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This paper gives an evaluation of low-cost MEMS digital accelerometer errors. Such evaluation is required to construct an appropriate model of the accelerometer. Allan Variance is a simple and efficient method for verifying and modelling the errors by representing the root mean square random drift error as a function of averaging time. In this paper the characteristics of MEMS accelerometers stochastic errors are identified and quantified, using Allan variance. The derived error model can be applied further to navigation systems of small aircraft. [ABSTRACT FROM AUTHOR]

Compared with traditional rate sensors, the Micro Electro Mechanical System (MEMS) gyroscope is smaller, lighter, cheaper and lower in power consumption. Thus, it has been widely used in consumer electronics, automation electronics and inertial navigation systems. However, because of the limitations of contemporary technology, the MEMS gyroscope usually has structure defect which will result in large drift. In this paper, we will report a method for analysis and compensation of MEMS gyroscope drift. Firstly, the gyro error characters are analyzed with the help of Allan variance. After that, Autoregressive (AR) model and auto-regressive moving-average (ARMA) model of gyroscope random drift are built. Besides, Kalman filter will be designed to decrease the random error of gyro. Test result shows that the variance of KF output is no more than 30% of the original signal variance. In conclusion, the combination of Allan variance, time series analysis and Kalman filter induce an excellent compensation effect of MEMS gyroscope drift. [ABSTRACT FROM PUBLISHER]

On the basis of Allan variance analysis performance parameters of ring laser, Coriolis vibratory and fiber optic gyros comparison is conducted. Manufacturers of the analyzed gyros are from USA, Russia and Ukraine. The main reason of this work is to determine potential performance of the developed in Ukraine low-cost metallic cylindrical resonator Coriolis vibratory gyro in comparison to high accuracy ring laser gyro produced by well-known USA company Honeywell and middle accuracy fiber optic gyro produced by Russian company Fizoptica. [ABSTRACT FROM PUBLISHER]

The paper is a review of a method to evaluate the inertial sensors stochastic errors in order to be used in the improvement of the sensors' signal-to-noise ratio, but also in the removing of the sensors errors that are mixed with the motion dynamics of a vehicle navigated by using a strap-down inertial system. After a brief description of the Allan variance, the main types of inertial sensor stochastic errors are reviewed. Further, the representation of quantization noise, angle random walk, bias instability, rate random walk, sinusoidal noise, and drift rate ramp in Allan variance is performed. Finally, the sample plot of Allan variance for each type of inertial sensors stochastic error and the analysis methodology are presented. [ABSTRACT FROM AUTHOR]

Precise oscillators such as quartz oscillators and atomic clocks are the heart-beat sources for power, banking, communication, satellite navigation, aerospace systems and so on. Two domains are applied to characterize the frequency instability of the precise oscillators, the Fourier frequency domain and the averaging time domain. The conversion exists from the Fourier frequency domain to the averaging time domain by an integral with the integral interval from the low cut-off frequency fl to the high cut-off frequency fh. It is pointed out firstly in this paper that the definitions of fh in history are ambiguous and there are two choices already in use: the measurement bandwidth in Fourier frequency domain and the one in the averaging time domain. Both choices are usually different and will give different conversion results. As for fl, it determines the achievable maximal averaging time ¦Ómax for the converted Allan variance within the endurable conversion loss. With the defined converted loss L=10%, ¦Ómax is 0.2081/ fl. [ABSTRACT FROM PUBLISHER]

Inertial sensor static calibration under changing temperature is proposed and analyzed. Due to relatively short test duration and non-stationary effects, a modification of the Allan variance, called Direct Predictor (DP), is proposed to describe the residual error model. With a reliable method of acquiring an error model, the calibration procedure is analyzed and the trade-off between temperature profile and calibration errors is shown. Results of an actual test and an in-depth discussion about models tightly bounding the residual errors complete the paper. [ABSTRACT FROM PUBLISHER]

GPS/INS integrated systems can provide accurate and reliable navigation information using data fusing algorithm such as a Kalman filter. Current research works related to GPS/INS navigation systems mainly focused on the absolute accuracy with dominant components of mid-term and long-term errors. However, the short-term relative accuracy will be required particularly in some applications, such as POS for LiDAR and InSAR, GPS/INS deeply-couple. This paper raises the importance of the short-term relative accuracy of the GPS/INS systems for certain applications. Then the method to evaluate the short-term navigation errors using Allan Variance analysis is proposed and the effort to improve the short-term accuracy by adjusting the Kalman filtering parameters is made. The feasibility and effectiveness of the proposed methods were verified by simulation results and typical field test results. The outcome of this paper will help to optimize the design of GPS/INS systems for specific applications areas where short-term relative accuracy is the key requirement; and facilitate the use of the low-end GPS/INS systems in these areas. [ABSTRACT FROM PUBLISHER]

In this paper, we present a wireless micro inertial measurement unit (IMU) with the smallest volume and weight requirements available at the moment. With a size of 18mm × 16mm × 4 mm, this IMU provides full control over the data of a three-axis accelerometer, a three-axis gyroscope, and a three-axis magnetometer. It meets the design prerequisites of a space-saving design and eliminates the need of a hard-wired data communication while still being comparable to state of the art commercially available MEMS IMUs. A CC430 microcontroller sends the collected raw data to a base station wirelessly with a maximum sensor sample rate of 640 samples per second. Thereby, the IMU performance is optimized by moving data post processing to the base station. This development offers important features in embedded microsystem applications with their significant size and weight requirements. [ABSTRACT FROM PUBLISHER]

