This application claims priority to Danish Patent Application PA 201300589 filed October 15, 2013, the contents of which are fully incorporated herein by reference.
The inventions described below relate to the field of bird radar systems and methods for use at for instance airports to provide a warning or an alarm when a bird is approaching a runway or in wind parks to provide a warning or an alarm when a bird is approaching a wind turbine.
Known bird radar systems, as disclosed in U.S. Pat. No. 8,456,349, have a static 3D coverage zone that can be defined as an alarm zone. Within that zone specific birds (e.g. large birds and flocks) generate an audio or visual alarm. This alarm can be used, for example, to warn air traffic control, scare away birds or shut down wind turbines. The alarms are based on size and location of the bird only. In practice this leads to situations where there may be too many alarms, too many false alarms or alarms that come too late.
On this background, it is an object of systems and methods described below to provide a system and method for eliciting warnings/alarms in those cases where the approach of objects, such as birds, to a prohibited area, such as a runway or a wind turbine farm, is regarded to constitute an actual danger to air planes landing on or taking off from a runway, or a wind turbine on a wind turbine farm.
This object is according to a first aspect achieved by providing a bird detection system for detecting and tracking birds that may pose a collision risk with a collision object such as air traffic or a wind turbine, where the bird detection system has a detection coverage range, and wherein the bird detection system comprises one or more processors configured to detect and track a bird and to generate an alarm or alert when a tracked bird enters an alarm zone inside the detection coverage range, and wherein the one or more processors are configured to dynamically arrange the alarm zone within the detection coverage range using real time information.
According to an example embodiment, the detection coverage range of the detection system is a static detection coverage range. According to another example embodiment, the detection coverage range of the detection system is a non-static detection coverage range.
By automatically and dynamically adapting the alarm zone the amount of false or irrelevant alarms can be significantly reduced, thereby improving acceptance of the warning system.
According to an example embodiment the above mentioned real time information relates to a detected bird, to weather conditions, to the collision object or to user characteristics.
According to an example embodiment the above mentioned processors are configured to define an alarm zone associated with a detected bird, and the processors are configured to dynamically determine the alarm zone associated with said bird using real time information.
According to an example embodiment the above mentioned processor is configured to determine the size and/or shape and/or location of said alarm zone based on real time information relating to a detected bird and/or relating to an object that is at risk of colliding with a bird and/or relating to weather conditions or user characteristics.
The above mentioned real time information can be one or more of the reflection and/or radar cross section (RCS) of the detected bird, the type of bird, the air or ground speed of the detected bird; the track length and/or track shape of the detected bird; the status of the collision object, wind speed and/or direction, weather conditions, and the distance from a (mobile) user to the detected bird. The (mobile) user may be a bird controller. The bird controller may have deterrent means, and the distance from the bird controller to the detected bird may equal the distance from the bird deterrent means to the detected bird.
According to an example embodiment, the processors are configured to allow generation of an alarm for a tracked bird or birds only when the following conditions are met: The reflection and or the radar cross section (RCS) of the detected bird is above a given threshold, and the ground or airspeed of the detected bird is above a given threshold, and the track length of the detected bird is above a given threshold.
According to an example embodiment the processors are configured to arrange the dynamic alarms zone based on the following requirements: the direction of the tracked bird potentially crosses a target zone, such as a runway or a planned, pre-calculated flight path; an estimated time to intersection with the target zone is above a predefined minimum time; and the height above ground of the tracked bird is within a predefined altitude window.
According to an example embodiment the processors are configured to generate an alarm when a tracked bird enters the dynamic alarm zone associated with the tracked bird.
According to an example embodiment, the processors are configured to allow generation of an alarm for a tracked bird or birds only when the following conditions are met: the direction of the tracked bird should potentially cross a target zone, such as a runway; an estimated time for the tracked bird to intersect with the target zone is above a predefined minimum time; and the height above ground of the tracked bird is within a predefined altitude window.
The bird detection systems described below may comprise a single or a set of radar transmitters, movable radar antennas, receivers, camera's, samplers sampling a received signal and processing units for processing the samples signal.
According to a second aspect, the objects are achieved by the provision of a method for arranging an alarm zone in the detection coverage range of a bird detection system, the method comprising: detecting and tracking a bird in the detection coverage range; associating an alarm zone with the tracked bird, and dynamically arranging the characteristics of the alarm zone based on real time information.
