Station watch alarm system

An automatic station watch system adapted for use with a radar system producing echo signals containing information relative to bearing and range of targets reflecting transmitted radar pulses an having a display scope upon which echo signals are displayed as to range and azimuth comprising

• a variable range gate having an adjustable inner and outer ranges for setting a range zone adapted for connection to said radar system for producing output signals only upon receipt of echo signals from targets within said range zone;
• a variable azimuth gate having adjustable bearing limits for setting an azimuth sector and adapted for connection to said radar system for producing output signals only upon receipt of signals from targets within said sector,
• means applying signals representing the adjusted inner and outer ranges of said range gate within the bearing limits of said azimuth gate to said radar system for display as lines outlining a station zone on said display scope normally encompassing a predetermined station target,
• a target verification discriminator connected to receive output signals from said variable range gate and said variable azimuth gate for producing output signals only upon a coincidence of input signals, and
• an alarm circuit including an alarm signal generator and control means responsive to the absence of discriminator output signals for operating said alarm signal generator to produce alarm signals.