No description available.

The purpose for writing this thesis is to prove the automatic carrier landing system (ACLS) a valuable Operational Risk Management (ORM) tool for recovering F/A-18A-D aircraft aboard the modern aircraft carrier. ORM is itself a subset of human factors and worthy of exploration in the aviation systems field. In proving the value of the ACLS, the author presents the following objectives: 1) describe the major components of the F/A-18A-D and modern aircraft carrier ACLS, 2) describe the current Mode I approach procedures, and the Precision Approach Landing Systems (PALS) certification process, 3) promote an increase in automatic landings during night time and low ceiling/visibility environments through an analysis of ACLS strengths and weaknesses, and 4) advocate the continued use of fully automatic carrier landings amidst addressing deeply rooted fleet squadron paradigms and the advent of future technologies. The information gathered for this thesis came primarily from the author’s own direct flight and test experiences as well as documentation of standardized Navy flight and test publications. Detailed background information on the ACLS and future landing programs along with data from the Naval Safety Center and the VX-23 Carrier Suitability department were used as evidence to support the findings. The author concludes that the Mode I ACLS capability is extremely vital to the safe and expeditious recovery of the F/A-18A-D Hornet aircraft onboard the modern aircraft carrier that the Mode I automatic carrier landing system as currently structured and utilized is a highly effective risk management tool for naval aviation. The routine testing and certification of the precision approach equipment, all-weather capability, redundant cockpit data and voice safety network, plus enhanced aircraft carrier mobility through the use of Mode I approaches are all strengths of the ACLS system. To enhance the effectiveness of the ACLS for future carrier operations, the author recommends: 1) creating RAG and fleet squadron command climates that promote and support the use of Mode I approaches, 2) increasing ACLS training for aircrew and maintainers, and 3) establishing a new CV-1 approach that can capitalize on JPALS functionality in order to improve upon automatic landings.

A self-contained, portable, inertial and positional measurement system was developed and tested for an HGU-55 model fighter pilot helmet. The system, designated the Portable Helmet Instrumentation System (PHIS), demonstrated the recording of accelerations and rotational rates experienced by the human head in a flight environment. A compact, self-contained, “knee-board” sized computer recorded these accelerations and rotational rates during flight. The present research presents the results of a limited evaluation of this helmet-mounted instrumentation system flown in an Extra 300 fully aerobatic aircraft. The accuracy of the helmet-mounted, inertial head tracker system was compared to the aircraft-mounted referenced system. The ability of the Portable Helmet Instrumentation System to record position, orientation and inertial information in ground and flight conditions was evaluated. The capability of the Portable Helmet Instrumentation System to provide position, orientation and inertial information with sufficient fidelity was evaluated. The concepts demonstrated in this system are: 1) calibration of the inertial sensing element without external equipment 2) the use of differential inertial sensing equipment to remove the accelerations and rotational rates of a moving vehicle from the pilot’s head-tracking measurements 3) the determination of three-dimensional position and orientation from three corresponding points using a range sensor. The range sensor did not operate as planned. The helmet only managed to remain within the range sensor’s field of view for 37% of flight time. Vertical accelerations showed the greatest correlation when comparing helmet measurements to aircraft measurements. The PHIS operated well during level flight.

Naval aviation is on the brink of taking advantage of a 12 year old capability. Naval commercial derivative aircraft have had the ability to navigate in instrument meteorological conditions using global positioning technology for nearly as long as civil commercial-for-hire aircraft. However, tactical naval aircraft, like the E-2C Hawkeye, are now only beginning to obtain and install the necessary technology to meet federal aviation regulations for satellite based area navigation. Worldwide airspace controlling agencies have mandated the use of navigation equipment that meets highly specific performance standards prior to entry in required navigation performance airspace. Aircraft not compliant with these standards are denied flight clearance or experience clearance delays. The Department of Defense has issued policy guidance that allows military aviation organizations to self-certify satellite based navigation technologies to meet required navigation performance standards. In many ways, military navigation technologies far exceed the performance requirements for civil and international airspace use. These technologies, however, are highly specific in their mission orientation and must demonstrate their compatibility with civil aviation standards. This study focused on the source and the specifics of navigation performance requirements. Domestic and international regulations and policies were reviewed as they pertain to civil aviation, and then applied to military aviation. Critical technical standards documents were reviewed to determine the best strategy for complying with civil and international regulations. Lessons learned from previous E-2C navigation system evaluations were also reviewed and incorporated within this compliance strategy. Compliance and self-certification responsibilities belong to aircraft specific program managers within the Navy’s acquisition organization. Sophisticated navigation systems incorporating satellite positioning technology require a tailored approach toward compliance demonstration. Military receivers with precise positioning capability satisfy many of the required availability, accuracy and containment standards. To satisfy civil requirements, correctly keyed, military navigation systems may be evaluated according to standards typically applied to the most highly augmented standard civil systems. This thesis contains a comprehensive list of compliance items selected for their applicability to the E-2C Hawkeye mission.