The automotive and videogame industries have driven the cost of Micro-Electro-Mechanical System (MEMS) accelerometers and gyroscopes down to the range of just a few dollars. Likewise, the personal computer and cell phone industries have driven the cost of relatively high-resolution camera chips down to comparably low levels. Due to these cost reductions, a low-cost robot navigation system using a combination of vision and inertial sensors would be an inexpensive and effective method of navigating without the aid of GPS signals. Vision and inertial sensors are ideally suited to work together because their error characteristics are complementary. MEMS accelerometers and gyroscopes are capable of tracking high-speed motions, but suffer from long-term drifts that make them impractical to use as standalone navigation sensors. However, using Bayesian estimation methods, vision information from a stereo camera pair can be used to correct these drift errors. Therefore, using both vision and inertial sensors in tandem can produce an accurate navigation system that can operate indoors or in other areas where GPS signals or other navigation aids are unavailable. In this paper, we present two data analysis methods that can be used to calibrate and characterize the noise that is produced by MEMS-based IMUs. [ABSTRACT FROM PUBLISHER]

The paper introduce two methods to identify the MEMS gyroscope, Allan variance method and AR(n) model. Both the method has broadly used in engineering. Through the two method, the statistical mathematical properties and dynamic system properties of MEMS gyroscope are proclaimed. [ABSTRACT FROM PUBLISHER]

The Americans With Disabilities Act (ADA) and other accessibility standards specify the requirements for assessing the architectural barriers for the built environment. And, the ADA -- Compliance Assessment Toolkit (ADACAT)provides simple pass-fail assessments of those requirements. Measurement Kit is the principal component of the ADACAT, which consists of various measuring instruments like, measuring tape, sound-level meter, light-level meter, magic slope block, etc. In this essay, we show that most of the instruments in the Measurement Kit can be effectively implemented as a software application on a smartphone equipped with sensors like, accelerometer, gyroscope, and microphone. Detailed algorithms have been presented and the experimental results show that an iPhone or iPod Touch 4:0 application can serve as measuring tape, sound-level meter, as well as slope meter, making the ADACAT both cheaper and more portable. [ABSTRACT FROM PUBLISHER]

Our goal of this paper is to provide a new method to construct the gyroscope random drift. Based on the State-space subspace system identification algorithm, the gyroscope random drift data are constructed to a series of scale gyroscope drift model to reduce the predict errors. The results of the experiment indicate that the gyroscope drift model constructed by State-space subspace system identification algorithm for the scale data low variance for the traditional method. [ABSTRACT FROM AUTHOR]

To provide a high accuracy of measuring system it is essential to minimize errors of that very system that is used in measurements. The accuracy of phase noise measurement system greatly depends on its own internal noise. Furthermore while investigating the phase noise in narrow band it is necessary to use the heterodyne scheme to apply deep low pass filtering and much decimation. As a heterodyne signal it had been applied direct digital synthesizer (DDS) signal which has many advantages in comparison with other kinds of synthesizers but quantization processes and finite digit capacity in digital signal processing systems cause quantization noise appearance. The investigation purpose is to analyze signal stability dependence on the DDS system resolution. Such exploration brings much interest for quantum frequency standard development and highly precision measurement systems which are based on exactly digital signal processing. It is preferably to use the Allan variance as a factor of signal stability as long as this very signal property is usually applied to describe quantum standard signal stability. In many cases the heterodyne scheme is not able to shift the central signal frequency exactly to zero. The offset area is always take place after multiplying by the heterodyne signal and its magnitude depends on the signal center frequency estimation accuracy and DDS resolution. The investigation of how such distortion affects the signal stability is very actual for precision instrument development. To minimize the influence of measurement system noise on the result precision it is preferably to use cross correlation signal processing. Such method is based on application of two channel signal processing with further averaging of cross spectrum sequence. Applying the cross spectrum solution brings a satisfaction level of the residual phase noise as a result. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The main factor of random walk in a high precision fiber optic gyroscope is the intensity noise using erbium-doped fiber source, so decrease the intensity noise can reduce random walk. An intensity noise suppression method is proposed to reduce the random walk. An approach to reduce the random walk using subtraction combined with depolarizer was advanced after analyzing the relation of light intensity, phase and degree of polarization between two light beams. Analyze the gyroscope output data with Allan variance and we could determine from the result that the random walk coefficient was reduced by 32% than before. [ABSTRACT FROM PUBLISHER]

The stability of a Hot Electron Bolometer (HEB) mixer can be improved by the use of microwave injection. In this article we report a refinement of this approach. We introduce a microchip controller to facilitate the implementation of the stabilization scheme, and demonstrate that the feedback loop effectively suppresses drifts in the HEB bias current, leading to an improvement in the receiver stability. The measured Allan time of the mixer's IF output power is increased to > 10 s. [ABSTRACT FROM PUBLISHER]