Informes Técnicos
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Item Open Access A new phase measuring technique for the minitrack satellite tracking system(Instituto Geofísico del Perú, 1960) Woodman Pollitt, Ronald FranciscoA New Phase Measuring Technique has been developed as a solution to some of the present limitation of Minitrack Satellite Tracking System. Two main problems are solved, one concerned with the processing of the information and the other, with the sensitivity of the system. The present Minitrack is not a real time system. The output information has to be solved from ambiguity, smoothed, and corrected at a centralized computer location with a resultant time delay. The output of the mew system is real time, free from ambiguity, and fully corrected. It will be used to plot the satellite position in X and Y coordinates and could be used to drive telemetry, antennas or optical cameras. Its digital output is a five decimal digit directional cosine number ready for transmission to the centralized computer for orbital computation. The present Minitrack sensitivity is determined by a passive 10 cps bandwidth filter. The bandwidth is the narrowest bandwidth with linear phase vs frequency characteristics for a maximun differential doppler shift of 2 cps (approximately 2 ° per second angular rate).Item Open Access A phase-locked phase filter for the minitrack system(National Aeronautics and Space Administration, 1962-09) Woodman Pollitt, Ronald FranciscoA variable-bandwidth filter has been designed and built to narrow the postdetection bandwidth of the Minitrack satellite tracking system. It is based on phase-lock techniques. Al its narrowest bandwidth, 0.03 cps, the phase peak-topeak noise deviations are reduced to ± 1.5 percent of a wavelength for a signal strength of -140 dbm coming into the receiver "front ends". The filter introduces no phase shift or time delay regardless of the signal phase rate.Item Open Access Tracking of radio stars with the minitrack system(Editor no identificado, 1963-07) Woodman Pollitt, Ronald FranciscoThis report will discuss the possibilities of using the Minitack system with a wider predetection Bandwidth in conjunction with the Narrow Band Tracking Filter for the tracking of Radio Stars.Item Open Access Phase measurement/display subsystem for the Apollo re-entry tracking system(NASA, 1963-12-13) Woodman Pollitt, Ronald FranciscoA combined system consisting of an Interferometer and a Range System has been proposed (Reference #1) for tracking the Apollo spacecraft during the re-entry phase. The system herein discussed processes the output of the above system and performs the following functions.Item Open Access A Narrow-Band Tracking Filter(NASA, 1964-01-17) Woodman Pollitt, Ronald FranciscoThe characteristics of a servo phase-lock tracking filter is described herein. The filter tracks a 100 cps carrier with a bandwidth of either 0.3 cps or 0.03 cps. The advantages of this type filter and its use is also discussed.Item Open Access Statistical study of equatorial scintillations at Ancon, Peru(Instituto Geofísico del Perú, 1970) Tisnado, G.; Woodman Pollitt, Ronald Francisco; Pomalaza, J.The 136 MHz interferometric system at the past NASA Satellite Tracking Station in Ancón, Perú, consists of two orthogonal baselines aligned along the North-South and East-West directions. A sizable number of interferometric records intended far operational tracking was spoiled by large amplitude and phase fluctuations. Ir - regularities In the ionosphere, those associated with the spread-F phenomena, are the cause of these fluctuations (scintillations). In most of the distorted records the North-South baseline interferometer shows only a slight distort(on from the expected satellite graph whlle in the East-West interferometer the distortions are severe. This clearly shows the anisotropy of the irregularities and that they are elongated and aligned the magnetic field lines(Z) as have been found by other authors. The absence of North-South phase distortions when EastWest distortions are present facilitates the detection of weak scintillations against the background noise. Far the purpose of this report the East-West baseline interferometric distortion was taken as an indication of scintillations.Item Open Access A progress report on scintillation observations at Ancón And Jicamarca observatories(Goddard Space Flight Center, GSFC, 1970-10) Pomalaza, José; Woodman Pollitt, Ronald Francisco; Tisnado, Gilberto; Sandoval, Jaime; Guillén, AlbertoThe purpose of this report is to present a preliminary analysis of the data collected in connection with NASA contract work with ESSA (ESSA contract No. E22-9-70(N)). Under this contract a study of equatorial ionospheric irregularities using satellite transmissions is being performed.Item Open Access Jicamarca incoherent scatter observations during the march 1970 storm(World Data Center A, 1971-04) Woodman Pollitt, Ronald FranciscoThe purpose of this note is to report on ionospheric observations taken at Jicamarca (lº N Magnetic Latitude) during the March 8, 1970 magnetic storm. This report includes measurements of the electron density, electron temperature and vertical drift (or E-W electric field) for the 7, 8 and 9 of March 1970. These measurements are complemented by C-4 ionograms and magnetic field measurements taken at the Huancayo Observatory which is located at the same magnetic latitude 100 km east from the Jicamarca Observatory. We are including Huancayo AH magnetograms to illustrate our discussion. The