Monitored background radiometer
AssigneeSpar Aerospace Limited
InventorChristian Ruel
Life of this patent
Estimating the term…
Abstract
This radiometer accurately measures IR and solar spectrum radiation in a vacuum, and accounts for radiation loss from its sensing plate by measuring the housing temperature. Calibration is performed by measuring the temperature of the sensing plate and housing while power to a heater attached to the sensing plate is varied. The square of the difference between the measured power dissipation of the heater and the heat absorbed by the sensing plate as determined from the heat balance equation of the sensing plate is minimized to obtain calibration factors for the heat balance equation.
Claims10
A monitored background radiometer comprising:
- a thermally conductive housing;
- low conductivity support means mounted on the housing;
- a sensing plate mounted on the low conductivity support means and spaced from the housing so as to be thermally insulated from the housing and having an outwardly facing first surface;
- the sensing plate being disposed relative to the housing to receive direct electromagnetic radiation from sources exterior to the radiometer upon said first surface only;
- means for controllably heating the sensing plate;
- first temperature sensitive means to measure the temperature of the housing;
- and
- second temperature sensitive means to measure the temperature of the sensing plate, so that the heat flux at the sensing plate may be determined from the temperatures of the housing and sensing plate after calibration of the radiometer by measuring the temperatures of the housing and sensing plate while controllably heating the sensing plate.
A method of measuring the amount of radiation absorbed by a body in a vacuum, said body being disposed in and thermally insulated from a thermally conductive housing and said body having heating means with a controllable power source coupled to said body, comprising calibrating the body and housing by;
- (a) energizing said heating means with said controllable power source at a plurality of different power levels in the absence of any of said radiation to simulate the radiative heat loads absorbed by the body during actual measurement of the heat absorbed by the body;
- (b) measuring the temperature of the body and the housing as a function of time for each power level;
- (c) determining the relationship between said power levels and said temperatures measured in step (b) so as to relate known heat aborption by the body to known temperatures of the body and housing;
- and subsequently measuring the heat absorbed by the body by;
- (d) measuring the temperatures of said body and said housing when said radiation is incident upon said body;
- and
- (e) determining the amount of the radiation absorbed by the body by relating the temperatures of said body and said housing as determined in step (d) to the corresponding power level determined in step (c).
Dependencies are inferred from the claim text.