FIELD: radio engineering. SUBSTANCE: lighting discharge signal received by antenna 1 is first amplified and then filtered off and passed at a time to delay line 4 where it is delayed for period equal to half the length of earth beam and to threshold unit 5 which generates short pulse at moment of first rise of received signal above of calculator 6 which calculates Q ratio using formula for entire specified range of probable distances. During calculations both ionospheric beam delay in respect to earth beam and their amplitude ratio are taken into account which improves range measurement accuracy. Then calculator 6 determines delay and, hence, range at which minimum Q ratio is ensured and yields this range to recorder 7 in the form of evaluation of range to lighting discharge source. This method is distinguished by measurement of instant values of received signal and determination of delay corresponding to minimum of Q function. EFFECT: enlarged measurement range of distances in region where earth and ionosphere beams are superimposed, improved range measurement accuracy. 4 dwg
