Patent GB-1047693-A (GB)
Title: Wave-energy navigational systems
IPC: G01S3/14
Filed: 1963-07-05
Abstract: 1,047,693. Radio and sound navigation. TELEFUNKEN PATENTVERWERTUNGSGESELLSCHAFT m.b.H. July 5, 1963 [July 6, 1962; Sept. 19,1962], No. 26745/63. Heading H4D. In a wave-energy navigation system utilizing the transit time of the energy for determining the distance of a " position " plane F p , Fig. 1 (not shown), from the plane of symmetry F s  of two fixed points E 1 , E 2 , the product is formed of two phase quantities, one of which represents or is equivalent to the phase difference between waves following paths E 1 P, E 2 P, and the other of which represents or is equivalent to the phase difference between a reference signal and the sum of signals following the two aforementioned paths. The waves may be radio or sound energy. In the basic embodiment, Fig. 2 (not shown), from which the other embodiments are derived, E 1  and Eg are transmitters and P is a receiver at which the distance determination is effected: a generator 1, Fig. 2, at E 1  produces a signal of frequency fi which after a time delay 2#t g , corresponding to the path E 1 , E 2 , modulates a first carrier; the generator 1 output passes via a transmission line, also giving a time delay 2#t g , to modulate a transmitter 3 at E 2  on a second carrier of different frequency to that of the first. At P receivers 9, 10 are tuned to the first and second carriers respectively, and to the corresponding receiver outputs S1 1  = A<SP>1</SP> 1  cos n(t - #t g11 ), S<SP>1</SP> 2  = A<SP>1</SP> 2  cos n(t - #t g21 ) issue, where n = 2#f i  and #t g11 , #t g21  are phase angles corresponding to the paths E 1 P, E 2 P respectively. A comparator 13 is utilized to effect receiver gain control such that A<SP>1</SP> 1 #A<SP>1</SP> 2 =A<SP>1</SP>. A circuit 11 compares the phases of signals S<SP>1</SP> 1 , S<SP>1</SP> 2 , the resulting signal being multiplied (15) with the output of a phase comparator 14 the inputs to the latter being a sum signal S s =2A<SP>1</SP> cos n(t - ¢[#t g11 +#t g21 ]) and the output of a reference signal generator 19 running at frequency f 1 . The output of multiplier 15 is multiplied (16) by a factor to bring the result into convenient units of distance. In the second embodiment, Fig. 3 (not shown), the measurement is effected at E 2 , a signal A 3  cos nt is modulated on to a carrier and transmitted from P and is received at E 1  and Eg where there are receivers only, the output of the receiver at E 1  being sent via a transmission line to E 2 . If there are several transmitting points a time multiplex system is employed. In the third embodiment, Fig. 4 (not shown), the signal originates from P, there being transponders at E 1  and E 2 ; measurement is at P as in the first embodiment. In a modification the signal from P is picked up only at E 1 , re-transmitted therefrom, the re-transmission picked up at P and E 2  and re-transmitted from the latter to P. In the fourth embodiment, Fig. 5 (not shown), signals originate at E 1  and are transmitted from E 1  and Eg in phase on different carrier frequencies; the demodulated signals received at P synchronize a generator, which modulates a transmitter thereat. The latter signals are received at E 1  and measurement is effected at E 2 . In further embodiments: (i) two co-ordinates of P are derived utilizing orthogonal, Fig. 8, or oblique position planes there being two pairs of E stations or three E stations with one in common. Fig. 9 (not shown), different modulation frequencies being utilized on the same carrier frequency with appropriate modulation frequency multipliers or dividers, Fig. 10 (not shown), or transmissions on different carrier frequencies or in time multiplex, (ii) to avoid the necessity of especial phase stabilization of reference signal generators extra transmitters may be employed, Figs. 11 and 12 (not shown), (iii) the second phase difference is not formed utilizing the sum signal S s  above but from the sum of the phase differences between (a) the E 1  signal and the reference signal, (b) the E 2  signal and the reference signal.