Abstract: Device for radar utilized to detect multiple-time-around echoes with the capability of transmitting in frequency agility and, besides the advantages due to this type of technique, further, capable of reading the ambiguity of distance directly by separating in frequency the multiple-time-around echoes. The device described is applicable to any pulses radar, such as for example, search or tracking, in which it is necessary to detect targets and recognize multiple-time-around echoes. Nevertheless its application is especially suited to a multifunctional radar (with phased-array antenna and monopulse capability).

Abstract: A radar of the MTI type has a transmitter connected to a source of outgoing pulses whose carrier frequency is variable under the control of a mode selector for selective operation with fixed frequency, frequency diversity or frequency agility, depending on detected environmental conditions. A multiweight Doppler filter serves for the detection of mobile targets in each of these three modes. With frequency-agility operation, samples of echoes of an outgoing pulse received during a given sweep are stored in a memory in accordance with the carrier frequency used for that pulse, this frequency changing in random fashion from one pulse to the next among a certain number of predetermined values.