Patent Publication Number: US-2021183214-A1

Title: Rescue support in large-scale emergency situations

Description:
RELATED APPLICATION DATA 
     This application claims the benefit of Swedish Patent Application No. 1951450-4, filed Dec. 13, 2019, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates generally to rescue operations in large-scale emergency situations and, in particular, to the use of unmanned aerial vehicles for providing situational awareness in such situations. 
     BACKGROUND ART 
     A large-scale emergency situation potentially involves several stranded, injured or dead persons and may be caused by a natural phenomenon such as a hurricane or tornado, an earthquake, a flooding, a tsunami, a volcano eruption, a landslide, an avalanche, a wildfire, etc., or an incidence such as a terrorist attack, an industrial accident, a plane crash, etc. 
     Search and rescue operations in these situations are hampered by a lack of overview and information. The victims may be entrapped and difficult to find for the rescue teams. Traditionally, search and rescue operations may be directed to areas identified by so-called structure triage, which pre-prioritize buildings or other structures for search teams. It is also common to initially deploy a reconnaissance (recon) team to perform a rapid visual check of a rescue environment to obtain information that may be used to develop a search plan and direct search and rescue operations. These measures are generally time-consuming, and time is critical for saving people in an emergency situation. 
     It has been proposed to deploy unmanned aerial vehicles, such as drones, to gather information to enhance situational awareness in emergency situations. US2018/0327091 discloses such a system in which a swarm of drones is deployed to monitor an affected area, for example by thermal sensors, and collectively relay information to remote dispatchers. However, given the chaotic nature of large-scale emergency situations, remote monitoring by drones is unlikely to provide sufficient information for an efficient search and rescue operation. 
     US2017/0092109 proposes to provide monitoring control units, each of which are associated with a respective property and configured to detect an emergency event based on data received from sensors installed throughout the property. A monitoring application server that receives an emergency event notification from one of the monitoring control units, transmits an instruction to launch one or more drones to the location associated with the emergency event notification. 
     There exists a need to provide support for more efficient use of resources when responding to large-scale emergency situations. 
     BRIEF SUMMARY 
     It is an objective to at least partly overcome one or more limitations of the prior art. 
     Another objective is to facilitate and/or improve prioritization of resources in responding to a large-scale emergency situation. 
     One or more of these objectives, as well as further objectives that may appear from the description below, are at least partly achieved by a system for rescue support, as well as a computer-readable medium, a device, and methods for rescue support according to the independent claims, embodiments thereof being defined by the dependent claims. 
     A first aspect of the present disclosure is a system for rescue support. The system comprises: a fleet of unmanned aerial vehicles for deployment within a geographic region, the unmanned aerial vehicles being configured to receive distress signals transmitted by transponder devices worn or carried by individuals in the geographic region subsequent to a large-scale emergency situation; and a computer system. The computer system is configured to: process the distress signals to obtain detection data for the individuals, the detection data comprising a location of a respective transponder device among the transponder devices and a health status of a respective individual among the individuals; and generate, based on the location and health status, a prioritization chart for the geographic region, the prioritization chart being indicative of one or more sub-regions to be prioritized for a rescue operation. 
     A second aspect of the present disclosure is a computer-implemented method for rescue support. The method comprises: obtaining detection data representative of distress signals that are transmitted subsequent to a large-scale emergency situation by transponder devices worn or carried by individuals in a geographic region and received by unmanned aerial vehicles in a fleet of unmanned aerial vehicles deployed within the geographic region, the detection data comprising a location of a respective transponder device among the transponder devices and a health status of a respective individual among the individuals; and generating, based on the location of and health status, a prioritization chart for the geographic region, the prioritization chart being indicative of one or more sub-regions to be prioritized for a rescue operation. 
     Any embodiment of the first aspect described herein may be adapted as an embodiment of the second aspect. 
     A third aspect of the present disclosure is a computer-readable medium comprising computer instructions which, when executed by a processing system, cause the processing system to perform the method of the second aspect or any of its embodiments. 
     A fourth aspect of the present disclosure is a device comprising logic configured to control the device to perform the method of the second aspect or any of its embodiments. 
     A fifth aspect of the present disclosure is a method for rescue support. The method comprises: distributing transponder devices to individuals in a geographic region; causing the transponder devices to be activated; controlling a fleet of unmanned aerial vehicles operable within the geographic region to receive distress signals transmitted by the transponder devices subsequent to a large-scale emergency situation in the geographic region, and operating a computer system to: process the distress signals to obtain detection data for the individuals, the detection data comprising a location of a respective transponder device among the transponder devices and a health status of a respective individual among the individuals, and generate, based on the location and health status of the respective individual, a prioritization chart for the geographic region, the prioritization chart being indicative of one or more sub-regions to be prioritized for a rescue operation. 
     The foregoing aspects ensure availability of both health status and location of individuals in a geographic region that is struck by a large-scale emergency situation. The combination of location and health status enables the prioritization chart to be generated to properly represent casualties and/or individuals in need of help and thereby enables more efficient use of resources when responding to large-scale emergency situations. 
     Still other objectives and aspects, as well as features, embodiments and technical effects will appear from the following detailed description, from the attached claims as well as from the drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Embodiments will now be described in more detail with reference to the accompanying schematic drawings. 
         FIG. 1  is an overview of an example system for rescue support. 
         FIG. 2  is a top plan view of a fleet to drones monitoring a region affected by a large-scale emergency situation. 
         FIGS. 3A-3B  are block diagrams of a personal transponder and a drone controller, respectively. 
         FIG. 4  is a flow chart of method for rescue support. 
         FIGS. 5A-5B  are examples of spatial grouping of detection data gathered by drones. 
         FIG. 6  shows a prioritization chart generated for a region affected by a large-scale emergency situation. 
