Horizon sensor

Claim 2

A horizon sensor comprising, in combination: an infrared detector for producing an output signal in response to radiant energy input thereto; means for scanning said infrared detector across a spatial region which includes at least one radiant body; a high-pass amplifier having at least one input and an output, one of said inputs being coupled to the output of said infrared detector, said amplifier having a response characteristic sensitive to the rate-of-change of the detector output signal at a crossing of a horizon of a radiant body and substantially insensitive to gradual changes through a scan across said radiant body; first means coupled to said amplifier output for generating output pulses of substantially constant amplitude during the time interval wherein said amplifier output signals exceed a reference level; second means coupled to said first means for transmitting at least a portion of those output pulses corresponding to horizon crossings of a preselected radiant body; third means coupled to the output of said amplifier for selecting and holding the peak amplitude of the output signals of said high-pass amplifier corresponding to horizon crossings of said preselected radiant body; fourth means responsive to said peak amplitude for setting a fixed ratio between said reference level and the peak amplitude of the output signals of said high-pass amplifier corresponding to said preselected radiant body; and fifth means for coupling the transmitted output pulses from said second means to a utilization device.

Claim 3

A horizon sensor according to claim 1 wherein said first means comprises a comparator for generating output pulses of substantially constant amplitude during the time interval wherein said amplifier output signals exceed a reference level.

Claim 4

A horizon sensor according to claim 2 wherein said second means comprises a pulse width discriminator, said pulse width disCriminator being of the type which transmits only those portions of said output pulses exceeding a specified width.

Claim 5

A horizon sensor according to claim 3 wherein said third means comprises: a peak detector having at least one input and an output, one of said inputs being coupled to the output of said amplifier, said peak detector being set and reset by the output signal of said comparator; and a normally open switch having an input and an output, said input being coupled to the output of said peak detector, said switch being responsive to the output signal of said pulse width discriminator.

Claim 6

A horizon sensor according to claim 4 wherein said fourth means comprises: means for controlling the gain of said high-pass amplifier; and an integrator having an input and an output, said input and output coupled respectively to the output of said switch and said gain control means.

Claim 7

A horizon sensor comprising, in combination: an infrared detector for producing an output signal in response to radiant energy input thereto; means for scanning said infrared detector across a spatial region which includes at least one radiant body; a high-pass amplifier having at least one input, output, and gain control port, said input being coupled to the output of said detector, said amplifier further having a response frequency corresponding to the rate-of-change of the output signal of said detector at a horizon crossing but being too short to respond to gradual changes in said signal through a scan across a radiant body; a comparator having at least one input and output, said input being coupled to the output of said amplifier, said comparator further generating a constant magnitude output pulse during the time interval wherein said amplifier output signals exceed a specified reference level; a pulse width discriminator having at least one input and output, said input being coupled to the output of said comparator, said pulse width discriminator transmitting only those portions of said output pulses exceeding a specified width; a negative voltage of amplitude twice the reference level; first means coupled to the output of said amplifier for additively combining said negative voltage and the output signal of said amplifier to form a composite signal; a peak detector having at least one input and an output; second means for coupling said composite signal to the input of said peak detector, said peak detector further detecting and holding the peak amplitude of an applied input signal during the the time interval wherein a pulse is present at the output of said comparator; a normally open switch having at least one input and an output, said input being coupled to the output of said peak detector, said switch being responsive to an output signal of said pulse width discriminator; an integrator having an input and an output, said input and output being coupled respectively to the output of said switch and the gain control port of said amplifier, said integrator developing a gain correction voltage, said correction voltage being applied to said gain control port to set a fixed ratio between the magnitude of the reference level and the peak magnitude of an output signal from said switch; and third means for coupling the transmitted output pulses from said second means to a utilization device.

Claim 8

A horizon sensor comprising, in combination: an infrared detector for producing an output signal in response to radiant energy input thereto; means for scanning said infrared detector across a spatial region which includes at least one radiant body; a high-pass amplifier having at least one input, output, and gain control port, said input being coupled to the output of said detector, said amplifier further having a response frequency corresponding to the rate-of-change of the output signal of said detector at a horizon crossing but being too short to respond to gradual changes in said signal through a scan across a radiant body; a comparator having at least one input and output, said input being coupled to the output of said amplifier, said comparator further generating a constant magnitude output pulse during the time interval wherein said amplifier output signals exceed a specified reference level; a pulse width discriminator having at least one input and output, said input being coupled to the output of said comparator, said pulse width discriminator transmitting only those portions of said output pulses exceeding a specified width; a negative voltage of amplitude twice the reference level; first means coupled to the output of said amplifier for additively combining said negative voltage and the output signal of said amplifier to form a composite signal; a peak detector having at least one input and an output; second means for coupling said composite signal to the input of said peak detector, said peak detector further detecting and holding the peak amplitude of an applied input signal during the the time interval wherein a pulse is present at the output of said comparator; a normally open switch having at least one input and an output, said input being coupled to the output of said peak detector, said switch being responsive to an output signal of said pulse width discriminator; an integrator having an input and an output, said input and output being coupled respectively to the output of said switch and the gain control port of said amplifier, said integrator developing a gain correction voltage, said correction voltage being applied to said gain control port to set a fixed ratio between the magnitude of the reference level and the peak magnitude of an output signal from said switch; and third means for coupling the transmitted output pulses from said second means to a utilization device.