Apparatus and method is presented for phase detection in binary signal tracking loops wherein two bandpass detectors are alternately interchanged between electrical connection with two local code reference tracking signals in order to cancel any adverse effect of gain imbalance in the bandpass detectors and direct current offset or drift. The detectors are time shared in multiplex fashion between the two local reference signals.
Topics: NASA Technical Reports Server (NTRS), BINARY CODES, DIGITAL SYSTEMS, PHASE DETECTORS, SIGNAL...
A tracking filter that includes an output that is logarithmically proportional to the amplitude of the filtered signal is used to measure the damping exponent of a transient decay. This method is analogous to the digital technique referred to as the moving-block or peak-plot method. The method is simple to use and quite accurate, avoids the numerical computations associated with similar digital techniques, but is constrained by the poor time-domain response characteristics of commercial...
Topics: NASA Technical Reports Server (NTRS), DAMPING, SIGNAL ANALYSIS, TRACKING FILTERS, TRANSIENT...
Code excited linear prediction coding is an efficient technique for compressing speech sequences. Communications quality of speech can be obtained at bit rates below 8 Kb/s. However, relatively large coding delays are necessary to buffer the input speech in order to perform the LPC analysis. A low delay 8 Kb/s CELP coder is introduced in which the short term predictor is based on past synthesized speech. A new distortion measure that improves the tracking of the formant filter is discussed....
Topics: NASA Technical Reports Server (NTRS), CHANNELS (DATA TRANSMISSION), CODERS, LINEAR PREDICTION,...
204
204
May 23, 2011
05/11
by
Kuipers, Benjami
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In three years of NASA-sponsored research preceding this project, we successfully developed a technology for: (1) building qualitative and semi-quantitative models from libraries of model-fragments, (2) simulating these models to predict future behaviors with the guarantee that all possible behaviors are covered, (3) assimilating observations into behaviors, shrinking uncertainty so that incorrect models are eventually refuted and correct models make stronger predictions for the future. In our...
Topics: DYNAMIC RESPONSE, TIME, SYSTEM IDENTIFICATION, ON-LINE SYSTEMS, MONITORS, EXAMINATION, EVALUATION,...
Portable battery operated LORAN-C receivers were fabricated to evaluate simple envelope detector methods with hybrid analog to digital phase locked loop sensor processors. The receivers are used to evaluate LORAN-C in general aviation applications. Complete circuit details are given for the experimental sensor and readout system.
Topics: NASA Technical Reports Server (NTRS), GENERAL AVIATION AIRCRAFT, LORAN C, PHASE LOCKED SYSTEMS,...
The application of fixed lag smoothing algorithms are presented for the problem of estimation of the phase and frequency of a sinusoidal carrier received in the presence of process noise and additive observation noise. A suboptimal structure consists of a phase-locked loop (PLL) followed by a post loop correction to the phase and frequency estimates. When the PLL is operating under a high signal-to-noise ratio, the phase detector is approximately linear, and the smoother equations then...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, PHASE DETECTORS, PREDICTIONS, SMOOTHING, TRACKING...
In a delay-lock one-delta (+or - 1/2 chip) dithered PN code tracking loop, an indication of lock in the PN code tracking loop is provided by delaying the dithered local PN code by a half chip to produce a +0, -1 dithered PN code that is then multiplied with the received PN-spread IF signal to produce a signal proportional to the correlation of this dithered code offset from the received code. The correlation signal is bandpass filtered, amplified with AGC control, and square-law detected to...
Topics: NASA Technical Reports Server (NTRS), FREQUENCY DISCRIMINATORS, PHASE LOCKED SYSTEMS, TRACKING...
231
231
Jun 20, 2010
06/10
by
Kruger, B
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General equations for standard deviation, and rms standard deviation of least squares fitted polynomials applied to Apollo tracking problems
Topics: APOLLO PROJECT, TRAJECTORY ANALYSIS, WAVE PROPAGATION, POLYNOMIALS, SPACECRAFT TRACKING,...
The effects of oscillator noise on Shuttle Global Positioning System (GPS) receiver performance, GPS navigation system self-test, GPS ground transmitter design to augment shuttle navigation, the effect of ionospheric delay modelling on GPS receiver design, and GPS receiver tracking of Shuttle transient maneuvers were investigated.
Topics: NASA Technical Reports Server (NTRS), GLOBAL POSITIONING SYSTEM, SPACE SHUTTLES, SYSTEMS...
This report presents the objectives, design, testing, and data analyses of the Solar Array Flight Experiment/Dynamic Augmentation Experiment (SAFE/DAE) that was tested aboard Shuttle in September 1984. The SAFE was a lightweight, flat-fold array that employed a thin polyimide film (Kapton) as a substrate for the solar cells. Extension/retraction, dynamics, electrical and thermal tests, were performed. Of particular interest is the dynamic behavior of such a large lightweight structure in space....
