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The APS-145 is the latest version of the Airborne Early Warning radar for the US Navy's carrier based E-2C Hawkeye. Early versions of the aircraft went into service in 1963. Since then, it and the radar have undergone numerous upgrades.
Designed for operation over both land or sea, the APS-145 can provide surveillance over 3,000,000 cubic miles of air space and can simultaneously monitor and track up to 2,000 targets. Looking beyond the horizon, it has a maximum detection range of 350 nmi.
Operating at UHF frequencies (0.3 to 1.0 GHz) to minimize sea clutter, the radar employs a linear array of yaggi antennas, having monopulse sum and difference outputs. This array is housed in a 24-foot-diameter rotating radome, called a rotodome, which rotates at 5 rpm.
The transmitter is a high-power coherent master-oscillator power-amplifier (MOPA). It is switched through three different PRFs to eliminate doppler blind zones and employs linear frequency-modulation (chirp) pulse compression.
By means of DPCA and a double-delay AMTI clutter canceller, mainlobe clutter is eliminated, thereby avoiding the problem of low-closing (or opening) rate targets being obscured by spreading of the clutter spectrum due to the aircraft's advance when looking in broadside directions (normal to the aircraft velocity). Clutter cancellation is followed by coherent signal integration with the FFT To minimize false alarms, the detection threshold is adaptively adjusted resolution-cell by resolution-cell in accordance with...
