TERPROM

TERPROM
Name	TERPROM
Type	Navigation and terrain-referenced navigation aid
Origin	United Kingdom
Manufacturer	Smiths Group
Introduced	1980s
Platforms	Fixed-wing aircraft, rotary-wing aircraft, unmanned aerial vehicles, armored vehicles, precision-guided munitions

TERPROM TERPROM is a terrain-referenced navigation and targeting aid that integrates inertial navigation and digital terrain data to provide position updates, navigation cues, and weapons delivery support. The system fuses inputs from inertial sensors, radar altimeters, navigation receivers, and digital terrain elevation databases to reduce positional drift for aircraft and ground platforms. TERPROM has been used to support low-level flight, terrain-following, weapons aiming, and situational awareness in contested and degraded-signal environments.

Overview

TERPROM operates by correlating measured altitude and slant range profiles with stored digital terrain elevation data such as mission-specific elevation models to produce updated position fixes. The system augments inertial navigation systems and complements signals from satellite navigation constellations by using onboard terrain databases and radar altimetry to detect and correct drift. TERPROM is designed to interface with avionics suites, fire-control systems, mission computers, and cockpit displays to support navigation, targeting, and threat-avoidance tasks for platforms engaged in Operation Desert Storm, Falklands War-era missions, and modern expeditionary operations. Its integration has been promoted by aerospace contractors and defense suppliers working with militaries and prime contractors on programs including Eurofighter Typhoon, Panavia Tornado, Boeing F-15, Lockheed Martin F-16, and rotary platforms such as the Sikorsky UH-60 and Westland Lynx.

History and Development

Development traces to research programs in the United Kingdom and allied laboratories focused on terrain-referenced navigation during the late Cold War, when dependence on inertial systems and emerging satellite navigation raised concerns about jamming and spoofing threats. Early programs involved academic institutions, defence research establishments, and contractors collaborating on digital elevation models and sensor fusion algorithms, with links to studies from Royal Aerospace Establishment, British Aerospace, and companies later organized under Smiths Group. Field trials occurred in partnership with air arms such as the Royal Air Force and export customers including the United States Air Force and various NATO air forces. Iterations of the system evolved alongside programs like Joint Helmet Mounted Cueing System integrations and were influenced by lessons from engagements such as Gulf War missions and coalition interoperability exercises with NATO partners.

System Architecture and Components

TERPROM comprises modular components: a mission computer running terrain-correlation algorithms; interfaces to inertial measurement units and tactical navigation systems; radar altimeter and barometric inputs; and a digital terrain elevation database stored on removable media or solid-state storage. The hardware and software are designed to integrate with avionics buses and standards used by integrators such as Rockwell Collins, Thales Group, Honeywell Aerospace, and Westinghouse Electric Company. Sensor fusion uses Kalman-filter style techniques refined with algorithms developed in collaboration with research groups at institutions like Imperial College London and laboratories such as Defence Science and Technology Laboratory. The database format has been adapted to accommodate data from national mapping agencies such as the Ordnance Survey, the United States Geological Survey, and multinational sources used in coalition operations. Interfaces support weapons interfaces used on platforms carrying munitions such as Brimstone (missile), Paveway, and guided bombs delivered from aircraft like Panavia Tornado IDS and General Dynamics F-16 Fighting Falcon.

Applications and Operational Use

TERPROM is applied to low-altitude navigation, terrain-following flight, nap-of-the-earth operations, weapon delivery cueing, and navigation in GPS-denied scenarios. Users have employed it to improve ingress and egress routes for strike packages during coalition operations and for rotary-wing terrain masking during special operations missions conducted by units modeled after United States Army Special Forces and British Special Air Service. It supports close air support integration with ground controllers from organizations such as Forward Air Controller (United States) and interoperability with command-and-control centers like those used by Combined Air Operations Center staffs. TERPROM has also been used in training and mission rehearsal with simulation vendors and programs associated with Lockheed Martin and Boeing flight-training suites.

Performance and Limitations

In performance assessments, TERPROM reduces long-term inertial drift by providing periodic terrain-correlated fixes, improving positional accuracy in denied environments for durations defined by sensor quality and database resolution. Its effectiveness depends on terrain distinctiveness, database currency, and the quality of radar altimeter returns; flat or featureless regions, urban canyons in cities such as Kabul or Baghdad, and heavily vegetated areas can reduce correlation performance. Integration complexity, storage requirements for high-resolution elevation models, and the need for regular database updates have been cited by program managers from ministries such as the Ministry of Defence (United Kingdom) and procurement staffs in partner nations. Countermeasures affecting altimetry, platform vibration on helicopters like Boeing CH-47 Chinook, and maintenance of interoperability with avionics suites from suppliers such as BAE Systems and Leonardo S.p.A. are practical considerations for operators.

International Users and Deployments

TERPROM has been exported and adapted for use by multiple countries and services, with operators in NATO members, Middle Eastern air forces, and other coalition partners. Notable platform integrations include European fighters like Eurofighter Typhoon and multirole jets of air forces such as those of Germany, Italy, Greece, and Spain; legacy fleet adaptations in the Royal Air Force and export installations with the United States Air National Guard and various Middle East partners. Shipborne and land variants have been supplied to armored vehicle programs and naval aviation units collaborating with industry partners including Finmeccanica and Thales Group. International procurement decisions have involved defence ministries, national procurement agencies, and prime contractors coordinating certification with airworthiness authorities like Civil Aviation Authority (United Kingdom) and military certification bodies.

Category:Navigation systems