108results about How to "Long sensing distance" patented technology

The invention discloses a super-long distance phase-sensitive optical time domain reflectometer (Phi-OTDR) system, which comprises a Phi-OTDR demodulating system and detecting optical fiber, wherein a forward amplifying unit and a backward amplifying unit are respectively arranged at the front end and the back end of the detecting optical fiber. Detecting signal light of the Phi-OTDR system is amplified in a distributed manner by utilizing a bidirectional second-order or bidirectional multi-order Raman amplifying method, so that the uniformity of the intensity and the distribution of Rayleigh scattering signals on the whole optical fiber is further improved, the problem of the prior amplifying method of the Phi-OTDR system is effectively overcome, and the sensing distance of a single segment of detecting optical fiber of the Phi-OTDR system is further prolonged; and meanwhile, by utilizing bidirectional Raman amplifying multi-segment cascade connection, the super-long distance Phi-OTDR system which requires a low cost and has high performance can be realized. The method of the super-long distance Phi-OTDR system is helpful to improvements on the whole performance and the performance price ratio of the Phi-OTDR system during the application to long-distance safety monitoring of oil and gas transmitting pipelines, large-range peripheries, large-scale civil engineering structures, and the like.

The invention relates to the technical field of fiber sensing, and especially to a pre-pumped pulse and Gray code based BOTDA instrument. The BOTDA instrument comprises a narrow-linewidth semiconductor sensor, a coupler, a first erbium doped fiber amplifier, a first polarization controller, a single sideband modulator, a microwave source, an optical isolator, a sensing fiber, an optical annular device, a second erbium doped fiber amplifier, a polarization scrambler, an electro-optical intensity modulator, a second polarization controller, an arbitrary waveform generator, an optical filter, a photoelectric detector and a signal collecting and processing system. On the premise that the high spatial resolution of a BOTDA system is maintained, the BOTDA instrument ensures the sensing distance and the measuring precision of the system, and improves the sensing performance of the system.

The invention relates to a distributed optical fiber sensing system, and particularly relates to a BOCDA (Brillouin Optical Correlation Domain Analysis) distributed optical fiber sensing device and amethod based on physical random code modulation, so as to solve the problems of a limited sensing distance and spatial resolution deterioration existing in the existing BOCDA distributed optical fibersensing system. The device comprises a distributed feedback semiconductor laser, an electro-optic phase modulator, a physical random code generator, a first optical isolator, a 1*2 optical fiber coupler, a high-speed electro-optic modulator, a microwave signal source, a variable optical delay line, a first optical amplifier, an optical polarization scrambler, a second optical isolator, a sensingoptical fiber, a second optical amplifier, an optical circulator, a tunable optical filter and a optical power detector. In comparison with a time domain system, the spatial resolution is higher, thesensing distance is longer, the problem of spatial resolution deterioration caused by existence of a weak period of chaotic laser signals is avoided, adjustment on the high spatial resolution acquisition is extremely convenient, and the signal-to-noise ratio of the sensing system is effectively improved.

The invention relates to the technical field of optical fiber sensing and particularly relates to an ultra long distance distributed optical fiber vibration sensing device. The device is characterized in that the device comprises a light source, an acousto-optic modulator, a 1*2 optical splitter, an erbium-doped fiber amplifier, 1*2 couplers, circulators, wavelength division multiplexers, photoelectric detectors, a signal processor, a data acquisition card, sensing fibers and an industrial control computer, the light source is connected with the 1*2 optical splitter, one output of the optical splitter is connected with a first 1*2 coupler, two outputs of the first 1*2 coupler are respectively connected with the output ends of a second 1*2 coupler and a third 1*2 coupler, another output of the optical splitter is connected with the fiber input end of the acousto-optic modulator, and the signal end of the acousto-optic modulator is connected with a synchronous pulse output channel of the data acquisition card, and the fiber output end of the acousto-optic modulator is connected with the erbium-doped fiber amplifier. According to the ultra long distance distributed optical fiber vibration sensing device, under the premise of not increasing the cost of the original main components, the sensing distance is increased by one time, and the ultra long distance vibration monitoring is realized.

