Gyro Output Signal Research Articles

Study on Fluidic Gyroscope Zero Temperature Compensation Method

This paper had studied on the zero temperature compensation of fluidic gyroscope based on MEMS thermistor. Through the analysis of temperature characteristics of jet gyro sensitive element, two methods of comparison of zero temperature compensation was compared. Then, introduction of SCM and temperature sensor, to achieve zero temperature compensation for gyro output signal. The experiment shows: after compensation, zero voltage variation gyro reduced from 150mV to 10mV, working temperature range from room temperature to-40°C ~+55 °C. The fluidic gyroscope zero temperature compensated with zero drift is low, wide working temperature range advantages.

Study on Fluidic Gyroscope Linearity Compensation Method

Based on the linearity of the MEMS thermal element fluidic gyroscope compensation. By analyzing the results of the linear characteristic of the fluidic gyroscope sensor output, comparator linearity compensation two implementation methods, the introduction of the microcontroller and the temperature sensor, to achieve the linearity compensation of the gyro output signal. The experiments show that: after compensation, the non-linearity of the fluidic gyroscope5%down to 0.5%, to-120°/s~+120°/s measurement range from-40°/s~+40°/s Fluidic gyroscope linearity compensation with low non-linearity, wide measuring range.

Study on the Output Signal Modulation for Laser Gyro with Mechanical Dither Bias

The amplitude of the output signal of prisms laser gyro with mechanical dither bias is always modulated. Theoretical analysis and experimental research on the ray trajectories, assembly situation and polarized properties of light were carried out. Results show that during the dither bias, the light transmitting route deviation caused by stress induced birefringence of prisms and the relative displacement between the photodetector and output light spot was the main reason responsible for the modulation. Polarized experiment data demonstrated that when the value of polarized power of output light below the 25.5% of that in ideal static situation, the standard error over 0.0337dBm, and the displacement extent of prism is higher than the 53% of radius of the beam waist in gyro cavity, the amplitude modulation extent of gyro output signal would be up to 16%, which badly influences measurement precision of laser gyro. Using the symmetric structure for laser gyro design, adopting prisms material with a suitable refractive index and reducing the photodetector deviation could reduce the extent of output signal's amplitude modulation obviously.

Zero drift of integrating gyroscope at asymmetrical deformation of suspension

The article reveals the nature of appearance of a systematic zero drift of the integrating gyroscope in hypersonic flight. It was found that with asymmetrical deformation of a suspension of a gyroscope its surface moves into the category of impedance structure that gives rise to disturbing moments in the existing quasi-harmonic drift of the fuselage. Identification of the extent of this influence will permit to improve the performance of the device . The method of successive approximations permits in the first approximation to assess the impact of Euler inertial forces on the appearance of periodic and systematic components in the output of the gyroscope during a flight. The values of the time-averaged systematic drift of the gyroscope output signal during synchronous and asynchronous angular motion of an aircraft were obtained. The results can be used in stand half-size tests of on-board equipment to make technical solutions for the elimination of additional errors of inertial sensors. When analyzing the errors of command and measurement complex devices, it is necessary to take into account not only the portable inertial forces, but also the disturbing moments of Coriolis forces, which occur at certain levels of ionizing shock sound N-wave. This outlines a range of technical solutions for acoustic comfort in the instrument compartment

Polarization properties in a prism laser gyro with mechanical dither bias

Theoretical analysis and experimental research on the polarization properties of output light in gyro are carried out to investigate the phenomenon that the amplitude of an output voltage signal is modulated by dither bias in laser gyros consisting of totally reflecting prisms. Taking the effect of prism stress birefringence into account, an analytical formula of the output light intensity in the gyro and the relationship between the polarization parameter and the amplitude modulation of the output signal are obtained and discussed. For the first time, the polarized power value of the output light is adopted as a basis to estimate the output signal amplitude fading extent of laser gyros. Experimental results demonstrate that when the value of polarized power of output light is below 25.5% of that in ideal static case, the standard error is over 0.0337 dBm, and the displacement extent of the prism is higher than 53% of the radius of the beam waist in the gyro cavity, the amplitude modulation extent of gyro output signal can reach up to 16%, which badly influences the measurement accuracy of the laser gyro. Using this polarized power detecting measurement method can repair the gyro immediately during its fabrication process, improve the testing and production efficiency and shorten the product development cycle.

A Micro-Machined Gyroscope for Rotating Aircraft

In this paper we present recent work on the design, fabrication by silicon micromachining, and packaging of a new gyroscope for stabilizing the autopilot of rotating aircraft. It operates based on oscillation of the silicon pendulum between two torsion girders for detecting the Coriolis force. The oscillation of the pendulum is initiated by the rolling and deflecting motion of the rotating carrier. Therefore, the frequency and amplitude of the oscillation are proportional to the rolling frequency and deflecting angular rate of the rotating carrier, and are measured by the sensing electrodes. A modulated pulse with constant amplitude and unequal width is obtained by a linearizing process of the gyroscope output signal and used to control the deflection of the rotating aircraft. Experimental results show that the gyroscope has a resolution of 0.008 °/s and a bias of 56.18 °/h.

