Meel, Thomas

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Apparatus (10) for warning an aircraft comprises a warning system (16), storage means (14) storing a database of ship identities and corresponding height data, and a ship position receiver (12). An Automatic Identification System (AIS) signal (22) emitted from a ship (20) carries information corresponding to the identity and the position of the ship. If the ship lies on, or within a pre-determined vicinity of, the horizontal trajectory of the aircraft, the warning system uses the ship's identity derived from the AIS signal to look up the height of the ship in the database. If the altitude of the aircraft does not exceed the height of the ship by more than a pre-determined value, the warning system generates a warning signal. The apparatus allows a commercial AIS signal to be used to warn an aircraft of a ship, but avoids false alarms in the event that the altitude of the aircraft significantly exceeds the height of the ship.

The invention relates to a method for the determination of a plurality of distinct echo pulses originating from the same emitted signal train of an active 3D sensor in order to provide distance measurements of the surroundings in front of the 3D sensor, whereas the signal train received by the 3D sensor is subjected to a predefined trigger condition, so that only those peaks of the signal train that fulfill the predefined trigger condition are taken into account in the determination of the distinct echo pulses, According to the invention for the determination of the distinct echo pulses, at least two different trigger conditions are applied.

The invention is concerned with a method for suppressing windmill returns in a ground based pulse Doppler radar comprising the following steps: a) emitting a waveform comprising a train of pulses at an average pulse repetition frequency of 3 to 7 kHz, b) upon reception of the echo pulses, transforming the echo pulses into a range Doppler matrix containing the signal power levels of the radar detections and indicating their respective range gate and Doppler filter, c) determining the detections in any of the second, third, penultimate and last Doppler filters in a range gate where windmills are suspected, d) determining the signal power levels of detections in the first Doppler filter at range gates that are identical or adjacent to the range gate where windmills are suspected, e) determining the maximum of the signal power levels determined in the previous step, f) comparing the corresponding radar cross section of the maximum signal power level determined in the previous step with a predefined threshold value derived from the characteristic radar cross section of a rotor head of a windmill, g) excluding the detections in the range gate where windmills are suspected in the second, third, penultimate and last Doppler filter from further processing if the radar cross section of the maximum signal power level is above the predefined threshold.

Zusammenfassung wird geladen …

Zusammenfassung wird geladen …

Zusammenfassung wird geladen …

Zusammenfassung wird geladen …

Zusammenfassung wird geladen …