Abstract: A method of measuring the distance between two objects and/or the speed of one object in relation to the other, the objects incorporating respectively a transmitter-receiver unit and a transponder or reflector, in which method a phase comparison is made between a signal transmitted by the transmitter-receiver unit and a signal received in the transmitter-receiver unit and transmitted from the transponder or reflector. In accordance with the invention the transmitter-receiver unit is caused to transmit signals of microwave frequency, preferably about 2450 MHz, this transmission comprising the transmission of a first signal having a first frequency, the transmission of at least one second signal having a higher or lower frequency, and the transmission of a third signal having the same frequency as the first mentioned signal, wherewith the phase differences .phi.

Abstract: A method for measuring the distance between a first object, which incorporates a transmitter-receiver unit, and a second object, which incorporates a transponder. In accordance with the invention there is transmitted from the transmitter-receiver unit (19) a first microwave signal (S1), which is received in the transponder (18). A second signal (S3) of much lower frequency F.sub.m is generated in the transponder and is modulated on a signal (S6) of microwave frequency in the transponder to form a modulated signal (S7). The modulated signal (S7) is transmitted from the transponder to the transmitter-receiver unit (19), where it is received and mixed down with the first signal (S1) and thereafter is (a) low-pass filtered to form a first measuring signal (S10) having the frequency F.sub.

Abstract: A method for determining a mutual position between two objects, comprising transmitting a microwave signal from the first object towards the second object, causing the second object to receive the transmittal signal and re-transmit a signal, which is caused to be received by the first object. According to the invention the first object includes a transmitter/receiver unit (S/M-unit), which transmits the aforesaid signal (f.sub.o) from a transmitter antenna. The second object (T) is caused to re-transmit the aforesaid signal modulated with a signal (f.sub.m), the first object being caused to receive the transmitted signal through at least two antennae (M.sub.1, M.sub.2) placed symmetrically on a respective side of the transmitter antenna (S) and in an antenna plane common with the transmitter antenna (S). The angle (.theta.

Abstract: A method and apparatus for measuring the thickness corrected moisture ratio of a material, particularly organic material, comprising transmitting microwaves and measuring therewith the damping (A) and phase change (F1) of the microwaves upon their transmission through the material. According to the invention (W.sub.w /Y) is calculated from the expression A=(W.sub.w /Y).multidot. .multidot.k.sub.1 +k.sub.3 .multidot.t, where t is the thickness of the material (10) and where k.sub.1 and k.sub.3 are constants and the term W.sub.w /Y is the weight of the water in the material per unit area. In addition, the term (W.sub.d /Y) is determined from the expression F1=(W.sub.w /Y).multidot.k.sub.4 +(W.sub.d /Y).multidot.k.sub.5 +k.sub.6 .multidot.t in which expression the aforedetermined term W.sub.w /Y is used. The term W.sub.d /Y is the weight of the material in a dry state per unit area and k.sub.4, k.sub.5, k.sub.6 are constants. The moisture ratio is obtained in a known manner through the quotient (W.sub.w /Y)/(W.