Search NASA⌕ Search

SEARCH · Search NASA

Results for “trajectory tracking”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

More About Gravitational Bumps And Repeating Orbits

Improved algorithm reduces computation needed to estimate dynamics affecting trajectory of satellite in orbit around Earth with approximately repeating ground track. Underlying concepts presented in "Computing Gravitational Bumps From Repeating-Orbit Data", (NPO-17925). Satellite presumed to undergo same gravitational perturbation upon each near-repetition. Tracking data from multiple nearly repeating arcs collected into segments called "bins" and processed together to reduce effects of random errors, and thereby obtain more-accurate estimates of dynamical parameters. Bumps in gravitational field of Earth estimated with less computation.

Wu, Jiun-Tsong↗
NASA NTRS1992

Galileo Earth Moon Flyby

This video has five sections. The first is a live discussion of the information that scientists hope to gain by the Galileo flyby of the Moon. This section has no introduction. There is a great deal of the discussion about the lunar craters and lunar volcanism. There is also some discussion of the composition of the far side of the moon. The second section is a short animation that shows the final step to Jupiter with particular emphasis on the gravitational assisted velocity boost, which was planned to give the spacecraft the requisite velocity to make the trip to Jupiter. The next section is an update of the status of the flyby of the Moon, and the Earth, with an explanation of the trajectory around the earth, and the moon. A photograph of the tracking station in Canberra, Australia is included. The next section is a tour of a full-scale model of the spacecraft. The last section is a discussion with the person charged with the procurement of the instrumentation aboard the spacecraft; the importance of the lunar flyby to assist in the calibration of the instruments is discussed.

Source record↗
NASA NTRS2004

Mars Exploration Rover - a new standard for interplanetary navigation

The twin Mars Exploration Rovers, Spirit and Opportunity, arrived at Mars for landings respectively at Gusev Crater (on January 4, 2004) and Meridiani Planum (on January 25, 2004). During the development of the mission, the capability of the navigation system to deliver the landers within a particular accuracy played a major role in landing site selection. This process ultimately resulted in commitments to deliver each lander within a specified landing ellipse (about 70 km x 5 km) determined to be safe for landing and also judged to be scientifically interesting. Achieving atmospheric entry delivery accuracies consistent with this landing requirement necessitated significant improvements to the interplanetary navigation system used for MER. These improvements included new processes and software for orbit determination, aggressive, mission-critical use of interferometric ADOR tracking data, propulsive maneuver design, and entry, descent, and landing (EDL) trajectory simulation. Because these advances pressed the state -of -the art, innovative methods to verify the assumptions in the pre-launch covariance analyses were also developed. The actual achieved atmospheric entry accuracies for Spirit and Opportunity significantly bettered the requirements.

navigation↗
NASA NTRS2006

Conflict Detection Using Variable Four-Dimensional Uncertainty Bounds to Control Missed Alerts

Decision-support tools for maintaining pairwise aircraft separation rely on conflict detection to alert the operator when the predicted trajectories of aircraft will result in a loss of separation. But aircraft frequently do not follow their predicted trajectories exactly. This can cause missed alerts and the failure of strategic separation procedures. We present a technique for modeling a bounded region of uncertainty around a four-dimensional predicted trajectory and an algorithm for detecting conflicts between trajectories modeled in this way that avoids missed alerts as long as the aircraft remain within the specified regions of uncertainty. In addition, we present an algorithm for detecting the intrusion of a trajectory modeled in this way into an area hazard modeled as a polygonal region. The size of the region of uncertainty can vary along the trajectory continually and independently in the along-path, cross-track, and vertical dimensions, providing an opportunity to reduce the likelihood of false alerts while protecting against typical prediction errors. The algorithm has been implemented in the Autonomous Operations Planner, a NASA Langley prototype decision support tool for airborne self-separation.

Karr, David A.↗
NASA NTRS2020

Impact of Convectively Detrained Ice Crystals on the Tropical Upper Troposphere and Lower Stratosphere

