Fixed-source array test station for calibration of a semi-active laser (SAL) seeker
First Claim
1. A test station for calibrating a semi-active laser (SAL) seeker including a SAL detector, comprising:
- a fixture for mounting the SAL seeker, said seeker having an entrance pupil to detect optical energy over a field of view (FOV) and focus the optical energy into a spot on the SAL detector;
an array of fixed collimated optical sources that generate respective temporally pulsed optical beams, said sources positioned over the FOV of the seeker and co-aligned so that their respective optical beams overlap the entrance pupil of the seeker;
a memory that stores a first source activation profile to generate a transfer function for the SAL detector, said transfer function mapping a spatial displacement Δ
X and Δ
Y in orthogonal axes of a centroid of the spot to azimuth and elevation angles for the source of the spot;
a controller responsive to the first source activation profile to activate the sources one at a time in a phase delayed manner to implement the activation profile; and
a computing device responsive to the measured spatial displacement Δ
X and Δ
Y for each source as the source is activated to create a table entry for the transfer function in a calibration table that maps the measured Δ
X and Δ
Y to the known azimuth and elevation angles of the activated source.
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Accused Products
Abstract
A fixed-source array test station provides a cost-effective high-throughput test bed for testing optical sensors that require stimulus at fixed angular positions. A SAL seeker requires stimulus at fixed angular position across its FOV to calibrate its spatial transfer function (STF). An array of fixed collimated sources at different angular positions is aligned so that their beams overlap the entrance pupil of the sensor under test. Each source may comprise an inexpensive light emitting diode (LED) or vertical cavity surface emitting laser (VCSEL) and collimator. To simplify alignment the sources may be positioned on and perpendicular to the surface of a sphere with the seeker'"'"'s entrance pupil located at the center of the sphere. The sources are activated in accordance with an activation profile in order to calibrate or otherwise test the sensor.
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Citations
17 Claims
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1. A test station for calibrating a semi-active laser (SAL) seeker including a SAL detector, comprising:
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a fixture for mounting the SAL seeker, said seeker having an entrance pupil to detect optical energy over a field of view (FOV) and focus the optical energy into a spot on the SAL detector; an array of fixed collimated optical sources that generate respective temporally pulsed optical beams, said sources positioned over the FOV of the seeker and co-aligned so that their respective optical beams overlap the entrance pupil of the seeker; a memory that stores a first source activation profile to generate a transfer function for the SAL detector, said transfer function mapping a spatial displacement Δ
X and Δ
Y in orthogonal axes of a centroid of the spot to azimuth and elevation angles for the source of the spot;a controller responsive to the first source activation profile to activate the sources one at a time in a phase delayed manner to implement the activation profile; and a computing device responsive to the measured spatial displacement Δ
X and Δ
Y for each source as the source is activated to create a table entry for the transfer function in a calibration table that maps the measured Δ
X and Δ
Y to the known azimuth and elevation angles of the activated source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A test station for calibrating a semi-active laser (SAL) seeker including a SAL detector, comprising:
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a fixture for mounting the SAL seeker, said seeker having an entrance pupil to detect optical energy over a field of view (FOV) and focus the optical energy into a spot on the SAL detector; an array of fixed collimated optical sources that generate respective temporally pulsed optical beams, said sources positioned over the FOV of the seeker on and substantially perpendicular to the surface of a sphere and co-aligned so that their respective optical beams overlap the entrance pupil of the seeker positioned at the center of the sphere, each said source comprising an LED or VCSEL that generates a pulsed diverging beam and a single optical-component that collimates the pulsed beam; a memory that stores a first source activation profile to generate a transfer function for the SAL detector, said transfer function mapping a spatial displacement Δ
X and Δ
Y in orthogonal axes of a centroid of the spot to azimuth and elevation angles for the source of the spot;a controller responsive to the first source activation profile to activate the sources one at a time in a phase delayed manner to implement the activation profile, said phase delay between activation of subsequent sources being less than 5 milliseconds; and a computing device responsive to the measured spatial displacement Δ
X and Δ
Y for each source as it is activated to create a table entry for the transfer function in a calibration table that maps the measured Δ
X and Δ
Y to the known azimuth and elevation angles of the activated source, the average time per table entry being less than 100 milliseconds.
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Specification