This study adapts some established target tracking techniques for use in the maritime surface surveillance role and tests them with computer generated data. Computer simulation of a track splitting tracker capable of operating in this undersampled and asynchronous environment is presented. The tracker uses standard and extended Kalman Filter algorithms to estimate target state from latitude and longitude or line of bearing position measurements. Prior to state estimation, all measurements are...

Topics: Multitarget Tracking, Track-Splitting Tracker, Kalman Filters

The tracking of space objects requires frequent and accurate monitoring for collision avoidance. As even collision events with very low probability are important, accurate prediction of collisions require the representation of the full probability density function (PDF) of the random orbit state. Through representing the full PDF of the orbit state for orbit maintenance and collision avoidance, we can take advantage of the statistical information present in the heavy tailed distributions, more...

Topics: NASA Technical Reports Server (NTRS), PROBABILITY THEORY, KALMAN FILTERS, COLLISION AVOIDANCE,...

Electrolytic capacitors are used in several applications ranging from power supplies for safety critical avionics equipment to power drivers for electro-mechanical actuator. Past experiences show that capacitors tend to degrade and fail faster when subjected to high electrical or thermal stress conditions during operations. This makes them good candidates for prognostics and health management. Model-based prognostics captures system knowledge in the form of physics-based models of components in...

Topics: NASA Technical Reports Server (NTRS), BAYES THEOREM, CAPACITORS, ELECTROLYTES, MODELS, LIFE...

The development of a digital automatic control law for a small jet transport to perform a steep final approach in automatic landings is reported along with the development of a steady-state Kalman filter used to provide smooth estimates to the control law. The control law performs the functions of localizer and glides capture, localizer and glideslope track, decrab, and place. The control law uses the microwave landing system position data, and aircraft body-mounted accelerators, attitude and...

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT GUIDANCE, AUTOMATIC LANDING CONTROL, CONTROL THEORY,...

There are no author-identified significant results in this report.

Topics: NASA Technical Reports Server (NTRS), DATA PROCESSING, LARGE AREA CROP INVENTORY EXPERIMENT, USER...

A technique to deduce the virtual temperature from the combined use of the equations of fluid dynamics, observed wind and observed radiances is described. The wind information could come from ground-based sensitivity very high frequency (VHF) Doppler radars and/or from space-borne Doppler lidars. The radiometers are also assumed to be either space-borne and/or ground-based. From traditional radiometric techniques the vertical structure of the temperature can be estimated only crudely. While it...

Topics: NASA Technical Reports Server (NTRS), DOPPLER RADAR, FLUID DYNAMICS, METEOROLOGICAL RADAR,...

Rotorcraft operating in high-threat environments fly close to the surface of the earth to utilize surrounding terrain, vegetation, or man-made objects to minimize the risk of being detected by the enemy. Two basic requirements for obstacle avoidance are detection and range estimation of the object from the current rotorcraft position. There are many approaches to the estimation of range using a sequence of images. The approach used in this analysis differes from previous methods in two...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, AUTONOMOUS NAVIGATION, IMAGING TECHNIQUES, KALMAN...

This conference publication includes 32 papers and abstracts presented at the Flight Mechanics/Estimation Theory Symposium on May 22-25, 1990. Sponsored by the Flight Dynamics Division of Goddard Space Flight Center, this symposium features technical papers on a wide range of issues related to orbit-attitude prediction, determination and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry,...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMICS, ATTITUDE (INCLINATION), CONFERENCES, ESTIMATES,...

A prototype of a versatile, observer-based magnetic bearing controller for aerospace flywheels was successfully developed and demonstrated on a magnetic bearing test rig (see the photograph) and an actual flywheel module. The objective of this development included a fast, yet low risk, control development process, and a robust, high-performance controller for a large variety of flywheels. This required a good system model, an efficient development procedure, and a model-based controller that...

Topics: NASA Technical Reports Server (NTRS), CONTROLLERS, FLYWHEELS, MAGNETIC BEARINGS, AEROSPACE...

A method which will be used to update the alignment of the Aeroassist Flight Experiment's Inertial Measuring Unit is simulated and analyzed. This method, the Star Line Maneuver, uses measurements from the Space Shuttle Orbiter star trackers along with an extended Kalman filter to estimate a correction to the attitude quaternion maintained by an Inertial Measuring Unit in the Orbiter's payload bay. This quaternion is corrupted by on-orbit bending of the Orbiter payload bay with respect to the...