         FIG. 7  is a flow chart of a method for rescue support. 
         FIGS. 8A-8C  are schematic side views of a drone in relation to a transponder. 
         FIG. 9A  is an overview of a system for rescue support,  FIG. 9B  is a flow chart of a method for rescue support, and  FIG. 9C  is a block diagram of a computer system that is included in the system of  FIG. 9A . 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure may satisfy applicable legal requirements. 
     Also, it will be understood that, where possible, any of the advantages, features, functions, devices, and/or operational aspects of any of the embodiments described and/or contemplated herein may be included in any of the other embodiments described and/or contemplated herein, and/or vice versa. In addition, where possible, any terms expressed in the singular form herein are meant to also include the plural form and/or vice versa, unless explicitly stated otherwise. As used herein, “at least one” shall mean “one or more” and these phrases are intended to be interchangeable. Accordingly, the terms “a” and/or “an” shall mean “at least one” or “one or more”, even though the phrase “one or more” or “at least one” is also used herein. As used herein, except where the context requires otherwise owing to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, that is, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments. The term “compute”, and derivatives thereof, is used in its conventional meaning and may be seen to involve performing a calculation involving one or more mathematical operations to produce a result, for example by use of a computer. 
     As used herein, the terms “multiple”, “plural” and “plurality” are intended to imply provision of two or more elements, whereas the term a “set” of elements is intended to imply a provision of one or more elements. The term “and/or” includes any and all combinations of one or more of the associated listed elements. 
     It will furthermore be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing the scope of the present disclosure. 
     Well-known functions or constructions may not be described in detail for brevity and/or clarity. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. 
     Like numerals refer to like elements throughout. 
     Before describing embodiments in more detail, a few definitions will be given. 
     As used herein, “large-scale emergency situation” refers any situation that may potentially cause harm to a large number of individuals, including but not limited to situations caused by natural phenomena, accidents or deliberate acts, for example as discussed in the Background section. 
     As used herein, “unmanned aerial vehicle” (UAV) refers to an aircraft controlled by an onboard automated control system, a ground-based control system or by a ground-based human pilot. Such an aircraft is also known as “uncrewed aerial vehicle” or drone. 
     Embodiments relate to a technique for supporting rescue operations in large-scale emergency situations. The purpose of a rescue operation is to help and eventually evacuate individuals that are in an actual or potentially dangerous situation. Depending on the state and local environment of the respective individual and/or the future development of the situation, a short time to rescue may be of essence. However, it is challenging to coordinate the rescue efforts in a large-scale emergency situation. Many individuals may be hidden from view and the health status of the respective individual is unknown. The technique described herein for supporting rescue operations may serve to facilitate coordination of rescue efforts and significantly shorten the time to locate individuals that are stranded, distressed, injured or otherwise in need of help. 
     Embodiments of the technique will be described with reference to  FIG. 1 , which schematically illustrates an example system for rescue support. In the illustrated example, the system comprises transponder devices (“transponders”)  11  (one shown), UAVs (“drones”)  20  (one shown), processing devices  40 ,  60  and a display device  61 . The transponder  11  is worn or otherwise carried by an individual  10  who is in a geographic region that is subject to a large-scale emergency situation. The transponder  11  has been activated to broadcast a distress signal DS, which comprises health data indicative of the health status of the individual. The health data may enable discrimination between living and dead individuals. In some embodiments, the health data may additionally enable classification of living individuals into different health categories. The respective drone  20  includes a control device (“controller”)  21  which is configured to intercept the distress signal DS and to generate and transmit first data DD 1  to a first processing device  40  over a first network  30 . The first data DD 1  is generated based on the distress signal DS and is indicative of the location of the transponder  11  and the health status of the individual  10 . The first processing device  40  processes the first data DD 1  to generate second data DD 2  and may provide the second data DD 2  for storage in a database  50 . The second data DD 2  may be a collection of first data DD 1  from different drones  20  and/or contain a refinement of the first data DD 1 , for example with respect to location or health status. The second processing device  60  obtains the second data DD 2  over a second network  31 , from the first processing device  40  and/or by retrieval from the database  50  (cf. dashed line in  FIG. 1 ). The second processing device  60  operates the display device  61 , which may be located at a rescue coordination center for the geographic region, to display supporting data for the rescue operation. The supporting data comprises a prioritization chart  600  that indicates one or more sub-regions to be prioritized for the rescue operation in the geographic region. The prioritization chart  600  may be generated by the first processing device  40  and/or the second processing device  60  based on the data collected by the drones in the geographic region. The prioritization chart  600  thereby provides a current status overview of the geographic region, and the system may be configured to present the prioritization chart  600  in real-time or near real-time. Further, the prioritization chart  600  may be updated, continuously or intermittently, based on data collected by the drones  20 . 
       FIG. 3A  is a block diagram of an example transponder  11  which is worn or otherwise carried by an individual. The transponder  11  comprises a processor  12 , a power source  13 , a signal transmitter  14 , a sensor arrangement  15 , an on/off switch  16 , and an indicator  17 . The power source  13  may comprise a battery or a fuel cell for supplying power to components such as the processor  12 , the transmitter  14  and the indicator  17 . The transmitter  14  is configured to transmit a wireless signal in any suitable frequency range, continuously or at intervals. The wireless signal may be a radio signal. The wireless signal may be capable of penetrating obstacles such as building material. The transmitter  14  may be configured to encode data in the wireless signal in accordance with any standardized or proprietary communication protocol. In some embodiments, the transmitter  14  is configured for short-range or medium-range communication, for example by a wireless standard such as Bluetooth, BLE, Wi-Fi, Wi-SUN, EnOcean, or UWB. The sensor arrangement  15  may comprise one or more sensors that are integrated in or otherwise associated with the transponder  11 . The sensor arrangement  15  is configured to sense parameter data representative of the individual that carries the transponder  11 . The parameter data may comprise one or more physiological parameters such as heart rate (“pulse”), body temperature, blood pressure or breathing rate. Alternatively or additionally, the parameter data may represent movement of the individual. Non-limiting examples of sensors that may be included in the sensor arrangement  15  comprise accelerometers, gyroscopes, magnetometers, altimeters, pedometers, vibration sensors, blood pressure sensors, skin temperature sensors, heart rate sensors, sweat sensors, moisture sensors, breathing rate sensors, and bioelectric current sensors. The processor  12  is operable to acquire the parameter data from the sensor arrangement  15  and cause the transmitter  14  to broadcast the above-mentioned distress signal DS containing the parameter data, or data derived therefrom. The on/off switch  16  is connected to the processor  12 , thereby allowing the transponder  11  to be manually activated. The indicator  17 , for example comprising one or more LEDs or lamps, may be arranged to indicate when the transponder  11  is activated and/or when the transmitter  11  is operated to broadcast the distress signal DS. 
