Two Dimensional Rate Gyro Bias Estimation for Precise Pitch and Roll Attitude Determination Utilizing a Dual Arc Accelerometer Array

Abstract

In this thesis, a previously developed, novel one-dimensional attitude estimation device is expanded through the development and implementation of an innovative method for estimation of two-dimensional attitude making use of a unique low-cost, dual arc accelerometer array measuring longitudinal and transverse rotational rates in real-time. The device and method proposed is an expansion of a previously developed method for one-dimensional attitude determination and rate gyro bias estimation utilizing a one-dimensional accelerometer array. This new revolutionary device utilizes a dual arc accelerometer array and an algorithm for accurate and reliable two-dimensional attitude determination and rate gyro bias estimation in real-time. The method determines the local gravitational field vector from which attitude information can be resolved. Upon determining the location of the local gravitational field vector relative to two consecutive accelerometer sensors, the orientation of the device may then be estimated and the attitude determined. However, this measurement is discrete in nature; therefore, integrated rate gyro measurements are used to determine attitude information resulting in a continuous signal. However, attitude estimates and measurements produced by instantaneous rate sensors and gyroscope integration tend to drift over time due to drift and bias inherent to the rate gyro sensor. The integration of the acquired instantaneous rate signals amplify measurement errors leading to an undependable and imprecise estimate of the vehicles true attitude and orientation. A method for compensation of these errors is proposed in this work resulting in a highly accurate and continuous attitude estimate. For this thesis, simulations of the proposed method and device will be conducted with the inclusion of characteristic, real-world sensor noise and bias estimates produced from corrupted and biased sensors to analyze and assess the feasibility and validity of the proposed method and system configuration for twodimensional attitude determination. The end goal of this work is to produce a precise and reliable longitudinal and transverse attitude estimation array capable of measuring rate senor and gyro bias online so as to produce highly accurate and reliable pitch and roll angle tracking in real-time while under subjection to simulated flight conditions and scenarios. While this thesis is an expansion of a previously developed device and method, it is a departure from past works in that a new, two-dimensional accelerometer array arc is utilized and additional rotational dimensions are being included in the simulated analysis. IV Acknowledgments I would like to thank the faculty and staff of the Mechanical Engineering department at the Rochester Institute of Technology for providing me with the guidance and assistance necessary to have a truly great educational experience. In particular, I would like to thank Dr. Agamemnon Crassidis for his tutelage, guidance, and faith in my abilities to grow and improve as an individual a...

State Estimation Filtering Algorithms for Vehicle Attitude Determination using a Dual-Arc Accelerometer Array and 3-Axis Rate Gyroscopes

“…The testing of these methods were demonstrated through the attitude estimate errors of pitch and roll with respect to simulated data from a high performance nonlinear aircraft model. While this work is a continuation of a previous study, [30] the methods developed in this work are a large step forward in achieving the final goal of a highly accurate and reliable three-dimensional attitude estimation device for use on micro aerial vehicles and unmanned aerial vehicles without compromising constraints such as weight, size, power and cost.…”

“…The work and research performed in this study is focused on the design, development and implementation of an algorithm for accurately determining, and eliminating, accelerometer measurement errors and applying a new filter for rate gyro bias and noise estimation in order to increase the accuracy and robustness from the previously implemented filter in [30]. This work is an expansion of a previous work, [30], where the concept was to develop a two-dimensional, pitch and roll, attitude estimation device for reliable pitch and roll attitude determination. The previous work, [30], did not consider accelerometer biases or drift and implemented a filter which involved the linearization of a nonlinear system for rate gyro bias and estimation.…”

“…This work is an expansion of a previous work, [30], where the concept was to develop a two-dimensional, pitch and roll, attitude estimation device for reliable pitch and roll attitude determination. The previous work, [30], did not consider accelerometer biases or drift and implemented a filter which involved the linearization of a nonlinear system for rate gyro bias and estimation. This thesis expands on the previous work, [30], by considering accelerometer measurement errors and developing a method for reducing their effects on the overall attitude determination algorithm(s) and by applying a new filter for rate gyro measurement errors which does not linearize the nonlinear system thus producing more accurate results.…”

“…The previously developed device, found in [30], consists of two semi-circular arcs consisting of 13, equally spaced, accelerometers with a rate gyroscope Figure 1.1 is taken from [30] and represents the configuration of the device where the black circles represent the accelerometers. The proposed method for determining accelerometer biases involves the use of PID controllers for the determination of a control input which will be subtracted from the accelerometer measurements and, thus, reduce the effects of the additive measurement errors.…”

“…The method is run simultaneously with the rate gyro bias estimation filter as both use information from the other for their estimates. The proposed filter for rate gyro bias estimation is an improvement over the previous [30], Extended Kalman filter, and is known as the Unscented Kalman filter.…”