PULSE-DOPPLER RADIO ALTIMETER Russian patent published in 2014 - IPC G01S13/02 

FIELD: instrumentation.

SUBSTANCE: invention can be used in pulse Doppler radio altimeters (RA). It consists in emitting probing pulse packet towards underlying terrain. Mote here that the number of radio pulses (RP) and pulse time are selected to ensure maximum number of RP for a priori delay (AD) set by exchange controller (EC). Besides, it serves to rule out ambiguity of altitude measurement and getting of emitted signal in uncertainty zone wherein reflected signal is sought. Packet of radio pulses reflected from underlying terrain is received to convert video pulses into the train of digital binary signals (DBS) at sampling rate. Theses are memorised in synchronism with RP and, at termination of radiation, the address of memory cell is defined that corresponds to AD of reflected signal relative to radiation packet start. Narrow-band Doppler filtration of DBS read from memory cells in the range of memory cell search is performed. Filtration total result is accumulated over all digital binary signals of received packet for every estimated delay. Decision is made on signal availability by excess over preset threshold of accumulation to define the reflected signal delay relative to RP packet start. Data on measured altitude is output to RA via EC.

EFFECT: enhanced performances, higher radiation hiding.

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