The invention discloses a single-ended chaotic Brillouin dynamic strain measuring device and method based on Rayleigh scattering, aiming at meeting the current requirements of long-distance, high-resolution, large dynamic range and real-time and rapid application of distributed sensing and simultaneously solving the problem that a system cannot work when a breakpoint occurs because a pump light and a detection light need double-end incidence in a Brillouin optical coherence domain analysis system. A continuous light output by a light source is divided into two paths through a coupler, one pathis used as the pump light, the other path is subjected to double-sideband modulation through a high-speed electro-optic modulator, a backward Rayleigh scattering light is used as the detection lightand generates stimulated Brillouin scattering with the pump light, and a corresponding dynamic strain value is demodulated through a corresponding relation between intensity information acquired by ahigh-speed data acquisition system and strain. The single-ended chaotic Brillouin dynamic strain measuring device is simple in structure and low in cost, can effectively reduce signal power fluctuation, and realizes dynamic strain measurement with single end, high spatial resolution, long distance and good stability.

The invention relates to a long-distance Raman distributed temperature sensing system which comprises an optical fiber pulse laser, an electrooptic modulator, a pump light source of 1480nm, wavelength division multiplexers, circulators, a signal processing and displaying module which are arranged at a front end of the system; the system is characterized by further comprising at least one stage of calibrating module, a sensing optical fiber and a relay amplifying module which are arranged at a rear end of the system and are connected with the wavelength division multiplexers at the front end of the system; the calibrating module, the sensing optical fiber and the relay amplifying module are connected in sequence; the relay amplifying module comprises a coupler, an Er-doped optical fiber amplifier, a first wavelength division multiplexer and a second wavelength division multiplexer are respectively provided with four channels, and a first circulator and a second circulator. The system has the beneficial effects that compared with a traditional Raman distributed optical fiber sensing system, the Raman distributed optical fiber temperature sensing system provided by the invention adds multiple stages of amplification, sensing distances are extended remarkably, and moreover, precision on temperature calibration is improved.

A combined type distributed optical fiber sensing system integrated with chaotic light source and coherent detection is disclosed and comprises a laser module, a polarization control module, a first optical switch, a first coupler, a pulse modulation and polarization scrambling module, a second coupler, a feedback device, a third coupler, a second optical switch, an EDFA light amplifier, a circulator, an optical fiber, a third optical switch, a fourth coupler, a fourth optical switch, a fifth optical switch, a balance photoelectric detector, a data collecting module, a data analyzing and processing module and a display device, wherein a coherent light time domain reflectometer or a chaotic light time domain reflectometer is chosen to be used in the system according to monitoring needs; by switching optical switch combinations, the coherent light time domain reflectometer or the chaotic light time domain reflectometer can be obtained. The beneficial effects of the combined type distributed optical fiber sensing method and system are that most of measuring devices in the system are employed by two measuring solution, the utilization efficiency of the sensing devices is improved, and system links are jointly monitored by the two measuring solutions; the detection sensitivity, the sensing distance and the positioning precision of the system can be optimized.

The invention relates to a coal and rock identification method based on laser scanning. The reflectivity of the coal surface to scanning laser beams from different distances and the reflectivity of the rock surface to scanning laser beams from different distances are measured through the laser scanning technology respectively, and the three-dimensional morphology information of the surfaces of a coal sample and a rock sample scanned by lasers is acquired in real time; the changing relation between the distance and the reflectivity of laser scanning of standard coal and standard rock is established, and reflectivity correction coefficients corresponding to different surface three-dimensional morphologies of the standard coal and the standard rock from different distances are determined; a characteristic database for the distance and reflectivity of laser scanning corresponding to the standard coal and the standard rock with different surface three-dimensional morphologies is established, while on-site coal and rock objects are identified, the actually measured characteristic values of the surfaces of the coal and rock objects are compared with the coal and rock standard characteristic data measured earlier, and thus the coal and rock type can be identified fast in real time. The method has the advantages of being simple, high in calculation speed, automation degree and accuracy rate and suitable for identifying the coal and rock types in complex environments.

The invention relates to an optical fiber vibration sensing system for pipeline leakage detection, which belongs to the technical field of optical fiber sensing and comprises a light source, a 3*3 optical fiber coupler, a first delay optical fiber, a first 2*2 optical fiber coupler, a second 2*2 optical fiber coupler, a sensing optical fiber, a second delay optical fiber, a third 2*2 optical fiber coupler and an optical detector. The optical fiber vibration sensing system is based on the Sagnac interference principle, the detection sensitivity and the stability of the sensing system are improved through adopting the introduction of fixed phase bias into the 3*3 optical fiber coupler, and the power of light returning the detector is enhanced through adding the optical fiber environment formed by the 2*2 optical fiber couplers, so the signal-to-noise ratio of the detector is improved, and the sensing distance is increased. The optical fiber vibration sensing system has the characteristics that the structure is simple, the sensitivity is high, and the stability is good. The optical fiber vibration sensing system can realize the real-time leakage detection on the transmission pipeline.