Research on Nozzle Array Structure Fluidic Gyroscope Sensitivity-Temperature Compensation

The nozzle array structure fluidic gyroscope sensitivity-temperature compensation was researched. The fluidic gyroscope’s sensitivity temperature characteristic was analyzed in the sensitive element and two sensitivity-temperature compensation methods were compared. Then, the software compensation method was used, which based on the Single chip microcomputer technology and realized sensitivity compensation for the gyroscope output signal. The results show that after the compensation, the gyroscope’s sensitivity-temperature coefficient decreases from 1.8mV/°/s/°C to 0.1mV/°/s/°C and operating temperature range increases from normal temperature to -40°C～+60°C. Therefore, this method provides the effective way for the gyroscope practical research.

Research on Nozzle Array Structure Fluidic Gyroscope Zero Temperature Compensation

The nozzle array structure fluidic gyroscope’s zero temperature compensation was researched. The fluidic gyroscope’s temperature characteristic was analyzed in the sensitive element and two zero temperature compensation methods were compared. Then, the software compensation method was used, which based on the Single chip microcomputer technology and realized temperature compensation for the gyroscope output signal. The results show that after the compensation, the gyroscope’s zero drift decreases from ≤1.3mV/°C to ≤0.1mV/°C and operating temperature range increases from normal temperature to -40°C~+60°C. Therefore, the fluidic gyroscope has the advantage of low zero drift and width operating temperature range after the zero temperature compensation, which provides the convenience for the production and application.

Detecting Singularities Based on Wavelet Transform and Eliminating Disturbance from External Environment to the output Signals of Gyroscope

Abstract Noises in the output signals of gyroscope influence the seeking north precision of gyroscope. In order to improve the seeking north precision of gyroscope, noises must be detected and eliminated. Noise of gyro was analyzed firstly. According to the corresponding relationship between the singularity of wavelet transform and the noise of gyroscope signals, through detecting the singularities of wavelet transform, the noises in the output signals of gyroscope were detected and deleted. Through comparing original signals and the processed signals with this method, it indicates that this method is effective, and the north-seeking precision of gyroscope is improved.

Signal Decomposition for Three-Axis Gyroscope

Study Algorithm of roll, pitch and yaw angular velocity for three-axis gyroscope. the gyro have only one sensitive quality, can sensitize the three axial angular velocity of the rotating carrier at the same time. in the case of gyro’s spin angular velocity presence and pitch or yaw angular velocity worked, gyro output signal contain spin, pitch and yaw angular velocity. Through Uniaxial Gravity Accelerometer’s application, the roll, pitch and yaw angular velocity for three-axis gyroscope can be demodulated.

High resolution demodulation technique for Sagnac fibre optics gyroscopes using a low frequency quasi-synchronous clock

Abstract A simple technique which employs a low frequency quasi-synchronous clock was developed to measure duty-cycles with high resolution. For the same measurement resolution, the proposed circuit can operate with clock frequencies typically 1000 times lower than in conventional digital duty-cycle measurement system with synchronous clock. The proposed circuit is composed of only two Digital Direct Synthesis integrated circuits and one Complex Programmable Logic Device. Experimental results obtained with a prototype of the proposed time measurement system show that, for an emulated zero-cross fibre optics gyroscope output signal with 100 kHz and Δ T = 100 ns (duty-cycle of 50.25%), a resolution of 100 ps can be achieved using a 10.01 MHz frequency clock.

Research on Acceleration Disturbance Suppression for Dynamic Detection of Level Attitude

The paper presents a new method to eliminate acceleration disturbance in level attitude measurement and control of moving carrier. Output signals of micro-machined inclinometer and gyroscope are analyzed in different states of moving carrier by experimental simulation, results show that gyroscope almost keeps the zero output voltage while inclinometer outputs in significant fluctuations. With the analysis results, a new method on acceleration disturbance suppression is developed base on a combination of inclinometers and gyroscopes, which includes establishment and derivation of its mathematical model and implementation, and an algorithm software design. Finally, tests to the acceleration disturbance suppression effect are demonstrated in line motion, line vibration, angular motion and angular motion plus pitch swing. Experimental results show that the method achieves its expected effect. The inertial system constitutes of inclinometers and gyros interacting with acceleration disturbance suppression method can dynamic detect the level attitude of moving carrier.

Research of Filtering Based on Wavelet De-Noising Method for Revolution-Modulation North-Finder

In order to improve the precision of revolution-modulation north-finder, a filtering method based on wavelet de-noising method is studied. The continuous revolution in constant rate is used to modulate the output signals of gyroscopes and accelerometers, and the signals are demodulated by using the integrated method. The filtering method based on wavelet de-noising method is used to filter the signals of gyroscopes. The disturbance is filtered by maximum modulus, whose Lipschitz exponent is bigger than zero. The mean value of non-maximum modulus adjacent to the selected maximum modulus is used to alternate the maximum value. The noise is filtered by soft-thresholding, whose Lipschitz exponent is smaller than zero. The experimental results show the filtering method based on wavelet de-noising method effectively restrains the effect of random drift of gyroscopes and disturbance of system, and improves the precision of the revolution-modulation north-finder.

