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Full-Text Articles in Aerospace Engineering

Ion Gnss Software-Defined Radio Metadata Standard, Sanjeev Gunawardena, Thomas Pany, James Curran Apr 2021

Ion Gnss Software-Defined Radio Metadata Standard, Sanjeev Gunawardena, Thomas Pany, James Curran

Faculty Publications

The past several years have seen a proliferation of software‐defined radio (SDR) data collection systems and processing platforms designed for or applicable to satellite navigation (satnav) applications. These systems necessarily produce datasets in a wide range of different formats. To correctly interpret this SDR data, essential information such as the packed sample format and sampling rate is needed. Communicating this metadata between creators and users has historically been an ad‐hoc, cumbersome, and error‐prone process. To address this issue, the satnav SDR community developed a metadata standard and normative software library to automate this process, thus simplifying the exchange of datasets …


Delayed Authentication System For Civilian Satellite, Sean M. Feschak Mar 2021

Delayed Authentication System For Civilian Satellite, Sean M. Feschak

Theses and Dissertations

This thesis presents the feasibility of a Delayed Authentication System (DAS) for civilian satellite navigation (satnav) receivers. In satnav systems, encrypted signal components are transmitted synchronously with civilian components. Hence, the civilian signals can be authenticated by detecting the presence of encrypted signal components within the received signal. To authenticate, a reference station transmits estimated encrypted signal spreading code symbols processed using a high gain antenna. In this thesis, it is shown that a 1-meter diameter dish antenna is adequate to provide a high probability of successful authentication, thereby reducing overall system complexity and cost.


Gps-Denied Localization Of Daughter-Ships In A Mother-Daughter Ship Collaborative Environment, Ethan W. Jacquin Mar 2021

Gps-Denied Localization Of Daughter-Ships In A Mother-Daughter Ship Collaborative Environment, Ethan W. Jacquin

Theses and Dissertations

This research investigates the possibility of using the communication link between a mothership and daughter-ship UAV and an Extended Kalman Filter algorithm as a replacement of GPS, assuming a ranging link exists between the mothership and daughter-ship and that the mothership is GPS-enabled. A simulation study examines the viability of the approach and the effect of parameters such as distance, altitude, roll angle, speed, ranging sensor noise, and inertial measurement unit uncertainty were considered. The magnitude of the errors between predicted and measured position were examined and a range of acceptable flight parameters was formed.


Automated Find Fix And Track With A Medium Altitude Long Endurance Remotely Piloted Aircraft, Aubrey L. Olson Mar 2021

Automated Find Fix And Track With A Medium Altitude Long Endurance Remotely Piloted Aircraft, Aubrey L. Olson

Theses and Dissertations

A limitation in RPA ISR operations is loss of target track if the command link is severed. For an RPA to effectively execute the ISR mission without a command link, it needs the capability to F2T targets autonomously. Automated Find Fix and Track (AFFTRAC) was developed to help solve this problem by demonstrating a proof of concept tactical autopilot. Monocular stereo vision was used to process sequential images acquired during orbit to produce a partial structural point cloud of the original structure. This partial structural point cloud was then exploited to create a holding area density for the aircraft to …


Modeling Aircraft Disturbance Fields For Magnetic Navigation Using Dense Anns And The Novel Manntl Architecture, Kyle A. Emery Mar 2021

Modeling Aircraft Disturbance Fields For Magnetic Navigation Using Dense Anns And The Novel Manntl Architecture, Kyle A. Emery

Theses and Dissertations

The ability to use GPS for navigation is becoming increasingly limited in certain areas of the world. Knowing this, the Air Force Research Labs is constantly looking for ways to improve alternate navigation methods such as magnetic navigation. In the interest of making advancements in aircraft disturbance field modelling, Lieutenant Emery recreates models from previous works to prove results. Lieutenant Emery also introduces a novel model architecture that attempts to mix the filtering properties of Tolles-Lawson with the non-linear capabilities of an artificial neural network. The introduction of this model could present better aircraft disturbance field modelling and in turn, …


Optimizing A Bank Of Kalman Filters For Navigation Integrity, Luis E. Sepulveda Mar 2021

Optimizing A Bank Of Kalman Filters For Navigation Integrity, Luis E. Sepulveda

Theses and Dissertations

Alternative navigation is an area of research which employs a variety of sensor technologies to provide a navigation solution in Global Navigation Satellite System degraded or denied environments. The Autonomy and Navigation Technology Center at the Air Force Institute of Technology has recently developed the Autonomous and Resilient Management of All-source Sensors (ARMAS) navigation framework which utilizes an array of Kalman Filters to provide a navigation solution resilient to sensor failures. The Kalman Filter array size increases exponentially as system sensors and detectable faults are scaled up, which in turn increases the computational power required to run ARMAS in areal-world …


Real-Time Aerial Magnetic And Vision-Aided Navigation, Daniel J. Clarke Mar 2021

Real-Time Aerial Magnetic And Vision-Aided Navigation, Daniel J. Clarke

Theses and Dissertations

Aerial magnetic navigation has shown to be a viable alternative navigation method that has the potential for world-wide availability, to include over oceans. Obtaining GPS-level accuracy using magnetic navigation alone is challenging, but magnetic navigation can be combined with other alternative navigation methods that are more posed to obtaining GPS-level accuracy in their current state. This research presents an aerial navigation solution combining magnetic navigation and vision-aided navigation to aid an inertial navigation system (INS). The navigation solution was demonstrated in real-time playback using simulated magnetic field measurements and flight-test captured visual imagery. Additionally, the navigation solution was flight-tested on …


Resilience For Multi-Filter All-Source Navigation Framework With Integrity, Jonathon S. Gipson, Robert C. Leishman Jan 2021

Resilience For Multi-Filter All-Source Navigation Framework With Integrity, Jonathon S. Gipson, Robert C. Leishman

Faculty Publications

The Autonomous and Resilient Management of All-source Sensors (ARMAS) framework monitors residual-space test statistics across unique sensor-exclusion banks of filters, (known as subfilters) to provide a resilient, fault-resistant all-source navigation architecture with assurance. A critical assumption of this architecture, demonstrated in this paper, is fully overlapping state observability across all subfilters. All-source sensors, particularly those that only provide partial state information (altimeters, TDoA, AOB, etc.) do not intrinsically meet this requirement.
This paper presents a novel method to monitor real-time overlapping position state observability and introduces an "observability bank" within the ARMAS framework, known as Stable Observability Monitoring (SOM). SOM …