Improving the CASIE SAR Images

In the summer 2009 NASA Characterization of Arctic Sea Ice Experiment (CASIE09), the microASAR, a small LFMCW SAR, was operated on the NASA Sierra unmanned aerial system (UAS). An overview of the microASAR and its role in CASIE09 are described in [1, 2]. While the limitations in the motion measurements stored with the microASAR data during the CASIE09 mission originally precluded full motion compensation, motion data collected for other CASIE sensors can be employed to improve the SAR image focus and calibration. This paper describes the methodology developed to time-align this motion data and applies this data along with other algorithm improvements to the processing of the microASAR data. This paper also presents a concise description of the backprojection image processing used

Sea Ice Topography Profiling using Laser Altimetry from Small Unmanned Aircraft Systems

Arctic sea ice is undergoing a dramatic transition from a perennial ice pack with a high prevalence of old multiyear ice, to a predominantly seasonal ice pack comprised primarily of young first-year and second-year ice. This transition has brought about changes in the sea ice thickness and topography characteristics, which will further affect the evolution and survivability of the ice pack. The varying ice conditions have substantial implications for commercial operations, international affairs, regional and global climate, our ability to model climate dynamics, and the livelihood of Arctic inhabitants. A number of satellite and airborne missions are dedicated to monitoring sea ice, but they are limited by their spatial and temporal resolution and coverage. Given the fast rate of sea ice change and its pervasive implications, enhanced observational capabilities are needed to augment the current strategies. The CU Laser Profilometer and Imaging System (CULPIS) is designed specifically for collecting fine-resolution elevation data and imagery from small unmanned aircraft systems (UAS), and has a great potential to compliment ongoing missions. This altimeter system has been integrated into four different UAS, and has been deployed during Arctic and Antarctic science campaigns. The CULPIS elevation measurement accuracy is shown to be 95 +/- 25 cm, and is limited primarily by GPS positioning error (\u3c25 \u3ecm), aircraft attitude determination error (\u3c20 \u3ecm), and sensor misalignment error (\u3c20 \u3ecm). The relative error is considerably smaller over short flight distances, and the measurement precision is shown to beprecision, the CULPIS is well suited for measuring sea ice topography, and observed ridge height and ridge separation distributions are found to agree with theoretical distributions to within 5%. Simulations demonstrate the inability of course-resolution measurements to accurately represent the theoretical distributions, with differences up to 30%. Future efforts should focus on reducing the total measurement error tochange

Diseño e implementación del procesamiento de señales SAR para estimación de la altura forestal

En el presente proyecto de tesis, se diseña e implementa el procesamiento SAR para estimación de la altura forestal, parámetro indispensable para el cálculo de la biomasa; el cual es una alternativa de gran utilidad para el proyecto “Desarrollo de tecnologías basadas en UAV para el uso de radar de apertura sintética para la estimación de la cobertura forestal en selva alta del distrito de Santa Ana en la Convención” que se realiza en la Universidad Nacional de San Antonio Abad del Cusco. La implementación del procesamiento para la generación de imágenes SAR, se realizó determinando la calidad de enfoque del algoritmo Omega-k cuyos parámetros son: resolución espacial, ISLR y PSLR. La implementación del algoritmo Omega-k se validó utilizando datos crudos SAR simulados, datos crudos SAR adquiridos por el satélite ERS-2 de la Agencia Espacial Europea (ESA), y los datos MicroASAR (Edwards, et al., 2008) por cortesía de David G. Long de Brigham Young University (Long & Stringham, 2011). Finalmente, se implementó el procesamiento utilizando la técnica de la interferometría SAR verificando con imágenes obtenidas a través del enfoque de datos crudos SAR maestro y esclavo. Adicionalmente, se validó con imágenes SAR Quad-Pol (Polarizaciones HH, HV, VH y VV) de árboles simulados con parámetros iniciales del sistema E-SAR utilizando el software PolSARproSim V6.0 desarrollado por el Dr. Mark L. Williams para la Agencia Espacial Europea

Модификация алгоритма обратного проецирования для повышения вероятности обнаружения движущихся целей при обработке данных РСА

Предмет и цель работы. Статья посвящена получению и обработке радиолокационных изображений (РЛИ) радиолокаторов с синтезированной апертурой (РСА). Целью работы является модификация известного алгоритма обратного проецирования (АОП) во временной области, который используется для создания РЛИ РСА, путем коррекции угла обзора радара на этапе обработки.Предмет і мета роботи. Статтю присвячено отриманню та обробленню радіолокаційних зображень (РЛЗ) радіолокаторів із синтезованою апертурою (РСА). Метою роботи є модифікація відомого алгоритму зворотного проеціювання (АЗП) у часовій області, який використовується для створення РЛЗ РСА, шляхом корекції кута огляду радара на етапі обробки.Subject and Purpose. The paper is concerned with Synthetic Aperture Radar (SAR) imaging and data processing and seeks to modify the conventional time-domain back projection algorithm (BPA) used for creating a SAR image. The modification consists in the radar squint-angle control at the stage of data processing

GPS-Denied Navigation Using Synthetic Aperture Radar

In most modern navigation systems, GPS is used to determine the precise location of the vehicle; however, GPS signals can easily be blocked, jammed, or spoofed. These signals can be blocked by canyons or tall buildings. Additionally, adversaries can transmit signals that either make GPS signals difficult to interpret or that imitate real GPS signals and cause a navigation system to think it is somewhere other than its true location. GPS-denied (GPS-D) navigation is the process of navigating in the absence of GPS. Many methods of performing GPS-D navigation have been proposed and explored. One such method is to use synthetic aperture radar (SAR) to provide information lost in the absence of GPS. SAR is a technique that uses radar to form images. To create high-quality SAR images, precise location information must be used. This thesis explores using the quality of SAR images to improve position accuracy. First, a method of measuring the quality of a SAR image is determined and tested. Next, a GPS-D algorithm is developed that uses this measure of SAR image quality. The algorithm is then tested on multiple sets of SAR data. The results show that the algorithm performs variably depending on the data set and the parameters of the algorithm

Autonomous, Collaborative, Unmanned Aerial Vehicles for Search and Rescue

Search and Rescue is a vitally important subject, and one which can be improved through the use of modern technology. This work presents a number of advances aimed towards the creation of a swarm of autonomous, collaborative, unmanned aerial vehicles for land-based search and rescue. The main advances are the development of a diffusion based search strategy for route planning, research into GPS (including the Durham Tracker Project and statistical research into altitude errors), and the creation of a relative positioning system (including discussion of the errors caused by fast-moving units). Overviews are also given of the current state of research into both UAVs and Search and Rescue

2010 NASA Range Safety Annual Report

this report provides a NASA Range Safety overview for current and potential range users. This report contains articles which cover a variety of subject areas, summaries of various NASA Range Safety Program activities conducted during the past year, links to past reports, and information on several projects that may have a profound impact on the way business will be done in the future. Specific topics discussed in the 2010 NASA Range Safety Annual Report include a program overview and 2010 highlights; Range Safety Training; Range Safety Policy revision; Independent Assessments; Support to Program Operations at all ranges conducting NASA launch/flight operations; a continuing overview of emerging range safety-related technologies; and status reports from all of the NASA Centers that have Range Safety responsibilities. Every effort has been made to include the most current information available. We recommend this report be used only for guidance and that the validity and accuracy of all articles be verified for updates. Once again, the web-based format was used to present the annual report