The F-14 D Tomcat incorporates a Hughes AN/APG-71 radar, that is a major upgrade to the AN/AWG-9 system and was initially referred to as the AN/AWG-9 Block V. The transmit and receive portion of the AN/APG-71 is basically a digital version of the AN/AWG-9, but represents a reworking of virtually every part of the system.
The new radar includes a low-side-lobe array antenna, digital scan control, monopulse tracking, frequency agility, and improved signal processing capabilities. Only the transmitter, power supply, and aft cockpit tactical information display are retained from the AWG-9. Reliability is doubled and detection and tracking ranges are increased by 40%. Many of the lessons learned from developing the USAF’s MSIP-II F-15 AN/APG-70 radar set were incorporated into the AN/APG-71.
The AN/APG-71 features a new digital programmable signal processor (PSP) based on the one developed for the USAF’s AN/APG-70. In fact, 75% of the three major electronics modules are common between the two sets, although most of the front-end equipment and some weapons interfaces are necessarily unique to the F-14D. The improved radar data processor operates at 3.2 million instructions per second, six times as fast as the AWG-9.
All major modes and capabilities of the AN/AWG-9 radar have been retained, and the system supports the launch and guidance of either six AIM-54Cs or six AIM-120As in the track-while-scan mode. Additional capabilities were also added, many of which had been developed for the F-15C’s MSIP-II program. These include advanced signal processing techniques for tasks such as clutter thresholding, range- and velocity-gate tracking, digital Doppler filtering and enhanced ECCM processing. In addition to the modes provided by the AN/AWG-9, the AN/APG-71 provides:
- Manual Rapid Lock-on (MRL)
- Pilot Automatic Lock-on (PAL)
- Hot Range While Search (HRWS)
- Vertical Scan Lock-on (VSL)
- Pilot Lock-on Mode (PLM)
- Raid Assessment (RA)
- Ground Map (GM)
- Air-to-Ground Ranging (AGR)
The greater processor power available has permitted greater simultaneous coverage of opening (target moving away) and closing (target heading toward aircraft) speeds. Additional modes permit Beyond Visual Range (BVR) target identification, raid assessment with high-resolution Doppler techniques to distinguish among closely spaced targets, monopulse angle tracking to predict the future position of a single target during high-speed maneuvers, and distortionless sector ground mapping of both ocean and land areas.
The APG-71 can also be linked to the infrared search and track set (IRSTS) for passive, long-range search making little use of the active radar. Digital scan control and improved frequency agility are also part of the upgrade. The low-side-lobe antenna is more difficult to jam. Its mount is different, but the antenna retains the gimbal system used in the AWG-9.