A sodar system for generating information about atmospheric parameters, wherein: there are at least three peripheral transmitter-receiver pairs (Tn, Rn; Te, Re; Ts, Rs; Tw, Rw) arranged substantially equidistant on a circle, the transmitter and receiver of each of said peripheral pairs are tilted radially outward with respect the circle at an angle to the vertical, each transmitter and receiver comprises an acoustic transducer, an acoustic reflector and a surrounding baffle such that acoustic echoes returned from the atmosphere resulting from acoustic transmissions of one transmitter are preferentially received by the receiver of the respective transmitter-receiver pair relative to all other receivers, and signal processing means is connected to each transmitter-receiver pair and adapted to: cause at least one transmitter of a transmitter-receiver pair to transmit an encoded acoustic chirp into the atmosphere, process signals received by the receiver of the respective pair during the transmission of said chirp and for a time interval thereafter so as to derive information indicative of said atmospheric parameters with respect to altitude, wherein said signal processing means includes a matched filter adapted to process the received signal by reference to the encoding of the acoustic chirp, and wherein: the transmitter of each transmitter-receiver pair has a dominant central transmit antenna lobe (Twm, Tem) and the receiver has a dominant central receive antenna lobe (Rwm, Rem), and said transmitter lobe and said receiver lobe overlap one another for substantially the entire range. there are at least three peripheral transmitter-receiver pairs (Tn, Rn; Te, Re; Ts, Rs; Tw, Rw) arranged substantially equidistant on a circle, the transmitter and receiver of each of said peripheral pairs are tilted radially outward with respect the circle at an angle to the vertical, each transmitter and receiver comprises an acoustic transducer, an acoustic reflector and a surrounding baffle such that acoustic echoes returned from the atmosphere resulting from acoustic transmissions of one transmitter are preferentially received by the receiver of the respective transmitter-receiver pair relative to all other receivers, and signal processing means is connected to each transmitter-receiver pair and adapted to: cause at least one transmitter of a transmitter-receiver pair to transmit an encoded acoustic chirp into the atmosphere, process signals received by the receiver of the respective pair during the transmission of said chirp and for a time interval thereafter so as to derive information indicative of said atmospheric parameters with respect to altitude, wherein said signal processing means includes a matched filter adapted to process the received signal by reference to the encoding of the acoustic chirp, and wherein: the transmitter of each transmitter-receiver pair has a dominant central transmit antenna lobe (Twm, Tem) and the receiver has a dominant central receive antenna lobe (Rwm, Rem), and said transmitter lobe and said receiver lobe overlap one another for substantially the entire range. cause at least one transmitter of a transmitter-receiver pair to transmit an encoded acoustic chirp into the atmosphere, process signals received by the receiver of the respective pair during the transmission of said chirp and for a time interval thereafter so as to derive information indicative of said atmospheric parameters with respect to altitude, wherein said signal processing means includes a matched filter adapted to process the received signal by reference to the encoding of the acoustic chirp, the transmitter of each transmitter-receiver pair has a dominant central transmit antenna lobe (Twm, Tem) and the receiver has a dominant central receive antenna lobe (Rwm, Rem), and said transmitter lobe and said receiver lobe overlap one another for substantially the entire range.