Modeling of Inertial Rate Sensor Errors Using Autoregressive and Moving Average (ARMA) Models

In this chapter, a low-cost micro electro mechanical systems (MEMS) gyroscope drift is modeled by time series model, namely, autoregressive-moving-average (ARMA). The optimality of ARMA (2, 1) model is identified by using minimum values of the Akaike information criteria (AIC). In addition, the ARMA model based Sage-Husa adaptive fading Kalman filter algorithm (SHAFKF) is proposed for minimizing the drift and random noise of MEMS gyroscope signal. The suggested algorithm is explained in two stages: (i) an adaptive transitive factor (a1) is introduced into a predicted state error covariance for adaption. (ii) The measurement noise covariance matrix is updated by another transitive factor (a2). The proposed algorithm is applied to MEMS gyroscope signals for reducing the drift and random noise in a static condition at room temperature. The Allan variance (AV) analysis is used to identify and quantify the random noise sources of MEMS gyro signal. The performance of the suggested algorithm is analyzed using AV for static signal. The experimental results demonstrate that the proposed algorithm performs better than CKF and a single transitive factor based adaptive SHFKF algorithm for reducing the drift and random noise in the static condition

Computer recommendations for an automatic approach and landing system for V/STOL aircraft. Volume 2 - Equations

Automatic approach and landing system for V/STOL aircraf

Increased error observability of an inertial pedestrian navigation system by rotating IMU

Indoor pedestrian navigation suffers from the unavailability of useful GNSS signals for navigation. Often a low-cost non-GNSS inertial sensor is used to navigate indoors. However, using only a low-cost inertial sensor for the system degrades its performance due to the low observability of errors affecting such low-cost sensors. Of particular concern is the heading drift error, caused primarily by the unobservability of z-axis gyro bias errors, which results in a huge positioning error when navigating for more than a few seconds. In this paper, the observability of this error is increased by proposing a method of rotating the inertial sensor on its y-axis. The results from a field trial for the proposed innovative method are presented. The method was performed by rotating the sensor mechanically–mounted on a shoe–on a single axis. The method was shown to increase the observability of z-axis gyro bias errors of a low-cost sensor. This is very significant because no other integrated measurements from other sensors are required to increase error observability. This should potentially be very useful for autonomous low-cost inertial pedestrian navigation systems that require a long period of navigation time

A user interactive calibration program for an object tracking system using a triaxial accelerometer

A major method in object tracking systems and other inertial measurement devices resolves around the use of one, two, or three axis accelerometers. A leader in the field such devices is Microstrain Incorporated. They have developed a three axis accelerometer that uses a three axis magnetic sensor array to compute the pitch, roll, and yaw of a compact inertial measurement unit. In researching such devices, it became apparent that data collected using such units is extremely sensitive both to local magnetic fields and human interactions with the devices. It is therefore of great importance to ensure the device or devices are properly calibrated. In the construction of an effective calibration program, it is necessary to measure and zero out even minor discrepancies, as even small misalignments have deleterious effects on device performance

Bank-to-turn control technology survey for homing missiles

The potential advantages of bank-to-turn control are summarized. Recent and current programs actively investigating bank-to-turn steering are reviewed and critical technology areas concerned with bank-to-turn control are assessed

Assessment of the AH-64D Longbow Apache’s Handling Qualities for Instrument Meteorological Conditions/Instrument Flight Rules Flight

