The Mohawk's mission would include observation, artillery spotting, air control, emergency resupply, naval target spotting, liaison, and radiological monitoring. The Navy specified that the aircraft had to be capable of operating from small "jeep" escort class carriers (CVEs). The DoD selected Grumman Aircraft Corporation's G-134 design as the winner of the competition in 1957. Marine requirements contributed an unusual feature to the design: since the Marines were authorized to operate fixed-wing aircraft in the close air support (CAS) role, the mockup featured underwing pylons for rockets, bombs, and other stores, and this caused a lot of discord. The Air Force did not like the armament capability of the Mohawk and tried to get it removed. On the other side, the Marines did not want the sophisticated sensors the Army wanted, so when their Navy sponsors opted to buy a fleet oil tanker, they eventually dropped from the program altogether. The Army continued with armed Mohawks (and the resulting competence controversy with the Air Force) and also developed cargo pods that could be dropped from underwing hard points to resupply troops in emergencies.

In mid-1961, the first Mohawks to serve with U.S. forces overseas were delivered to the 7th Army at Sandhofen Airfield near Mannheim, Germany. Before its formal acceptance, the camera-carrying AO-1AF was flown on a tour of 29 European airfields to display it to the U.S. Army field commanders and potential European customers. In addition to their Vietnam and European service, SLAR-equipped Mohawks began operational missions in 1963 patrolling the Korean Demilitarized Zone.

Germany and France showed early interest in the Mohawk, and two OV-1s were field-tested by both nations over the course of several months. No direct orders resulted, though, but the German Bundesheer (Army) was impressed by the type’s performance and its capability as an observation and reconnaissance platform. Grumman even signed a license production agreement with the French manufacturer Breguet Aviation in exchange for American rights to the Atlantic maritime patrol aircraft, but no production orders followed.

This could have been the end of the OV-1 in Europe, but in 1977 the German government, primarily the interior ministry and its intelligence agency, the Bundesnachrichtendienst (BND), showed interest in a light and agile SIGINT/ELINT platform that could fly surveillance missions along the inner-German border to the GDR and also to Czechoslovakia. Beyond visual reconnaissance with cameras and IR sensors, the aircraft was to be specifically able to identify and locate secret radio stations that were frequently operated by Eastern Block agents (esp. by the GDR) all across Western Germany, but primarily close to the inner-German border due to the clandestine stations’ low power. The Bundeswehr already operated a small ELINT/ECM fleet, consisting of converted HFB 320 ‘Hansa’ business jets, but these were not suited for stealthy and inconspicuous low flight level missions that were envisioned, and they also lacked the ability to fly slowly enough to locate potential “radio nests”.

The pan and the objective were clear, but the ELINT project caused a long and severe political debate concerning the operator of such an aerial platform. Initially, the Bundesheer, who had already tested the OV-1, claimed responsibility, but the interior ministry in the form of the German customs department as well as the German police’s Federal Border Guard, the Bundesgrenzschutz and the Luftwaffe (the proper operator for fixed-wing aircraft within the German armed forces), wrestled for this competence. Internally, the debate and the project ran under the handle “Schimmelreiter” (literally “The Rider on the White Horse”), after a northern German legendary figure, which eventually became the ELINT system’s semi-official name after it had been revealed to the public. After much tossing, in 1979 the decision was made to procure five refurbished U.S. Army OV-1As, tailored to the German needs and – after long internal debates – operate them by the Luftwaffe.

The former American aircraft were hybrids: they still had the OV-1A’s original short wings, but already the OV-1D’s stronger engines and its internal pallet system for interchangeable electronics. The machines received the designation OV-1G (for Germany) and were delivered in early 1980 via ship without any sensors or cameras. These were of Western German origin, developed and fitted locally, tailored to the special border surveillance needs.

The installation and testing of the “Schimmelreiter” ELINT suite lasted until 1982. It was based on a Raytheon TI Systems emitter locator system, but it was locally adapted by AEG-Telefunken to the airframe and the Bundeswehr’s special tasks and needs. The system’s hardware was stowed in the fuselage, its sensor arrays were mounted into a pair of underwing nacelles, which occupied the OV-1’s standard hardpoints, allowing a full 360° coverage. In order to cool the electronics suite and regulate the climate in the internal equipment bays, the OV-1G received a powerful heat exchanger, mounted under a wedge-shaped fairing on the spine in front of the tail – the most obvious difference of this type from its American brethren. The exact specifications of the “Schimmelreiter” ELINT suite remained classified, but special emphasis was placed upon COMINT (Communications Intelligence), a sub-category of signals intelligence that engages in dealing with messages or voice information derived from the interception of foreign communications. Even though the “Schimmelreiter” suite was the OV-1Gs’ primary reconnaissance tool, the whole system could be quickly de-installed for other sensor packs and reconnaissance tasks (even though this never happened), or augmented by single modules, what made upgrades and mission specialization easy. Beyond the ELINT suite, the OV-1G could be outfitted with cameras and other sensors on exchangeable pallets in the fuselage, too. This typically included a panoramic camera in a wedge-shaped ventral fairing, which would visually document the emitter sensors’ recordings.

