| 摘要 |
FIELD: instrumentation.SUBSTANCE: measurement of rocket velocity at its head-on approaching an asteroid implies measurement of the time interval t between the moments of detection, at a radar with a frequency-modulated signal installed on the rocket, of two signals with different frequencies formed between the moment when the rocket flies a known distance interval S=D-Dand the calculation of approaching speed V=S/t of the objects, the differential signals are the signals with the frequency Fp=(N+4)Fp and Fp=N(Fp=Fdo+A=2Vofo/C+Btd), where N - number which is significantly greater than 1, when the distances commensurable with the following will be found between the radar antenna and the asteroid: D=(Fp-A+Fi)C/2B and D=(Fp-A+Fi)×C/2B, where Fi=2Vifo/C - Doppler frequency at exact closing of the objects with Vi, Vo and C standing respectively for the approaching speeds of: the objects, the rocket and light, fo - frequency of continuously sent signal with frequency modulation as per the one-sided sawlike linearly increasing law (NLFM signal), B=Fmdfm - rate of frequency change for the NLFM signal, A=Btd - part of the differential signal frequency occurred due to the artificial delay for the time td of the NLFM signal being sent, Fm and dfm are respectively the modulation frequency and the NLFM signal frequency deviation chosen by the condition Do/Vo=fo/B, where Do is the known basic distance. The device for measuring the asteroid head-on approaching rocket speed comprises: a transmit-receive antenna, a delay element, a mixer, a transmitter of the continuous signal with frequency modulation as per the one-sided sawlike linearly increasing law and the following units installed in sequence: filter of differential frequencies, detector of signals of narrow-band frequency range, time interval measuring unit and calculator.EFFECT: improved reliability of measuring the approaching speed of objects due to more reliable detection of ultra-fast goal objects by a radar.2 cl |
