Real time correction of optical window thermal gradients

Abstract

A thermal detection system for detecting a thermal profile of an optical window may be used in an airborne body that contains a sensor system. The system may include a thermal imager arranged within the airborne body for imaging a portion of the optical window and the portion may coincide with an optical path of the sensor system. The system may further include a processor in communication with the thermal imager for receiving images of the portion and determining a thermal gradient of the portion. The processor may be configured to apply corrections to active optical elements of the sensor system to accommodate for adverse thermal effects on the optical sensor that interferes with the sensor system performance.

Description

FIELD OF THE INVENTION[0001]The invention relates to a system and method for measuring the thermal profile of an airborne optical window in real-time, and more particularly to measuring the thermal profile of the window and applying corrections to an optical system to accommodate for thermal distortions of the window that impact the performance of the optical system.DESCRIPTION OF THE RELATED ART[0002]Optical windows may be used in a variety of applications, such as in defense type applications that use airborne vehicles. Examples of airborne vehicles include missiles, aircrafts, and spaceplanes, or other vehicles that may be used to execute a mission. The airborne vehicle may include a sensor system that is located within the main body of the vehicle for performing various functions. The vehicle generally includes a radome or optical window that surrounds the sensor system. The sensor performance may rely on optical rays that enter and exit through the optical window. During flight...

AI Technical Summary

Benefits of technology

The invention is a system for detecting the temperature of an optical window in an airborne body that contains a sensor system. The system includes a thermal imager that images the optical window and a processor that receives the images and converts them into a thermal gradient map. The processor then uses the thermal gradient map to apply corrections to the sensor system to account for adverse thermal effects. The system can be used in various airborne vehicles and can include a long-wave infrared sensor or a visible camera as the thermal imager. The invention helps to improve the accuracy and reliability of the sensor system in harsh environments.

Problems solved by technology

The resulting thermal gradient may change an optical index of refraction and optical absorption coefficients of the window materials such that the normal paths of the optical rays may be distorted.

Thus, the thermal distortion may cause a reduction in sensor performance and impact the normal vehicle functions.

However, using a lookup table may be disadvantageous in that the aero effects are not directly measured in real-time and the thermal gradient may not be precisely determined.

However, using thermocouples may be disadvantageous due to thermocouples reducing transparency of the optical window, causing scatter, and increasing the complexity of the window configuration.

Additionally, thermocouples are generally suited for flat-shaped windows and may be inadequate for windows having more complex and conformal geometries.

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