Abstract: A radar apparatus which includes a transmitter that generates a train of pulses arranged in groups of two, each group including a long pulse and a short pulse of different frequencies. These long and short pulses are separated in a receiver by a range gate which passes the pulses through the upper receiving channel when reflected from long ranges and the lower receiving channel when received from short ranges. The upper channel includes a filter which passes only the long pulses, which are frequency swept, and then compressed. The lower channel includes a filter which passes only the short pulses which are not frequency swept. The transmitter reverses the order of the pulses in adjacent groups. Alternatively, both the long and short pulses may be frequency swept. In either event there are adjacent pairs of swept pulses in contrast to known systems in which each swept pulse has immediately been preceded or followed by an unswept pulse.

Abstract: A radar transmitter transmits a group of pulses as shown at I of FIG. 2, the group consisting of first short pulse of a frequency f.sub.1 transmitted during time interval t.sub.1 to t.sub.2. A second, longer pulse of frequency f.sub.2 is transmitted during time interval t.sub.2 and t.sub.3 and a third, short pulse of frequency f.sub.1 is transmitted during time interval t.sub.3 to t.sub.4. The return from a close range small target is shown at II and the return from a large source of clutter or another large target at a slightly greater range is shown at III. The return from the larger target or source of clutter is so strong as to saturate the receiver during the time interval t.sub.7 to t.sub.12 and thus the return from the second short pulse during period t.sub.9 to t.sub.10 is obscured as shown at IV. However, since a short pulse is also transmitted before the long pulse its return, at time interval t.sub.5 to t.sub.6, is not obscured.