The scientific objective of this study is to design an aircraft flight experiment that will provide airborne imaging data, augmenting satellite data, to advance the fundamental understanding of polar mesospheric clouds (PMCs). By capturing simultaneous top and bottom views of the PMCs, these airborne images will both provide insight into the time evolution of PMCs, and into the micro-features of these clouds, from which gravity waves and other details of the clouds vertical structures may be obtained. These data may help us better understand the driving mechanisms of these clouds and ultimately those elements of global climatic change, which are believed to cause their expanding presence. The proposed imager will use a similar charged-coupled device and interface as that of the Aeronomy of Ice in the Mesosphere’s (AIM’s) Cloud Imager and Particle Size (CIPS) imager and will observe the clouds in both the visible spectra and in a near-ultraviolet spectrum closer to the sensitivity of the CIPS imager. The sensor is to be integrated aboard UTSIs Piper Navajo. Algorithms for satellite intercept trajectories and airborne imager positioning are developed for flight campaigns, scheduled for the 2007 Boreal Summer along a series of airstrips in both Northern Quebec and Alaska.

A self-contained, portable, inertial and positional measurement system was developed and tested for an HGU-55 model fighter pilot helmet. The system, designated the Portable Helmet Instrumentation System (PHIS), demonstrated the recording of accelerations and rotational rates experienced by the human head in a flight environment. A compact, self-contained, “knee-board” sized computer recorded these accelerations and rotational rates during flight. The present research presents the results of a limited evaluation of this helmet-mounted instrumentation system flown in an Extra 300 fully aerobatic aircraft. The accuracy of the helmet-mounted, inertial head tracker system was compared to the aircraft-mounted referenced system. The ability of the Portable Helmet Instrumentation System to record position, orientation and inertial information in ground and flight conditions was evaluated. The capability of the Portable Helmet Instrumentation System to provide position, orientation and inertial information with sufficient fidelity was evaluated. The concepts demonstrated in this system are: 1) calibration of the inertial sensing element without external equipment 2) the use of differential inertial sensing equipment to remove the accelerations and rotational rates of a moving vehicle from the pilot’s head-tracking measurements 3) the determination of three-dimensional position and orientation from three corresponding points using a range sensor. The range sensor did not operate as planned. The helmet only managed to remain within the range sensor’s field of view for 37% of flight time. Vertical accelerations showed the greatest correlation when comparing helmet measurements to aircraft measurements. The PHIS operated well during level flight.

An extended Kalman filter is modified to support only magnetometer data as a measurement for spacecraft attitude information. Actual on-orbit data from a student satellite is used in the filter from three different time periods and varying data frequencies. The extended Kalman filter has a thermal model that utilizes external temperature data as a verification tool for filter convergence and for parameter tuning. It can capture the frequency of temperature changes and the correct side panel being lit by the sun as long as the filter converges properly, but not the magnitude of the temperature at a specific time. A solar panel power model is also attempted, which was found to be unusable due to power budget issues and the side panel current sensors railing. Convergence of the three sets of data showed that a 30 second snapshot rate converges to a more accurate attitude information when the satellite has a 0.1 rev/min rotation rate compared to the 1.0 rev/min rotation rate data. A 10 second snapshot rate gives more accurate attitude information for data from a satellite with a 1.0 rev/min rotation rate. By investigating the drastic reduction in the satellite’s rotation rate over 6 months, it was discovered that the satellite’s antenna is most likely magnetized, causing it to try to align itself with the Earth’s magnetic field, slowing down the rotation rate of the satellite from 1 rev/min to 0.1 rev/min.

