Method and system for identifying an aviation obstacle

Abstract

The present disclosure relates to a computer-implemented method for identifying an aviation obstacle (10), comprising the following steps: providing first transponder signals (16), each of which is assigned to one of a plurality of first aircraft (12) and each of which has current position information of the aircraft (12), and providing respective first signal strength values ​​for the first transponder signals (16); determining, from the first transponder signals (16), respective distances of the first aircraft (12) to an aviation obstacle (10); determining standardized signal strength values ​​by respectively standardizing the first signal strength values; determining a reference value from one or more lowest of the standardized signal strength values;Providing a second transponder signal (16) associated with a second aircraft (12) and a second signal strength value for the second transponder signal (16); determining the second aircraft (12) as a relevant aircraft or determining the second aircraft (12) as an irrelevant aircraft using a comparison of the second signal strength value with the reference value; and generating an output signal for an identification device (11) for identifying the aviation obstacle (10) depending on the presence or absence of at least one relevant aircraft. Furthermore, a method and a system for identifying an aviation obstacle, as well as a data processing device, are disclosed. (Fig. 1);

Description

[0001] The invention relates to a method and a system for marking an aviation obstacle and a data processing device. background

[0002] Obstacle lighting is used to mark aviation obstacles such as wind turbines, especially at night or in poor visibility, so that aircraft such as airplanes or helicopters can avoid collisions. The obstruction lighting can be activated only when an aircraft is approaching the wind turbine critically. This can reduce light emissions that could affect residents living near the wind turbine. Furthermore, this method allows compliance with legal aviation safety requirements, since only the obstacle markings relevant to the respective aircraft pilot are active.

[0003] An arrangement for controlling a demand-based obstacle lighting system of a wind turbine is known from document EP 3 926 166 A1. Summary

[0004] The object of the invention is to provide technologies that enable the marking of an aviation obstacle in an efficient and energy-saving manner.

[0005] To solve this problem, a computer-implemented method and a system for marking an aviation obstacle are provided according to claims 1 and 15. Furthermore, a data processing device is provided. Further embodiments are the subject of dependent subclaims.

[0006] According to one aspect, a computer-implemented method for identifying an aviation obstacle is provided, comprising the following steps: providing first transponder signals, each of which is assigned to one of a plurality of first aircraft and each of which contains current position information of the aircraft, and providing respective first signal strength values ​​for the first transponder signals; determining, from the first transponder signals, respective distances of the first aircraft to an aviation obstacle; determining standardized signal strength values ​​by standardizing the first signal strength values; determining a reference value from one or more of the lowest standardized signal strength values; providing a second transponder signal, which is assigned to a second aircraft, and a second signal strength value for the second transponder signal;Determining the second aircraft as a relevant aircraft or determining the second aircraft as an irrelevant aircraft using (or by means of) a comparison of the second signal strength value with the reference value; and generating an output signal for an identification device for identifying the aviation obstacle depending on the presence or absence of at least one relevant aircraft.

[0007] A method for marking an aviation obstacle may be provided, which is carried out in a system with a receiving device, a data processing device, and a marking device, and comprises the following steps: receiving first transponder signals and a second transponder signal in the receiving device; transmitting the first transponder signals and the second transponder signal to the data processing device; carrying out the computer-implemented method in the data processing device; transmitting an output signal from the data processing device to the marking device; switching a marking of the aviation obstacle by means of the marking device depending on the output signal.

[0008] According to a further aspect, a data processing device is provided which has at least one processor and is configured to carry out the computer-implemented method.

[0009] According to a further aspect, a system for marking an aviation obstacle is provided, which system comprises a receiving device, a data processing device, and a marking device. The receiving device is configured to receive first transponder signals and a second transponder signal and transmit them to the data processing device. The data processing device is configured to execute the computer-implemented method and transmit an output signal to the marking device, and the marking device is configured to switch a marking of the aviation obstacle depending on the output signal.