The detection coverage range of the detection system may be a static detection coverage range or a non-static detection coverage range.
According to an example embodiment of the method, the alarm zone comprises determining the size and/or shape and/or location of the alarm zone based on real time information relating to a detected bird and/or relating to an object that is at risk of colliding with a bird and/or relating weather conditions and/or related to the user characteristics.
According to an example embodiment of the method , the method further comprises generation of an alarm for a tracked bird only when the following conditions are met: The reflection and/or the radar cross section (RCS) of the detected bird is above a given threshold, and the ground or airspeed of the detected bird is above a given threshold, and the track length of the detected bird is above a given threshold or the track has a predefined shape (e.g. a circular shape for soaring birds).
According to an example embodiment of the method, the method further comprises arranging the dynamic alarms zone based on the following requirements: the direction of the tracked bird should potentially cross a target zone, such as a runway; an estimated time to intersection with the target zone is above a predefined minimum time; and the height above ground of the tracked bird is within a predefined altitude window.
The method may further comprise generating an alarm when a tracked bird enters the dynamic alarm zone associated with the tracked bird.
According to an example embodiment of the method, the method further comprises generation of an alarm for a tracked bird only when the following conditions are met: the direction of the tracked bird should potentially cross a target zone, such as a runway; an estimated time for the tracked bird to intersect with the target zone is above a predefined minimum time; and the height above ground of the tracked bird is within a predefined altitude window.
According to an example embodiment, the information gathered by means of the method and/or system is used for continuously updating a collision probability analysis.
Further objects, features, advantages and properties of the apparatus and method according to the disclosure will become apparent from the detailed description.
a and 7b show a flow charts illustrating generation of a dynamic alarm zone and requirements for generation of an alarm according to an example embodiment;
The following example embodiments and definitions relate to the bird detection system and the method.
A dynamic alarm zone is an alarm zone that recurrently changes based on external parameters and bird characteristics. This reduces the number of alarms, but more importantly makes them more relevant. Besides location and bird size, all kind of parameters can be used to generate the dynamic alarm zones, such as, but not necessarily limited to the following:
The following detailed description relates to a specific, but non-limiting, example embodiment of the inventions. This embodiment is a bird detection system for detecting and tracking birds that may pose a collision risk with a collision object such as air traffic or a wind turbine, where the bird detection system has a static coverage range. It would however also be possible to use non-static coverage ranges that might for instance adapt to certain specific dynamic conditions at the site of application of the detection system and embodiments applying such non-static coverage ranges will also fall within the scope of the present inventions.
The bird detection system comprises one or more processors configured to detect and track a bird and to generate an alarm or alert when a tracked bird enters an alarm zone inside said static (or non-static) detection coverage range.
The above mentioned one or more processors are configured to dynamically, such as repeatedly, arrange the alarm zone within the detection coverage range using real time information. The real time information relates for instance to a detected bird, to weather conditions, to the collision object, such as an air plane or a wind turbine, or to specific user characteristics.
The one or more processors may accordingly be configured to determine the size and/or shape and/or location of the alarm zone based on real time information relating to a detected bird and/or relating to an object that is at risk of colliding with a bird and/or relating to weather conditions or to specific user characteristics.
As described herein, the detection system is based on radar detection of the birds, but it is understood that also other detection means could be employed and would fall within the scope of the present invention. Such detection means could for instance be cameras or even microphones (for instance directional microphones) or hydrophones or sonars for special applications of the system and method.
The functioning of the system and method can be illustrated by the following non-limiting example in which the system—uses the following alarm algorithm:
If all points are valid, an alarm will be generated.
It is also within embodiments, that risk birds are selected according to the requirements:
It is within embodiments of the invention that the dynamic alarm zone is generated based at least partly on the location of a collision object or target zone and based on the ground speed of a detected risk bird, so that the time for the detected bird to intersect with the collision object or target zone is above a predefined minimum time, such as larger than 100 seconds. An alarm will be generated for a detected or tracked bird, if it fulfills the requirements for being a risk bird, such as the requirements aa-ddscrabble, is detected as being located within the generated dynamic alarm zone, and the moving direction of the tracked bird is towards the collision object or target zone.
