Fiber Optic Gyroscope System Research Articles

Error analysis of dual-polarization fiber optic gyroscope under the magnetic field-variable temperature field

A dual-polarization fiber optic gyroscope system is built to systematically analyze the nonreciprocal errors of the system under the magnetic field-variable temperature field. Under the magnetic field-variable temperature field, the nonreciprocal errors are caused by magnetic-thermal coupling birefringence nonreciprocal error, linear birefringence nonreciprocal error and Shupe effect error. The nonreciprocal errors of dual-polarization fiber optic gyroscope system are related to temperature and temperature gradient. In X and Y polarization states, the signs of magnetic-thermal coupling birefringence nonreciprocal error and linear birefringence nonreciprocal error are opposite, and these two errors can be suppressed in the dual-polarization system. But the Shupe effect errors are the same in X and Y polarization states, which can not be suppressed in the dual-polarization system. The experimental results are consistent with the theoretical analysis, which verifies the correctness of the nonreciprocal error model under the magnetic field-variable temperature field. The research results provide a theoretical and experimental basis for the study of the environmental adaptability of the fiber optic gyroscope and other common-path fiber sensing systems based on dual-polarization.

Angular velocity measurement with wide range based on dual-comb Sagnac interferometer.

Interferometric fiber optic gyroscopes are widely used in spacecraft, navigation, and autopilot and missile systems due to their high accuracy and fast speed. However, the dynamic measurement range is generally limited to a small value. In this paper, an angular velocity measurement system based on a dual-comb Sagnac interferometer is proposed. The theoretical dynamic range can reach the order of 108 deg/s, which is remarkably superior to that of the conventional fiber optic gyroscopes. To the best of our knowledge, this is the first demonstration of a dual-comb-based passive fiber optic gyroscope system, offering an attractive tool for measuring angular velocity with large dynamic range.

Adaptive intensity noise suppression of fiber optic gyroscopes based on period LMS algorithm

Reducing the noise level of fiber optic gyroscope (FOG) has been paid much attention. The relative intensity noise (RIN) of the light source is a dominant noise source and different methods have been used to reduce the RIN. However, the performance of the RIN suppression methods suffering from parameter variation is rarely discussed. In this paper, we introduced a method that uses the period LMS (PLMS) adaptive filter in the FOG system with noise subtraction implementation to ensure the sensor’s performance in varying environment. By analyzing the sampled detector signals in the system, the parameters in the system are determined based on the convergence requirement and noise performance of PLMS. Simulations as well as experiments of a FOG system with the PLMS algorithm implemented in the signal processing board are used to verify the feasibility of the method. The performance comparison between the PLMS filter and the predetermined Wiener filter in different temperature is tested and analyzed, which reveals the variability of the system parameters and verifies the necessity and ability of the introduced method to adapt to the varying environment.

Application of the Wiener filter for intensity noise reduction in fiber optic gyroscopes.

An essential issue for the low-noise system application of the fiber optic gyroscope (FOG) is to reduce its noise level. The relative intensity noise (RIN) of the light source is the dominant noise of the FOG when the light power on the detector reaches a certain level. The noise subtraction method is effective for RIN reduction and easy to implement in a FOG. This paper theoretically analyzes the factors that influence the result of the method and deduces the function to calculate the noise suppression ratio that can be achieved. A method that uses an optimum filter design based on the Wiener filter in the reference detector signal is proposed to improve the subtraction result. A FOG system is set up to test the feasibility of the method. The experiment results meet with the theoretical analysis, and by using the Wiener filter, the achieved noise subtraction factor reaches the limitation that restrains the optical system and detection circuit.

The application of low-noise DC-DC power source in fiber-optic gyroscope system

In high-precision fiber-optic gyroscope (FOG) system, the spike noise of DC-DC power source can lead to a considerable disturbance to the signal processing circuit of FOG, which results in a sampling error. In this work, the cause of spike noise and the influence mechanism were clarified. The slew rate control technology was researched and proved to be an effective solution to prevent spike noise of FOG power source. Using slew rate control technology, a kind of low-noise power module has been developed and applied successfully in the FOG system. This power module consists of DC-DC circuit and LDO circuit, and slew rate control circuit was used in the DC-DC circuit to realize low-noise performance. The peak-to-peak noise value of the developed power module was tested to be about 1 mV in a bandwidth of 200 MHz. Two typical FOG systems were tested with the use of this low-noise power source, and their output noise improvement were 3.1% and 4.4%.

Technology Research of Digital Closed-Loop Fiber-Optic Gyroscope

Digital fiber-optic gyroscope with linear scale factor, phase high accuracy, dynamic range, etc. This article proposed one kind of closed-loop digital fiber optic gyroscope system based on DSP, and designs the closed-loop fiber-optic gyro for signal detection and processing circuit, and the whole digital closed loop of fiber optic gyroscope light path part and circuit of the concrete analysis. With DSP as logic circuit, make the gyro operation speed and reliability have improved greatly.

A New Dynamic Test Method of Fiber Optic Gyroscope

The sway motion of ships follows sine law. Therefore, it needs high dynamic performance of fiber optic gyroscope (FOG) to meet the serious working environment. A new test method was introduced to make reasonable assessment on the dynamic performance of FOG. The principle of this new test method was that the sine wave provided by the IP core in FPGA was superimposed on the digital ladder to simulate the input signal of sway motion. It could be proved that the serial of sine signal, which was generated by this method, was equivalent to the external input signal. Moreover, the dynamic error model of FOG was established to provide the theory of dynamic test. The results of dynamic test of FOG indicated that the dynamic error did not have divergent trends, the system parameters set was reasonable and the FOG system was stable. It also can be seen that dynamic error of FOG was increased with the increasing of sine wave amplitude, which was accord with the actual situation. The new dynamic test method of FOG was verified.

Research on time division multiplexing modulation approach applied in three-axis digital closed-loop fiber optic gyroscope

In this paper, the structure and the fundamental principle of a three-axis Time Division Multiplexing (TDM) fiber optic gyroscope system are presented. The design of TDM fiber-optic gyroscope system is mathematically analyzed. An effective modulation approach is developed, the bias stability compared with that of a normal fiber-optic gyroscope is theoretically given and the system dynamic character is presented. In order to test the correctness of the approach, the dynamic simplified model is introduced and the simulation is conducted. The experimental result matches the simulation, indicating that the TDM modulation approach is feasible.