Topics: NASA Technical Reports Server (NTRS), AEROASSIST, COMPUTERIZED SIMULATION, INERTIAL NAVIGATION,...

A real-time, high-rate precision navigation Kalman filter algorithm is developed and analyzed. This Navigation algorithm blends various navigation data collected during terminal area approach of an instrumented helicopter. Navigation data collected include helicopter position and velocity from a global position system in differential mode (DGPS) as well as helicopter velocity and attitude from an inertial navigation system (INS). The goal of the Navigation algorithm is to increase the DGPS...

Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AIRSPEED, ALGORITHMS, APPROACH, INERTIAL...

277
277

Jun 3, 2011
06/11

by
Tsao, Jen-Chin

texts

######
eye 277

######
favorite 0

######
comment 0

The present study examines the impact of large-scale cross flow on the creation of ice roughness elements on the leading edge of a swept wing under glaze icing conditions. A three-dimensional triple-deck structure is developed to describe the local interaction of a 3 D air boundary layer with ice sheets and liquid films. A linear stability analysis is presented here. It is found that, as the sweep angle increases, the local icing instabilities enhance and the most linearly unstable modes are...

Topics: ALGORITHMS, KALMAN FILTERS, VECTORS (MATHEMATICS), EULER EQUATIONS OF MOTION, CONTROLLERS, FAR UV...

A class of detection-estimation problems on matrix Lie groups is defined in which the observation noise is multiplicative in nature. By examining the differential versions of the hypotheses, which are bilinear in nature, it is possible to derive the relevant likelihood ratio formula and the associated optimal estimation equations for the signal given the observations and the assumption that the signal is present. These estimation equations are of interest in their own right, in that they...

Topics: NASA Technical Reports Server (NTRS), LIE GROUPS, SIGNAL DETECTION, SIGNAL TO NOISE RATIOS,...

No abstract available

Topics: NASA Technical Reports Server (NTRS), NUMERICAL WEATHER FORECASTING, SOIL MOISTURE, SALINITY,...

This report presents algorithms that can be utilized in a GPS receiver to convert satellite-to-receiver pseudo-ranges to receiver position estimates. The report discusses a method that is used to determine instantaneous estimates of receiver position and then goes on to develop three Kalman filter based estimators, which use stationary receiver, low dynamics, and high dynamics models for the receiver motion, respectively. These particular dynamic models are utilized because they are commonly...

Topics: DTIC Archive, Sarunic,Peter W, Defence Science and Technology Group Edinburgh, South Australia...

239
239

Jun 13, 2011
06/11

by
Parsons-Wingerter, Patricia; McKay, Terri L.; Leontiev, Dmitry; Condrich, Terence K.; DiCorleto, Paul E

texts

######
eye 239

######
favorite 0

######
comment 0

The development of effective vascular therapies requires the understanding of all modes of vessel formation contributing to vasculogenesis, angiogenesis (here termed hemangiogenesis) and lymphangiogenesis. We show that lymphangiogenesis proceeds by blind-ended vessel sprouting via recruitment of isolated endothelial progenitor cells to the tips of growing vessels, whereas hemangiogenesis occurs by non-sprouting vessel expansion from the capillary network, during middevelopment in the quail...

Topics: ATTITUDE (INCLINATION), KALMAN FILTERS, NONLINEAR FILTERS, SATELLITE ORIENTATION, NONLINEARITY

435
435

Jul 21, 2010
07/10

by
NON

texts

######
eye 435

######
favorite 0

######
comment 0

A test bench was designed and fabricated for the purpose of improving control of hot-spot test accuracy. Electrochemical corrosion research focused on corrosion mechanisms to which both crystalline and a-Si modules may be subjected in central station applications. A variety of cells and several designs were subjected to accelerated stress tests. Humiditiy degradation rates were determined and key electrochemical failure mechanisms were identified. Software was developed for the prediction of...

Topics: DATA ACQUISITION, CHIPS (ELECTRONICS), HALLEY'S COMET, HOLOGRAPHY, KALMAN FILTERS, OPTICAL...

The Magnetospheric Multiscale (MMS) mission consists of four identically instrumented, spin-stabilized observatories, elliptically orbiting the Earth in a tetrahedron formation. For the operational success of the mission, on-board systems must be able to deliver high-precision orbital adjustment maneuvers. On MMS, this is accomplished using feedback from on-board star sensors in tandem with accelerometers whose measurements are dynamically corrected for errors associated with a spinning...

Topics: NASA Technical Reports Server (NTRS), KALMAN FILTERS, ATTITUDE (INCLINATION), SPIN STABILIZATION,...