[0010] By using this method, particularly the method-based determination of the reference value based on transponder signals for classifying aircraft as relevant or irrelevant, calibrations, processing and material variations, and weather conditions can be ignored. This allows for simple testing and use of marking devices at the installation site, thus avoiding, in particular, aerial and vehicle inspections.

[0011] It also makes it possible to identify additional detected aircraft as irrelevant, so that the identification device, in particular an obstacle light, can be deactivated for an extended period of time. For example, transponder signals with data blocks of the DF11 format number are generally less noisy due to their length and can still be received clearly even from greater distances. However, such DF11 transponder signals contain only a unique transponder number and no position and / or altitude information of the aircraft. Using the method, even such aircraft can be identified as irrelevant.

[0012] The marking device may comprise one obstacle light or a plurality of obstacle lights. The obstacle light or the plurality of obstacle lights may be arranged adjacent to, in particular on, the aviation obstacle. The aviation obstacle may comprise a spatial object (e.g., a wind turbine) or a plurality of spatial objects (in particular, a plurality of wind turbines). The marking device may be configured for lighting, in particular for night lighting (night marking) and / or daytime lighting and / or flight visibility lighting. The marking device (in particular the obstacle light(s)) may be configured to emit electromagnetic signals, in particular light signals and / or radio signals. For example, the marking device may comprise at least one LED and / or at least one gas discharge lamp and / or at least one radio beacon.

[0013] The receiving device can be configured to receive radio signals, in particular transponder signals. The (first and / or second) transponder signals can thus (respectively) be radio signals. The (first and / or second) transponder signals can each be one of a Mode A signal, a Mode C signal, or a Mode S signal. Accordingly, a transponder operating mode (of the transponder of the corresponding aircraft) can be Mode A, Mode C, or Mode S.

[0014] The receiving device can be located in the center of the effective area of ​​the aviation obstacle and / or at the aviation obstacle. This way, shadowing analyses, for example, can be eliminated.

[0015] In general, a plurality of second transponder signals can also be provided, each of which is assigned to one of a plurality of second aircraft. The plurality of second transponder signals can be received in the receiving device and forwarded to the data processing device. Furthermore, respective second signal strength values ​​can be provided for the second transponder signals. A plurality of second aircraft can be determined as a respective relevant aircraft or irrelevant aircraft using / by means of a respective comparison with the reference value.

[0016] The second transponder signal or signals may be free of position information of the (respective) aircraft.

[0017] The first and / or second signal strength values ​​and / or normalized signal strength values ​​and / or the reference value may, for example, each be RSSI values ​​(RSSI: Received Signal Strength Indicator ). Alternative scaling of the signal strength values ​​may also be provided.

[0018] The first signal strength values ​​can be standardized to a common distance value. In other words, the method can comprise determining standardized signal strength values ​​by respectively standardizing the first signal strength values ​​to a common distance value. In this way, signal strength values ​​whose emission sources are at different distances from the aviation obstacle can be made comparable.

[0019] The respective distances (of the first aircraft to the aviation obstacle) can be determined from the (respective) position information.

[0020] The common distance value can correspond to a predetermined safety distance from the aviation obstacle. The safety distance can, for example, be (pre-)determined as a doubled safety space radius (around the aviation obstacle), in particular as a doubling of an effective area radius around the aviation obstacle plus an additional radius. Specifically, the safety distance can be between 4.0 km and 30.0 km, preferably between 4.5 km and 20.0 km, particularly preferably 10.4 km. The distances and / or the (safety) distances can be spatial (three-dimensional) distances / distances. Alternatively, the distances and / or the distances can be two-dimensional distances / distances, in particular horizontally projected distances / distances. The distances and / or the distances can, for example, be defined with respect to a center point or an outer boundary of the aviation obstacle.

[0021] The standardization of the first signal strength values ​​can be performed using the Friis transfer equation. In other words, the method can comprise the following step: determining standardized signal strength values ​​by respectively standardizing the first signal strength values ​​using the Friis transfer equation.

