Dual-frequency, complementary-sequence pulse radar

A system for transmitting signals toward a target for echo ranging, said system comprising:

• first transmitting means for transmitting toward said target a carrier signal at a first frequency modulated by a first pulse set consisting of a predetermined plurality of first pulses, said pulses of said first set being dispersed in time pursuant to a predetermined phase code;
• second transmitting means for transmitting toward said target a second carrier signal at a second frequency, different from said first frequency, said second carrier signal being modulated by a second pulse set consisting of said predetermined plurality of second pulses, said pulses of said second set being dispersed in time pursuant to a second phase code selected to be complementary to said predetermined phase code in a manner such that, after pulse compression of said first and second pulses, the resulting range sidelobes are substantially equal in amplitude and opposite in sign;
• receiving means for receiving echoes of said first and second pulse from said target to produce received first and second pulse sets;
• matched-filtering means coupled to said receiving means for matched filtering each of said received first and second pulse sets to produce first and second compressed pulses;
• combining means coupled to said matched filtering means for combining said first and second compressed pulses to produce reduced-range-sidelobe signals.