2,251
2.3K

texts

######
eye 2,251

######
favorite 0

######
comment 0

This special bibliography includes research on reusable launch vehicles, aerospace planes, shuttle replacement, crew/cargo transfer vehicle, related X-craft, orbital space plane, and next generation launch technology.

Topics: KALMAN FILTERS, ATTITUDE (INCLINATION), MATHEMATICAL MODELS, SPACECRAFT CONTROL, QUATERNIONS,...

405
405

Jun 13, 2011
06/11

by
Epp, L.; Khan, P.; Silva, A

texts

######
eye 405

######
favorite 0

######
comment 0

Motivated by recent advances in wide-bandgap (WBG) gallium nitride (GaN) semiconductor technology, there is considerable interest in developing efficient solid-state power amplifiers (SSPAs) as an alternative to the traveling-wave tube amplifier (TWTA) for space applications. This article documents proof-of-concept hardware used to validate power-combining technologies that may enable a 120-W, 40 percent power-added efficiency (PAE) SSPA. Results in previous articles [1-3] indicate that...

Topics: ATTITUDE (INCLINATION), NUMERICAL INTEGRATION, STABILIZED PLATFORMS, KALMAN FILTERS, STATE VECTORS,...

279
279

Jun 12, 2011
06/11

by
Guggilla, Padmaja; Batra, A. K.; Currie, J. R.; Aggarwal, M. D.; Penn, B.; Lal, R. B

texts

######
eye 279

######
favorite 0

######
comment 0

Pyroelectric and dielectric properties of modified PZT and PZ have been studied for their use in infrared detectors. Various material figure-of-merits for their use in infrared detector are calculated including when the pyroelectric element is placed on heat-sink condition. The results are compared with exiting candidate materials.

Topics: GLOBAL POSITIONING SYSTEM, NAVIGATION, KALMAN FILTERS, FEEDBACK CONTROL, FORMATION FLYING, REAL...

285
285

Jun 13, 2011
06/11

by
Bartels, Robert E.; Moses, Robert W.; Scott, Robert C.; Templeton, Justin D.; Cheatwood, F. McNeil; Gnoffo, Peter A.; Buck, Greg M

texts

######
eye 285

######
favorite 0

######
comment 0

On 14 January 2004, NASA received a mandate to return astronauts to the Moon, evolve a sustained presence there, then head out into the solar system to Mars and perhaps beyond. This new space exploration initiative directs NASA to develop human and robotic technologies that can deliver payloads larger than Apollo to the Moon, to Mars, and bring astronauts and samples safely back to Earth at costs much lower than Apollo. These challenges require creative aerospace systems. On proposed technology...

Topics: KALMAN FILTERS, ENGINE TESTS, MODELS, PROPULSION SYSTEM CONFIGURATIONS, AIRCRAFT ENGINES, GAS...

Truly autonomous operation for any field robot relies on a well-defined pyramid of technical competencies. Consider the case of an autonomous car - we require the vehicle to be able to perceive its environment through noisy sensors, robustly fuse this information into an accurate representation of the world, and use this representation to plan and execute complex tasks - all the while dealing with the uncertainties inherent in real world operation. Of fundamental importance to all these...

Topics: DTIC Archive, Baldwin,Ian, University of Oxford Oxford United Kingdom, robots, OPTICAL DETECTORS,...

283
283

May 24, 2011
05/11

by
Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Chang, Sherwood; Scharberg, Maureen A

texts

######
eye 283

######
favorite 0

######
comment 0

The InfraRed (IR) spectra of UltraViolet (UV) and thermally processed, methanol-containing interstellar / cometary ice analogs at temperatures from 12 to 300 K are presented. Infrared spectroscopy, H-1 and C-13 Nuclear Magnetic Resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry indicate that CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane), HCO (the formyl radical), H2CO (formaldehyde), CH3CH2OH (ethanol), HC([double bond]O)NH2 (formamide), CH3C([double bond]O)NH2...

Topics: STRUCTURAL ANALYSIS, COVARIANCE, DEGREES OF FREEDOM, STRUCTURAL DESIGN, FEEDBACK CONTROL, MATRICES...

An Extended Kalman Filter is developed to estimate the linearized direct and indirect stiffness and damping force coefficients for bearings in rotor dynamic applications from noisy measurements of the shaft displacement in response to imbalance and impact excitation. The bearing properties are modeled as stochastic random variables using a Gauss-Markov model. Noise terms are introduced into the system model to account for all of the estimation error, including modeling errors and uncertainties...

