Mobile combined PSR/SSR L-band Radar MARS-L is a ground-based radar system implementing combined operation of primary and secondary channels. Design of transmitter and receiver of MARS-L relies on advanced technology of operation with complex strobing signals and jamming protection. MARS-L is intended for automatic target detection of aerial objects (AO) at small, average and big altitudes, determination of target current position, locking of AO movement trajectory and AO automatic tracking. MARS-L includes surveillance primary radar channel (PRC), which uses approach of active location with passive response, and secondary radar channel (SRC), which uses approach of location with active response, that work for one common antenna.Combined operation of primary and secondary channels allows for significant increase in detection range and accuracy at relatively low radiation power. Besides, availability of additional flight information (flight number, altitude, remaining fuel, technical status, etc.) increases flight safety and diminishes the probability of anti-aircraft missile accidental engagement against commercial aircraft.