A setting method of a low-Brillouin scattering threshold sensing fiber-based optical time domain reflectometer contains the following steps: an optical pulse signal generated by an optical pulse signal generation unit (100) passes through a scrambler (106) and then enters a first port of a circulator (107); the optical pulse signal enters a sensing fiber (108) from a second port of the circulator; backscattering light of pulse signal light in the sensing fiber (108) enters a filter unit (109) through a third port of the circulator; signal light outputted by the filter unit (109) and light outputted by a local oscillator unit (110) are coupled through a coupler (117); and the signal enters a detection and signal processing unit (118) for acquisition and processing of the signal. The sensing fiber of the Brillouin optical time domain reflectometer adopts a single-mode sensing fiber, and the sensing fiber is a sensing fiber composed of multiple different Brillouin frequency shifts.

The invention discloses a light emitting diode (LED) induction lamp. The LED induction lamp comprises an induction part and a lamp part, wherein the induction part consists of a light induction module, a microwave induction module and a data acquisition and processing unit which are connected with one another; the lamp part consists of an LED light source and a power source which are connected with each other; the light induction module comprises a photosensitive resistor which displays a high-resistance state under the condition of strong light irradiation and displays a low-resistance state under the environment of weak light; a brightness signal and an attendance signal are acquired by using the photosensitive resistor and a microwave sensor; lighting and duration of the lamp are controlled by using a singlechip; when the surrounding environment is brighter, the power supply of the LED lamp is cut off; and when the surrounding environment is darker, whether a person exists around the lamp is judged, and the LED lamp is lighted if the person exists and is turned off if no person exists. The intelligent induction device is suitable for various occasions, and has the characteristics of high flexibility, anti-interference, silence, high response speed, long induction distance and the like.

The present invention relates to a Golay complementary sequence-based phase-sensitive type optical time domain reflectometer. The reflectometer comprises an input light generating unit (1), a polarization-maintaining beam splitter (2), a coding sequence modulation unit (3), a circulator (6), an optical fiber to be measured (5), a zero-difference frequency shifter (6), a polarization control unit (7), a detection unit (8) and a signal demodulation unit (9). The invention also discloses an implementation method of the Golay complementary sequence-based phase-sensitive type optical time domain reflectometer. According to the Golay complementary sequence-based phase-sensitive type optical time domain reflectometer and the implementation method thereof of the invention, the detection unit adopts an I/Q demodulation system, and all optical field information, especially absolute phase information, of real backward Rayleigh scattered light can be effectively restored through a refined structure; local oscillation light gain makes the extremely weak signals of the tail end of the optical fiber become possible, and therefore, the sensing distance of the system can be prolonged.

The invention discloses a delay pulse Raman amplification based distributed sensing system. The delay pulse Raman amplification based distributed sensing system comprises a narrow line width light source, a Raman pump light source, a first modulation module and a second modulation module; the first modulation module is connected with the narrow line width light source; the second modulation module is connected with the Raman pump light source; the first modulation module passes through an erbium-doped fiber amplifier and a circulator in turn to be connected with a wavelength division multiplexer; the second modulation module is connected with the wavelength division multiplexer directly; the wavelength division multiplexer is connected with a sensing fiber; the first modulation module is connected with the second modulation module through a signal generator; the circulator is connected with a detector, a data acquisition module and a computer in turn through a filter. According to the delay pulse Raman amplification based distributed sensing system, the long effective sensing distance of the detection light can be achieved through the pulse modulation pumped Raman amplification with a certain amount of time delay.

The invention discloses a display screen gesture control circuit and method based on capacitive sensing. The circuit includes a display screen and sensors arranged around the display screen. The sensors are arranged in strips, and a shielding layer is provided around each sensor. Multiple sensors output sensing signals to the detection circuit; the ground terminal of the display screen is disconnected from the ground, and the ground terminal of the display screen, the sensor and the shielding layer are all connected to the oscillating signal source. The method comprises the detection circuit detecting the signal output by the sensor, and determining the current working sensor; loading an oscillating voltage signal to the non-working sensor, so that the non-working sensor and the current working sensor are loaded with the voltage signal Synchronous oscillation; the detection circuit detects the signal output by the currently working sensor, and determines the gesture according to the change of the signal output by the currently working sensor. The invention can accurately detect the change of the gesture of the user, and the production cost is low.

