# US 8,541,720 B2 · Apparatus for remotely measuring surface temperature using embedded components > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,720 B2 - Document ID: US8541720B2 - Status: Granted - Kind: B2 - Application number: 13/084,811 - Filed: 2011-04-12 - Published: 2012-10-18 - Granted: 2013-09-24 - Earliest claimed: 2011-04-12 - Assignees: Raytheon Company - Applicants: Michael S. Schwerer - Inventors: Michael S. Schwerer - Web page: https://patentgrep.com/patent/US8541720B2 ## CPC - H05B 1/0252: {Domestic applications} - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract In one embodiment, a temperature sensing apparatus includes a temperature sensor disposed in a structure at a first depth from a first surface of the structure. A heat flux sensor is also disposed in the structure at substantially the same depth as the first depth. A measurement circuit is coupled to the temperature sensor and the heat flux sensor. The measurement circuit calculates a surface temperature of the first surface based on a temperature of the temperature sensor and a heat flow of the heat flux sensor. ## Claims ### Claim 1 A temperature controlling apparatus comprising: a radome having at least a first layer, a second layer and a third layer that are disposed adjacent one another, the first layer having a first surface opposite the second layer; a temperature sensor disposed between the first layer and the second layer; a heat flux sensor, separate from the temperature sensor, disposed between the first layer and the second layer; a heater element disposed on a second surface of a third layer opposite the second layer; and a measurement circuit coupled to the temperature sensor, the heat flux sensor, and the heater element, the measurement circuit operable to: calculate an outside surface temperature of the radome based on a temperature of the temperature sensor and the heat flux of the heat flux sensor; and control the outside surface temperature of the radome by selectively applying electrical power to the heater element based on the calculated outside surface temperature. ### Claim 2 A temperature sensing apparatus comprising: a temperature sensor disposed in a structure at a first depth from a first surface of the structure; a heat flux sensor, separate from the temperature sensor, disposed in the structure at substantially the same depth as the first depth; and a measurement circuit coupled to the temperature sensor and the heat flux sensor and operable to calculate a surface temperature of the first surface based on a temperature of the temperature sensor and a heat flux of the heat flux sensor. ### Claim 3 (depends on 2) The temperature sensing apparatus of claim 2, wherein the structure comprises a first layer and a second layer, the first layer including the first surface of the structure, the temperature sensor being disposed between the first layer and the second layer and the heat flux sensor being disposed between the first layer and the second layer. ### Claim 4 (depends on 2) The temperature sensing apparatus of claim 2, wherein the structure comprises a first layer, a second layer, and a third layer, the first layer including the first surface of the structure, the temperature sensor being disposed between the second layer and the third layer and the heat flux sensor being disposed between the second layer and the third layer. ### Claim 5 (depends on 2) The temperature sensing apparatus of claim 2, wherein the measurement circuit is operable to determine the first surface temperature based on a known thermal resistance, a known thickness of any layers disposed between the temperature sensor and the first surface, and the heat flow through the layers disposed between the heat flux sensor and the first surface. ### Claim 6 (depends on 2) The temperature sensing apparatus of claim 2, wherein the structure is a radome. ### Claim 7 (depends on 6) The temperature sensing apparatus of claim 6, wherein the heat flux sensor is a transducer. ### Claim 8 (depends on 2) The temperature sensing apparatus of claim 2, further comprising a heater element disposed in the structure at a second depth from the first surface, the second depth being greater than or equal to the first depth, the measurement circuit coupled to the heater element and operable to control the surface temperature by selectively applying electrical power to the heater element using the calculated surface temperature. ### Claim 9 (depends on 8) The temperature sensing apparatus of claim 8, wherein the measurement circuit is operable to control the temperature of the first surface using a cascading control loop algorithm. ### Claim 10 (depends on 8) The temperature sensing apparatus of claim 8, wherein the measurement circuit is operable to control the temperature of the first surface using a proportional/integral/derivative (PID) control loop algorithm. ### Claim 11 (depends on 8) The temperature sensing apparatus of claim 8, wherein the measurement circuit is operable to control the temperature of the first surface using a cascading control loop algorithm and a proportional/integral/derivative (PID) control loop algorithm. ### Claim 12 A method comprising: measuring a temperature of a structure at a first depth from a first surface; measuring a heat flow of the structure, separate from measuring the temperature of the structure, at the first depth from the first surface; calculating a surface temperature of the first surface based on the temperature at the first depth from the surface and the heat flow at the first depth from the first surface. ### Claim 13 (depends on 12) The method of claim 12, wherein measuring the temperature of the structure further comprises measuring a temperature of a radome. ### Claim 14 (depends on 12) The method of claim 12, further comprising controlling the surface temperature of the first surface by applying electrical power to a heater element disposed a second depth from the first surface, the second depth being greater than or equal to the first depth. ### Claim 15 (depends on 14) The method of claim 14, wherein controlling the surface temperature of the first surface further comprises controlling the surface temperature using a proportional/integral/derivative (PID) control loop algorithm. ### Claim 16 (depends on 14) The method of claim 14, wherein controlling the surface temperature of the first surface further comprises controlling the surface temperature using a cascading control loop algorithm. ### Claim 17 (depends on 14) The method of claim 14, wherein controlling the surface temperature of the first surface further comprises controlling the surface temperature using a proportional/integral/derivative (PID) control loop algorithm and a cascading control loop algorithm control loop algorithm. ### Claim 18 (depends on 12) The method of claim 12, further comprising removing electrical power to the heater element if a heater element temperature exceeds a threshold temperature. ### Claim 19 (depends on 14) The method of claim 14, wherein applying electrical power to the heater element further comprising applying, using a silicon controlled rectifier, electrical power to the heater element at a zero crossing point. ### Claim 20 (depends on 12) The method of claim 12, wherein calculating a surface temperature of the first surface further comprises calculating the surface temperature of the first surface based on a first known thermal resistance and a first thickness of the structure at the first depth and the heat flow at the first depth from the first surface.