This thesis is a brief look at a new solution to a problem that has been approached in many different ways in the past - the N body problem. By focusing on planetary systems, satellite dynamics can be modeled in a fashion similar to the Circular Restricted Three Body Problem (CR3BP) with the Circular Restricted N Body Problem (CRNBP). It was found that this new formulation of the dynamics can then utilize the tools created from all the research into the CR3BP to reassess the possibility of different complex trajectories in systems where there are more than just two large gravitational bodies affecting the dynamics, namely periodic and semi-periodic orbits, halo orbits, and low energy transfers It was also found that not only system dynamics, but models of the Jacobi constant could also be formulated similarly to the CR3BP. Validating the authenticity of these new sets of equations, the CRNBP dynamics are applied to a satellite in the Earth-Moon system and compared to a simulation of the CR3BP under identical circumstances. This test verified the dynamics of the CRNBP, showing that the two systems created almost identical results with relatively small deviations over time and with essentially identical path trends. In the Jovian system, it was found the mass ratio required to validated the assumptions required to integrate the equations of motion was around .1$\%$. Once the mass ratio grew past that limit, trajectories propagated with the CRNBP showed significant deviation from trajectories propagated with a higher fidelity model of Newtonian motion. The results from the derivation of the Jacobi constant are consistent with the 3 body system, but they are fairly standalone.

The use of Unmanned Aerial Vehicles (UAVs) are rapidly expanding and taking on new roles in the military. In the area of training and targeting vehicles, control systems are expanding the functionality of UAVs beyond their initially designed purpose. Aeromech Engineering’s NXT UAV is a high speed target drone that is intended to simulate a small aircraft threat. However, in the interest of increasing functionality, enabling NXT to accomplish wings level skidding turns provides the basis for a UAV that can simulate a threat from a missile. Research was conducted to investigate the aerodynamic and performance characteristics of a winged vehicle performing high acceleration skidding turns. Initially, a linear model was developed using small disturbance theory. The model was further improved by developing a six degree of freedom simulation. A controller using four loop closures and utilizing both rudder and aileron for control was developed. Any outside guidance system that navigates using a heading command can easily be integrated into this controller design. Simulations show this controller enables the NXT UAV to accomplish up to 3 G wings level skidding turns. Further testing, showed that the controller was able to tolerate significant turbulence, sensor noise, loop failures and changes within the plant dynamics. This research shows how it is possible for a winged UAV to easily maneuver using wings level skid turns.

This thesis addresses the problem of how to control an autonomous mobile robot navigation in indoor environments, in the face of sensor noise, imprecise information, uncertainty and limited response time. The thesis argues that the effective control of autonomous mobile robots can be achieved by organising low level and higher level control activities into a layered architecture. The low level reactive control allows the robot to respond to contingencies quickly. The higher level control allows the robot to make longer term decisions and arranges appropriate sequences for a task execution. The thesis describes the design and implementation of a two layer control architecture, a task template based sequencing layer and a fuzzy behaviour based low level control layer. The sequencing layer works at the pace of the higher level of abstraction, interprets a task plan, mediates and monitors the controlling activities. While the low level performs fast computation in response to dynamic changes in the real world and carries out robust control under uncertainty. The organisation and fusion of fuzzy behaviours are described extensively for the construction of a low level control system. A learning methodology is also developed to systematically learn fuzzy behaviours and the behaviour selection network and therefore solve the difficulties in configuring the low level control layer. A two layer control system has been implemented and used to control a simulated mobile robot performing two tasks in simulated indoor environments. The effectiveness of the layered control and learning methodology is demonstrated through the traces of controlling activities at the two different levels. The results also show a general design methodology that the high level should be used to guide the robot's actions while the low level takes care of detailed control in the face of sensor noise and environment uncertainty in real time.