CORDIC algorithm based digital detection technique applied in resonator fiber optic gyroscope

A digital detection technique based on the coordinate rotation digital computer (CORDIC) algorithm is proposed for a resonator fiber optic gyroscope (R-FOG). It makes the generation of modulation signal, synchronous demodulation and signal processing in R-FOG to be realized in a single field programmable gate array (FPGA). The frequency synthesis and synchronous detection techniques based on the CORDIC algorithm have been analyzed and designed firstly. The experimental results indicate that the precision of the detection circuit satisfies the requirements for the closed-loop feedback in R-FOG system. The frequency of the laser is locked to the resonance frequency of the fiber ring resonator stably and the open-loop gyro output signal is observed successfully. The dynamic range and the bias drift of the R-FOG are ±1.91 rad/s and 0.005 rad/s over 10 s, respectively.

Open-loop experiments of resonator micro-optic gyro

An open-loop resonator micro-optic gyro (R-MOG) with a 6 cm-long waveguide-type ring resonator is set up using the phase modulation spectroscopy technique. In the experiment, according to the test parameters of the resonator, the shot-noise-limited sensitivity is estimated to be 1.07×10−4 rad/s. From the test demodulation signal, the gyro dynamic range of ±7.0×103 rad/s is obtained. Using different phase modulation frequencies, the open-loop gyro output signal is observed when the equivalent gyro rotation is applied to the acoustic-optical modulators (AOMs). The sensitivity of the R-MOG can be increased by some countermeasures against system noise.

Open-loop operation experiments in a resonator fiber-optic gyro using the phase modulation spectroscopy technique

A detection system in the resonator fiber-optic gyro is set up by the phase modulation (PM) spectroscopy technique. The slope of the demodulated curve near the resonant point is found to affect the ultimate sensitivity of the gyro. To maximize the demodulated signal slope, the modulation frequency and index are optimized by the expansion of the Bessel function and optical field overlapping method. Using different PM frequencies for the light waves, the open-loop gyro output signal is observed. The modulation frequency in this PM technique is limited only by the cutoff frequency of the LiNbO3 phase modulators, which can reach several gigahertz. This detection technique and system can be applied to the resonator micro-optic gyro with a less than 10 cm long integrated optical ring.

New interferometric fiber-optic gyroscope with amplified optical feedback

A novel interferometric fiber-optic gyroscope with amplified optical feedback by an Er-doped fiber amplifier (EDFA) is proposed and theoretically investigated (the proposed gyroscope is named the feedback EDFA-FOG, FE-FOG in what follows). The FE-FOG functions like a resonant fiber-optic gyro (R-FOG) because of its multiple utilization of the Sagnac loop; however, it is completely different because a low-coherence light source is used. In addition, the gyro output signal is pulsed because the modulation frequency of the phase modulator placed in the Sagnac loop is selected to match the total round-trip time delay of the light, which includes the Sagnac-loop delay plus that of the feedback loop of the fiber amplifier. The sharpness of the output pulse can be adjusted by both the gain of an EDFA and the modulation depth of the phase modulator. When rotation occurs the peak position of the output pulse is shifted as a result of the Sagnac effect. The resolution of the rotation measurement depends on the sharpness of the output pulse. The techniques of both the open-loop and closed-loop methods are described in detail, which shows the great advantage of the proposed gyroscope over the to the conventional interferometric fiber-optical gyroscope (I-FOG).

Proposal of a novel interferometric fiber‐optic gyroscope

AbstractA novel interferometric fiber‐optic gyroscope with amplified optical feedback by an Er‐doped fiber amplifier (EDFA) is proposed and theoretically investigated (the proposed gyro is called FE‐FOG). FE‐FOG functions like an R‐FOG (resonant fiber‐optic gyro) due to its multiple utilization of the Sagnac loop; however, it is completely different, because a low‐coherence light source is used. In addition, the gyro output signal is pulsed, because the modulation frequency of the phase modulator placed in the Sagnac loop is selected to match the round‐trip time delay of the light. When the rotation occurs the peak position of output pulse is shifted due to the Sagnac effect. The resolution of rotation measurement depends on the sharpness of the output pulse. Both open‐loop and closed‐loop methods are described in detail. © 1995 John Wiley & Sons, Inc.

Bias drift reduction in polarization-maintaining fiber gyroscope

The output signal of a birefringent fiber gyroscope is analyzed, and sources of error due to polarization cross coupling in the fiber and fiber components are identified. Techniques to suppress such errors by modulating the fiber birefringence and balancing the optical power in the two polarization modes are proposed and demonstrated.