A system and method for distributed dynamic strain measurement using optical fiber that is based on Brillouin optical time-domain reflectometry (BOTDR) with stimulated Brillouin scattering (SBS). A short-time Fourier transform (STFT) is used to rebuild the Brillouin frequency shift (BFS) of the SBS scattered signal to perform the dynamic strain measurement.

The invention discloses a high-temperature-resistant double-parameter sensing optical cable based on close winding of an optical fiber on a high-temperature elastomer sensibilization structure to remarkably enhance sound wave and temperature sensitivity, and relates to the field of optical fiber distributed sensing and well oil and gas exploration and development. Sensing optical fibers coated with high-temperature-resistant materials are arranged in the sensing optical cable and can sense external sound waves and temperature information at the same time. And the optical fiber interval sectionin the optical cable is tightly wound on the high-temperature-resistant elastomer sensibilization structure, so that the variation of a measured signal in unit length is larger, and the sound pressure and temperature sensitivity of the sensing optical cable can be remarkably improved. The surface of the elastic sensitization structure is plated with a metal layer, so that the heat-conducting property of the elastic sensitization structure and the temperature sensitivity of the sensing optical cable can be further improved. The sensing optical cable has the advantages that the sensing sensitivity is remarkably improved, double parameters can be measured at the same time, the sound pressure sensitivity and the temperature sensitivity of the sensing optical cable are expected to be improvedin order of magnitudes, and the sensing optical cable can be used for long-term and high-sensitivity exploration, development and monitoring in a high-temperature environment in a well.

A package structure of a long-distance sensor includes a substrate, a light-emitting chip, a sensing chip, two packaging gel bodies, and a cap. The substrate has a bearing surface. The light-emitting chip and the sensing chip are disposed on the bearing surface and separated from each other. The two packaging gel bodies cover the light-emitting chip and the sensing chip respectively and are separated from each other. The cap is disposed on the bearing surface and the packaging gel bodies, fastened to the bearing surface and the packaging gel bodies by adhesive, and provided with a light-emitting hole located above the light-emitting chip and a light-receiving hole located above the sensing chip.

The invention discloses a passive ultrahigh frequency RFID (Radio Frequency Identification Devices) tour guiding system and an operation method. The tour guidance and the management of scenic spots or large exhibition halls can be realized by adopting the ultrahigh frequency RFID technology. The tour guiding system comprises a handset control system and an electronic tag, wherein the electronic tag is a passive electronic tag; when identifying the existence of the electronic tag, the handset control system starts to read ID number data of the electronic tag, and transmits the ID number data to an MCU (Microprogrammed Control Unit); the MCU transmits the received ID number data to an audio decoding unit; and the audio decoding unit starts to find an audio file corresponding to the ID number data in an SD (Secure Digital Memory) card, decodes the audio file, and play an analog stereo signal to a stereo output device. The tour guiding system is convenient to use, is low in cost, is convenient to maintain, and has far reading distance and quick identification speed.

The invention belongs to the field of distributed optical fiber sensing, and discloses a distributed optical fiber sensing device and method based on noise matched filtering, and the device comprisesan ASE noise laser which emits a noise laser signal, the noise laser signal is converted into a pulse signal through an isolator and an acoustic optical modulator, and then the pulse signal is dividedinto two beams through an optical fiber coupler. One light beam is used as a detection light beam and enters a sensing optical fiber after passing through a wavelength division multiplexer, and backward noise Rayleigh scattering light and noise Raman anti-Stokes scattering light generated in the sensing optical fiber are separated by the wavelength division multiplexer and then are amplified by afirst erbium-doped optical fiber amplifier and a second erbium-doped optical fiber amplifier respectively; and the beam is detected by a first detector and a second detector respectively, and the other beam is detected by a third detector as a reference beam; detection signals of the three detectors are collected through a collection card and sent to the computer. According to the invention, a farther sensing distance can be achieved, simultaneous sensing of temperature and stress is realized, and the resolution of the system is improved.