Topics: NASA Technical Reports Server (NTRS), DAMPING, KALMAN FILTERS, ROTOR DYNAMICS, STIFFNESS,...

A landing scheme for landing V/STOL aircraft on rolling ships was sought using computerized simulations. The equations of motion as derived from hydrodynamics, their form and the physical mechanisms involved and the general form of the approximation are discussed. The modeling of the sea is discussed. The derivation of the state-space equations for the DD-963 destroyer is described. Kalman filter studies are presented and the influence of the various parameters is assessed. The effect of...

Topics: NASA Technical Reports Server (NTRS), COMPUTERIZED SIMULATION, ESTIMATES, KALMAN FILTERS, LANDING...

Translational state estimation in terminal area operations, using a set of commonly available position, air data, and acceleration sensors, is described. Kalman filtering is applied to obtain maximum estimation accuracy from the sensors but feasibility in real-time computations requires a variety of approximations and devices aimed at minimizing the required computation time with only negligible loss of accuracy. Accuracy behavior throughout the terminal area, its relation to sensor accuracy,...

Topics: NASA Technical Reports Server (NTRS), AREA NAVIGATION, AUTOMATIC FLIGHT CONTROL, DIGITAL...

The fifth monthly progress report includes corrections and additions to the previously submitted reports. The addition of the SRB propellant thickness as a state variable is included with the associated partial derivatives. During this reporting period, preliminary results of the estimation program checkout was presented to NASA technical personnel.

Topics: NASA Technical Reports Server (NTRS), DATA SMOOTHING, KALMAN FILTERS, SOLID ROCKET PROPELLANTS,...

This fourth monthly progress report again contains corrections and additions to the previously submitted reports. The additions include a simplified SRB model that is directly incorporated into the estimation algorithm and provides the required partial derivatives. The resulting partial derivatives are analytical rather than numerical as would be the case using the SOBER routines. The filter and smoother routine developments have continued. These routines are being checked out.

Topics: NASA Technical Reports Server (NTRS), DATA SMOOTHING, GROUND SUPPORT EQUIPMENT, KALMAN FILTERS,...

The mathematical developments and their computer program implementation for the Space Shuttle propulsion parameter estimation project are summarized. The estimation approach chosen is the extended Kalman filtering with a modified Bryson-Frazier smoother. Its use here is motivated by the objective of obtaining better estimates than those available from filtering and to eliminate the lag associated with filtering. The estimation technique uses as the dynamical process the six degree...

Topics: NASA Technical Reports Server (NTRS), PROPULSION SYSTEM CONFIGURATIONS, SPACE SHUTTLES, SPACECRAFT...

During the highly maneuverable aircraft technology (HiMAT) flight test program recently completed at NASA Ames Research Center's Dryden Flight Research Facility, numerous problems were experienced in airspeed calibration. This necessitated the use of state reconstruction techniques to arrive at a position-error calibration. For the HiMAT aircraft, most of the calibration effort was expended on flights in which the air data pressure transducers were not performing accurately. Following discovery...

Topics: NASA Technical Reports Server (NTRS), CALIBRATING, FLIGHT TESTS, FLOW VELOCITY, HIGHLY MANEUVERABLE...

To develop advanced control systems for optimizing aircraft engine performance, unmeasurable output variables must be estimated. The estimation has to be done in an uncertain environment and be adaptable to varying degrees of modeling errors and other variations in engine behavior over its operational life cycle. This paper represented an approach to estimate unmeasured output variables by explicitly modeling the effects of off-nominal engine behavior as biases on the measurable output...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, CONTROL SYSTEMS DESIGN, KALMAN FILTERS, STATE...

Part of the Space Mathematics Division in CNES, the Flight Dynamics Center provides attitude and orbit determinations and maneuvers during the Launch and Early Operation Phase (LEOP) of geostationary satellites. Orbit determination is based on a Kalman filter method; when the 2 GHz CNES/NASA network is used, Doppler measurements are available and allow orbit determination during the apogee maneuvers. This method was used for TELE-X and TDF 2 LEOP (3-axis controlled satellites) and also for...

Topics: NASA Technical Reports Server (NTRS), APOGEES, GROUND BASED CONTROL, KALMAN FILTERS, ORBIT...