[0022] Specifically, the standardized signal strength values ​​RSSI n can be calculated using the equation RSSI n = RSSI 1 + 20 ⋅ log r 1 / r 2 be determined (with distance (to the aviation obstacle) r 1 , first signal strength value RSSI 1 and safety distance r 2 ).

[0023] The standardization of the first signal strength values ​​can also be done using a modified Friis transfer equation, in which, for example, further attenuation parameters for electromagnetic waves (such as air humidity) are taken into account.

[0024] The method may further comprise smoothing the second signal strength value taking into account at least one previous second signal strength value for at least one previous second transponder signal. Furthermore, the method may comprise smoothing the first signal strength values ​​taking into account previous first signal strength values ​​for previous first transponder signals.

[0025] The previous first signal strength values ​​may be provided for previous first transponder signals (together with the previous first transponder signals, which are preferably each assigned to one of the plurality of first aircraft and each include current position information of the aircraft). The at least one previous second signal strength value may be provided for at least one previous second transponder signal (together with the at least one previous second transponder signal, which is preferably assigned to a second aircraft).

[0026] The smoothing of the second signal strength value (and / or the first signal strength values) can be performed by determining a simple or weighted moving (arithmetic) average. In particular, the second signal strength value (and / or the first signal strength values) can be replaced by a simple or weighted moving average (in which the second signal strength value can preferably be processed).

[0027] For example, the second signal strength value RSSI 2 can be weighted between 0.01 and 0.3, preferably between 0.1 and 0.3, particularly preferably 0.2, and the previous second signal strength value RSSI 2,old can be weighted between 0.7 and 0.99, preferably between 0.7 and 0.9, particularly preferably 0.8. In particular, the second signal strength value RSSI 2 can be replaced by the moving average (RSSI 2 + 4 · RSSI 2,old ) / 5.

[0028] The reference value may correspond to the lowest standardized signal strength value (the standardized signal strength value of the lowest signal strength) or an average value (in particular an arithmetic and / or weighted average value) of the several lowest standardized signal strength values. For example, the reference value may be the average value of the m lowest of the normalized signal strength values, where 1 ≤ m ≤ 10, preferably 3 ≤ m ≤ 7, particularly preferred m = 3.

[0029] The second aircraft can be determined as a relevant aircraft if the second signal strength value is at least as high as the reference value. Furthermore, the second aircraft can be determined as an irrelevant aircraft if the second signal strength value is lower than the reference value.

[0030] Alternatively, the second aircraft may be determined as a relevant aircraft if the second signal strength value is higher than the reference value, and / or the second aircraft may be determined as an irrelevant aircraft if the second signal strength value is equal to or lower than the reference value. Further alternatively, the second aircraft may be determined as a relevant aircraft if the second signal strength value is at least as high as the reference value minus a safety margin, and / or the second aircraft may be determined as an irrelevant aircraft if the second signal strength value is lower than the reference value minus the safety margin.

[0031] Additionally, the second aircraft can be identified as a relevant aircraft or as an irrelevant aircraft using a transponder code from the second transponder signal. Thus, the second aircraft can be identified as relevant or irrelevant depending on the transponder code.

[0032] The method may comprise storing information identifying the second aircraft as a relevant aircraft or an irrelevant aircraft, preferably in the data processing device (in a database and / or list). Furthermore, the method may comprise deleting or replacing information identifying the second aircraft as a relevant aircraft or an irrelevant aircraft.

[0033] The method may comprise: generating the output signal for the marking device for marking the aviation obstacle in dependence on information that identifies the second aircraft as a relevant aircraft or an irrelevant aircraft.

[0034] The method may further comprise: adapting, prior to the comparison, the reference value or the second signal strength value depending on a transponder operating mode for the second transponder signal (the transponder operating mode of a transponder of the second aircraft with which the second transponder signal was generated).

[0035] The first transponder signals may be transponder signals of a first group of transponder operating modes, and the second transponder signal(s) may be a transponder signal of a second group of transponder operating modes that is (at least partially) different from the first group. For example, the first transponder signals may comprise (or be) Mode S transponder signals and / or the second transponder signal may be a Mode A or Mode C transponder signal. The second transponder signal may also be a Mode S transponder signal.

