# US 11,994,464 B2 · Analog signal processing for a lightweight and compact laser-based trace gas sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,464 B2 - Document ID: US11994464B2 - Status: Granted - Kind: B2 - Application number: 17/601,538 - Filed: 2020-04-01 - Published: 2022-06-09 - Granted: 2024-05-28 - Earliest claimed: 2019-04-05 - Assignees: SeekOps Inc. - Applicants: SeekOps Inc. - Inventors: Victor Alexander Miller, II; Brendan James Smith - Web page: https://patentgrep.com/patent/US11994464B2 ## CPC - G01N 21/39: using tunable lasers - G01C 21/20: Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence) - G01J 3/0264: {Electrical interface; User interface} - G01J 3/28: Investigating the spectrum (using colour filters G01J3/51) - G01J 3/42: Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry (beam switching arrangements G01J3/08) - G01M 3/04: by detecting the presence of fluid at the leakage point - G01S 19/01: Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO - G01N 2201/0221: Portable; cableless; compact; hand-held - G01N 2201/12: Circuits of general importance; Signal processing - G01N 2201/125: Digital circuitry - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - 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 ## Abstract Systems, devices, and methods for a trace-gas sensor configured to generate a raw detector signal (118) based on a gas sample; an analog processing configured to filter, amplify, lock-in, and/or normalize the generated raw detector signal; analog to digital converters configured to convert the filtered and amplified detector signal to a digital signal; and a drive computer configured to: receive the converted digital signal from the analog to digital converters; and apply a spectroscopic model to the received digital signal to extract one or more properties of the gas sample. ## Claims ### Claim 1 A method comprising: generating, by a trace-gas sensor, a raw detector signal based on detecting a trace gas in a gas sample; locking-in, by an analog processing module, the detector signal to generate a locked-in detector signal; normalizing, by the analog processing module, the locked-in detector signal to generate a normalized detector signal; converting the normalized detector signal to a digital signal; and extracting one or more properties of the gas sample based on the digital signal. ### Claim 2 (depends on 1) The method of claim 1, wherein the raw detector signal is modulated. ### Claim 3 (depends on 1) The method of claim 1, wherein the raw detector signal is unmodulated. ### Claim 4 (depends on 1) The method of claim 1 further comprising: generating a laser drive signal by a waveform generator, wherein the trace-gas sensor utilizes the laser drive signal for detecting the trace gas. ### Claim 5 (depends on 1) The method of claim 1 further comprising, prior to locking-in the generated raw detector signal: filtering, by the analog processing module, the raw detector signal. ### Claim 6 (depends on 1) The method of claim 1, wherein normalizing the locked-in detector signal further comprises: normalizing the locked-in detector signal based on changes in at least one of: an average magnitude of the raw detector signal and an overall magnitude of the raw detector signal. ### Claim 7 (depends on 1) The method of claim 1, wherein locking-in the detector signal further comprises: locking-in the detector signal based on a reference signal; and tuning based on a phase of the reference signal. ### Claim 8 (depends on 1) The method of claim 1, wherein locking-in the detector signal further comprises: locking-in the detector signal utilizing an analog lock-in amplifier, and tuning based on a width of a low pass filter. ### Claim 9 (depends on 1) The method of claim 1, wherein locking-in the detector signal further comprises utilizing an analog lock-in amplifier and the tuning the lock-in amplifier by a waveform generator. ### Claim 10 (depends on 1) The method of claim 1, wherein extracting one or more properties of the gas sample further comprises: applying a spectroscopic model to the digital signal to extract one or more properties of the gas sample. ### Claim 11 (depends on 1) The method of claim 1, wherein normalizing the locked-in detector signal further comprises: normalizing the locked-in detector signal based on the raw detector signal to generate the normalized detector signal. ### Claim 12 A system comprising: a trace-gas sensor configured to generate a raw detector signal based on detecting a gas sample; an analog lock-in amplifier configured to: lock-in the detector signal to generate a locked-in detector signal; an analog normalizer configured to normalize the locked-in detector signal to generate a normalized detector signal; an analog to digital converter configured to convert the normalized detector signal to a digital signal; and a driver configured to extract one or more properties of the gas sample based on the digital signal. ### Claim 13 (depends on 12) The system of claim 12, wherein the raw detector signal is at least one of: modulated and unmodulated. ### Claim 14 (depends on 12) The system of claim 12, wherein the driver is configured to apply a spectroscopic model to the digital signal to extract one or more properties of the gas sample. ### Claim 15 (depends on 12) The system of claim 12, wherein: the trace-gas sensor comprises a laser trace-gas sensor; and wherein the system further comprises: an analog filter configured to filter the raw detector signal to generate a filtered signal; a plurality of analog lock-in amplifiers, wherein each analog lock-in amplifier is configured to lock-in the filtered signal based on a respective reference signal and generate a locked-in signal; a plurality of analog normalization blocks, wherein each analog normalization block is configured to receive one or more locked-in signals and generate an analog normalized signal; a plurality of analog to digital converters, wherein each analog to digital converter is configured to convert an analog normalized signal to a digital normalized signal; and the driver comprises a drive computer configured to receive multiple digital normalized signals and extract one or more properties of the gas sample based on the digital normalized signals. ### Claim 16 A system comprising: an aerial vehicle comprising: a trace-gas sensor configured to generate a raw detector signal based on detecting a gas sample; an analog lock-in amplifier configured to: lock-in the detector signal to generate a locked-in detector signal; an analog normalizer configured to normalize the locked-in detector signal to generate a normalized detector signal; an analog to digital converter configured to convert the normalized detector signal to a digital signal; and a driver configured to extract one or more properties of the gas sample based on the digital signal. ### Claim 17 (depends on 16) The system of claim 16, wherein the aerial vehicle further comprises: a global positioning system (GPS) configured to determine a position of the aerial vehicle and the detected gas sample. ### Claim 18 (depends on 16) The system of claim 16, wherein the raw detector signal is at least one of: modulated and unmodulated. ### Claim 19 (depends on 16) The system of claim 16, wherein the driver is configured to apply a spectroscopic model to the digital signal to extract one or more properties of the gas sample. ### Claim 20 (depends on 16) The system of claim 16, wherein: the trace-gas sensor comprises a laser trace-gas sensor; and wherein the aerial vehicle further comprises: an analog filter configured to filter the raw detector signal to generate a filtered signal; a plurality of analog lock-in amplifiers, wherein each analog lock-in amplifier is configured to lock-in the filtered signal based on a respective reference signal and generate a locked-in signal; a plurality of analog normalization blocks, wherein each analog normalization block is configured to receive one or more locked-in signals and generate an analog normalized signal; a plurality of analog to digital converters, wherein each analog to digital converter is configured to convert an analog normalized signal to a digital normalized signal; and the driver comprises a drive computer configured to receive multiple digital normalized signals and extract one or more properties of the gas sample based on the digital normalized signals.