Normalization circuit for position locator

Claim 2

Position locator apparatus comprising; means for providing a distance signal indicative of distance traveled; means for generating first and second heading signals related to the direCtion traveled, said first and second heading signals being subject to deviations of the Earth''s magnetic field; reference means for providing a predetermined reference signal in relation to some initial value of said first and second heading signals; means for providing a resultant signal related to the magnitude of the Earth''s magnetic field at the locator position; means for providing an error signal related to the difference between said reference signal and said resultant signal; and means for multiplying said distance signal with said error signal and with each said first and second heading signals to provide output signals which are indicative of the distance traversed in the direction traveled, said error signal reducing the effect of said deviations in the Earth''s magnetic field on said output signals.

Claim 3

The apparatus of claim 1 including adjusting means operable to adjust the magnitude of said resultant signal substantially to the magnitude of said reference signal.

Claim 4

The apparatus of claim 1 wherein said means for providing said resultant signal includes square means for squaring said first and second heading signals, summing means for adding together said squared signals and for providing a sum signal equal to the sum of said squared signals, and means for taking the square root of said sum signal.

Claim 5

The apparatus of claim 1 wherein the means for providing said error signal includes a conversion circuit means having a voltage controlled frequency generator means having an input and an output, said frequency generator means producing a variable frequency at its output in response to a variable signal at its input.

Claim 6

The apparatus of claim 4 wherein said conversion circuit means further includes a comparison circuit for obtaining a signal equal to the difference between said reference signal and said resultant signal and wherein the variable signal input to said frequency generator means is a function of said difference signal.

Claim 7

The apparatus of claim 5 wherein said variable signal is a variable voltage and said voltage controlled frequency generator includes a voltage controlled oscillator, the output frequency of said voltage controlled oscillator being variable in response to said variable voltage.

Claim 8

A circuit for receiving component signals derived from a parameter subject to deviations, said component signals being subject to said deviations, the improvement comprising; means responsive to said component signals for providing a resultant signal indicative of the magnitude of said parameter; reference means for providing a reference signal; adjustment means for establishing a predetermined relationship between the magnitude of said resultant signal and said reference signal by initially adjusting at least one of them; conversion means having input means and output means; means for conducting said resultant signal and said reference signal to said input means, said output means being operative to provide an error signal indicative of the magnitude of said deviations as the magnitude of said resultant signal changes from the magnitude which provided said predetermined relationship; and conducting means for conducting said error signal to signal receiving means for comparison with said component signals.

Claim 9

A circuit for receiving component signals derived from a parameter subject to deviations, said component signals being subject to said deviations, the improvement comprising; means responsive to said component signals for providing a resultant signal indicative of the magnitude of said parameter; reference means for providing a reference signal; adjustment means for establishing a predetermined relationship between the magnitude of said resultant signal and said reference signal by initially adjusting at least one of them; conversion means having input means and output means; means for conducting said resultant signal and said reference signal to said input means, said output means being operative to provide an error signal indicative of the magnitude of said deviations as the magnitude of said resultant signal changes from the magnitude which provided said predetermined relationship; and conducting means for conducting said error signal to signal receiving means for comparison with said component signals.

Claim 10

The circuit of claim 7 wherein the input means of said conversion means includes a difference circuit for comparing the magnitude of said resultant signal with the magnitude of said reference signal and for producing an output signal indicative of the difference between said resultant signal and said reference signal.

Claim 11

The circuit of claim 8 wherein the output means of said conversion means includes a variable frequency generator, the output frequency of said generator being controlled by the output signal of said difference circuit of said conversion means.

Claim 12

The circuit of claim 9 wherein said output means includes nominal voltage means for providing a predetermined nominal voltage and wherEin said variable frequency generator includes a voltage controlled oscillator operable to provide a nominal frequency output, said predetermined nominal voltage being conducted to said voltage controlled oscillator to cause said voltage controlled oscillator to provide said nominal frequency output whenever the magnitude of said resultant signal is substantially equal to the magnitude of said reference signal.

Claim 13

The circuit of claim 7 wherein the output means of said conversion means is operable to provide a predetermined signal when said adjustment means establishes said predetermined relationship between said resultant signal and said reference signal.

Claim 14

The circuit of claim 7 wherein said predetermined relationship is established when said adjustment means adjusts the magnitude of said resultant signal such that it is substantially equal to the magnitude of said reference signal.