AN/APG-65

The AN/APG-65 is a multi-mode, digital radar used by the US Navy's F/A-18 Hornet strike fighter.  It can be used with the Sparrow and Sidewinder missiles and the 20-mm gun for air-to-air combat as well as a variety of conventional and guided weapons for ground attack.

The system consists of five line-replaceable units (LRU) each of which can be removed and replaced in as little as 7 to12 minutes.  Faults are identified by the radar's built-in test (BIT) which also runs pre-flight and in-flight diagnostics.  The specified mean time between failures (MBTF) is 106 hours.

The elliptical, flat-plate, planar array antenna has low sidelobes for better electronic countermeasures (ECM) resistance. It is electrically driven.

The gridded travelling wave tube (TWT) transmitter is located behind the antenna and under the other LRU.  It is liquid-cooled, which Hughes claims reduces stress on the components and increases reliability and software programmability.  Immediately behind the antenna mount is the receiver-exciter LR U, which houses the analog-to-digital converter and uses field-effect transistors (FET). Behind the receiver-exciter is the general-purpose radar data processor (RDP) which has a 250,000-word 16-bit bulk storage memory . Behind the RDP is the digital, fully software-programmable (as opposed to "hard-wired") instructions.

The programmable signal processor (PSP) operates at 7.2 million operations per second (MOPS).

The radar has a large variety of air-to-air and air-to-surface modes. In the air-to-air mode, the APG-65 presents a clean display in both look-up and look-down conditions and has all-aspect target detection. The radar can perform:

• Velocity search using a high pulse repetition frequency (PRF) for relative velocity measurement;
• Range-while-search (RWS) using high/medium PRF interleaving and including long-range automatic target acquisition;
• Single-target tracking using monopulse angle logic to predict the future location of a target during high-g maneuvers;
• Track-while-scan (TWS) up to 10 targets simultaneously and displaying eight of them (long-range automatic tracking is included);
• Rapid assessment to distinguish among closely spaced targets); and
• Gun director using pulse-to-pulse frequency agility for short-range sighting for the 20-mm cannon.

Three short-range air-combat maneuvering (ACM) target acquisition modes including a target in the head-up display (HUD), vertical acquisition (target-tracking in the vertical axis) and boresight acquisition by pointing the antenna in the direction of an already-identified target.

Surface attack modes include:

• Real beam ground mapping;
• Doppler beam sharpening for sector (19:1 resolution improvement) or patch (67:1 resolution improvement) mapping;
• Terrain avoidance;
• Precision velocity update for the inertial navigation System (INS);
• Sea-surface search;
• Air-to-surface ranging;
• Fixed- or moving-target tracking;
• Synthetic aperture mode.

CHARACTERISTICS

 WEIGHT:  340 lb (154 kg)
 DIMENSIONS:   Volume   < 14.8 cu ft (0.42 cu m)
 PERFORMANCE:

Band                           I-J

Frequency                      8-12 GHz

Detection range                60 nm

APG-65/APG-73 Upgrade

The United States and Canada signed an MoU in 1990, outlining a U.S.- Canadian APG-65 upgrade program. The effort centers on the PSP and RDP LRUs, replacing them with new units that have three times the speed and memory capacity and revising the software algorithms. See separate database entry for the APG-73.

Source:  usni.org