[0036] The adjustment can be performed by adding or subtracting an offset value to / from the reference value or to / from the second signal strength value, wherein the offset value is preferably determined by comparing (maxima of) frequency distributions of signal strength values ​​(from received transponder signals) for different transponder operating modes. In particular, the offset value can be determined by calculating the difference between the maxima of the frequency distributions.

[0037] For example, a reference value formed from Mode S transponder signals can be increased by a (positive) offset value for comparison with a Mode A or Mode C transponder signal as a second transponder signal.

[0038] The frequency distributions can comprise a first frequency distribution of transponder signals of at least one first transponder operating mode (e.g., Mode S) and a second frequency distribution of transponder signals of at least one second transponder operating mode (e.g., Mode A and / or Mode C). The offset value can be determined from a difference between a (first) maximum of the first frequency distribution and a (second) maximum of the second frequency distribution.

[0039] The received transponder signals may comprise the first and / or second transponder signals. The received transponder signals may additionally or alternatively comprise further transponder signals.

[0040] The method may further comprise (repeatedly) updating (redetermining) the offset value within a (predefined) offset value time interval. The offset value time interval may be between 0.1 seconds and one month. In other words, the offset value may be updated every 0.1 seconds or once a month (or at a time interval in between).

[0041] The offset value can be updated as a moving average. For example, the frequency distributions can be continuously updated and compared with each other (with respect to their maximum values).

[0042] Alternatively, the offset value can be fixed (in time).

[0043] The method may further comprise (repeatedly) updating (redetermining) the reference value within a (predefined) reference value time interval.

[0044] The reference value time interval can be approximately between 0.5 seconds and 3600 seconds, preferably between 0.5 seconds and 30 seconds, and particularly preferably between 0.5 seconds and 5 seconds. In other words, the reference value can be updated once per period between 0.5 seconds and 5 seconds, for example, once per second.

[0045] Alternatively, the reference value can be updated based on detected meteorological changes (for example, when a threshold value for a meteorological quantity is exceeded).

[0046] The reference value can be updated, for example, based on additional first transponder signals, additional first signal strength values, and additional standardized signal strength values, which are received or determined with a time offset, in particular with respect to the first transponder signals, the first signal strength values, and the standardized signal strength values. The reference value can be updated as a moving average.

[0047] The output signal can be generated in the absence of (information about) at least one relevant aircraft. In particular, the output signal can be generated repeatedly for the duration of the absence of at least one relevant aircraft, for example, at intervals of 100 ms to 500 ms, in particular every 250 ms. If (information about) at least one relevant aircraft is present, the generation of the output signal can be interrupted.

[0048] It can be provided that the marking is (and / or remains) deactivated as long as the output signal is (repeatedly) received in the marking device. The marking can be (and / or remains) activated in the absence of an output signal received in the marking device, for example, after a predefined time interval has elapsed.

[0049] Alternatively, it can be provided that the marking is switched on when the output signal is present and / or received in the marking device and / or switched off when the output signal is absent in the marking device.

[0050] The first and / or second signal strength values ​​can be determined in the receiving device and / or the data processing device. If the first and / or second signal strength values ​​are determined in the receiving device, the first and / or second signal strength values ​​are transmitted to the data processing device.

[0051] In conjunction with the system for marking an aviation obstacle, the configurations described above in connection with the method can be provided accordingly.

[0052] In the context of the present disclosure, parameter range specifications ("between", "from ... to") are to be understood as encompassing the endpoints. Description of implementation examples

[0053] Further embodiments are explained in more detail below with reference to the figures of a drawing. Herein: Fig. 1 shows a schematic representation of an area around an aviation obstacle; Fig. 2 shows a schematic representation of a system for marking an aviation obstacle; Fig. 3 shows a schematic representation of a computer-implemented method for marking an aviation obstacle; Fig. 4 shows a graphic representation of the dependence of RSSI and distance; Fig. 5 shows a graphic representation of the frequency distribution of signal strengths for different transponder operating modes; and Fig. 6 shows a schematic representation of a method for marking an aviation obstacle.