     In some embodiments, the transponder  11  is a simple and inexpensive electronic device. For example, the transponder  11  may be a wearable electronic device. In some embodiments, the transponder  11  is included in a mobile phone or a smart watch. In some embodiments, the transponder  11  is configured to be activated manually by the individual  10 , for example via the on/off switch  16 . In some embodiments, the transponder  11  is configured to be activated automatically when attached to the individual  10 , e.g. based on a signal from the sensor arrangement  15 . In some embodiments, the transponder  11  is configured to be remotely activated, for example by a signal received by a signal receiver (not shown) in the transponder  11 . In some embodiments, the transponder  11  is configured to be power-efficient. In some embodiments, the transponder  11  is operable in an ultra-low power state when not activated and a low power state when activated. 
       FIG. 3B  is a block diagram of an example controller  21  for installation on a drone. The controller  21  comprises a processor  22 , a GNNS receiver  23 , a signal receiver  24 , a signal transceiver  25 , and a sensor arrangement  26 . The controller  21  may be connected to or part of a main controller for the drone  20 . The processor  22  operates the controller  21 . The controller  21  may be configured to determine global positions of the drone  20  based on position data from the GNNS receiver  23  by use of a satellite navigation system, including but not limited to GPS, QZSS, GLONASS, NAVIC, BDS, and optionally in combination with one or more further positioning techniques such as INS (Inertial Navigation System) and/or SLAM (Simultaneous Localization and Mapping), which are well-known to the person skilled in the art. The signal receiver  24  is configured to receive the wireless signals transmitted by the transponder  11 . The signal transceiver  25  is configured to wirelessly communicate with the first processing device  40  over the first network  30  ( FIG. 1 ), in accordance with any standardized or proprietary communication protocol. However, since mobile and other ground-based communication networks may be unavailable in an emergency situation, the signal transceiver  25  may be configured with a radio layer with a long signal range, for example at least 0.5 km, or at least 5 or 10 km. The signal transceiver  25  may further be operable for non-cellular communication. In some embodiments, the signal transceiver  25  supports satellite communication or LPWAN (Low-Power Wide-Area Networks) communication, for example in accordance with LoRa, Sigfox, RPMA (Random Phase Multiple Access), Weightless, etc. The sensor arrangement  26  may include one or more environmental sensors configured to collect information about the local environment. By the environmental sensor(s), the sensor arrangement  26  may generate environment data representative of the surroundings of the drone  20 . The environmental sensor(s) may include one or more imaging devices, for example a digital camera, a thermographic camera, a multispectral camera, a LIDAR sensor, etc., and/or one or more ambient sensors, such as temperature sensor, pressure sensor, sound detector, weather sensor, wind sensor (speed, direction), humidity sensor, dew point sensor, substance sensor (gas, chemicals), radioactivity sensor, etc. Although not shown in  FIG. 3B , the controller  21  may further comprise a spotlight to illuminate the local environment, for example the terrain beneath the drone. The sensor arrangement  26  may also include one or more orientation sensors, such as one or more accelerometers, gyroscopes, magnetometers, altimeters, etc. The controller  21  may be configured to determine the current orientation of the drone  20  based on data from the orientation sensor(s). For example, the current orientation may be given by any combination of pitch, roll and yaw. 
     Reverting to  FIG. 1 , the second network  31  may be any suitable LAN, MAN or WAN, or combination thereof. If the first processing device  40  is located sufficiently far from the emergency situation, the second network  31  may be or comprise an existing wireless cellular network, for example compliant with the 3GPP standard and/or a land-based communication network. 
       FIG. 4  is a flow chart of an overall method  400  for rescue support in accordance with an embodiment, which method may be implemented within the system of  FIG. 1 . 
     In step  401 , transponders  11  are distributed to individuals  10  within a geographic region in anticipation of a large-scale emergency situation. For example, the transponders  11  may be distributed within a region that is known, predicted or deemed likely to suffer from a natural disaster, such as a hurricane, a flooding, an avalanche, an earthquake, a tsunami, etc. Transponders  11  may also be distributed within a region deemed likely to be targeted by a terrorist attack or a region with industries that would cause large-scale devastation in the event of a major malfunction or accident, for example a chemical plant, an oil refinery or a nuclear power plant. In another example, transponders may be preemptively distributed to all individuals within a country, state, province, county, city etc. In step  402 , activation of the transponders  11  is initiated, for example, in response to an emergency situation. When activated, the respective transponder  11  operates its transmitter  14  to transmit the distress signal. Step  402  may be performed before step  401 , so that the transponders  11  are active when distributed. Alternatively, step  402  may be performed in anticipation of the emergency situation. If the transponders  11  are configured to be manually activated, step  402  may involve distributing, by any communication channel, an appeal to the people in the geographic region to activate their transponders. If the transponders  11  are configured to be activated automatically when attached to the individuals, step  402  may be inherent to step  401 . If the transponders  11  comprise a signal receiver and are configured for remote activation, step  402  may involve transmitting an activation signal to the transponders  11 . It is also conceivable that the transponders  11  are being activated, manually or remotely, during the emergency situation. 
