a mine sweeping operation, sensors  110  can be located aboard suitable platforms ( 102 ,  104 ,  106  and  108 ), such that block  202  can include deploying unmanned mine sweeping platform  102 , as well as USV  104 , UAV  106 , UUV  108  and other sensors or platforms as needed. 
     Sensors  110  monitor the environment (block  204 ) to detect one or more events, as described with respect to  FIG. 2 . If an event is detected, as determined at block  206 , the corresponding data is transmitted (block  208 ) to processing platform (or processor)  112 . Sensors  110  continue monitoring the environment if no characteristics are detected. 
     When the data is received, platform (or processor)  112  correlates the sensor data (block  210 ) to determine if an actual event has occurred, or the data received is an anomaly. If an event is confirmed (block  212 ), timing and location information is obtained (block  214 ) based on the GPS and timing capabilities of sensors  110 . 
     Additionally, by comparing the sensor data to historical data, the event is characterized (block  216 ), as described with respect to  FIG. 4 . As also described with respect to  FIG. 3  and  FIG. 4 , the event confirmation, timing and location information and characterization of the event can be displayed (block  218 ). Method  200  can then await new data (block  220 ). If new data is received, as determined at block  222 , method  200  returns to block  210  to correlate the sensor data. Method  200  also awaits new data when an event is not confirmed after correlating sensor data (block  212 ). 
     What have thus been described are systems and methods to determine and ascertain the occurrence of an underwater mine explosion. The system can include multiple manned or unmanned platforms, sensors deployed on one or more of the platforms and a processing platform. Event data from each sensor is transmitted to the processing platform. The processing platform correlates the data to determine if a mine explosion has occurred and further determines the location of an event. 
     The sensors can be incorporated on a single device or can be a distributed set of independent sensors on separate devices that share their information with the data processing platform. The processing platform can also include one or more sensors. 
     As previously noted, the systems and methods are described herein relative to unmanned mine sweeping operations, wherein the event occurrence to be ascertained is a mine firing or explosion event. However, the systems and methods can be generalized to ascertain the occurrence of events whose transient signatures can be detected by one or more sensors. 
     Many modifications and variations of the present invention may become apparent in light of the above teachings. For example, the types of platforms used need not be limited to, nor include all of, the platforms shown in  FIG. 1 . Depending on the type of event to be detected, platforms may be airborne, satellite based, ground based, mobile, surface based, underwater based, or some combination thereof. Additionally, the sensors may be chosen for the specific characteristics of the event or events to be detected. 
     It will be understood that many additional changes in details, materials, steps, and arrangements of parts which have been described herein and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.