[0054] In Fig. 1A schematic representation of an area around an aviation obstacle 10 is shown. The aviation obstacle 10 can, for example, be a (single) wind turbine or a plurality of wind turbines (in particular, a wind farm or multiple wind farms). In principle, each aviation obstacle 10 acts on the space surrounding the aviation obstacle 10. In particular, air currents can be influenced. An area around the aviation obstacle 10 that is particularly exposed to the effect of the aviation obstacle can generally be formed as a spherical or cylindrical area around the aviation obstacle 10 (area of ​​effect 13). For example, the area of ​​effect centered around the aviation obstacle 10 can have a (cylindrical) radius of 4 km and a total height of 600 m plus the height of the aviation obstacle 10.

[0055] To be detectable and, in particular, visible to aircraft 12 (e.g., airplanes or helicopters), the aviation obstacle 10 is provided with a suitable marking. For this purpose, a marking device 11 is arranged near the aviation obstacle 10, for example, on the nacelle and / or the tower of wind turbines. The marking device 11 can be a lighting device (obstacle light). For example, the marking or lighting can be provided using LEDs.

[0056] The marking shall be activated when an aircraft 12 identified as relevant enters a previously defined area, for example a detection area 15, and in particular moves towards a safety area 14 around the aviation obstacle 10.

[0057] The determination of the aircraft 12 as relevant is made using transponder signals 16, which are emitted by the aircraft 12 (in particular a transponder of the aircraft 12). The transponder signals 16 are radio signals. Aircraft 12 generally have to have a transponder. The transponder can be operated according to one of various operating modes, in particular according to Mode A, Mode C or Mode S. The transponder can be a Class 1 transponder or a Class 2 transponder and in particular must meet the minimum operational performance standards (MOPS) for secondary surveillance radar Mode S transponders, specifically in the case of a Class 2 transponder, a peak output power of +18.5 dBW (70W) at the antenna.

[0058] The transponder signals 16 are received by a receiving device 25, which is part of a system 20 for marking an aviation obstacle (cf. Fig. 2). The receiving device 25 is arranged in the center of the effective area 13, for example, at the aviation obstacle 10. In this way, there is a correspondence between the effect of the aviation obstacle 10 and the reception of the transponder signals. Thus, if no transponder signals are received at the receiving device 25, there is also no direct effect between the aircraft 12 and the aviation obstacle 10. Consequently, complex shadowing analyses can be omitted. The transponder signals 16 can be (response) telegrams, for example, in response to an initial or one of several interrogation signals from a secondary radar. The transponder signals 16 can also be generated independently of interrogation signals (e.g., in squitter mode / ADS-B).

[0059] In addition to the marking device 11 (and, if applicable, the aviation obstacle 10 itself), the system 20 also comprises a data processing device 21 with a processor 22, a memory 23, and a communications interface 24 (in particular for communication with the receiving device 25 and the marking device 11). The data processing device 21 is communicatively connected to the receiving device 25 and the marking device. The data processing device 21 can be implemented as a (single) computer, as a distributed computing system, or as part of a computer, in particular as a microcontroller or integrated circuit, specifically an FPGA (Field Programmable Gate Array).

[0060] The signal strength of the received transponder signals 16 is used to determine the distance to the aviation obstacle 10. This requires appropriate calibration of various factors that can lead to signal attenuation. Due to the varying installation conditions in the aviation obstacle 10, it is advantageous to perform the calibration dynamically and continuously.

[0061] In Fig. 3 A schematic representation of a computer-implemented method for marking an aviation obstacle is shown.

[0062] In a first step 31, first transponder signals 16, each associated with a first aircraft 12 and each containing current position information of the aircraft 12, are provided in the data processing device. For the first transponder signals, respective first signal strength values, in particular RSSI values ​​RSSI 1, are also provided.

[0063] From the first transponder signals 16, respective distances r 1 of the first aircraft 12 is determined to be the aviation obstacle 10 (using the respective current position information) (step 32).

