61results about How to "Improve bias stability" patented technology

The invention discloses a three-optical-path signal compensation system in an optical MEMS accelerometer and a method thereof. The three-optical-path signal compensation system comprises a three-optical-path compensation optical path and a signal processing system, wherein the three-optical-path compensation optical path comprises an optical isolator, a miniature beam splitter prism, a plane mirror, an adjustable attenuator and an photoelectric detector; and the compensation signal processing system comprises three analog-to-digital (AD) conversion modules, a subtracter, a divider, a data storage, summation and average module and multiplier, and the modules are realized through a programmable digital signal processor. The three-optical-path signal compensation system is relatively simple in structure, and can effectively reduce influences imposed on output signals by power fluctuation of a light source and ambient light. Compared with a scheme of adopting a laser with extremely high power stability, the cost of the optical MEMS accelerometer can be effectively reduced. In addition, the system and the method disclosed by the invention can be effectively applied to the optical MEMS accelerometer, disturbance of the output signals is reduced, and finally the zero-bias stability and the precision of accelerometer measurement are improved.

The invention provides a digital domain balanced detecting method for an optical fiber gyroscope, which comprises the following steps of: applying a phase modulation signal to a phase modulator, wherein the phase modulation signal is obtained after a sinusoidal signal and a cosine signal which have the same modulation frequency are linearly combined; using the applied sinusoidal signal as an I-path reference signal and carrying out derivation on the I-path reference signal to obtain a Q-path reference signal; respectively carrying out coherent processing on a signal output by the optical fiber gyroscope and the I-path reference signal and the Q-path reference signal so as to obtain an I-path detection signal and a Q-path detection signal; respectively demodulating the I-path and Q-path detection signals to obtain an I-path angular velocity measured value and a Q-path angular velocity measured value; and according to a preset linear formula, combining the I-path and Q-path angular velocity measured values to obtain a measured value of an angular velocity to be measured, wherein the preset linear formula is predetermined according to the linear combination of the applied sinusoidal signal and cosine signal. Due to the utilization of the method, the bias stability of the optical fiber gyroscope can be improved.

The invention relates to a microgyroscope, that is to say an inertial micromechanical sensor dedicated to the measurement of angular velocities, which is produced by micromachining techniques, and has a novel arrangement of the modules for measuring the movement of the vibrating masses. The gyroscope comprises two symmetrical moving assemblies (30, 50; 30′, 50′) that are coupled by a coupling structure (20, 20′, 22). Each of the two assemblies comprises a moving mass (30) surrounded by a moving intermediate frame (50). The frame (50) is connected to the coupling structure (20, 20′, 22) and can vibrate in two degrees of freedom in orthogonal directions Ox and Oy of the plane of the wafer. The mass (30) is connected, on one side, to the frame and, on the other side, to fixed anchoring regions (34, 36) via linking means (40-46; 52-58) that allow the vibration movement in the Oy direction to be transmitted to the mass without permitting any movement of the mass in the Ox direction. An excitation structure (70) is associated with the frame in order to excite its vibration along Ox. A movement detection structure (90) is associated with the mass (30) in order to detect its vibration along Oy.

The invention relates to a coil of an optical fiber current sensor and the optical fiber current sensor. The coil comprises a first current sensing light path which is wound on a current to be measured and a second current sensing light path which is wound on the current to be measured and is opposite to the first current sensing light path in winding direction. The invention provides the coil of the optical fiber current sensor and the optical fiber current sensor, which are high in sensitivity and precision, are insensitive to vibration as the Sagnac effect can be eliminated, and are insensitive to a temperature as double-light-path sensing is adopted.

The invention provides a method for measuring angular speed of an interference optical fiber gyroscope by utilizing double-frequency modulating signals. The method comprises the following steps of: applying a phase modulating signal obtained by carrying out linear combination on two sinusoidal signals with different modulating frequencies omega 1 and omega 2 to a phase modulator; extracting respective first harmonic components, second harmonic components and fourth harmonic components of the two modulating frequencies from output signals of the optical fiber gyroscope; substituting the light intensity amplitudes of the extracted harmonic components into a preset revised solving equation to respectively solve angular speed measurement values aiming at the two modulating frequencies; and averaging the two obtained angular speed measurement values to obtain an angular speed measurement value to be measured. By utilizing the method, the bias stability of the optical fiber gyroscope can be improved, noise of rate random walks can be reduced, and the signal to noise ratio of detection signals can be improved.

The invention discloses an in-situ measurement method based on an electron paramagnetic resonance-magnetic resonance imaging three-dimensional magnetic field. The in-situ measurement method comprisesthe following steps: step 1, performing heating; step 2, performing polarization; step 3, performing electron paramagnetic resonance and magnetic resonance imaging; and step 4, performing three-dimensional magnetic field in-situ measurement. The method has the following beneficial effects: the measurement sensitivity and precision of the residual magnetic field measurement after passive magnetic shielding in the magnetic resonance imaging gyroscope are improved; a sensitive source of the measured magnetic field and a sensitive source for measuring angular motion are located in the same atomicair chamber and are real magnetic fields with nuclear spin feeling, the active magnetic compensation precision is improved and thus the zero-bias stability of the gyroscope is further improved; meanwhile, an atom magnetometer constructed based on the method can work in a geomagnetic field environment, high sensitivity and precision are realized, and the in-situ measurement method can be applied tothe fields of magnetic anomaly detection, geomagnetic navigation, deep space detection and the like.

