# US 9,519,052 B2 · Distance measuring device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,519,052 B2 - Document ID: US9519052B2 - Status: Granted - Kind: B2 - Application number: 15/045,730 - Filed: 2016-02-17 - Published: 2016-08-11 - Granted: 2016-12-13 - Earliest claimed: 2014-04-29 - Assignees: Trimble Inc. - Applicants: Trimble AB - Inventors: Yuri P. Gusev - Web page: https://patentgrep.com/patent/US9519052B2 ## CPC - G01S 7/4865: Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) - G01C 3/08: Use of electric radiation detectors - G01C 15/002: {Active optical surveying means (optical plumbing G01C15/105)} - G01S 7/489: Gain of receiver varied automatically during pulse-recurrence period - G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - 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 - 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) ## Abstract An optical device is disclosed that may be employed in distance measuring devices. In at least one embodiment, the optical device includes a control unit that is adapted to cause at least one control signal generator unit to generate at least one control signal according to a predetermined temporal function on the basis of an elapsed time from a predetermined point in time. On the basis of the generated at least one control signal, at least one parameter of a receiver unit may be adjusted during the travel time of the optical pulse, wherein the at least one parameter affects the dynamic range of the receiver unit. In this way, the dynamic range of the receiver unit may be increased. A method is further disclosed for operating such an optical device, along with a distance measuring device including such an optical device and a surveying instrument including such a distance measuring device. ## Claims ### Claim 1 An optical device including: an optical radiation source configured to emit optical pulses; a receiver configured to receive reflected optical pulses; a time-measuring unit configured to generate an elapsed time from a point in time related to emission of an optical pulse from the optical radiation source; at least one control signal generator unit configured to generate at least one control signal according to a temporal function on a basis of the elapsed time; and a control unit configured to adjust at least one parameter of said receiver affecting the dynamic range of said receiver based on the generated at least one control signal, wherein the temporal function is configured such that the temporal function at least partly includes a shape that is determined on a basis of parameters of an optical system of the optical device. ### Claim 2 (depends on 1) The optical device of claim 1, wherein the optical system is an optical system configured to collimate the emitted optical pulses into a beam. ### Claim 3 (depends on 1) The optical device of claim 1, wherein the optical system includes at least one of one or more lens elements, prisms, wave guides and mirror elements. ### Claim 4 (depends on 1) The optical device of claim 1, wherein the control unit is configured to adjust said at least one parameter during a travel time of an optical pulse from the optical device to a target and back. ### Claim 5 (depends on 1) The optical device of claim 1, wherein the control unit is configured to adjust said at least one parameter until another pulse is emitted from the optical radiation source. ### Claim 6 (depends on 1) The optical device of claim 1, wherein the receiver includes a photodetector unit configured to generate electrical return signals from said reflected optical pulses, said at least one parameter including the optical responsivity of the photodetector unit. ### Claim 7 (depends on 1) The optical device of claim 1, wherein said receiver further comprises at least one of: a variable attenuator unit configured to attenuate electrical return signals generated from said reflected optical pulses by a photodetector unit, and a variable optical attenuator unit configured to attenuate said reflected optical pulses, wherein said at least one parameter includes the attenuation of at least one of said variable attenuator unit and the attenuation of said variable optical attenuator unit. ### Claim 8 (depends on 1) The optical device of claim 1, wherein said point in time is a point in time when the optical pulse is emitted, or wherein said point in time is a point in time when an optical reference pulse is received at the receiver, said optical reference pulse being emitted concurrently with or in connection to emission of the optical pulse from the optical radiation source. ### Claim 9 (depends on 1) The optical device of claim 1, wherein the receiver includes a variable gain amplifier unit configured to amplify electrical return signals generated from said reflected optical pulses by a photodetector unit, wherein said at least one parameter includes the gain of said variable gain amplifier unit. ### Claim 10 (depends on 1) The optical device of claim 1, wherein said control unit is further configured to, if the elapsed time exceeds a maximum elapsed time, reset said time-measuring unit. ### Claim 11 (depends on 10) The optical device of claim 10, wherein the maximum elapsed time is set on the basis of the maximum measurable travelling time of the at least one optical pulse from the point in time. ### Claim 12 (depends on 1) The optical device of claim 1, wherein the temporal function at least partly includes a shape matching or approximating at least one of an estimated function of the received optical power versus the elapsed time for said optical pulse and an inverse of said estimated function. ### Claim 13 (depends on 1) The optical device of claim 1, wherein the temporal function at least partly includes a shape matching or approximating at least one of an estimated function of the received optical power versus the elapsed time for an optical pulse reflected from a target having a substantially constant albedo, and an inverse of said estimated function. ### Claim 14 (depends on 1) The optical device of claim 1, wherein the temporal function at least partly includes a shape according to a step function, a polynomial function, a linear function, a quadratic function, a rectangular function, an exponentially decaying function, or any combination thereof. ### Claim 15 (depends on 1) The optical device of claim 1, wherein the control signal generator unit comprises a memory unit configured to store data, and the control signal generator unit is configured to generate control signals by retrieving control signal values previously stored in the memory unit. ### Claim 16 (depends on 1) The optical device of claim 1, wherein the control unit is configured to set said at least one parameter of said receiver to a first value at the instant the optical pulse is emitted from the optical radiation source or after the optical pulse has been emitted from the optical radiation source and then, adjust said at least one parameter temporarily to other values as a function of time. ### Claim 17 (depends on 1) The optical device of claim 1, wherein the control unit is configured to set an attenuation or an amplification of said receiver to a high value or a low value, respectively, at the instant an optical pulse is emitted from the optical radiation source and then, immediately after the optical pulse has been emitted, as the elapsed time increases, decrease or increase, respectively, the attenuation or amplification, respectively, temporarily on the basis of the generated at least one control signal until another pulse is emitted from the optical radiation source. ### Claim 18 A distance measuring device including: an optical device; and a processor configured to determine a distance to a target from said distance measuring device on the basis of a comparison between a transmitted optical pulse and a received optical pulse; wherein said optical device includes: an optical radiation source configured to emit optical pulses; a receiver configured to receive reflected optical pulses; a time-measuring unit configured to generate an elapsed time from a point in time related to emission of an optical pulse from the optical radiation source; at least one control signal generator unit configured to generate at least one control signal according to a temporal function on a basis of the elapsed time; and a control unit configured to adjust at least one parameter of said receiver affecting the dynamic range of said receiver based on the generated at least one control signal, wherein the temporal function is configured such that the temporal function at least partly includes a shape that is determined on a basis of parameters of an optical system of the optical device. ### Claim 19 (depends on 18) The distance measuring device of claim 18, wherein the optical system is an optical system configured to collimate the emitted optical pulses into a beam. ### Claim 20 (depends on 18) The distance measuring device of claim 18, wherein the optical system includes at least one of one or more lens elements, prisms, wave guides and mirror elements.