AN/APQ-116 is one of the most numerous

terrain-following radar Terrain-following radar (TFR) is a military aerospace technology that allows a very-low-flying aircraft to automatically maintain a relatively constant altitude above ground level and therefore make detection by enemy radar more difficult. It is ...

s (TFRs) produced in the world, and with over 500 units built, it was a member of a family of TFRs consisted of nearly two dozen models, all of which are based on the same general design principle. First developed by

Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...

, and later produced by

Raytheon Raytheon Technologies Corporation is an American multinational aerospace and defense conglomerate headquartered in Arlington, Virginia. It is one of the largest aerospace and defense manufacturers in the world by revenue and market capitali ...

when the latter purchased the radar business of the former.

AN/APN-149

This is the first terrain-following radar for use on crewed aircraft, designed by Bert Bechtel, a former Navy engineer, who had designed a radar scan template control technique that permitted safe aircraft descent in adverse weather. The concept was the basis of winning a $750,000 US Army contract to develop a radar system to automatically guide a drone aircraft. The US Army did not pursue the project to production, but the US Air Force became interested and believed that Bechtel's innovation would protect the low-flying planes.

AN/APN-165

Terrain-following/ground-mapping radar by

for

OV-1 Mohawk The Grumman OV-1 Mohawk is an armed military observation and attack aircraft that was designed for battlefield surveillance and light strike capabilities. It has a twin turboprop configuration, and carries two crew members in side-by-side seating ...

AN/APQ-89

TFR (Terrain-Following Radar) tested on

T-2 Buckeye The North American T-2 Buckeye was the United States Navy's intermediate training aircraft, intended to introduce U.S. Navy and U.S. Marine Corps student naval aviators and student naval flight officers to jets. It entered service in 1959, begi ...

for pilots to familiarize TFR operation on other combat aircraft.

AN/APQ-99

Developed by TI as a multi-modes radar, in addition to terrain avoidance and terrain-following modes, and AN/APQ-99 can also be used for ground mapping. Smaller in size then the Westinghouse AN/APQ-72 and fitted in the nose of for A-7A, RF-4B/C. AN/APQ-99 is also supplied to Germany, Iran and Japan.

AN/APQ-101

Terrain-following radar by Texas Instruments.

AN/APQ-110

K_u band

for

General Dynamics F-111 The General Dynamics F-111 Aardvark is a retired supersonic, medium-range, multirole combat aircraft. Production variants of the F-111 had roles that included ground attack (e.g. interdiction), strategic bombing (including nuclear weapons c ...

A and

RF-4C The McDonnell Douglas F-4 Phantom II variants were numerous versions and designations of the F-4 and are described below. Production numbers for major versions asterisk indicates converted from other version Variants ;XF4H-1 :Two prototype ...

. It replaced the side-looking mapping radar by

Goodyear Tire and Rubber Company The Goodyear Tire & Rubber Company is an American multinational tire manufacturing company founded in 1898 by Frank Seiberling and based in Akron, Ohio. Goodyear manufactures tires for automobiles, commercial trucks, light trucks, motorcycles, S ...

AN/APQ-115

Improved AN/APQ-110

for the A-7A,

, and C-130E. AN/APQ-115 has a single contoured, spoiled parabola antenna, with a search cone of 5 degrees wide, spanning from +7 degrees above to -18 degrees below to the boresight of the aircraft. AN/APQ-115 suffered from inaccurate references (poor stabilization and Doppler inputs), which directly lead to the development of more advanced system such as AN/APQ-122. The

I-band AN/APQ-116 is a TFR used in

A-7 Corsair II The LTV A-7 Corsair II is an American carrier-capable subsonic light attack aircraft designed and manufactured by Ling-Temco-Vought (LTV). The A-7 was developed during the early 1960s as replacement for the Douglas A-4 Skyhawk. Its design w ...

and C-130 Hercules aircraft. AN/APQ-116 was basically the integration of previously independent AN/APQ-115 TFR into the ILAAS digital navigation system. The radar also fed a digital weapons computer which made possible accurate delivery of bombs from a greater stand-off distance, greatly improving survivability compared with faster platforms such as the F-4 Phantom II.

AN/APQ-122

X band multi-mode radar by

for C-130 Hercules,

Boeing RC-135 The Boeing RC-135 is a family of large reconnaissance aircraft built by Boeing and modified by a number of companies, including General Dynamics, Lockheed, LTV, E-Systems, and L3 Technologies, and used by the United States Air Force and Royal ...