     Steps  403 - 407  are performed during the emergency situation. In step  403 , a fleet or swarm of drones  20  are operated to co-operatively work together to cover a region of interest, which may be the geographic region or part thereof. The drones  20  may be actively dispatched to the region of interest during or before the emergency situation or they may be already present in the region of interest for another purpose. In step  404 , while moving within the region of interest, the drones  20  are operated to intercept (receive) distress signals from transponders  11 .  FIG. 2  is a top plan view of a plurality of drones  20  that are operated to fly over an area in search for distress signals from transponders  11  (black dots). In some scenarios, a swarm of drones  20  may be programmed into a bird-like formation cutting through the sky. In other scenarios, a smaller number of drones  20  may take individual paths to work together to scan an area. For example, a swarm of drones  20  may share a common map of a terrain, communicating to each other the position already monitored, and choose (in real-time or near real-time) the next position to be visited. 
     In step  405 , the respective distress signal is processed for determination of detection data comprising the location of the transponder  11  and the health status of the individual carrying the transponder  11 . The health status may be determined based on one or more physiological parameters that are measured (cf. sensor arrangement  15  in  FIG. 3A ) and may be embedded in the distress signal by the transponder  11 . In one embodiment, the location is measured and embedded in the distress signal by the transponder  11 , for example by use of an integrated GNNS sensor. In another embodiment, which eliminates the need for a GNNS sensor in the transponder  14  and thus enables the transponder  14  to have low power consumption, cost and complexity, the location is determined based on position parameters measured by the drone  20  that intercepts the distress signal. The position parameters may include a global position of the drone  20  and at least one of a distance and/or a direction from the drone  20  to the transponder  11 . The global position of the drone  20  may be given by a GNNS receiver (cf.  23  in  FIG. 3B ) on the drone  20 . 
     In the example of  FIG. 1 , step  405  may be performed by the controller  21 , and the first data DD 1  may comprise a combination of location and health status for each unique distress signal DS. In one embodiment, the distress signal DS comprises a transponder identifier (TID) which is unique to the originating transponder  11 , and step  405  comprises extracting the TID from the respective distress signal and determining the location and health status for each unique TID. The TID enables discrimination between transponders  11  and ensures consistent data collection. In the example of  FIG. 1 , the TID may be included in the first data DD 1  in association with the location and health status. This will enable the first processing device  40 , when receiving first data DD 1  from different drones  20 , to detect data sets originating from the same transponder  11 . In one embodiment, one data set may be selected from such data sets. In another embodiment, the data sets may be merged, for example by computing an average location and/or health status. 
     Step  407  generates the prioritization chart  600  with prioritized sub-region(s) for the rescue operation. The prioritization chart  600  is generated based on the detection data determined in step  405  for transponders within the geographic region. Examples of prioritization charts will be presented further below with reference to  FIG. 6 . 
     As indicated in  FIG. 4 , the method may comprise a step  406  that determines a grouping of the detection data as a function of at least the location of the respective transponder  11 , resulting in a plurality of groups. In one embodiment of step  406 , shown in  FIG. 5A , the detection data is mapped, by its content of locations, to a fixed arrangement of cells or sections within the geographic region. In one example, the cells are defined by a predefined grid. In  FIG. 5A , the grid comprises quadrilateral cells which are uniquely identified by a pair of x-y coordinates, and the locations are represented by white dots. In another embodiment of step  406 , shown in  FIG. 5B , a clustering function is operated on the detection data to identify clusters of locations. The clustering function may be a density-based clustering function. Any such clustering function may be used, including but not limited to DBScan, OPTICS, mean-shift, etc. In  FIG. 5B , clusters a delimited by dashed lines and designated by G 1 -G 4 , and the locations are represented by white dots. Step  406  may further determine the density of individuals in the respective group. 
     Step  406  may further factor in the health status when determining the grouping. In one embodiment, step  406  identifies selected individuals based on the health status and determines the grouping for the selected individuals. In one example, individuals indicated as dead by the health status are excluded, leaving all living individuals as selected individuals. In another example, if the health status enables classification of living individuals into different health categories, the selected individuals may belong to one or more selected health categories. In a further alternative, the health status may be analyzed after the grouping, for example to exclude dead individuals and/or individuals in one or more health categories before determining the density of the respective group. 
       FIG. 6  shows an example of a prioritization chart  600  generated by step  407 . The chart  600  comprises a graphical overview (“graphics”)  601  of the geographic region, for example a map, a  3 D representation, or a satellite image (real-time or pre-recorded). Sub-regions of one or more priorities are indicated on the chart. In  FIG. 6 , the chart  600  indicates sub-regions assigned three different priorities, with sub-regions P 1  having top priority, sub-regions P 2  having high priority and sub-regions P 3  having medium priority. Step  407  may assign any number of different priorities and determine sub-regions P 1 -P 3  in any size and shape. The different priorities may be visually separated on the chart  600 . In one embodiment, the sub-regions P 1 -P 3  are indicated by a choropleth map, in which the graphics  601  is shaded or patterned in proportion to the priority value. In one example, the choropleth map implements a color coding to produce a so-called heat map. Step  407  may generate the chart  600  based on the plurality of groups from step  406 . For example, a sub-region may be equal to or include one or more of the groups. In one embodiment, step  407  assigns a priority value to the respective group, for example based on its density of individuals and/or the health status of the included individuals and indicates the sub-regions in the chart  600  based on the priority values of the groups. In one example, step  407  includes, in one or more sub-regions, group(s) with the highest density of individuals. 