[0064] In a third step, 33 standardized signal strength values ​​RSSI n are determined from the first signal strength values ​​RSSI 1 by dividing the first signal strength values ​​RSSI 1 into a common distance value, the safety distance r 2 around the air obstacle 10. The normalization is performed using the Friis transfer equation: RSSI n = RSSI 1 + 20 ⋅ log r 1 r 2 .

[0065] The safety distance r 2 is a predefined value by which a safety zone is formed around the aviation obstacle 10. The safety distance r 2 can be 10.4 km for a wind turbine, for example.

[0066] In a fourth step 34, the standardized signal strength values ​​RSSI n a reference value RSSI ref This is determined either from the lowest of the standardized signal strength values ​​RSSI n equal to or as an average of a plurality of the lowest of the normalized signal strength values ​​RSSI n , for example the mean of the five lowest normalized signal strength values ​​RSSI n , certainly.

[0067] Determining the reference value RSSI ref is illustrated by the following example. Initial transponder signals 16 are received from six aircraft (AFC) 12, designated by numbers 1, 2, 6, 7, 11, and 13 (Table 1, column 1). The distances determined from the position information are shown in Table 1, column 2 below, and the corresponding initial signal strength values ​​RSSI 1 are shown in Table 1, column 3. Table 1: aircraft distance r 1 RSSI 1 1 82 475 m 97 2 86 101 m 109 6 121 641 m 99 7 127 023 m 96 11 188 735 m 97 13 215 989 m 107

[0068] Normalized signal strength values ​​RSSI determined using the Friis transfer equation n are shown in the following Table 2. In addition to the reference distance of 10.4 km (highlighted), which corresponds to the predetermined safety distance, other distances are listed as examples. Table 2: r 2 LFZ1 LFZ2 LFZ6 LFZ7 LFZ11 LFZ13 1 155.33 167.70 160.70 158.08 162.52 173.69 2 149.31 161.68 154.68 152.06 156.50 167.67 3 145.78 158.16 151.16 148.54 152.97 164.15 4 143.29 155.66 148.66 146.04 150.48 161.65 5 141.35 153.72 146.72 144.10 148.54 159.71 6 139.76 152.14 145.14 142.51 146.95 158.13 7 138.42 150.80 143.80 141.18 145.62 156.79 8 137.26 149.64 142.64 140.02 144.46 155.63 9 136.24 148.62 141.62 138.99 143.43 154.60 10 135.33 147.70 140.70 138.08 142.52 153.69 10,4 134.99 147.36 140.36 137.74 142.18 153.35 20 129.31 141.68 134.68 132.06 136.50 147.67 30 125.78 138.16 131.16 128.54 132.97 144.15 40 123.29 135.66 128.66 126.04 130.48 141.65 50 121.35 133.72 126.72 124.10 128.54 139.71 60 119.76 132.14 125.14 122.51 126.95 138.13 70 118.42 130.80 123.80 121.18 125.62 136.79 80 117.26 129.64 122.64 120.02 124.46 135.63 90 116.24 128.62 121.62 118.99 123.43 134.60 100 115.33 127.70 120.70 118.08 122.52 133.69 110 114.50 126.87 119.87 117.25 121.69 132.86 120 113.74 126.12 119.12 116.49 120.93 132.11

[0069] In Fig. 4A corresponding plot to the values ​​in Table 2 is shown. Each curve is assigned to an aircraft, for example, curve 41 is LFZ1. The intersection point 42 indicates the safety distance r 2 as abscissa value and the reference value RSSI ref as the ordinate value.

[0070] Table 2 and Fig. 4 illustrate that LFZ1, at a distance of approximately 82 km, has the lowest standardized signal strength value with a first signal strength value of 97 and should therefore be set as a reference value. At the safety distance (here 10.4 km), this means a reference value RSSI ref of 134.99. Conversely, if no position information had been transmitted with transponder signal 16, LFZ13, for example, would already be classified as relevant at a distance of between 80 km and 90 km.

