The factors of temperature characteristic of detectivity and background are not described in detail in the traditional operating distance of the infrared system.In this paper,operating distance equation is corrected.A new operating distance equation of infrared point target detect system has been derived from considering physical characteristic of detectivity and introducing correcting factor of wave band detectivity.A mathematics model was advanced as theoretical basis for the system design and performance evaluation.

Operating Distance Equation for Infrared Point Target Detect System Based on Temperature Characteristic of Detectivity and Background Influence

The Space Infrared Telescope Facility (SIRTF) is a space-borne astronomical near-infrared to submillimeter telescope. Because of its high sensitivity, SIRTF will significantly increase observational capability over what is currently available. SIRTF is being developed by NASA to fly in the mid 90's. It will be carried to orbit by the Space Transportation System and placed in its final orbit by the Orbiting Maneuvering Vehicle.

SIRTF, A Cryogenically Cooled IR Telescope

The operating frequency of the networked control system (NCS) determines both its control performance and heat flux density. Considering the significant effect of thermal stress on the reliability of electronics, a quantitative reliability analysis framework is proposed for NCSs with the consideration of its operating frequency. It includes 5 main steps: 1) compute the power consumption of all its electronic components using circuit simulation; 2) obtain the thermal stress of these components by thermal simulation; 3) apply the thermal stress results to assess the reliability of components using the part stress analysis method; 4) calculate the reliability of the modules using reliability block diagrams; and 5) quantify the reliability of the NCS by combining the graph reduction method and other network reliability algorithms together. A double loop networked control system is used as an example to verify the effectiveness of our method.

Reliability Analysis of Networked Control Systems with the Consideration of Operating Frequency

In research fields such as infrared astronomical observation and space fragments distribution analysis etc, the first and
possibly the most critical evaluation parameter of interest is detection sensitivity. Without adequate detection sensitivity,
it is impossible for infrared detector to detect the target at a distance great enough and play the role of terminal detector
of background. Although cryogenic optical system can be employed for the aim of increasing detection sensitivity up to
the possible maximum extent, research on detection characteristics test method for infrared detector in low temperature
background must be undertaken primarily before the cryogenic optical system is designed and manufactured. In this
paper, some of the fundamentals of detection characteristics test method are presented, and a set of experimental
apparatus is designed and established. Based on this apparatus and by employing an extend plane source blackbody, the
general rule of detection characteristics of infrared detector from normal temperature background to low temperature
background are investigated. The voltage-output signals of every pixel are continuously acquisitioned for F (≥100)
frames under two different blackbody temperatures, and as a result we obtain the evolving regularity of different
performance index, e.g. limiting integration time and detectivity D * . The measurement results reported in the paper
confirm that the integration time can be improved by a large margin in comparison with normal temperature background,
and the specific detecivity D * has the same variation tendency, which can be increased up to one order of magnitude.

Wei Zhang

Papers

Research on detection characteristics test method for infrared detector in low temperature background