The role of convectively detrained ice crystals on the humidity of the tropical upper troposphere and lower stratosphere (UTLS) is investigated in simulations of cirrus clouds along trajectories launched from the 378K potential temperature level in the tropics. The one-dimensional (vertical) cloud model tracks individual ice crystals through their lifecycle beginning with detrainment from convection, followed by deposition growth, sedimentation and sublimation. Convective influence of the parcels is diagnosed by tracing the trajectories through time-dependent fields of convective cloud-top height adjusted to match the CloudSAT and CALIPSO statistics. Model simulations of UTLS water vapor and cloud fields are evaluated and constrained by comparison with Aura MLS and CALIPSO measurements. Preliminary results indicate sensitivity of the detrained ice crystal lifecycle to atmospheric conditions downstream of convection. Specifically, cooling (high relative humidity and supersaturation) downstream of convection leads to deposition growth and sedimentation of detrained ice crystals, resulting in net dehydration of the UTLS. In contrast, warming (low relative humidity and subsaturation) downstream of convection leads to sublimation of detrained ice crystals and subsequent hydration. As such, the impact of detrained ice crystals on the humidity of the UTLS exhibits distinct spatial variability. Detrained ice crystals predominantly dehydrate the UTLS in the tropical mean. Sensitivities to the convectively detrained ice crystal size and concentration are also examined using measurements from the StatoClim aircraft campaign. The importance of convectively detrained ice crystals will be discussed within the context of the overall contribution of convection to the lower stratospheric humidity.

Ueyama, Rei↗
NASA NTRS2019

A Global Climatology of Extratropical Transition Part I: Characteristics Across Basins

The authors present a global climatology of tropical cyclones (TCs) that undergo extratropical transition (ET). ET is objectively defined based on a TC's trajectory through the cyclone phase space (CPS), which is calculated using storm tracks from 1979-2017 best-track data and geopotential height fields from reanalysis datasets. Two reanalyses are used and compared for this purpose, the Japanese 55-year Reanalysis and the ECMWF Interim Reanalysis. The results are used to study the seasonal and geographical distributions of storms undergoing ET and inter-basin differences in the statistics of ET occurrence. About 50% of all TCs in the North Atlantic and the Western North Pacific undergo ET. In the southern hemisphere, ET fractions range from about 20% in the South Indian Ocean and the Australian region to 45% in the South Pacific. In the majority of ETs, TCs become thermally asymmetric before forming a cold core. However, a substantial fraction of TCs takes the reverse pathway, developing a cold core before becoming thermally asymmetric. This pathway is most common in the Eastern North Pacific and the North Atlantic. Different ET pathways can be linked to different geographical trajectories and environmental settings. In ETs over warmer sea-surface temperatures, TCs tend to lose their thermal symmetry while still maintaining a warm core. Landfalls by TCs undergoing ET occur 3-4 times per year in the North Atlantic and 7-10 times per year in the Western North Pacific, while coastal regions in the Australian region are affected once every 1-2 years.

Melanie Bieli↗
NASA NTRS2003

Assessing Impacts of Global Warming on Tropical Cyclone Tracks

A new approach is proposed to assess the possible impacts of the global climate change on tropical cyclone (TC) tracks in the western North Pacific (WNP) basin. The idea is based on the premise that the future change of TC track characteristics is primarily determined by changes in large-scale environmental steering flows. It is demonstrated that the main characteristics of the current climatology of TC tracks can be derived from the climatological mean velocity field of TC motion by using a trajectory model. The climatological mean velocity of TC motion, which is composed of the large-scale steering and beta drift, is determined on each grid of the basin. The mean beta drift is estimated from the best track data, and the mean large-scale steering flow is computed from the NCEP/NCAR reanalysis for the current climate state. The derived mean beta drift agrees well with the results of previous observational and numerical studies in terms of its direction and magnitude. The outputs of experiments A2 and B2 of the Geophysical Fluid Dynamics Laboratory (GFDL) R30 climate model suggest that the subtropical high will be persistently weak over the western part of the WNP or shift eastward during July-September in response to the future climate change. By assuming that the mean beta drift in the future climate state is unchanged, the change in the general circulation by 2059 will decrease the TC activities in the WNP, but favor a northward shift of typical TC tracks. As a result, the storm activities in the South China Sea will decrease by about 12%, while the Japan region will experience an increase of TCs by 12-15%. During the period of 2000-2029, the tropical storms that affect the China region will increase by 5-6%, but return to the current level during 2030-2059. It is also suggested that, during the period of 2030-2059 tropical storms will more frequently affect Japan and the middle latitude region of China given that the formation locations remain the same as in the current climate state.

