In each border company of the GDR border troops there were specially trained and very reliable soldiers who were trained to provide border service in front of the fence. These border patrols were composed exclusively of seniority guards. In all, 140,000 Grenzers served as Grenzaufklärer (GAK) since the early 70s. They had special training in documentation, observation, photography, criminal law, topography and blasting. The mission of the GAK was to collect and document information. And that was more effective in front of the border fence than in the hinterland. As mentioned, only very reliable soldiers were suitable as GAK. The technical equipment of the GAK was always up to date, often with equipment from the West.

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High-quality Praktica cameras with very strong lenses, video cameras as well as tape recorders for audio recordings were present with practically every use in front of the fence. With the help of this technique, everything was documented that seemed interesting on the German side. These included BGS and customs strips, visitor groups, and motor vehicles. License plates, workers, farmers, etc. To allow the passage through the border fence, the gates were used in the fences, or created special passages were the poorly visible. Even secret tunnels were used. Among the advantages of GAK was the right to sleep at home, certain types of financial allowances, special leave and bonuses. Nevertheless, in 1981, a system of double patrols was instituted to watch these special elite troops to keep them from going over to the Federal Republic of Germany.

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The Grenzaufklärer (GAK) were either brought to the border with a vehicle and dropped off there, or (less often) they drove themselves with a vehicle to the border. The vehicle was then parked concealed in the hinterland, so that their use was not immediately discovered by the federal Republic side.