, Boeing T-43 and

Boeing E-4 The Boeing E-4 Advanced Airborne Command Post (AACP), the current "Nightwatch" aircraft, is a strategic command and control military aircraft operated by the United States Air Force (USAF). The E-4 series are specially modified from the Boeing ...

. AN/APQ-122 has a slotted planar array antenna with a separate X-band receiver used to generate MRI video, with a search cone of 7.5 degrees wide, spanning from +8 degrees above to -17 degrees below to the boresight of the aircraft. For AN/APQ-122(V)B, the stabilization reference could either be manually or automatically switched to MD-1 gyro if the LN-15J inertial navigational system become unreliable or inoperable, thus terrain following operation can still continue, where in earlier system such as AN/APQ-115, if the Doppler fails, the terrain following operation would be discontinued.

AN/APQ-126

60 kW improved AN/APQ-116 J band

for A-7D/E

AC-130 The Lockheed AC-130 gunship is a heavily armed, long-endurance, ground-attack variant of the C-130 Hercules transport, fixed-wing aircraft. It carries a wide array of ground-attack weapons that are integrated with sophisticated sensors, naviga ...

and

CH-53 Sea Stallion The CH-53 Sea Stallion (Sikorsky S-65) is an American family of heavy-lift transport helicopters designed and built by the American manufacturer Sikorsky Aircraft. It was originally developed in response to a request from the United States N ...

. This is primarily AN/APQ-116/122 incorporating improved maritime capability. Specifications: *Maritime surface search: (high altitude): 150NM *Maritime surface search: (low altitude): 106NM *Maritime surface search (vs. small contacts): 51NM *Land surface search (med altitude): 34NM *Air search: 20NM *Terrain following: 19NM

AN/APQ-134

K_u band

to replace AN/APQ-110 for F-111A/FB-111A.

AN/APQ-139

K_u band multi-mode radar by

for B-57G specially designed for night interdiction missions in Vietnam.

AN/APQ-146

Improved AN/APQ-134 K_u band

for F-111C/F.

AN/APQ-147

TFR (Terrain-Following Radar) for initial batch of MH-60K

AN/APQ-154

Improved AN/APQ-141

for

HH-53 The Sikorsky MH-53 Pave Low series is a retired long-range special operations and combat search and rescue (CSAR) helicopter for the United States Air Force. The series was upgraded from the HH-53B/C, variants of the Sikorsky CH-53 Sea Stall ...

AN/APQ-158

Improvement of AN/APQ-126 with 15 line replaceable units for the

MH-53 Pave Low The Sikorsky MH-53 Pave Low series is a retired long-range special operations and combat search and rescue (CSAR) helicopter for the United States Air Force. The series was upgraded from the HH-53B/C, variants of the Sikorsky CH-53 Sea Stal ...

helicopter and PAVE LOW III requirement. Designed to perform terrain following mode/function in high clutter area such as in cities.

AN/APQ-162

Development of AN/APQ-99 for RF-4C, incorporating experience gained from AN/APQ-116 and other radars in the family.

AN/APQ-168

Multi-mode radar by

for HH-60D & MH-60K. Increased jamming resistance, improved weather penetration, better guidance in turn flight, and better power management function in semi-covert mission. The radar can operate in terrain-clearance, terrain-avoidance, air-to-air ranging and cross-scan modes, the latter combining ground-mapping or terrain-avoidance with terrain-following. A terrain storage facility permits the radar to have a reduced duty cycle, thereby reducing the probability of detection by enemy ESM equipment. There's also the incorporation of built-in test (BITE) provides a high degree of fault isolation and detection.

AN/APQ-171

Improved AN/APG-146

for F-111C/F, developed by Texas Instruments in the mid- eighties with the objective of replacing the four different TFR models used across the USAF F-111 fleet with a single type. While the old TFR had an

MTBF Mean time between failures (MTBF) is the predicted elapsed time between inherent failures of a mechanical or electronic system during normal system operation. MTBF can be calculated as the arithmetic mean (average) time between failures of a syst ...

around 20 hours, MBTF for the AN/APQ-171 is better than 50 hrs.

AN/APQ-172

Improved AN/APQ-162 TFR (Terrain-Following Radar) for

AN/APQ-174

For the MH-60K and MH-47E helicopters

AN/APQ-186

Improved AN/APQ-174 by

for CV-22

AN/APN-237

K_u band

part of AN/AAQ-13

References

{{DEFAULTSORT:AN APQ-116 Aircraft radars Military radars of the United States Radars of the United States Air Force