[0071] In a fifth step 35, a second transponder signal 16 (including a second signal strength value RSSI 2 for the second transponder signal 16) is provided to the data processing device 21, which is associated with a second aircraft 12 (for example, a light aircraft or small aircraft). The second aircraft 12 is then determined as a relevant aircraft or an irrelevant aircraft by comparing the second signal strength value with the reference value (sixth step 36).

[0072] In particular, if the second signal strength value is at least as high as the reference value (RSSI 2 ≥ RSSI ref ), the second aircraft 12 can be determined as relevant, otherwise (RSSI 2 < RSSI ref ) as irrelevant.

[0073] Corresponding information identifying an aircraft as relevant or irrelevant is stored in a database (in the data processing device 21).

[0074] In addition, the reference value (or alternatively the second signal strength value) can be adjusted prior to the comparison depending on the transponder operating mode of the transponder of the second aircraft 12, for example by adding an offset value. For example, Mode A transponder signals or Mode C transponder signals have a higher signal-to-noise ratio and thus a different average RSSI value due to their shorter telegram length (length of the transponder signal) compared to Mode S transponder signals and their different signal characteristics. A reference value adjusted by adding an offset value can thus be used for Mode A transponder signals and Mode C transponder signals. To determine the offset, frequency distributions of the signal strength values ​​of Mode A transponder signals and Mode C transponder signals as well as Mode S transponder signals are compared.

[0075] In Fig. 5The corresponding frequency distributions are illustrated. Curves 51 represent frequency distributions of RSSI values ​​for Mode S transponder signals for three different days. Curves 52 represent frequency distributions of RSSI values ​​for Mode A and Mode C transponder signals for the same three days. While for Mode A and Mode C most transponder signals have an RSSI value of around 62 to 63, the maximum for Mode S transponder signals is at RSSI values ​​of 51 or 52, depending on the day. This results in an offset value between 10 and 12.

[0076] Consequently, a reference value determined from Mode S transponder signals would be, if the second transponder signal 16 is a Mode A or Mode C transponder signal, increased by an offset value between 10 and 12 before comparing the second signal strength value with the reference value.

[0077] Additionally, the first and / or second signal strength values ​​(or the second signal strength value) can be smoothed. In this case, previous (previously provided) first or second signal strength values ​​are taken into account. For example, the second signal strength value RSSI 2 can be smoothed as a moving average. In particular, when calculating the average, the previous second signal strength value RSSI 2,old can be given a weight of 4 / 5 and the (current) second signal strength value RSSI 2 a weight of 1 / 5, i.e., the second signal strength value RSSI 2 is replaced by the moving average. RSSI 2 + 4 ⋅ RSSI 2 , alt 5 .

[0078] In a seventh step, an output signal for the marking device 11 for marking the aviation obstacle 10 is generated depending on the presence or absence of at least one relevant aircraft (for example, depending on the presence or absence of a database entry for a relevant aircraft) and transmitted to the marking device 11 for switching the marking / obstacle light.

[0079] Fig. 6 a schematic representation of a method for marking an aviation obstacle, which is carried out in the system 20 with the receiving device 25, the data processing device 21 and the marking device 11.

[0080] First, the first transponder signals 16 and (possibly with a time delay) the second transponder signal 16 are received in the receiving device 25, transmitted to the data processing device 21, and thus provided in the data processing device 21 (step 61). According to step 62, the above (computer-implemented) method is carried out in the data processing device 21 using the provided signals, thereby generating the output signal. This is transmitted to the marking device 11 (step 63). Depending on the output signal (received in the marking device 11), the marking of the aviation obstacle 10 is switched by the marking device 11 (step 64).

[0081] In particular, the output signal is repeatedly generated and transmitted for the duration of the absence of at least one relevant aircraft. The marking is / remains deactivated only if the output signal is regularly received in the marking device 11. This ensures that the lighting is activated even in the event of a fault.