     In some embodiments, step  407  generates the chart  600  to enable a user to zoom in on the graphics  601  and/or be presented with further information about a sub-region or part thereof. An example is shown in  FIG. 6 , where the chart  600  comprises highlight panels  602  with enlarged graphics  602 A. The highlight panels  602  may be fixed or shown on command. 
     In some embodiments, step  407  generates the chart  600  based on the environment data from the above-mentioned environmental sensor(s) in the sensor arrangement on the respective drone (cf.  26  in  FIG. 3B ). In some embodiments, step  407  includes at least part of environment data detected by one or more drones in chart  600 , for example images, temperature, pressure, gas content, humidity, sound, etc. An example is shown in  FIG. 6 , where the chart  600  comprises sub-panels  602 B providing access to image(s) or video recorded by the imaging device on a respective drone and possibly audio recorded by a sound detector. Further, sub-panels  602 C show temperature and wind speed detected by ambient sensors on a respective drone. 
     In some embodiments, step  407  determines the prioritized sub-region(s) as a function of the environment data. For example, step  407  may predict a local worsening of the emergency situation based on the environment data, for example images recorded by one or more drones. For example, step  407  may detect a fire that calls for a high priority of a sub-region or a group. 
     In some embodiments, step  407  processes the environment data, such as one or more images, from one or more drones to determine an infrastructure status within the geographic region. The infrastructure status may represent the current condition of roads, bridges, airports, seaports, etc. Step  407  may further indicate the infrastructure status on the chart  600 . In  FIG. 6 , a demolished bridge is indicated by square E 1  in the graphics  601 . In some embodiments, step  407  determines the prioritized sub-region(s) as a function of the infrastructure status. For example, as indicated in  FIG. 6 , sub-region P 1  may be set to top priority since the bridge is demolished and individuals are trapped on an island. 
     In some embodiments, step  407  determines, based on the infrastructure status, an estimated time of arrival to the sub-region(s) for one or more rescue teams located at a respective current location in relation to the geographic region, and includes the estimated time of arrival in the chart  600 . Step  407  may be performed for different modes of transport that are available to the respective rescue team. In  FIG. 6 , the chart  600  comprises sub-panels  602 D indicating a rescue team (“resource”) and an estimated time of arrival (“ETA”) for the rescue team to a respective sub-region by use a specified mode of transport (“mode”). Step  407  may determine the current location of the respective rescue team from location signals transmitted by rescue teams, or from input data provided by an operator at the rescue coordination center. 
     In some embodiments, step  407  indicates, in the chart  600 , the current location of one or more rescue teams in relation to the geographic region. It is understood that the current location may be within or outside the geographic region. 
     In some embodiments, step  407  selects, based on the infrastructure status, one or more candidate rescue teams among a set of available rescue teams, and indicates the selected candidate rescue team(s) in the chart  600 . The candidate rescue teams may be selected based on estimated time of arrival, availability of rescue equipment in relation the health status of individuals in the respective sub-region, etc. In  FIG. 6 , the resources indicated in sub-panels  602 D may be such selected candidate teams. 
     In some embodiments, step  407  selects, based on the infrastructure status, a mode of transport among a set of available modes of transport for at least one rescue team, and indicates the selected mode of transport in the chart  600 . In  FIG. 6 , the modes indicated in sub-panels  602 D may be such selected modes. 
     In some embodiments, step  407  obtains rescue status data indicative of locations visited by one or more operative rescue teams, and indicates the locations visited on the chart  600 . Step  407  may determine the rescue status data from status signals transmitted by the operative rescue teams or from input data provided by an operator at the rescue coordination center. 
     In some embodiments, step  407  determines, based on the infrastructure status, a transportation route for a rescue team to the sub-region(s), and indicates the transportation route in the chart  600 . Further, step  407  may cause the determined route to be transmitted to the rescue team, subject to approval by an operator at the rescue coordination center, to synchronize the activity of the rescue team with the decisions taken at the rescue coordination center. 
     In some embodiments, step  407  includes indicators of individuals or ensembles of individuals in the chart  600 . The indicators may designate the location of the individuals/ensembles, and optionally the health status. In  FIG. 6 , the locations of living and dead individuals are indicated by white and black dots, respectively, in the enlarged graphics  602 A. 
     In some embodiments, step  407  generates, based on the detection data (location and health status), a count of living individuals in the sub-region(s) and includes the count in the chart  600 . In  FIG. 6 , the chart  600  includes sub-panels  602 E that designate the number of living individuals (#PA), the number of individuals with critical health status (#PC), and the number of dead individuals (#PD) in the respective sub-region P 1 . 
     In some embodiments, step  407  provides, via the chart  600 , real-time access to the controller  21  on a drone  20  in the fleet of drones. Thus, step  407  may establish real-time communication with the signal transceiver  25  of the controller  21  on the drone  20  ( FIG. 3B ) and transmit control signals for the processor  22  of the controller  21 . In some embodiments, the access to the controller  21  comprises an interface on the chart  600  for controlling the drone to a selected location in the geographic region. In  FIG. 6 , the interface is represented by a crosshair icon CH which is moveable over the graphics  601 , by an operator at the rescue coordination center, to control a drone  20  to the specific location. In some embodiments, the access to the controller  21  comprises an interface on the chart  600  for real-time access to the sensor arrangement on a drone  20 . In  FIG. 6 , the chart  600  comprises sub-panels  602 F providing real-time access to image(s) or video recorded by the imaging device on a drone and possibly audio recorded by a sound detector. In some embodiments, step  407  determines and indicates the current field of view of the imaging device in relation to the geographic region. In  FIG. 6 , the current field of view is represented by a dashed rectangle CW overlaid on the enlarged graphics  602 A. 
