# US 10,772,053 B2 · Background crystal oscillator calibration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,772,053 B2 - Document ID: US10772053B2 - Status: Granted - Kind: B2 - Application number: 16/402,203 - Filed: 2019-05-02 - Published: 2019-08-22 - Granted: 2020-09-08 - Earliest claimed: 2012-06-29 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Jie Wu; Daniel Fred Filipovic; Emilija Milorad Simic; Vishal Agarwal - Web page: https://patentgrep.com/patent/US10772053B2 ## CPC - H04W 56/00: Synchronisation arrangements - G01S 19/235: {Calibration of receiver components} - H03L 1/022: {by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature (H03L1/021 takes precedence)} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B) ## Abstract System and method for temperature-calibration of a crystal oscillator (XO) in a mobile device. A temperature-calibration status of the XO is determined and a trigger condition related to temperature-calibration of the XO is detected. If the temperature-calibration status of the XO is not fully temperature-calibrated or if the XO has not been previously temperature-calibrated, a temperature-calibration session is initiated by an XO manager based on the condition, wherein a receiver is configured to receive signals and temperature-calibration of the XO is performed in a background mode based on the received signals. The condition based triggering ensures that the XO is temperature-calibrated prior to launch of any position based or global navigation satellite systems (GNSS) based applications on the mobile device. The trigger condition can include first use or power-on, charging, presence in an outdoor environment, variation in operating temperature, pre-specified time, and/or user input pertaining to the mobile device. ## Claims ### Claim 1 A method of temperature-calibrating a non-temperature compensated crystal oscillator (XO) in a mobile device, the method comprising: initiating a temperature-calibration session at a powering on of the mobile device, wherein the temperature-calibration session comprises: receiving wireless signals of a known frequency; and temperature-calibrating the XO in a background mode based on the received wireless signals, in parallel with performing one or more processes unrelated to temperature-calibrating the XO in the background mode, wherein the background mode comprises a mode of operation that executes independently of position based applications or global navigation satellite systems (GNSS) based applications. ### Claim 2 (depends on 1) The method of claim 1, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source. ### Claim 3 (depends on 1) The method of claim 1, wherein the powering on of the mobile device is a first use of the mobile device. ### Claim 4 (depends on 1) The method of claim 1, further comprising updating a temperature-calibration status of the XO as completed and suppressing further temperature-calibration based on the updated temperature-calibration status. ### Claim 5 (depends on 1) The method of claim 1, further comprising recording a first time associated with temperature-calibrating the XO and if a pre-specified time has lapsed since the first time, initiating a second temperature-calibration session. ### Claim 6 (depends on 1) The method of claim 1, wherein temperature-calibrating the XO comprises formulating a frequency-temperature (FT) model based on temperature-calibrating at a plurality of temperatures. ### Claim 7 (depends on 6) The method of claim 6, wherein the temperature-calibrating further comprises determining coefficients of the FT model for the XO. ### Claim 8 (depends on 6) The method of claim 6, wherein the FT model is expressed as a polynomial function and wherein frequency is expressed as an nth degree polynomial function of temperature. ### Claim 9 (depends on 1) The method of claim 1, further comprising: detecting a variation in operating temperature of the mobile device; and initiating a second temperature-calibration session. ### Claim 10 (depends on 9) The method of claim 9, wherein the variation in operating temperature is detected over a period of time. ### Claim 11 (depends on 9) The method of claim 9, wherein the variation in operating temperature is detected based upon reaching or exceeding one or more predefined temperatures. ### Claim 12 (depends on 9) The method of claim 9, wherein the variation in operating temperature is detected based upon randomly selected temperatures. ### Claim 13 (depends on 1) The method of claim 1, wherein the temperature-calibration session is performed prior to the XO being used for global navigation satellite systems (GNSS) based applications. ### Claim 14 A mobile device comprising: a non-temperature compensated crystal oscillator (XO); a receiver; and a processor configured to initiate a temperature-calibration session at a powering on of the mobile device, wherein the temperature-calibration session is further configured to: receive wireless signals of a known frequency; and temperature-calibrate the XO in a background mode based on the received wireless signals, in parallel with performing one or more processes unrelated to temperature-calibrating the XO in the background mode, wherein the background mode comprises a mode of operation that executes independently of position based applications or global navigation satellite systems (GNSS) based applications. ### Claim 15 (depends on 14) The mobile device of claim 14, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source. ### Claim 16 (depends on 14) The mobile device of claim 14, wherein the powering on of the mobile device is a first use of the mobile device. ### Claim 17 (depends on 14) The mobile device of claim 14, further configured to: update a temperature-calibration status of the XO as completed; and suppress further temperature-calibration based on the updated temperature-calibration status. ### Claim 18 (depends on 14) The mobile device of claim 14, further configured to: record a first time associated with temperature-calibrating the XO; and if a pre-specified time has lapsed since the first time, initiate a second temperature-calibration session. ### Claim 19 (depends on 14) The mobile device of claim 14, wherein the temperature-calibration session is further configured to: formulate a frequency-temperature (FT) model based on temperature-calibrating at a plurality of temperatures. ### Claim 20 (depends on 19) The mobile device of claim 19, wherein the temperature-calibration session is further configured to determine coefficients of the FT model for the XO. ### Claim 21 (depends on 19) The mobile device of claim 19, wherein the FT model is expressed as a polynomial function and wherein frequency is expressed as an nth degree polynomial function of temperature. ### Claim 22 (depends on 14) The mobile device of claim 14, further configured to: detect a variation in operating temperature of the mobile device; and initiate a second temperature-calibration session. ### Claim 23 (depends on 22) The mobile device of claim 22, wherein the variation in operating temperature is detected over a period of time. ### Claim 24 (depends on 22) The mobile device of claim 22, wherein the variation in operating temperature is detected based upon reaching or exceeding one or more predefined temperatures. ### Claim 25 (depends on 22) The mobile device of claim 22, wherein the variation in operating temperature is detected based upon randomly selected temperatures. ### Claim 26 (depends on 14) The mobile device of claim 14, wherein the temperature-calibration session is performed prior to the XO being used for global navigation satellite systems (GNSS) based applications. ### Claim 27 A mobile device comprising: a non-temperature compensated crystal oscillator (XO); means for receiving wireless signals of a known frequency; and means for initiating a temperature-calibration session at a powering on of the mobile device, wherein the temperature-calibration session comprises: means for temperature-calibrating the XO in a background mode based on the received wireless signals, in parallel with performing one or more processes unrelated to temperature-calibrating the XO in the background mode, wherein the background mode comprises a mode of operation that executes independently of position based applications or global navigation satellite systems (GNSS) based applications. ### Claim 28 (depends on 27) The mobile device of claim 27, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source. ### Claim 29 A non-transitory computer-readable storage medium comprising code, which, when executed by a processor, causes the processor to perform operations for temperature-calibrating of a crystal oscillator (XO) in a mobile device, the non-transitory computer-readable storage medium comprising: code for initiating a temperature-calibration session at a powering on of the mobile device, wherein the temperature-calibration session comprises: code for receiving wireless signals of a known frequency; and code for temperature-calibrating the XO in a background mode based on the received wireless signals, in parallel with performing one or more processes unrelated to temperature-calibrating the XO in the background mode, wherein the background mode comprises a mode of operation that executes independently of position based applications or global navigation satellite systems (GNSS) based applications. ### Claim 30 (depends on 29) The non-transitory computer-readable storage medium of claim 29, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source.