[0082] The features disclosed in the above description, the claims and the drawings may be important for the realization of the various embodiments both individually and in any combination. List of reference symbols

[0083] 10 Aviation obstacle 11 Identification device 12 First / second aircraft 13 Effective area 14 Safety area 15 Detection area 16 First / second transponder signal 20 System 21 Data processing device 22 Processor 23 Memory 24 Communication interface 25 Receiving device 31-37 Steps 41 Curve 42 Intersection 51, 52 Curves 61-64 Steps

Claims

1. A computer-implemented method for identifying an aviation obstacle (10), comprising the following steps: - providing first transponder signals (16), each of which is assigned to one of a plurality of first aircraft (12) and each of which has current position information of the aircraft (12), and providing respective first signal strength values ​​for the first transponder signals (16); - determining, from the first transponder signals (16), respective distances of the first aircraft (12) to an aviation obstacle (10); - determining standardized signal strength values ​​by standardizing the first signal strength values; - determining a reference value from one or more of the lowest standardized signal strength values; - providing a second transponder signal (16), which is assigned to a second aircraft (12), and a second signal strength value for the second transponder signal (16);- Determining the second aircraft (12) as a relevant aircraft or determining the second aircraft (12) as an irrelevant aircraft using a comparison of the second signal strength value with the reference value; and - Generating an output signal for an identification device (11) for identifying the aviation obstacle (10) depending on the presence or absence of at least one relevant aircraft.

2. The method according to claim 1, wherein the first signal strength values ​​are normalized to a common distance value.

3. The method according to claim 2, wherein the common distance value corresponds to a predetermined safety distance from the aviation obstacle (10).

4. Method according to at least one of the preceding claims, wherein the normalization of the first signal strength values ​​is carried out by means of the Friis transfer equation.

5. The method according to at least one of the preceding claims, further comprising: - smoothing the second signal strength value taking into account at least one previous second signal strength value for at least one previous second transponder signal.

6. The method according to claim 5, wherein the smoothing of the second signal strength value is carried out by determining a simple or weighted moving average.

7. Method according to at least one of the preceding claims, wherein the reference value corresponds to the lowest normalized signal strength value or an average of the plurality of lowest of the normalized signal strength values.

8. Method according to at least one of the preceding claims, wherein the second aircraft (12) is determined as the relevant aircraft if the second signal strength value is at least as high as the reference value.

9. The method according to at least one of the preceding claims, further comprising: - adapting, prior to the comparison, the reference value or the second signal strength value depending on a transponder operating mode for the second transponder signal (16).

10. The method according to claim 9, wherein the adaptation is carried out by adding or subtracting an offset value to / from the reference value or to / from the second signal strength value, wherein the offset value was determined by comparing frequency distributions of signal strength values ​​for different transponder operating modes.

11. The method of claim 10, further comprising: - updating the offset value within an offset value time interval.

12. The method according to at least one of the preceding claims, further comprising: - updating the reference value within a reference value time interval.

13. A method for marking an aviation obstacle (10), carried out in a system (20) with a receiving device, a data processing device (21), and a marking device (11), and comprising the following steps: - receiving first transponder signals (16) and a second transponder signal (16) in the receiving device (25); - transmitting the first transponder signals (16) and the second transponder signal (16) to the data processing device (21); - carrying out the method according to at least one of the preceding claims in the data processing device (21); - transmitting an output signal from the data processing device (21) to the marking device (11); and - switching a marking of the aviation obstacle (10) by means of the marking device (11) depending on the output signal.

14. Data processing device (21) comprising at least one processor (22) configured to carry out the method according to at least one of claims 1 to 12.

15. A system (20) for marking an aviation obstacle (10), comprising a receiving device (25), a data processing device (21), and a marking device (11), wherein - the receiving device (25) is configured to receive first transponder signals (16) and a second transponder signal (16) and to transmit them to the data processing device (21); - the data processing device (21) is configured to carry out the method according to at least one of claims 1 to 12 and to transmit an output signal to the marking device (11); and - the marking device (11) is configured to switch a marking of the aviation obstacle (10) depending on the output signal.