       FIG. 7  is a flowchart on an embodiment of a method performed in the system of  FIG. 1 . The method is distributed between the transponders  11  (one shown), the controllers  21  (one shown), and a processing system comprising one or both of the processing devices  40 ,  60 . In step  701 , the transponder  11  broadcasts the distress signal DS. In step  702 , the distress signal DS is intercepted by the controller  21 . 
     In step  702 , the controller  21  may also extract the above-mentioned TID from the distress signal and compare the TID with previous TIDs extracted within a time period. If the TID has been previously extracted within the time period, steps  703 - 706  may be omitted. In a variant, step  703  is performed on the distress signal that comprises such a subsequent TID, and steps  704 - 706  may be performed if the determined position of origin (see below) differs significantly between the subsequent TID and the previous TID. In step  702 , a transmitter in the controller  21  may also transmit a confirmation signal for receipt by a receiver in the transponder  11 , the confirmation signal causing the processor  12  ( FIG. 3A ) to activate the indicator  17  to signal that the distress signal has been intercepted. 
     In step  703 , the controller  21  determines the position of origin for the distress signal DS, for example by extracting position data embedded by the transponder  11  in the distress signal or by processing the distress signal (cf.  FIG. 8  below). The position of origin designates the location of the transponder  11  and thus an approximate location of the individual carrying the transponder  11 . In step  704 , the controller  21  determines the health status of the individual based on parameter data embedded in the distress signal by the transponder  11 . In step  705 , the controller  21  obtains environment data from its sensor arrangement  25 . In step  706 , the controller  21  generates detection data DD which comprises a combination of TID, location and health status from one or more distress signals, as well as the environment data, and transmits the detection data DD to the processing system  40 / 60 , which performs steps  707 - 714  on detection data DD received from a plurality of drones located within the geographic region. The controller  21  may include further parameters in the detection data, such as a unique identifier of the drone, a current global position of the drone, a current timestamp, etc. 
     In step  707 , the detection data DD is received and processed for extraction of the location, health status and environment data. In step  707 , combinations of location and health status from the same transponder  11  may be identified based on the TID and processed as described hereinabove. In step  708 , the extracted data from step  707  may be processed as a function of health status, for example to determine locations associated with living individuals and/or individuals of a specific health category. In step  709 , a grouping analysis may be performed for the locations in the detection data from step  708  to determine one or more spatially-coherent groups of individuals and a density of individuals for each group. In step  710 , the environment data may be processed, for example for determination of an infrastructure status. In step  711 , a prioritization may be performed among the groups determined by step  709 , for example based on the density of individuals, and possibly in view of the infrastructure status, health status or any other data, for example as described with reference to  FIG. 6 . Step  711  results in the sub-regions to be indicated on the prioritization chart  600 . In step  712 , recommendations for the rescue operation may be generated by based on detection data. Such recommendations may comprise the above-mentioned mode of transport, candidate rescue team(s), transportation route, estimated-time of arrival, etc. The prioritization chart is generated (step  713 ) and presented (step  714 ) on the display device  61 . 
     To reduce complexity and cost of the transponder  11 , the location of the respective transponder  11  may be computed externally of the transponder  11 , for example by step  405  and step  703 , based on the distress signal DS as received by the controller  21  on the drone  20  irrespective of the content of the distress signal. Various example embodiments for such computations are illustrated in  FIGS. 8A-8C . In  FIG. 8A , the distress signal is processed to determine the angle-of-incidence a at the signal receiver  24  ( FIG. 3B ). Given that the current drone position PD in a fixed coordinate system  80  is known, for example a GNNS position, and that the topography of the terrain around PD is known or estimated, for example from the environmental sensors on the drone, the location PT of the transponder  11  in the coordinate system  80  may be computed by intersecting the angle-of-incidence with the topography. In  FIG. 8B , the distress signal is processed to determine both the angle-of-incidence a and the distance D 1  from the drone  20  to the transponder  11 . The distance D 1  may be determined based on the signal strength at the signal receiver  24  ( FIG. 3 ). By combining the angle-of-incidence a, the distance D 1  and the current drone position PD, the location PT of the transponder  11  in the coordinate system  80  may be computed irrespective of topography. In  FIG. 8C , the distress signal is processed to determine the distance D 1 , D 2 , D 3  from the drone  20  to the transponder  11  at three or more different drone positions PD 1 , PD 2 , PD 3 , which may be attained by one drone at three or more time points (as shown) and/or by different drones. By combining the distances D 1 -D 3  and the drone positions PD 1 -PD 3 , the location PT of the transponder  11  in the coordinate system  80  may be computed irrespective of topography. Further alternatives are conceivable, as understood by the skilled person. The accuracy of the location PT, when determined based on angle-of-incidence, may be improved by also accounting for the current orientation of the drone  20 . As noted above, the controller  21  may determine the current orientation based on data from one or more orientation sensors on the drone  20 . 
     The processing need not be distributed between the controller  21 , the first processing device  40  and the second processing device  60  as described in the foregoing. Generally, as depicted in  FIG. 9A , the system may be considered to include a computer system  90 , which may encompass one or more of the controller  21 , the first processing device  40  and the second processing device  60  and which may implement the method  400 ′ represented by a flow chart in  FIG. 9B . Step  405 ′ obtains detection data that comprises one or more pairs of location and health status. Step  405 ′ may obtain the detection data by processing one or more distress signals received by the signal receiver  24  on one or more drones  20 , as shown in  FIG. 9A , or by extracting one or more pairs of location and health status from the first data DD 1  and/or the second data DD 2  ( FIG. 1 ). Steps  406 - 407  have been described with reference to  FIG. 4  and will not be repeated. 
     Thus, the method  400 ′ may be implemented on a single one of the controller  21 , the first processing device  40  or the second processing device  60 . To enable the controller  21  on a drone  20  to perform the method, the drones may be equipped for inter-drone communication that allows a master drone to receive detection data from slave drones, whereby the controller  21  on the master drone may generate the chart and transmit the chart to a remote display device, for example at a rescue coordination center. 