Wu, Li-Guang↗
NASA NTRSDate not supplied

Trajectory Generation for Distributed Electric Propulsion Vehicles with Propeller Synchronization

In this paper, we propose a method for generating dynamically feasible trajectories for an acoustically aware vehicle with propeller phase control. The trajectory generation procedure allows both propeller phase control and navigation objectives to be considered simultaneously. The presented method is demonstrated where the mission objectives are given as a desired position and phase trajectory. From these trajectories, the full desired state of the vehicle is calculated. Furthermore, the control inputs that realize the desired mission objectives are computed. The acoustic performance for the given trajectory is estimated in terms of sound pressure level as a function of tracking performance. The method is demonstrated in simulation, where the vehicle must navigate through an urban environment with both spatial and acoustic constraints. In the presented scenario, the vehicle must follow a given flight path, and can only reduce sound pressure level by changing the propeller phase targets.

Acoustically-aware vehicle↗
NASA NTRSDate not supplied

Trajectory Generation for Distributed Electric Propulsion Vehicles with Propeller Synchronization

In this paper, we propose a method for generating dynamically feasible trajectories for an acoustically aware vehicle with propeller phase control. The trajectory generation procedure allows both propeller phase control and navigation objectives to be considered simultaneously. The presented method is demonstrated where the mission objectives are given as a desired position and phase trajectory. From these trajectories, the full desired state of the vehicle is calculated. Furthermore, the control inputs that realize the desired mission objectives are computed. The acoustic performance for the given trajectory is estimated in terms of sound pressure level as a function of tracking performance. The method is demonstrated in simulation, where the vehicle must navigate through an urban environment with both spatial and acoustic constraints. In the presented scenario, the vehicle must follow a given flight path, and can only reduce sound pressure level by changing the propeller phase targets.

acoustically-aware vehicle↗
NASA NTRS2016

Orion Exploration Flight Test 1 (EFT-1) Best Estimated Trajectory Development

The Orion Exploration Flight Test 1 (EFT-1) mission successfully flew on Dec 5, 2014 atop a Delta IV Heavy launch vehicle. The goal of Orions maiden flight was to stress the system by placing an uncrewed vehicle on a high-energy trajectory replicating conditions similar to those that would be experienced when returning from an asteroid or a lunar mission. The Orion navigation team combined all trajectory data from the mission into a Best Estimated Trajectory (BET) product. There were significant challenges in data reconstruction and many lessons were learned for future missions. The team used an estimation filter incorporating radar tracking, onboard sensors (Global Positioning System and Inertial Measurement Unit), and day-of-flight weather balloons to evaluate the true trajectory flown by Orion. Data was published for the entire Orion EFT-1 flight, plus objects jettisoned during entry such as the Forward Bay Cover. The BET customers include approximately 20 disciplines within Orion who will use the information for evaluating vehicle performance and influencing future design decisions.

Holt, Greg N.↗
NASA NTRS1985

Trajectory reconstruction and aerodynamic results from the first Discovery flight, STS-14(41-D)

Trajectory reconstruction results for the first Discovery flight are presented. Spacecraft dynamic measurements from IMU2 were utilized in conjunction with the ground based tracking data from two S-band stations, eight C-band, and five cameras at Edwards Air Force Base to determine the spacecraft trajectory from epoch through roll-out on Runway 17. Specifics as to the trajectory reconstruction are discussed in Section 1. The final inertial profile is BT14NO2/UN=169750N. Merging of this file with the final LAIRS atmosphere is discussed in Section 2. The final Extended BET is ST14BET/UN=274885C. Section 3 presents plots of relevant parameters from the AEROBET as well as aerodynamic performance comparison results. High frequency files for maneuver extraction were also generated as discussed in Section 4. Appendices are attached which contain: (1) spacecraft and physical parameters utilized, (2) final residuals obtained from the data fitting process, (3) listing of trajectory parameters, and (4) archival information.

Kelly, G. M.↗
NASA NTRS2018

Supervised Learning Applied to Air Traffic Trajectory Classification

Given the recent increase of interest in introducing new vehicle types and missions into the National Airspace System, a transition towards a more autonomous air traffic control system is required in order to enable and handle increased density and complexity. This paper presents an exploratory effort of the needed autonomous capabilities by exploring supervised learning techniques in the context of aircraft trajectories. In particular, it focuses on the application of machine learning algorithms and neural network models to a runway recognition trajectory-classification study. It investigates the applicability and effectiveness of various classifiers using datasets containing trajectory records for a month of air traffic. A feature importance and sensitivity analysis are conducted to challenge the chosen time-based datasets and the ten selected features. The study demonstrates that classification accuracy levels of 90% and above can be reached in less than 40 seconds of training for most machine learning classifiers when one track data point, described by the ten selected features at a particular time step, per trajectory is used as input. It also shows that neural network models can achieve similar accuracy levels but at higher training time costs.