The simulated microgravity environment aboard a KC-135 aircraft flying along a parabolic trajectory was used to study the ability of an autonomous space robot to grasp a freely translating and rotating object. Since the KC-135 cabin environment and the instrumentation for the Extravehicular Activity Helper/Retriever (EVAHR) do not provide a practical intertial reference frame, estimators based on the extended Kalman filter algorithm were used to model the relative translational dynamics of the...

Topics: NASA Technical Reports Server (NTRS), AUTOMATIC CONTROL, COMPUTER VISION, KALMAN FILTERS,...

Progress and results in the development of an integrated air quality modeling, monitoring, fault detection, and isolation system are presented. The focus was on development of distributed models of the air contaminants transport, the study of air quality monitoring techniques based on the model of transport process and on-line contaminant concentration measurements, and sensor placement. Different approaches to the modeling of spacecraft air contamination are discussed, and a three-dimensional...

Topics: NASA Technical Reports Server (NTRS), AIR QUALITY, CONTAMINANTS, SPACECRAFT CONTAMINATION, INDOOR...

Earth Observing System (EOS) spacecraft will take measurements of the Earth's clouds, oceans, atmosphere, land, and radiation balance. These EOS spacecraft are part of the National Aeronautics and Space Administration's Mission to Planet Earth, and consist of several series of satellites, with each series specializing in a particular class of observations. This paper focuses on the EOS AM-1 spacecraft, which is the first of three satellites constituting the EOS AM series (morning equatorial...

Topics: NASA Technical Reports Server (NTRS), ATTITUDE (INCLINATION), SATELLITE ATTITUDE CONTROL, EARTH...

This paper presents an iterative Linear Quadratic Gaussian (LQG) controller design approach for a linear stochastic system with an uncertain open-loop model and unknown noise statistics. This approach consists of closed-loop identification and controller redesign cycles. In each cycle, the closed-loop identification method is used to identify an open-loop model and a steady-state Kalman filter gain from closed-loop input/output test data obtained by using a feedback LQG controller designed from...

Topics: NASA Technical Reports Server (NTRS), LINEAR QUADRATIC GAUSSIAN CONTROL, DESIGN ANALYSIS,...

An innovative approach to autonomous attitude and trajectory estimation is available using only magnetic field data and rate data. The estimation is performed simultaneously using an Extended Kalman Filter (EKF), a well known algorithm used extensively in onboard applications. The magnetic field is measured on a satellite by a magnetometer, an inexpensive and reliable sensor flown on virtually all satellites in low earth orbit. Rate data is provided by a gyro, which can be costly. This system...

Topics: NASA Technical Reports Server (NTRS), KALMAN FILTERS, ATTITUDE INDICATORS, ORBITAL POSITION...

A document discusses sequential probability ratio tests that explicitly allow decision-makers to incorporate false alarm and missed detection risks, and are potentially less sensitive to modeling errors than a procedure that relies solely on a probability of collision threshold. Recent work on constrained Kalman filtering has suggested an approach to formulating such a test for collision avoidance maneuver decisions: a filter bank with two norm-inequality-constrained epoch-state extended Kalman...

Topics: NASA Technical Reports Server (NTRS), SPACECRAFT MANEUVERS, COLLISION AVOIDANCE, KALMAN FILTERS,...

Independent Earth orientation measurements taken by the space-geodetic techniques of lunar and satellite laser ranging, very long baseline interferometry, and the Global Positioning System have been combined using a Kalman filter. The resulting combined Earth orientation series, SPACE2011, consists of values and uncertainties for Universal Time, polar motion, and their rates that span from September 28, 1976, to July 13, 2012, at daily intervals and is available in versions with epochs given at...

Topics: NASA Technical Reports Server (NTRS), EARTH ORIENTATION, UNIVERSAL TIME, GLOBAL POSITIONING SYSTEM,...

A class of fault detection and identification (FDI) methods for bias-type actuator and sensor faults is explored in detail from the point of view of fault identifiability. The methods use state augmentation along with banks of Kalman-Bucy filters for fault detection, fault pattern determination, and fault value estimation. A complete characterization of conditions for identifiability of bias-type actuator faults, sensor faults, and simultaneous actuator and sensor faults is presented. It is...

Topics: NASA Technical Reports Server (NTRS), ACTUATORS, FAULT DETECTION, BIAS, KALMAN FILTERS, ADDITIVES,...

Data assimilation (DA) holds considerable potential for improving hydrologic predictions as demonstrated in numerous research studies. However, advances in hydrologic DA research have not been adequately or timely implemented in operational forecast systems to improve the skill of forecasts for better informed real-world decision making. This is due in part to a lack of mechanisms to properly quantify the uncertainty in observations and forecast models in real-time forecasting situations and to...

