Abstract: A collision avoidance system includes a processor configured to determine first and second positions of an intruder in first and second images, respectively, determine an angular position change of the intruder by comparing the first and second positions, determine a rate of change of a line of sight angle from an aircraft to the intruder based on the angular position change and a time between the first and second images, determine a rate of change of the angular size of the intruder based on a difference in angular size of the intruder from the first to second image and the time between the first and second images, and provide an alert to an operator of the aircraft in response to the ratio of the rate of change of the line of sight angle and the rate of change of the angular size of the intruder being less than a threshold.

Abstract: A collision avoidance system includes a processor configured to determine first and second positions of an intruder in first and second images, respectively, determine an angular position change of the intruder by comparing the first and second positions, determine a rate of change of a line of sight angle from an aircraft to the intruder based on the angular position change and a time between the first and second images, determine a rate of change of the angular size of the intruder based on a difference in angular size of the intruder from the first to second image and the time between the first and second images, and provide an alert to an operator of the aircraft in response to the ratio of the rate of change of the line of sight angle and the rate of change of the angular size of the intruder being less than a threshold.

Abstract: A system for determining the orientation of a fixture relative to the Earth includes at least one sensor configured to detect a celestial body and provide signals indicative of a plurality of positions of a detected celestial body relative to the sensor over a period of time. The system further includes a processor configured to receive information relating to a time and date associated with the period of time during which the celestial body is detected, and information relating to an expected relationship between the detected celestial body and the Earth at the time and date. The processor is further configured to determine the orientation of the fixture relative to the Earth based on signals from the at least one sensor, and the information relating to the time and date and the expected relationship between the detected celestial body and the Earth at the time and date.

Abstract: A system for determining the orientation of a fixture relative to the Earth includes at least one sensor configured to detect a celestial body and provide signals indicative of a plurality of positions of a detected celestial body relative to the sensor over a period of time. The system further includes a processor configured to receive information relating to a time and date associated with the period of time during which the celestial body is detected, and information relating to an expected relationship between the detected celestial body and the Earth at the time and date. The processor is further configured to determine the orientation of the fixture relative to the Earth based on signals from the at least one sensor, and the information relating to the time and date and the expected relationship between the detected celestial body and the Earth at the time and date.