Bosson, Christabelle S.↗
NASA NTRS2018

Supervised Learning Applied to Air Traffic Trajectory Classification

Given the recent increase of interest in introducing new vehicle types and missions into the National Airspace System, a transition towards a more autonomous air traffic control system is required in order to enable and handle increased density and complexity. This paper presents an exploratory effort of the needed autonomous capabilities by exploring supervised learning techniques in the context of aircraft trajectories. In particular, it focuses on the application of machine learning algorithms and neural network models to a runway recognition trajectory-classification study. It investigates the applicability and effectiveness of various classifiers using datasets containing trajectory records for a month of air traffic. A feature importance and sensitivity analysis are conducted to challenge the chosen time-based datasets and the ten selected features. The study demonstrates that classification accuracy levels of 90% and above can be reached in less than 40 seconds of training for most machine learning classifiers when one track data point, described by the ten selected features at a particular time step, per trajectory is used as input. It also shows that neural network models can achieve similar accuracy levels but at higher training time costs.

Bosson, Christabelle↗
NASA NTRS2004

Optimizing Mars Airplane Trajectory with the Application Navigation System

Planning complex missions requires a number of programs to be executed in concert. The Application Navigation System (ANS), developed in the NAS Division, can execute many interdependent programs in a distributed environment. We show that the ANS simplifies user effort and reduces time in optimization of the trajectory of a martian airplane. We use a software package, Cart3D, to evaluate trajectories and a shortest path algorithm to determine the optimal trajectory. ANS employs the GridScape to represent the dynamic state of the available computer resources. Then, ANS uses a scheduler to dynamically assign ready task to machine resources and the GridScape for tracking available resources and forecasting completion time of running tasks. We demonstrate system capability to schedule and run the trajectory optimization application with efficiency exceeding 60% on 64 processors.

Frumkin, Michael↗
DOE OSTI2025

Digital Twin for Chemical Science: a case study on water interactions on the Ag(111) surface

Directly visualizing chemical trajectories offers insights into catalysis, gas-phase reactions and photoinduced dynamics. Tracking the transformation of chemical species is best achieved by coupling theory and experiment. Here we developed Digital Twin for Chemical Science (DTCS) v.01, which integrates theory, experiment and their bidirectional feedback loops into a unified platform for chemical characterization. DTCS addresses a core question: given a set of experimental conditions, what is the expected outcome and why? It consists of a forward solver that takes a chemical reaction network and predicts spectra under experimental conditions, and an inverse solver that infers kinetics from measured spectra. We applied DTCS to ambient-pressure X-ray photoelectron spectroscopy measurements of the Ag–H2O interface as an example. This approach enables real-time knowledge extraction and guides experiments until a stopping condition is met based on accuracy and degeneracy. As a step toward autonomous chemical characterization, DTCS provides mechanistic knowledge in a verified, standardized manner.

Chemistry↗
NASA NTRS1980

A sensor for control of arterials and networks

The sensor for control of arterials and networks (SCAN) uses imaging technology and processing technology to jointly provide real-time quantification. The SCAN concept consists of a television camera mounted on a pole to obtain images of the traffic, and a microprocessor to process the image data into traffic parameters. The current activities focus on the development of SCAN for surveillance of arterials or urban highways. If these efforts are successful, an attempt will be made to extend the concept to network applications. The key software developed for the SCAN is a vehicle detection and tracking algorithm which reduces the TV image data to vehicle descriptions and trajectories. These preprocessed trajectory data can be transmitted over a phone line or can be easily reduced to a wide range of traffic parameters. A SCAN breadboard has been implemented and installed in a van which enables remote field tests and evaluations. The SCAN breadboard and its operation, evaluation, and potential applications are described.

Hilbert, E. E.↗
NASA NTRS1992

Embryogenesis and organogenesis of Carausius morosus under space flight conditions (7-IML-1)

The experiment is part of a radiobiological space research program to obtain experimental data on the biological effectiveness of the structured component of cosmic radiation during spaceflight. In this proposed experiment, Carausius morosus embryos of different ages will develop under spaceflight conditions. The experiment is designed to determine the influence of galactic heavy ions of very high energy deposition in microgravity on developmental processes of different radiation sensitivity and regenerative capacity. Layers of Carausius morosus eggs are sandwiched between different track detectors (cellulose nitrate, CR39). This method allows the localization of the trajectory of each heavy ion in the biological layer and the identification of the site of the penetration inside the egg.

Buecker, D. H.↗