Automatic track insertion and display

Claim 2

A navigation computer comprising: means providing a first carrier signal X sin wt and a second carrier signal Y sin wt, the magnitudes of which are representative of X and Y coordinates of an aircraft with respect to a selected way point; storage means presenting a selected one of a plurality of designated track angles in the form of a multibit group of digital signals; a counter, the output of which is representative of track angles, said counter being advanced from a zero count to a count relating to maximum track angle during each cyclic period; means comparing the output of said storage device with the output of said counter and for generating a signal when the outputs thereof are equal, and means responsive to said compare output signal for generating a first square wave signal at the same frequency as said carrier signal but delayed in phase from sin wt by a designated track angle phi corresponding to said selected way point, and a second square wave signal at the same frequency as said carrier signals but delayed from cos wt by said angle phi ; means for combining said carrier signals with said first square wave signal to generate cross track error as X cos phi - Y sin phi ; and means for combining said carrier signals with said second square wave signal to generate along-track distance as X sin phi + Y cos phi .

Claim 3

An aircraft navigation computer according to claim 1 wherein said square wave signal generating means includes further means responsive to said compare output signal for generating signals delayed one quArter period, one half period and three quarter periods therefrom for controlling said square wave signal generating means.

Claim 4

A navigation computer comprising: means providing a pair of carrier signals the magnitudes of which are representative of orthogonal coordinates of an aircraft with respect to a selected way point; storage means presenting a selected one of a plurality of designated track angles in the form of a multibit group of digital signals; a counter, the output of which is representative of track angles, said counter being advanced from a zero count to a count relating to maximum track angle during each cyclic period; means comparing the output of said storage device with the output of said counter and for generating a signal when the outputs thereof are equal; means responsive to said compare output signal for providing square wave signals at the same frequency as said carrier signals, one of said square wave signals delayed in phase from the sine of said carrier by a designated track angle corresponding to said selected way point, and the other of said square wave signals delayed from the cosine of said carrier signals by said designated track angle; four synchronous demodulators, a first pair thereof synchronously demodulating respective ones of said coordinate carrier signals in response to one of said square wave signals, the other pair thereof synchronously demodulating respective ones of said coordinate carrier signals in response to the other of said square wave signals; and means for summing the output of each synchronous demodulator with the output of the other synchronous demodulator of the same pair, the outputs of said summing means comprising cross track error and along track distance to the way point.

Claim 5

A navigation computer comprising: means providing a pair of carrier signals the magnitudes of which are representative of orthogonal coordinates of an aircraft with respect to a selected way point; storage means presenting a selected one of a plurality of designated track angles in the form of a multibit group of digital signals; a counter, the output of which is representative of track angles, said counter being advanced from a zero count to a count relating to maximum track angle during each cyclic period; means comparing the output of said storage device with the output of said counter and for generating a signal when the outputs thereof are equal; means responsive to said compare output signal for providing square wave signals at the same frequency as said carrier signals, one of said square wave signals delayed in phase from the sine of said carrier by a designated track angle corresponding to said selected way point, and the other of said square wave signals delayed from the cosine of said carrier signals by said designated track angle; four synchronous demodulators, a first pair thereof synchronously demodulating respective ones of said coordinate carrier signals in response to one of said square wave signals, the other pair thereof synchronously demodulating respective ones of said coordinate carrier signals in response to the other of said square wave signals; and means for summing the output of each synchronous demodulator with the output of the other synchronous demodulator of the same pair, the outputs of said summing means comprising cross track error and along track distance to the way point.

Claim 6

An aircraft navigation computer according to claim 3 wherein said square wave signal generating means includes further means responsive to said compare output signal for generating signals delayed one quarter period, one half period and three quarter periods therefrom for controlling said square wave signal generating means.