Advantages obtained with the system and method can be illustrated by a comparison of the functioning of prior art systems and methods with the new system and method. In the following a (non-limiting) comparison is given:
Currently, alarm zones are three-dimensional, but based on location (latitude/longitude and height) and radar cross-section of the bird only. The current situation is illustrated in
In
Track 1 is a track of large birds (RCS>0.5 m2) of a critical height (h<150 meters) and it moves into the alarm zone 7 as indicated by reference numeral 1′. Track 1 will hence generate an alarm.
Track 2 is also a track of large birds of a critical height, but terminating in the warning zone 8 as indicated by reference numeral 2′. Track 2 will hence generate a warning.
Track 3 is a track of small birds (RCS<0.5 m2) and will hence neither generate a warning or an alarm.
Track 4 will neither generate a warning nor an alarm as it terminates outside the warning zone 8 as indicated by reference numeral 4′.
Track 5 is a track of birds moving above the critical height above the runway, i.e. more than 150 meters above the runway. It will hence neither generate a warning nor an alarm.
Using the system or method applying the dynamic alarm zones, the alarm zone may look different for every track. The functioning of the system and method is illustrated in
Referring to
Track 1 will not generate an alarm. Although it might cross the runway 6, the terminating point 1′ is too close to avoid crossing the runway and requirement (e) above, i.e. that the time to intersection should be >100 seconds (based on groundspeed) is not fulfilled. This requirement will not be fulfilled when the terminating point 1′ is located in an inner zone 12 indicated in
Thus, the alarm zone 9 in
Referring to
Referring to
Referring to
Referring to
The alarm zone 9 may also move together with planes that are approaching a runway or taking off. This may lead to a situation where alarms are only generated when there is a plane on collision course. This is illustrated in
a and 7b show flow charts illustrating generation of a dynamic alarm zone and requirements for generation of an alarm according to an example embodiment using a radar based detection system.
Referring to
For a static object like a runway the future location, step 705, is the location of the runway itself. For a wind turbine the future location may be a circular area where rotor blades can be spinning, the rotor swept area. For a plane, which may be approaching a runway, the future location may correspond to the flight path of the plane, which is where the plane can be within a predetermined time period of x minutes or seconds, such as 100 seconds. The flight path of the plane may depend on the speed of the plane, the type of the plane, and weather conditions such as wind conditions.
When a bird is detected, step 709, then from obtained information it is determined if the bird is a risk bird, step 710. In order to be a risk bird, the information of the detected bird shall fulfill at least part of some predefined requirements, such as: a) RCS shall be >0,5 m2, b) ground or airspeed shall be >20 m/s, and c) the track of the bird shall be longer than 15 seconds, or have a predefined shape. It is also preferred that the information of the detected bird fulfills the predefined requirement f: the height of the detected bird shall be <than 150 meters.
If the bird is not a risk bird, then no alarm will be generated, step 711, and no resulting dynamic alarm zone and no inner alarm zone boundary need to be generated. If the bird is a risk bird, then moving direction and speed of the bird is determined, step 712.
The inner boundary of the alarm zone can be determined, step 707, from: the location of the collision object, or when the collision object is moving, the future location, which is defined as the location within a predetermined time period of x minutes or seconds, such as 100 seconds, step 705; the groundspeed of the detected bird, step 706; and the wind speed and direction.
Based on the groundspeed of the bird, the travelling distance of the bird is determined for the predetermined time period of x of minutes or seconds, such as 100 seconds. The determined travelling distance thus equals the length the detected bird can fly in the predetermined time, here 100 seconds, at the detected ground speed. However, based on wind conditions, the travelling distance will vary for different directions.
The inner boundary of the alarm zone can now be determined, step 707, by an area or sector surrounding the collision object where the boundary of the area has a distance to the collision object equal to a travelling distance of the bird, where the travelling distance defining the boundary is the determined ground speed based travelling distance being adjusted in different directions taking into account the wind speed and direction. Thus, the resulting bird travelling distance varies for different directions, and the resulting distance from the inner boundary of the alarm zone to the collision object will vary for different directions.
The outer alarm zone boundary determined in step 703 and the inner alarm zone boundary determined in step 707 now defines the resulting dynamic alarm zone, step 708. The location and direction of the detected bird is being tracked, step 713, and compared to the dynamic alarm zone, step 708.
