The invention concerns a device for checking radio aerial navigational aids. In the device according to the invention, the infra-red scanning head is mounted on a turret by means of two groups each comprising a tachometric generator-motor unit and an angular coder and respectively mounted along the inclination axis and the bearing axis. The motors are supplied by voltages characteristic of the angular aiming errors furnished, after processing, by the scanning head. The orientable beacon on board the aircraft is controlled by orientation servomotors supplied by a recopying system.

A search and locate system includes a search station having an active, low light level electro-optic unit. A search beacon of nonvisible laser radiation is transmitted from the search station. A person to be located has a locator unit including a corner-cube retro-reflector which reflects a portion of the radiation of the search beacon back to the search station where it is detected by the low light level receiving apparatus. The locator unit also includes a photo-detector and indicator which provides a signal when the locator unit is positioned within the radiation from the search beacon. This enables the person utilizing the locator unit to sustain the reflection back to the search station, thus enhancing the likelihood of detection. The locator unit further includes a low power modulation system whereby the person can transmit a message to the search station via the reflected beam. Means are additionally provided for coding the radiation from the search beacon and for detecting a predetermined code at the locator unit. This enables the person using the locator unit to reflectively respond only to a search beacon transmitting radiation with the correct code.

A system is provided for remote determination of the attitude of a vehicle. he system utilizes two remotely located transmitting-receiving stations and two retroreflecting single plane roof prisms mounted on a vehicle which may exhibit high angular rates about a roll axis relative to the angular rates about two other orthogonal axes. The two remotely located transmitter-receiver stations provide tracking of the vehicle, continuously illuminating the vehicle with a light source located at each station so that the position of the object relative to the remote stations is obtained.

A three dimensional laser tracking and control system is disclosed. The system includes a laser beacon generating a three dimensional rotating and scanning laser beam that covers a three-dimensional area. Each mobile unit has identification number (ID) and is equipped with a intelligent reflector (IR). Each mobile unit uses its intelligent reflector (IR) to communicate to the signal system its ID and the time of illumination by the laser beam. The signal system calculates the three dimensional coordinates for each mobile unit and communicates the positional data back to each mobile unit using the same laser beam during the subsequent rotation cycles.

For simplification of storage of measured range and direction values in surveying, as well as for coordination and processing of these values with additional information these values are transmitted from the measuring station (1,2) to the target point (2'). The additional information is mainly obtained at the target point (2') at a distance from the measuring station (1,2) and at the other end of the measured range, whereas the measured values are transmitted by modulating electric signals upon the infrared beam of an electrooptic range-finder (2) or by means of a separate short wave link. At the target point (2') there are a signal receiver and a programmable data storage device (3) which accepts the additional information keyed in by hand via a keyboard (17). Advantages are obtained by this method in simplifying the observer's task and preparation of reports, providing automatic data transmission and therefore reducing reading and transmission errors.