     The computer system  90  may be implemented by hardware or a combination of software and hardware. In some embodiments, such hardware comprises one or more software-controlled computer resources.  FIG. 9C  schematically depicts such a computer resource  90 ′, which comprises a processing system  91 , computer memory  92 , and a communication interface  93  for input and/or output of data. The processing system  91  may e.g. include one or more of a CPU (“Central Processing Unit”), a DSP (“Digital Signal Processor”), a microprocessor, a microcontroller, an ASIC (“Application-Specific Integrated Circuit”), a combination of discrete analog and/or digital components, or some other programmable logical device, such as an FPGA (“Field Programmable Gate Array”). A control program  92 A comprising computer instructions is stored in the memory  92  and executed by the processing system  91  to perform any of the methods, operations, functions or steps described in the foregoing. As indicated in  FIG. 9C , the memory  92  may also store control data  92 B for use by the processing system  92 . The control program  92 A may be supplied to the computer resource  90 ′ on a computer-readable medium  100 , which may be a tangible (non-transitory) product (e.g. magnetic medium, optical disk, read-only memory, flash memory, etc.) or a propagating signal. 
     While the subject of the present disclosure has been described in connection with what is presently considered to be the most practical embodiments, it is to be understood that the subject of the present disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the appended claims. 
     In one alternative embodiment, the transponders  11  transmit the distress signals for receipt by one or more fixed or moveable transponder centrals in the geographic region. The respective transponder central may perform the processing of the distress signals in accordance with step  405  in  FIG. 4  to determine location and health status and may then transmit corresponding detection data for receipt by one or more drones. 
     In one alternative embodiment, the transponders  11  may be configured for inter-transponder communication and arranged to autonomously form groups of transponders with a master transponder each. The master transponder may be configured to receive data on health status (and optionally location) from the other transponders in the group and generate a distress signal containing the data, as well as health status (and optionally location) of the master transponder. The role as master transponder may be rotated among the transponders in the group. This alternative embodiment may reduce the power consumption of the transponders as a whole. 
     In another alternative embodiment, the distress signal does not include a transponder identifier. Instead, the computer system  90  performs a statistical analysis of the combinations of location and health status derived from the intercepted distress signals to estimate the distribution of individuals in need of rescue within the geographical region. 
     Further, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, parallel processing may be advantageous. 
     In the following, items are recited to summarize some aspects and embodiments as disclosed in the foregoing. 
     Item 1: A system for rescue support, comprising: 
     a fleet of unmanned aerial vehicles ( 20 ) for deployment within a geographic region, the unmanned aerial vehicles ( 20 ) being configured to receive distress signals (DS) transmitted by transponder devices ( 11 ) worn or carried by individuals in the geographic region subsequent to a large-scale emergency situation, and 
     a computer system ( 90 ) configured to: 
     process the distress signals to obtain detection data (DD) for the individuals, the detection data (DD) comprising a location of a respective transponder device among the transponder devices ( 11 ) and a health status of a respective individual among the individuals, and 
     generate, based on the location and health status, a prioritization chart ( 600 ) for the geographic region, the prioritization chart ( 600 ) being indicative of one or more sub-regions (P 1 , P 2 , P 3 ) to be prioritized for a rescue operation. 
     Item 2: The system of item 1, wherein the distress signals (DS) comprise physiological data from one or more sensors ( 15 ) in or associated with the respective transponder ( 11 ), and wherein the computer system ( 90 ) is configured to: determine the health status of the respective individual as a function of the physiological data. 
     Item 3: The system of item 1 or 2, wherein the computer system is further configured to: determine a grouping of the detection data (DD) as a function of at least the location of the respective transponder device ( 11 ), wherein the prioritization chart ( 600 ) is generated based on the grouping. 
     Item 4: The system of item 3, wherein the computer system ( 90 ) is configured to: identify, based on the health status the respective individual, selected individuals among the individuals in the geographic region, and determine the grouping for the selected individuals. 
     Item 5: The system of item 3 or 4, wherein the grouping results in a plurality of groups of individuals, wherein the computer system ( 90 ) is configured to determine a density of individuals in a respective group among the plurality of groups, wherein the one or more sub-regions (P 1 -P 3 ) comprises one or more groups with the highest density of individuals among the plurality of groups. 
     Item 6: The system of any preceding item, wherein the computer system ( 90 ), when processing the distress signals (DS), is configured to: extract an identifier in a respective distress signal among the distress signals and determine the location and the health status for each unique identifier. 
     Item 7: The system of any preceding item, wherein the computer system ( 90 ) is configured to: indicate locations of individuals or ensembles of individuals in the prioritization chart ( 600 ). 
     Item 8: The system of any preceding item, wherein the computer system ( 90 ) is configured to: generate, based on the health status in the detection data (DD), a count of living individuals in said one or more sub-regions (P 1 , P 2 , P 3 ), and include the count in the prioritization chart ( 600 ). 
     Item 9: The system of any preceding item, wherein the computer system ( 90 ) is configured to: indicate, in the prioritization chart ( 600 ), a location of one or more rescue teams in relation to the geographic region. 
     Item 10: The system of any preceding item, wherein the computer system ( 90 ) is further configured to: receive rescue status data indicative of locations visited by one or more operative rescue teams, and indicate the locations visited on the prioritization chart ( 600 ). 
     Item 11: The system of any preceding item, wherein the unmanned aerial vehicles ( 20 ) comprise one or more environmental sensors ( 26 ) for generating environment data representative of surroundings of the fleet of unmanned aerial vehicles ( 20 ), wherein the computer system ( 90 ) is further configured to: generate the prioritization chart ( 600 ) based on the environment data. 
