US2292722A - Telemetric indicator of corrected angular positions - Google Patents

Description

1942 A. STIEGLER TELEMETRIC INDICATOR 0F CORRECTED ANGULAR POSITIONS Filed Sept. 5, 1939 K r ll Siam/ms Zhwentor Zi/erlf ma /er .niecl Aug. iii, 11942 TELEME'RRIC INDICATOR F CORRECTED ANGULAR POSE'IIIQNS Albert Stiegler, Berlin-Marienfeldc, Germany,

assignor to Telefunken Gesellschaft fiir lDrahtlose Telegraphic m. To. Hit, Berlin, Germany, a corporation of Germany Application September 5, 1939, Serial No. 293,480 in Germany September 17, 1938 (Ci. 250-1l) 4 Claims.

In the installation of direction-finders, marine or aircraft, it is often desirable to mount rotatable directional antenna systems at some distance from the control point or observers station. In cases of this kind, the position of the antenna may be subject to remote control actions sent out from the observers station. In any event, the position of the antenna must be indicated at the control point. Mechanical and electrical remote control arrangements have been disclosed in the prior art and some of them have been tried out in practice.

A certain diinculty in this connection resides in the necessary compensation or correction of the deviational or quadrantal error. It is known from practice that the uncorrected radio bearing obtained from normal direction-finding requires correction because the direct radiation, coming from a beacon whence bearings are to be taken, combines with the waves reflected from the bull or other parts of the craft. The combined waves produce a directional indication which difiers from the actual beam or beacon direction by a certain quadrantal error which may either be positive or negative and which is a function of the bearin angle at a given angular position of the directional antenna. To compensate for this error, mechanical means have been suggested in the prior art in which the bearing indication means is moved so as to lag or lead the rotation of the directional antenna by angle corresponding to the quadrantal error.

In using directional antenna systems as heretofore known which are mechanically remote controlled, for instance, by means of a flexible shaft, the error correction has been applied and introduced directly at the control point. In electrical remote control such an arrangement is not well adapted because the power required'for the actuation of the radio compensator would have to be transmitted back from the remote control driving motor to the control place either mechanically or electrically.

According to the invention, all of these drawbacks are avoided in telemetric arrangements with synchronous systems in that the power required for error correction is furnished at the sendin end, and furthermore the correction consisting of a corresponding relative shift or rotation of a stator in respect to the cooperating rotor of a telemetric device such for example as a Selsyn motor. The telemetered value, as will thus be seen. is the true bearing so that at the receiving end no corrections will have to be inunited with each other.

troduced and only the power required for telemetric indication will have to be transmitted.

The invention will be described by reference to the accompanying drawing in which Figure 1 is a schematic circuit diagram of one form of telemetric device embodied in the invention, and Figures 2a and 2b are perspective views illustrating, respectively, a transmitter and receiver for transmitting and receiving the bearing indications. Similar reference numerals will be used to indicate similar elements in the several figures.

In Fig. 1 is shown an embodiment of the basicidea of the invention, a synchronous system of the kind used for telemetric work in which the stators SI and S2 of the transmitter G and the receiver E are connected delta fashion and are The rotors R1 and R2 are connected in parallel to a source of alternating potential supply. Relative rotation of the rotor in reference to the stator at the sending end, as well known in the art, will be telemetered and indicated at the receiver with angular fidelity. Now, according to the invention, the rotor of the transmitter is turned in synchronism with the directional antenna system A (see Fig. 2a) while the stator is turned in clockwise or counterclockwise direction corresponding to the quadrantal error correction value required at each specific rotor position. For instance, if the relative position of the stator and the rotor as shown in the drawing corresponds to an error 1, which,

by way of example, may be assumed to be in the the true angle p=f+q. This relative angle or position of rotor and. stator is sent to the receiver where the true bearing P will be indicated.

Fig. 2a shows a transmitter device in which a. directional antenna system A is coaxially mounted with the rotor R1 of the transmitter and the compensator cam K. By a crank lever system H the stator, as well known in the art, is turned in relation to the rotor an angle corresponding to various quadrantal errors. The relative angular position between rotor and stator is transmitted to the receiver E (Fig. 2b) with the result that rotor R2 conjointly with pointer Z is caused to turn the true bearing angle P which is indicated on the scale Sic.

It will be understood that the arrangement hereinbefore disclosed is not to be restricted to the exemplified embodiments hereinbefore described by reference to the drawing nor to the particular practical purpose herein mentioned. In fact this arrangement will be useful advantageously Wherever an ang lar position is to be telemetered or transmitted to a distant point and where there is a necessity for correcting the position as a function of an angle. It is also possible to include signal errors of the synchronized system itself in the correction or compensator curve so that these are also eliminated.

I claim as my invention:

1. A telemetric indicating system for a radio direction finder subject to quadrantal errors ,in which the transmitter and receiver each include an electromagnetic rotor and an electromagnetic stator, means for moving the rotor of the transmitter in accordance with a position to be indicated, means for moving the stator of the transmitter as a function of said quadrantal errors, and means electrically connecting the transmitter and receiver for synchronized operation of said rotors so that the rotor at the receiver indicates said position independent of said quadrantal errors. I

2. A telemetric indicating system for indicating at a remote point radio bearings subject to the quadrantal errors of a directional antenna in which the telemetric transmitter and telemetric receiver each include an electromagnetic rotor and an electromagnetic stator, means for moving the rotor of the transmitter in accordance with the position of said directional antenna, means for moving the stator of the transmitter to cor pensate for the quadrantal errors of said rectional antenna, and means electrically co meeting the transmitter and receiver for sy chronized operation of said rotors so that t rotor of said receiver indicates said bearings i dependently of said quadrantal errors.

3. A telemetric indicating system for a rat direction finder subject to quadrantal errc in which the telemetric transmitter and receiv each include an electromagnetic rotor and electromagnetic stator coaxially mounted, mea: for moving the rotor of the transmitter in a cordance with a position to be indicated, meal including a compensating cam for moving t] stator of the transmitter as a function of sa quadrantal errors, and means electrically COl necting the transmitter and receiver for syi chronized operation of said rotors to indicate 1 said receiver said position free from said quar rantal errors.

4. A telemetric indicating system for apparat1 subject to periodically repeated errors in whir the transmitter and receiver of said system eac include an electromagnetic rotor and an electr magnetic stator, means for moving the rotor 1 the transmitter in accordance with the ind cation to be transmitted, means for moving ti stator of the transmitter as a function of sai periodically repeated errors, and means eler trically connecting the transmitter and receiv for synchronized operation of said rotors so th: the rotor at the receiver gives the proper ind: cation independent of said periodically repeate errors.

ALBERT STIEGLER.

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