Patent GB-1052929-A (GB)
IPC: G01S5/10
Abstract: 1,052,929. Electric analog calculating. COMPUTING DEVICES OF CANADA Ltd. Nov. 8, 1963 [Aug. 1, 1963], No. 44081/63. Heading G4G. Apparatus for hyperbolically navigating a mobile craft receives a pair of analog inputs representing pathlength differences from the craft to first and second pairs of geographic reference points, and comprises manual setting means providing a pair of analog inputs representing cartesian co-ordinates of an origin of a first cartesian axis system located midway between the first pair of reference points, with respect to a second cartesian axis system having a first axis joining the second pair of reference points and a second axis the right bisector of the first; manual setting means providing an analog input of the angle between the lines joining the respective pairs of reference points; and a pair of manual setting means providing analog inputs representing the semi-basal distances of the respective pairs of reference points; together with electric analog computing means responsive to all such analog inputs conjointly to indicate the geographic position of the craft referred to at least one of the cartesian axis systems. In Fig. 2, a pair of slave transmitting stations G, R co-operating with a single master station M in a navigational system define a pair of families of hyperbolµ having foci G, M and R, M respectively; GM defining the X axis of a pair of cartesian co-ordinates axes X, Y of orgin O between G and M while MR defines the X<1> axis of a pair of cartesian axes X<1>, Y<1> of origin O<1> between M and R ; the axes being displaced by angle #. A further pair of cartesian co-ordinate axes X<11>, Y<11> have origin O<11> coincident with O and are respectively parallel with X<1>, Y<1>. The X<11> axis intercepts m on the Y<1> axis and the Y<11> axis intercepts l on the X<1> axis; the origin O having coordinates l, m in the X<1>Y<1> system and the quantities l, m, # are defined by the positions of stations M, G, R. The position p of a craft is on hyperbola A having intercept distance a on the XY co-ordinates and on an intersecting hyperbola B having intercept distance a1 on the X<1>Y<1> co-ordinates; analogs of the numbers being continuously derived from known navigational apparatus into which the semi-basal distances F of stations G, M and R, M and the angle # of the two X axes have been manually inserted. The intercepts a, a1 &c. may designate intersecting hyperbolic lanes ofthe navigational system. For hyperbolµ A and B' referred respectively to the X, Y and X<1>. Y<1> axes it is shown mathematically that which are soluble explicitly for (X,Y)p and (X<1>,Y<1>)p the cartesian co-ordinates of the craft position on the X, Y; X<1>, Y<1> axes by the electric analog computing apparatus shown in Fig. 3, wherein the outputs 40 and 41 yield analog solutions for the corresponding co-ordinates of point p. It is also shown by mathematics that where X<11>p, Yp are the co-ordinates of p on the (X<11>, Y<11>) axes and that The known navigational apparatus 10, 11 responsive to signals at the craft p from stations G and M, M and R yield electrical analogue information of the intercept distances a, a1 of hyperbole A and B; the intercept distances identifying particular hyperbolic curves of a family thereof drawn for a pair of predetermined stations, and the analogs being fed to computing elements 12, 13 of chains 1, 2 (Fig. 3) also receiving the electrical analogues of parameters Yp (from the output of chain 2), F (by manual adjustment), Y<1>p (from the output of chain 1) and F1 (by manual adjustment). Element 1-2 (Fig. 4) receives electrical analogs of F and a in function generator 14 producing the analog of function which is fed to multiplier 15 also receiving the analog of Yp from output 40 of chain 2 to produce the analog of energizing primary 18 of a biphase induction resolver whose other primary orthogonal to the first is energized by a unity signal. The orthogonal secondaries 19, 21 are rotatable relative to the primaries, and 19 produces the analog signal to energize a multiplier 24 also energized by the analog signal of a to produce an output signal analogous to Xp (Equation 1). The remaining secondary 21 energizes amplifier 22 and servomotor 23 rotating the secondaries, until 21 produces null voltage. A similar arrangement in computing element 13 produces the analog signal of X<1>p in response to inputs a, F, and Y<1>p (Equation 2). A further biphase resolver in element 25 receives analog signals Xp and Yp to energize its orthogonal primaries 31, 32 (Fig. 5), and orthogonal secondaries 33, 34 are manually adjusted to angle # to produce the analog signals X<11>p, Y<11>p (Equations 3, 4) which are applied to addition/subtraction element 37 (Fig. 6, not shown) together with manually inset analog signals representing - l, - m to produce at equilibrium the analog signals X<1>p, Y<1>p at output 41 (Equations 7, 8). A similar device in element 36 receives analog signals X<1>p, Y<1>p from 13 and +l, +m manually inset to produce analog signals X<11>p, Y<11>p which energize computing element 26, which comprises a biphase resolver as shown in Fig. 5 also receiving the analog signal of - 0 manually inset to compute at equilibrium the analog signals of Xp, Yp at output 40 (Equations 5, 6). The system is continuously responsive to varying values of a and a1 as the craft moves over the field of the navigational system in cooperation with the prescribed pair of stations, but on changing to operation with a new pair of stations, new values of F, F1, #, l and m must be manually inset. In a modification (Figs. a 7. 8, not shown) where Q = -- F and an electric analog of variable a is supplied from navigational apparatus 10 to a function generator, wherein a tap energized from a is servodriven over a potentiometer centre tapped to earth and energized by the analog signal of F. A similar potentiometer energized from a reference voltage has a tap driven with that of the first potentiometer to produce the analog signal of Q at equilibrium; the analog signal of a being then equated to a fraction of the analog signal of F. The Q signal is then fed into element 14 as in Fig. 4 and the required output is derived from the winding 19 without interposition of multiplier 24.