A special feature of the German OV-1s was the integration of a brand new, NATO-compatible “Link-16” data link system via a MIDS-LVT (Multifunctional Information Distribution System). Even though this later became a standard for military systems, the OV-1G broke the ground for this innovative technology. The MIDS was an advanced command, control, communications, computing and intelligence (C4I) system incorporating high-capacity, jam-resistant, digital communication links for exchange of near real-time tactical information, including both data and voice, among air, ground, and sea elements. Outwardly, the MIDS was only recognizable through a shallow antenna blister behind the cockpit.

Even though the OV-1Gs initially retained their former American uniform olive drab livery upon delivery and outfitting in German service, they soon received a new wraparound camouflage for their dedicated low-level role in green and black (Luftwaffe Norm 83 standard), which was better suited for the European theatre of operations. In Luftwaffe service, the OV-1Gs received the tactical codes 18+01-05 and the small fleet was allocated to the Aufklärungsgeschwader (AG) 51 “Immelmann”, where the machines formed, beyond two squadrons with RF-4E Phantom IIs, an independent 3rd squadron. This small unit was from the start based as a detachment at Lechfeld, located in Bavaria/Southern Germany, instead of AG 51’s home airbase Bremgarten in South-Western Germany, because Lechfeld was closer to the type’s typical theatre of operations along Western Germany’s Eastern borders. Another factor in favor of this different airbase was the fact that Lechfeld was, beyond Tornado IDS fighter bombers, also the home of the Luftwaffe’s seven HFB 320M ECM aircraft, operated by the JaBoG32’s 3rd squadron, so that the local maintenance crews were familiar with complex electronics and aircraft systems, and the base’s security level was appropriate, too.

With the end of the Cold War in 1990, the OV-1Gs role and field of operation gradually shifted further eastwards. With the inner-German Iron Curtain gone, the machines were now frequently operated along the Polish and Czech Republic border, as well as in international airspace over the Baltic Sea, monitoring the radar activities along the coastlines and esp. the activities of Russian Navy ships that operated from Kaliningrad and Saint Petersburg. For these missions, the machines were frequently deployed to the “new” air bases Laage and Holzdorf in Eastern Germany.

In American service, the OV-1s were retired from Europe in 1992 and from operational U.S. Army service in 1996. In Germany, the OV-1 was kept in service for a considerably longer time – with little problems, since the OV-1 airframes had relatively few flying hours on their clocks. The Luftwaffe’s service level for the aircraft was high and spare parts remained easy to obtain from the USA, and there were still OV-1 parts in USAF storage in Western German bases.

The German HFB 320M fleet was retired between 1993 and 1994 and, in part, replaced by the Tornado ECR. At the same time AG 51 was dissolved and the OV-1Gs were nominally re-allocated to JaboG 32/3. With this unit the OV-1Gs remained operational until 2010, undergoing constant updates and equipment changes. For instance, the machines received in 1995 a powerful FLIR sensor in a small turret in the aircraft’s nose, which improved the aircraft’s all-weather reconnaissance capabilities and was intended to spot hidden radio posts even under all-weather/night conditions, once their signal was recognized and located. The aircrafts’ radio emitter locator system was updated several times, too, and, as a passive defensive measure against heat-guided air-to-air missiles/MANPADS, an IR jammer was added, extending the fuselage beyond the tail. These machines received the suffix “Phase II”, even though all five aircraft were updated the same way.

Reports that the OV-1Gs were furthermore retrofitted with the avionics to mount and launch AIM-9 Sidewinder AAMs under the wing tips for self-defense remained unconfirmed, even more so because no aircraft was ever seen carrying arms – neither the AIM-9 nor anything else. Plans to make the OV-1Gs capable of carrying the Luftwaffe’s AGM-65 Maverick never went beyond the drawing board, either. However, BOZ chaff/flare dispenser pods and Cerberus ECM pods were occasionally seen on the ventral pylons from 1998 onwards.