If the bird is out of the dynamic alarm zone, there is no alarm, step 716, but if the bird is in the dynamic alarm zone, step 714, then it is determined if the bird has a direction towards the location or future location of the collision object.
If the direction is not towards the collision object, there is no alarm, step 717, but if the direction is towards the collision object, an alarm is generated, step 718.
It is noted that the inner boundary of the dynamic alarm zone is defined based on the distance that a risk bird can fly within a predetermined time of reaction, where the reaction time may be set to 100 seconds. If a detected bird is flying towards the collision object, but it is so close to the object that is may collide with the object within a time period being shorter than the determined reaction time, such as 100 seconds, then there is not enough time to react to the bird anyway. Hence, there is no reason to generate an alarm, which is why the bird in this case is outside of the dynamic alarm zone, although the bird is inside the inner boundary of the alarm zone.
The dynamic alarm zones illustrated in
In cases where the collision object is a moving object, such as a plane approaching a runway, the determined future location or flight path of the plane may be at a certain height above ground plane. Here, the dynamic alarm zone may extend both above and below the altitude of the determined flight path. The above discussed maximum flying height of a risk bird may be added to the altitude of the flight path, defining an upper boundary height of the dynamic alarm zone, and if the altitude of the flight path is higher than the maximum flying height of the risk bird, this maximum flying height can be withdrawn from the altitude of the flight path to define a lower boundary height of the dynamic alarm zone.
In
Referring to
The system according to this example embodiment comprises a number of data acquisition sensors 15, 16, 17, 18, 19. These sensors comprise one or more radars 15, 16, 17. There may be only a single radar, but a network of radars may alternatively be used. The radars can be local radars (S-band/X-band) but also long-range radars may be applied. According to a specific embodiment, two radars, one vertical and one horizontal are used. The horizontal radar provides latitude/longitude and size information of the birds, while the vertical radar provides height information and detailed information like wing beats. Besides radars a number of other sensors can be used to provide relevant data for the system. A weather station 18 is provided to for instance calculate ground or airspeed (groundspeed/direction and/or wind speed/direction). Cameras 19 can be used to compare radar reflection with images (type recognition). It would also fall within the scope of the present invention to use ADS-B systems to locate or double-check airplane locations and speed or predict future flight-paths.
The sensors provide information to the processing unit 20, which in practice consists of multiple processors (depending on number of servers). This information has multiple formats, but for the radar itself it consists of raw images with radar reflections. All of this information ends up in the bird monitor 21 in the form of raw data 22, which is the central part of the processing unit 20. In the first step (block 23) filtering is done. This filtering may comprise filtering of rain, ground clutter and moving objects (not being birds). The filters are contrary to prior art filters used in this technical field fully dynamic. It is understood that different image processing and filter algorithms may be used depending on the type of data acquisition device (such as the radars 15, 16 , 17 and the digital cameras 19) that actually provide the raw data 22 to the bird monitor 21 shown in the block diagram in
The information provided by the bird monitor is then stored in a database 33 (PostgreSQL or MySQL). This database 33 is preferably located on a separate server, with powerful data management/back-up facilities.
The second part of the processor 20 is the bird analysis part 34. In this part data is post processed (blocks 35 through 40) for all kind of different interfaces. The most common ones are the visualizer 44 (real time monitoring), the remote monitor 45 (operator interface) and the report viewer 42 (data base analysis). The output of the bird monitor 21 is processed in such a way that data becomes available for interfacing tools in a light and standard communication protocol. All processing is done in the bird analysis module 34, whereas the applications 47 themselves only have to do the visualization and user-interaction.
The applications 47 can vary a lot. First of all there are all kind of users (end users, operators, maintenance and support) and these groups have fully different requirements per market: ATC versus bird control versus wind turbine or wind park operator.
Thus, the application of the dynamic zones according to the systems and methods described above reduces the number of alarms and only the relevant ones remain. The system may calculate a specific zone for each track and collision object (e.g. plane) and may refresh/recalculate it at every radar update.
While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. The elements of the various embodiments may be incorporated into each of the other species to obtain the benefits of those elements in combination with such other species, and the various beneficial features may be employed in embodiments alone or in combination with each other. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.
Number | Date | Country | Kind |
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PA201300589 | Oct 2013 | DK | national |