The invention relates to a Y-shaped cavity orthogonal polarization laser-based force and mass measurement method and device. The device consists of a Y-shaped cavity orthogonal polarization laser, a gas diaphragm capsule, a force-applying unit, an operating point selection and control unit and a signal acquisition and processing unit. A force to be measured or the self-gravity of an object to be measured is transferred to an ultra-thin diaphragm of the gas diaphragm capsule through the force-applying unit, the ultra-thin diaphragm is subjected to elastic deformation, the volume of sensing gas in the gas diaphragm capsule is caused to be changed, the refractive index of sensing gas in a P subsection of the Y-shaped cavity orthogonal polarization laser communicated with the gas diaphragm capsule correspondingly changes, thus, the optical length difference between a resonant cavity of S polarized light and a resonant cavity of P polarized light is caused to be changed, the beat frequency difference between the S polarized light and the P polarized light is finally caused to be changed, and the change value of the beat frequency difference is directly proportional to the size of the inputted force. The Y-shaped cavity orthogonal polarization laser-based force and mass measurement method and device have the characteristics of high resolution, large dynamic range, high linearity, direct digital output and the like, and the device can be used as a micro/nano force and micro/nano mass measurement standard transferring instrument through optimizing structural parameters.

The invention discloses a two-dimensional compensation method of an optical fiber gyroscope magnetic temperature cross-linking coupling error. The method comprises the following steps of A, attachingat least one temperature sensor to each of upper and lower surfaces of an optical fiber ring of an optical fiber gyroscope; B, attaching two magnetic field sensors to a side surface of the optical fiber ring of the optical fiber gyroscope, wherein magnetic sensitive shafts of the two magnetic field sensors are orthogonal to the side surface of the optical fiber ring and pass through a central axisof the optical fiber ring; C, through an experiment, acquiring an error model of a relationship among the optical fiber gyroscope magnetic temperature cross-linking coupling error, magnetic field distribution and temperature distribution, wherein the error model Y=B T (the Y is the optical fiber gyroscope magnetic temperature cross-linking coupling error, the B is the magnetic field distribution,and the T is the temperature distribution); and D, using the error model to compensate the optical fiber gyroscope magnetic temperature cross-linking coupling error in a two-dimensional mode. In theinvention, the optical fiber gyroscope magnetic temperature cross-linking coupling error is compensated through detecting a radial magnetic field and a temperature of an environment where the opticalfiber gyroscope is located in real time, a non-reciprocal error generated by the optical fiber gyroscope under a combined action of a magnetic field and a temperature field is effectively reduced, andenvironmental adaptability and application precision of the optical fiber gyroscope are finally increased.

The invention belongs to the technical field of gyroscopes, and particularly discloses a micro gyroscope excitation and protection device and method. The micro gyroscope excitation and protection device is used for detecting and analyzing the resonant frequency of the gyroscope in real time and adjusting the passband frequency of the passband adjustable buffer on line, so that low-frequency and high-frequency noises can be effectively prevented from entering the gyroscope, and the detection resolution ratio and the dynamic response range of the gyroscope are improved. Besides, high-frequency harmonics superposed in the tuning signal are processed, so that the modal matching performance of the gyroscope is improved, and the zero-bias stability of the gyroscope is further improved. Finally,measures such as isolation and passband adjustability are adopted, input ripples, backflow noise and direct-current bias components are inhibited from entering the gyroscope, irreversible damage to the mechanical structure of the gyroscope is prevented, potential safety threats are effectively avoided, the service life of the gyroscope is prolonged, and the gyroscope is suitable for the application field of long-time operation.

The invention discloses an ST-NBT-BT ceramic material with high energy storage density and a preparation method thereof. The preparation method comprises the following steps: firstly, weighing raw materials with corresponding masses respectively according to a molar ratio to synthesize ST powder, NBT powder and BT powder, mixing the ST powder, the NBT powder and the BT powder, performing ball milling, drying and briquetting to form fully-graded materials, and then screening the fully-graded materials sequentially to form sieved materials; secondly, pressing the sieved materials into samples, and sintering the prepared samples to obtain sintered samples; and finally, grinding and cleaning the sintered samples, uniformly coating front and back surfaces of the polished and cleaned sintered samples with silver electrode slurry, and sintering the samples coated with silver electrodes to obtain the ST-NBT-BT ceramic material with high energy storage density. The ST-NBT-BT ceramic material high energy storage density, obtained by the method provided by the invention, not only has high energy storage density, but also has a simple preparation process and a low material cost and is environment-friendly.