Abstract A heading indicator for power-driven units, especially land vehicles, is disclosed which comprises a rate gyro, an integrator controlled by the gyro and a comparator for generating an output signal proportional to the difference between the instantaneous value of azimuthal information from the integrator and a corresponding information from a magnetic course transmitter. The output signal is supplied to a circuit controlling the integrator so as to correct its output azimuthal information in response to said difference. The control circuit comprises a low-pass filter for removing from the output signal of the comparator highfrequency spurious signals. The limiting frequency of the filter is variable in response to the ground speed of the vehicle in the way that the limiting frequency is increased upon an increase in ground speed.
A heading indicator comprising a rate gyro, an integrator controlled by the gyro and a comparator generating an output signal proportional to the difference between the azimuthal information supplied from the integrator and from a magnetic heading transmitter, the output signal being delivered to a control circuit of the integrator so as to correct its output azimuthal information signal in response to said difference, the control circuit also comprising means acting as a low-pass filter for removing from the output signal of the comparator highfrequency spurious components therein, the limiting frequency of the filter being variable in response to the ground speed of the vehicle so that an increase in speed is accompanied by an increased limiting frequency.
Claim 2
Dependent Claim
118 words
A heading indicator comprising a rate gyro, an integrator controlled by the gyro and a comparator generating an output signal proportional to the difference between the azimuthal information supplied from the integrator and from a magnetic heading transmitter, the output signal being delivered to a control circuit of the integrator so as to correct its output azimuthal information signal in response to said difference, the control circuit also comprising means acting as a low-pass filter for removing from the output signal of the comparator highfrequency spurious components therein, the limiting frequency of the filter being variable in response to the ground speed of the vehicle so that an increase in speed is accompanied by an increased limiting frequency.
Claim 3
Dependent Claim
35 words
A heading indicator as claimed in claim 1, wherein the means acting as a low-pass filter comprises a means which provides a limiting frequency which is variable as a linear function of the vehicle speed.
Claim 4
Dependent Claim
29 words
A heading indicator as claimed in claim 1 wherein said control circuit comprises means for blocking the comparator control circuit when the vehicle speed drops below a predetermined value.
Claim 5
Dependent Claim
15 words
A heading indicator as claimed in claim 1, wherein the integrator comprises a mechanical servo.
Claim 6
Dependent Claim
21 words
A heading indicator as claimed in claim 4, the rate gyro unit is mounted on the heading shaft of the servo.
Claim 7
Dependent Claim
29 words
A heading indicator as claimed in claim 4 wherein the comparator comprises a synchro mounted on the heading shaft of the servo, the magnetic heading transmitter being separately mounted.