Method for Detecting Wind Power Plants Using a Radar System

A method for detection of wind power installations using a radar installation, the method comprising:

• a) transmitting a number N of predetermined sequences Bx of K modulated transmission pulses at a predetermined pulse repetition frequency successively in time, where x=1, . . . , N, wherein after each transmitted sequence a cyclic switching is performed to a different pulse repetition frequency of a predetermined number of pulse repetition frequencies;
• b) receiving and processing, by the radar installation, transmission pulses reflected by an object, wherein the processing creates received pulses corresponding to the transmitted pulses, wherein a number R of received pulses are received for each transmission pulse;
• c) determining a range to the object using a signal delay-time measurement from the received pulses belonging to the sequences Bx of modulated transmission pulses, and producing a range Doppler matrix with R rows and N*K columns;
• d) cyclically performing a number M of measurement processes in an azimuth direction in an azimuth range, wherein N sequences Bx of modulated transmission pulses are transmitted in the respective azimuth direction for each measurement process, and a range Doppler matrix is produced for each measurement process M;
• e) arranging, in sequence using a predetermined correction term, sample values of Z sequences BN of modulated transmission pulses from M measurement processes, where Z=2 . . . N, and processing the arranged sequences, wherein a harmonic oscillation with a least square error with respect to the sample values is calculated using a maximum likelihood estimator;
• f) obtaining a result matrix with R rows and N/Z columns from the range Doppler matrix with R rows and N*K columns using the maximum likelihood estimator, wherein the signal strength, phase and Doppler frequency of the object are known for each cell;
• g) successively producing two result matrices E1, E2 in time after method steps a)-f), and comparing the two result matrices with one another,
• wherein a range Doppler cell is marked as a location of a wind power installation if
• i. the signal strength of a range Doppler cell is above a predeterminable threshold value in both result matrices E1, E2,
• ii. the Doppler frequency shift in a range Doppler cell is within a normal value range for wind power installations in both result matrices E1, E2, and
• iii. the difference between the Doppler frequencies in a range Doppler cell in both result matrices E1, E2 is below a predetermined threshold value.