Patent GB-1033945-A (GB)
Title: Radio and like navigational systems
IPC: G01S1/24
Filed: 1963-03-22
Abstract: 1,033,945. Radio or sound navigation. TELEFUNKEN PATENTVERWERTUNGSGESSELLSCHAFT. March 22, 1963 [March 24, 1962; Sept. 18, 1962], No. 11426/63. Heading H4D. In a radio or sound navigation system utilizing distance measurement by wave energy transit, time, a signal is transmitted effectively at a time to from two spaced transmission points and at a receiving point P the product of (t<SP>1</SP> 1  # t<SP>1</SP> 2 ) and (t<SP>1</SP> 12  # t 0 ) is formed, where t<SP>1</SP> 1 , t<SP>1</SP> 2  are the instants of reception of the signals transmitted and t<SP>1</SP> 12  is an instant dividing the interval t<SP>1</SP> 1  # f<SP>1</SP> 2  in a predetermined ratio; an analogous system, mutatis mutandis, may be provided using a central point fed from two receiving stations and transmissions take place from point P. Preferably, the above predetermined ratio is 1:1; the loci of points P at which the aforesaid product is constant are planes parallel to a plane normal to the line joining the transmitting (or receiving) points. Two pairs of transmitting stations may be employed whereby two cartesian co-ordinates values of point P are derivable, Fig. 2. Atomic clocks may be utilized to ensure synchronism of reference pulses produced at point P with the pulses transmitted; or two pairs of transmitters may be employed whereby lack of synchronism of the reference generator at point P may be corrected, Figs. 3, 4, 5. A transmitter Eg is synchronized with the other (E 1 ) via line or radio and a delay #(t u  is introduced into transmitter E 2 , # tu  being made greater than the wave transit-time between transmitters whereby the signal from transmitter E 1  always arrives at point P before that from transmitter E 2 , Figs. 7, 8. Receiving circuits, Figs. 9, 10.-The output of receiver 7 is fed to a gate circuit 28 directly and via a delay equal to # tu  and the gate circuit inputs control a toggle 32 via an OR circuit 31. The gate circuit is controlled by a toggle 29, itself controlled by a toggle 32 and the output of a gate circuit 30 fed from reference timing mark generator 9. Gate circuit 30 is controlled by a toggle 33, the inputs to which are from an OR circuit 34 and the output of a multiplier 14. Device 11 measures the time interval between the received pulses, now corrected for effective simultaneous transmission from the transmitters E 1 , E 2 ; circuit 13 performs division-bytwo; device 10 measures the time interval between the transmission from transmitter E 2  and the " corrected " instant of reception of the transmission from transmitter E 1 ; an adder 12 is provided; and the output of multiplier 14, representing the position of the plane in which the receiving point lies, is fed to an indicator 15. A toggle 35 determines the sign of that plane relative to the plane bisecting the line connecting the transmitters and perpendicular thereto. The outline of a receiving arrangement incorporating automatic correction of the reference timing mark generator 9 is outlined, Fig. 12. The receiving arrangement, analogous to Figs. 9 and 10, for a system in which transmissions take place from point P, is described with reference to Fig. 11. Timing marking may be by pulses, rapid phase change, passing through zero or maxima of a sine oscillation, or sudden change of frequency.