     Item 12: The system of item 11, wherein the one or more environmental sensors ( 26 ) comprise one or more of an imaging device, a temperature sensor, a pressure sensor, a sound detector, a weather sensor, a wind sensor, a humidity sensor, a dew point sensor, a substance sensor, or a radioactivity sensor. 
     Item 13: The system of item 11 or 12, wherein the computer system ( 90 ) is further configured to: determine the one or more sub-regions (P 1 , P 2 , P 3 ) as a function of the environment data. 
     Item 14: The system of any one of items 11-13, wherein the computer system ( 90 ) is further configured to: include at least part of the environment data in the prioritization chart ( 600 ). 
     Item 15: The system of any one of items 11-14, wherein the environment data comprises one or more images, wherein the computer system ( 90 ) is further configured to: process the one or more images to determine an infrastructure status within the geographic region. 
     Item 16: The system of item 15, wherein the computer system ( 90 ) is further configured to: determine, based on the infrastructure status, an estimated time of arrival to the one or more sub-regions (P 1 , P 2 , P 3 ) for one or more rescue teams located at a respective current location in relation to the geographic region, and include the estimated time of arrival in the prioritization chart ( 600 ). 
     Item 17: The system of item 15 or 16, wherein the computer system ( 90 ) is further configured to: select, based on the infrastructure status, one or more candidate rescue teams among a set of available rescue teams, and indicate the one or more candidate rescue teams in the prioritization chart ( 600 ). 
     Item 18: The system of any one of items 15-17, wherein the computer system ( 90 ) is further configured to select, based on the infrastructure status, a mode of transport among a set of available modes of transport for at least one rescue team, and indicate the mode of transport in the prioritization chart ( 600 ). 
     Item 19: The system of any one of items 15-18, wherein the computer system ( 90 ) is further configured to determine, based on the infrastructure status, a transportation route for a rescue team to the one or more sub-regions (P 1 , P 2 , P 3 ), and indicate the transportation route in the prioritization chart ( 600 ). 
     Item 20: The system of any preceding item, wherein the computer system ( 90 ) is further configured to: provide, via the prioritization chart ( 600 ), access to a controller ( 21 ) of an unmanned aerial vehicle ( 20 ) in the fleet of unmanned aerial vehicles ( 20 ). 
     Item 21: The system of item 20, wherein the access to the controller ( 21 ) comprises an interface (CH) on the prioritization chart ( 600 ) for controlling the unmanned aerial vehicle to a selected location in the geographic region and/or an interface ( 602 F) on the prioritization chart ( 600 ) for real-time access to an environmental sensor ( 26 ) on the unmanned aerial vehicle ( 20 ). 
     Item 22: The system of any preceding item, wherein the distress signals (DS) comprise at least one of a distance (D 1 , D 2 , D 3 ) and a direction (a) from a respective unmanned aerial vehicle ( 20 ) to the respective transponder device ( 11 ), wherein the computer system ( 90 ) is configured to: generate the location of the respective transponder device ( 11 ) as a function of a current position of the respective unmanned aerial vehicle ( 20 ) and said at least one of a distance (D 1 , D 2 , D 3 ) and a direction (a). 
     Item 23: The system of any preceding item, further comprising the transponder devices ( 11 ) which are configured to be worn or carried by the individuals and operable to transmit the distress signals, the transponder devices being further operable to measure one or more physiological parameters of the individuals and include the thus-measured one or more physiological parameter in the distress signals. 
     Item 24: The system of any preceding item, wherein the computer system ( 90 ) is further configured to: operating a display device ( 61 ) to present the prioritization chart ( 600 ). 
     Item 25: A computer-implemented method for rescue support, comprising: 
     obtaining ( 405 ′) detection data representative of distress signals that are transmitted subsequent to a large-scale emergency situation by transponder devices worn or carried by individuals in a geographic region and received by unmanned aerial vehicles in a fleet of unmanned aerial vehicles deployed within the geographic region, the detection data comprising a location of a respective transponder device among the transponder devices and a health status of a respective individual among the individuals; and 
     generating ( 407 ), based on the location of and health status, a prioritization chart for the geographic region, the prioritization chart being indicative of one or more sub-regions to be prioritized for a rescue operation. 
     Item 26: The method of item 25, wherein said obtaining ( 405 ′) the detection data comprises: determining the health status of the respective individual as a function of physiological data included in the distress signals. 
     Item 27: A computer-readable medium comprising computer instructions ( 92 A) which, when executed by a processing system ( 91 ), cause the processing system ( 91 ) to perform the method of item 25 or 26. 
     Item 28: A device comprising logic (91, 92) configured to control the device to perform the method of item 25 or 26. 
     Item 29: The device of item 28, which further comprises a signal receiver ( 24 ) for receiving the distress signals, wherein the logic (91, 92) is further configured to obtain at least part of the detection data (DD) by processing ( 405 ) one or more distress signals received by the signal receiver ( 24 ). 
     Item 30: The device of item 28 or 29, wherein the device is an unmanned aerial vehicle ( 20 ). 
     Item 31: A method for rescue support, comprising: 
     distributing ( 401 ) transponder devices to individuals in a geographic region; 
     causing ( 402 ) the transponder devices to be activated; 
     controlling ( 403 ) a fleet of unmanned aerial vehicles operable within the geographic region to receive distress signals transmitted by the transponder devices subsequent to a large-scale emergency situation in the geographic region, and 
     operating a computer system to: 
     process ( 405 ) the distress signals to obtain detection data for the individuals, the detection data comprising a location of a respective transponder device among the transponder devices and a health status of a respective individual among the individuals, and 
     generate ( 407 ), based on the location and health status of the respective individual, a prioritization chart for the geographic region, the prioritization chart being indicative of one or more sub-regions to be prioritized for a rescue operation.