Topics: NASA Technical Reports Server (NTRS), LARGE SPACE STRUCTURES, SOLAR ARRAYS, SOLAR DYNAMIC POWER...
The basic navigation solution is described for position and velocity based on range and delta range (Doppler) measurements from NAVSTAR Global Positioning System satellites. The application of discrete filtering techniques is examined to reduce the white noise distortions on the sequential range measurements. A second order (position and velocity states) Kalman filter is implemented to obtain smoothed estimates of range by filtering the dynamics of the signal from each satellite separately....
Topics: NASA Technical Reports Server (NTRS), ERROR ANALYSIS, GLOBAL POSITIONING SYSTEM, GROUND STATIONS,...
State-of-the art on phase locked loops PLL is reported by summarizing some specific results. Following a statement of the overall analysis and design objectives, results are presented in a format identifying working terminology, inherent assumptions, and references for each result. The use of PLL in tracking, synchronization, and demodulation is reemphasized, as well as the mathematical challenge involved in solving nonlinear stochastic differential equations.
Topics: NASA Technical Reports Server (NTRS), PHASE LOCKED SYSTEMS, PRODUCT DEVELOPMENT, STOCHASTIC...
T-Shaped Emitter Metal Structures for HBTs Rigorous Estimation of SNR of a PSK Communication Link Advanced Ka-Band Transceiver With Monopulse Tracking EMI Filters for Low-Temperature Applications Lightweight Electronic Camera for Research on Clouds Pilot Weather Advisor System Waveguide Power-Amplifier Module for 80 to 150 GHz Better Back Contacts for Solar Cells on Flexible Substrates Topics covered include:Tunable, Highly Stable Lasers for Coherent Lidar; Improved Photon-Emission-Microscope...
Topics: NASA Technical Reports Server (NTRS), COMMUNICATION NETWORKS, FOIL BEARINGS, LASER ALTIMETERS,...
The experiments carried out at MIT during 1984 focussed on two aspects of Loran-C relative navigation that would impact system performance at the sub-microsecond level of accuracy: tracking loop bandwidth and localized field deformation. Figures are given to illustrate the results from both effects.
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AIRBORNE RADAR APPROACH, AIRCRAFT GUIDANCE,...
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581
Jul 5, 2010
07/10
by
Romere, P. R.; Fossler, I. H
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The transonic phase of the 0.0088105-scale MSC orbiter booster separation test was conducted in the LTV 4-foot high speed wind tunnel, at Mach numbers of 0.6,0.9, 1.1, and 1.38. The purpose of this test was to define the effects of the orbiter/ booster proximity interference on the aerodynamic characteristics of the launch configuration during separation or abort maneuvers. Each model had both straight and delta wings available for variation of launch vehicle configuration concepts.
Topics: PHASE LOCKED SYSTEMS, PRODUCT DEVELOPMENT, STOCHASTIC PROCESSES, SYNCHRONIZED OSCILLATORS, TESTS,...
A digital phase-locked loop was developed and implemented for use in a low cost Loran C receiver. The digital phase-locked loop design is described and it's application to Loran C is discussed.
Topics: NASA Technical Reports Server (NTRS), DIGITAL NAVIGATION, LORAN C, TRACKING FILTERS, CMOS, LOGIC...
Monitoring the dynamic response of structures is often performed for a variety of reasons. These reasons include condition-based maintenance, health monitoring, performance improvements, and control. In many cases the data analysis that is performed is part of a repetitive decision-making process, and in these cases the development of effective on-line monitoring schemes help to speed the decision-making process and reduce the risk of erroneous decisions. This report investigates the use of...
Topics: NASA Technical Reports Server (NTRS), DYNAMIC RESPONSE, MONITORS, EXAMINATION, EVALUATION, TRACKING...
The design problem of adaptive observers applied to linear, constant and variable parameters, multi-input, multi-output systems, is considered. It is shown that, in order to keep the observer's (or Kalman filter) false-alarm rate (FAR) under a certain specified value, it is necessary to have an acceptable proper matching between the observer (or KF) model and the system parameters. An adaptive observer algorithm is introduced in order to maintain desired system-observer model matching, despite...
Topics: NASA Technical Reports Server (NTRS), ADAPTIVE FILTERS, DETECTION, FAILURE, KALMAN FILTERS,...
245
245
Jul 26, 2010
07/10
by
NON
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No Abstract Available
Topics: FREQUENCY MEASUREMENT, ROLL, SATELLITE ROTATION, SATELLITE TEMPERATURE, TEMPERATURE PROFILES,...