Topics: NASA Technical Reports Server (NTRS), HYDROLOGY, WEATHER FORECASTING, CLIMATOLOGY, ALGORITHMS, DATA...

Scheduled to launch in September 2014 atop a Delta IV Heavy from the Kennedy Space Center, the Orion Multi-Purpose-Crew-Vehicle (MPCV's) maiden flight dubbed "Exploration Flight Test -1" (EFT-1) intends to stress the system by placing the uncrewed vehicle on a high-energy parabolic trajectory replicating conditions similar to those that would be experienced when returning from an asteroid or a lunar mission. Unique challenges associated with designing the navigation system for EFT-1...

Topics: NASA Technical Reports Server (NTRS), CREW EXPLORATION VEHICLE, NAVIGATION INSTRUMENTS, FLIGHT...

The prediction of anomalies or adverse events is a challenging task, and there are a variety of methods which can be used to address the problem. In this paper, we introduce a generic framework developed in MATLAB (sup registered mark) called ACCEPT (Adverse Condition and Critical Event Prediction Toolbox). ACCEPT is an architectural framework designed to compare and contrast the performance of a variety of machine learning and early warning algorithms, and tests the capability of these...

Topics: NASA Technical Reports Server (NTRS), CONDITIONS, ANOMALIES, EVENTS, PREDICTIONS, ALGORITHMS, DATA...

This paper addresses the problems of building a functional mobile robot for urban site navigation and modeling with focus on keeping track of the robot location. We have developed a localization system that employs two methods. The first method uses odometry, a compass and tilt sensor, and a global positioning sensor. An extended Kalman filter integrates the sensor data and keeps track of the uncertainty associated with it. The second method is based on camera pose estimation. It is used when...

Topics: DTIC Archive, Georgiev,Atanas, COLUMBIA UNIV NEW YORK NEW YORK United States, ROBOTS, ROBOT...

AESOP is a computer program for use in designing feedback controls and state estimators for linear multivariable systems. AESOP is meant to be used in an interactive manner. Each design task that the program performs is assigned a "function" number. The user accesses these functions either (1) by inputting a list of desired function numbers or (2) by inputting a single function number. In the latter case the choice of the function will in general depend on the results obtained by the...

Topics: NASA Technical Reports Server (NTRS), COMPUTER AIDED DESIGN, INTERACTIVE CONTROL, KALMAN FILTERS,...

Kalman filters have been used for some time to process clock measurement data. Due to instabilities in the standard Kalman filter algorithms, the results have been unreliable and difficult to obtain. During the past several years, stable forms of the Kalman filter have been developed, implemented, and used in many diverse applications. These algorithms, while algebraically equivalent to the standard Kalman filter, exhibit excellent numerical properties. Two of these stable algorithms, the Upper...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, CLOCKS, DATA PROCESSING, DEEP SPACE NETWORK,...

An adaptive Kalman filter design that utilizes recursive maximum likelihood parameter identification is discussed. At the center of this design is the Kalman filter itself, which has the responsibility for attitude determination. At the same time, the identification algorithm is continually identifying the system parameters. The approach is applicable to nonlinear, as well as linear systems. This adaptive Kalman filter design has much potential for real time implementation, especially...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ATTITUDE (INCLINATION), KALMAN FILTERS, MAXIMUM...

Algorithms for on-board attitude determination and control of the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) have been expanded to include a constant gain Kalman filter for the spacecraft angular momentum, pulse width modulation for the reaction wheel command, an algorithm to avoid pointing the Heavy Ion Large Telescope (HILT) instrument boresight along the spacecraft velocity vector, and the addition of digital sun sensor (DSS) failure detection logic. These improved...

Topics: NASA Technical Reports Server (NTRS), ANGULAR MOMENTUM, ATTITUDE INDICATORS, BORESIGHTS, HEAVY...

A second-order form of discrete Kalman filtering equations is proposed as a candidate state estimator for efficient simulations of control-structure interactions in coupled physical coordinate configurations as opposed to decoupled modal coordinates. The resulting matrix equation of the present state estimator consists of the same symmetric, sparse N x N coupled matrices of the governing structural dynamics equations as opposed to unsymmetric 2N x 2N state space-based estimators. Thus, in...

Topics: NASA Technical Reports Server (NTRS), CONTROL SYSTEMS DESIGN, DYNAMIC STRUCTURAL ANALYSIS,...