| 摘要 |
FIELD: radio engineering, communication.SUBSTANCE: measured length of a moving object is determined by the expression L=4Dot/t, where tis the time interval between moments of onset and detection, at a radar station, signals with frequency NFdo=N2Vofn/C and (N+4)Fdo, over which the object traverses the distance Sinterval from (1-?)(Do/Vo)(Vi+NVo) to (1+?)(Do/Vo)[Vi+(N+4)Vo], where fn is the average frequency of the continuous chirp signal emitted by the radar station, selected based on the condition Do/Vo=fn/Fmfd; fd and Fm denote the frequency deviation and modulation frequency of the continuous chirp signal, respectively; Vo is the minimum possible value of the radial velocity of the target; Do is the selected base distance; C and Vi denote the speed of light and velocity of the target, respectively; ? is a coefficient which defines the length of the known distance Sinterval on which the object is detected; N is a positive number which defines the distance between the radar station and the beginning of detection of the target on the distance Sinterval; tis the time interval during which the object traverses the distance Sinterval from (1-?)(Do/Vo)(Vi+NVo) to (1+?)(Do/Vo)(Vi+NVo), during detection of a signal with frequency NFdo±?Fdo at the radar station, where ±?FDo is the narrow-band spectral range of signals detected at the radar station. The device for measuring the length of a moving object has an antenna, a continuous chirp signal transmitter, a mixer, a differential frequency filter, a narrow-band spectral signal detector, a shift register, two AND gates, two pulse counters, a delay element, a count pulse generator, a multiplier circuit and a divider circuit, a memory unit and constant digital number bus.EFFECT: wider range of devices for measuring the length of objects.2 cl, 1 dwg |