An assessment of the handling of the AH-64D for flight in IMC and under IFR was conducted. Testing was performed in the configurations listed in table 1 and under the conditions presented in tables 3 and 4. All test objectives were met. IMC mission maneuvers with all systems working resulted in satisfactory handling qualities with no excessive compensation required from the pilot (altitude and attitude holds ON). However, as the aircraft systems were progressively degraded the workload for the evaluating pilot increased significantly. The high workload coupled with the absence of a vertical speed indicator (VSI) and torque indication during an AC failure and the observed errors in the standby altimeter and airspeed indicators would most likely prevent flying a successful unusual attitude recovery, an airport surveillance radar (ASR) approach, or a precision approach radar (PAR) approach. The inadequacy of the standby instruments is a deficiency. The aircraft’s longitudinal gust response with FMC OFF required extensive pilot compensation to maintain altitude and airspeed within adequate parameters, further increasing the overall pilot workload, and is a deficiency. Additionally, the aircraft’s battery life does not meet the 30- min requirement for IMC/IFR flight that would be required in the unlikely event of an aircraft AC power failure and results in a deficiency. Engineering maneuvers conducted to quantify the handling qualities of the AH-64D with FMC OFF confirmed the high pilot workload and extensive compensation required. These maneuvers revealed an oscillatory divergent long-term mode, an oscillatory divergent lateral-directional oscillation (LDO), negative spiral stability when banked to the right, and significant coupling between pitch and roll. While conducting these maneuvers, excessive instrumentation lag was observed in the standby altimeter during climbs and descents. This resulted in errors of up to 300 ft between boom data and the standby altimeter. The excessive observed instrument lag and inaccuracy of the standby altimeter is a shortcoming. Other findings included the absence of any information on IMC/IFR procedures in the operator’s manual was also found to be a shortcoming. Consequently a clearance for aircraft operation in IMC is not recommended. Plots of representative engineering data collected in the heavy weapons (configuration 3) and two-tank configurations (configuration 5) are in Appendix D

Safe navigation for vehicles

La navigation par satellite prend un virage très important ces dernières années, d'une part par l'arrivée imminente du système Européen GALILEO qui viendra compléter le GPS Américain, mais aussi et surtout par le succès grand public qu'il connaît aujourd'hui. Ce succès est dû en partie aux avancées technologiques au niveau récepteur, qui, tout en autorisant une miniaturisation de plus en plus avancée, en permettent une utilisation dans des environnements de plus en plus difficiles. L'objectif aujourd'hui est de préparer l'utilisation de ce genre de signal dans une optique bas coût dans un milieu urbain automobile pour des applications critiques d'un point de vue sécurité (ce que ne permet pas les techniques d'hybridation classiques). L'amélioration des technologies (réduction de taille des capteurs type MEMS ou Gyroscope) ne peut, à elle seule, atteindre l'objectif d'obtenir une position dont nous pouvons être sûrs si nous utilisons les algorithmes classiques de localisation et d'hybridation. En effet ces techniques permettent d'avoir une position sans cependant permettre d'en quantifier le niveau de confiance. La faisabilité de ces applications repose d'une part sur une recherche approfondie d'axes d'amélioration des algorithmes de localisation, mais aussi et conjointement, sur la possibilité, via les capteurs externes de maintenir un niveau de confiance élevé et quantifié dans la position même en absence de signal satellitaire. ABSTRACT : Satellite navigation has acquired an increased importance during these last years, on the one hand due to the imminent appearance of the European GALILEO system that will complement the American GPS, and on the other hand due to the great success it has encountered in the commercial civil market. An important part of this success is based on the technological development at the receiver level that has rendered satellite navigation possible even in difficult environments. Today's objective is to prepare the utilisation of this kind of signals for land vehicle applications demanding high precision positioning. One of the main challenges within this research domain, which cannot be addressed by classical coupling techniques, is related to the system capability to provide reliable position estimations. The enhancement in dead-reckoning technologies (i.e. size reduction of MEMS-based sensors or gyroscopes) cannot all by itself reach the necessary confidence levels if exploited with classical localization and integration algorithms. Indeed, these techniques provide a position estimation whose reliability or confidence level it is very difficult to quantify. The feasibility of these applications relies not only on an extensive research to enhance the navigation algorithm performances in harsh scenarios, but also and in parallel, on the possibility to maintain, thanks to the presence of additional sensors, a high confidence level on the position estimation even in the absence of satellite navigation signals

Report on the development of the Manned Orbital Research Laboratory /MORL/ system utilization potential. Task area IV - MORL SYSTEM improvement study, book 3

Manned Orbital Research Laboratory system improvement study on stabilization and control subsystem