data reported here are still under study and it is being reported in response to the request of the World Data Center A, Upper Atmosphere Geophysics, in its effort to gather world-wide data taken during the magnetic storm in a single publication. Therefore, we shall present the experimental facts limiting our discussion and conclusions to those which can be ,derived from simple inspection of the records. The techniques used to gather the data have been reported previously. The electron densities have been obtained using the Faraday rotation method and the electron temperatures using the cross correlation technique, both systems have been described by Farley [1969a,b). The technique to obtain the vertical drift (E-W electric field) is described by Woodman and Hagfors [1969). The three parameters were measured almost simultaneously. We do not have quiet day measurements of density and temperature sufficiently close to the day of the storm to be taken as a control day. The reader will have to refer to the statistical behavior of these parameters as measured at Jicamarca and reported by J. P. McClure, D. T. Farley and R.Cohen ll970J and J. P. McClure [1970). We have included here the statistical behavior of vertical drifts for the same season taken from Woodman [1970).Item Open Access Ionospheric drift velocity measurements at Jicamarca, Peru (July 1967 - March 1970)(World Data Center A, 1971-10) Balsley, Ben B.; Woodman Pollitt, Ronald FranciscoThis report is a collection of measurements of electrón drift velocity in the E and F regions of the equatorial ionosphere, made at the Jicamarca Radar Observatory (dip latitude ~1°N). The data consist of about eighty days of observations during the period July 1967 to March 1970. The measurements consist of (1) the vertical component of the electrón drift velocity in the F región, and (2) the east-west component of the electrón drift velocity in the E región. Other components of the drifts have been measured but the data are sparse and have not been included here. The horizontal component (H trace) of the magnetic field strength records of Huancayo, Perú, has also been included for reference. The purpose of this report is to make these data available to the scientific community. Comparison between these measurements and other geophysical phenomena should aid in the understanding of a variety of ionospheric and magnetospheric processes. This type of data continúes to be taken at JRO from time to time. For information regarding the more recent data, we suggest contacting either of the authors of this report. The data included in this report are also available in digital form on magnetic tape and punched cards.Item Open Access Interfase para acoplar un sistema de conversión Analógico/Digital a una computadora DATACRAFT 6024(Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 1972) Guillén C., Alberto; Woodman Pollitt, Ronald FranciscoMuchos procesos para su estudio óptimo por medio de computadoras requieren de diferentes sistemas de transducción. El presente trabajo describe el diseño de un sistema digital para acoplar un sistema de mulplex y de conversión analógica/digital a una computadora, permitiendo el procesamiento simultáneo de hasta 8 señales y con velocidades de hasta 500 mil muestras por segundo. El diseño ha aplicado al sistema de computación del Radio Observatorio de Jicamarca, uno de los observatorios del Instituto Geofísico del Perú. Este sistema permitirá el procesamiento de señales analógicas producto de diferentes proyectos de investigación científica tales como física ionosférica, sismología, infrasonido, cintilaciones, oceanografía, etc. El sistema diseñado podría adecuarse para el acoplamiento de otros sistemas de conversión analógica a otras computadoras involucradas en proyectos de investigación científica.Item Open Access Study of equatorial scintillations. A progress report(Goddard Space Flight Center, 1972-12) Pomalaza, José; Woodman Pollitt, Ronald Francisco; Tisnado, Gilberto; Nakasone, EduardoObservations of amplitude scintillations produced by F-Region ionopheric irregularities has been performed at the Ancón observatory (Latitude - 11°46', longitude 77°9') since 1968. At first minitrack interferometric records at 137 MHz were used in the studies. The purpose of this report is to present results of some of the work performed on the data during the period late 1971 and 1972.Item Open Access Implementación del software para el sistema de digitalización del ROJ(Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 1973) Hoz, César La; Woodman Pollitt, Ronald FranciscoSe ha escrito un conjunto de rutinas en el lenguaje Assembler de la computadora Datacraft 6024/3 (Ref. 1) con la finalidad de facilitar el uso eficiente del nuevo Sistema de Digitalización (Ref. 2) del R.O.J. Estos programas pueden ser invocados por otro progra ma conductor escrito en lenguaje FORTRAN. Este programa conductor es confeccionado apropiadamente por el usuario de acuerdo a su objetivo. Las rutinas que se han escrito son de un carácter completamente general. Hacen uso efectivo de las más avanzadas opciones del Sistema DC 6024/3, tales como uso extensivo de interrupciones y el empleo de Controladores de Bloque Automáticos (Automatic Block Controllers, ABC Ref. 3), que operan con el peculiar y eficiente modo de "robar un ciclo" a la Unidad Central de Procesamiento (CPU) (Ref. lf). Estas características permiten las más variadas aplicaciones del Sistema de Digitalización, obteniéndose importantes ventaja,,especialmente en el aprovechamiento máximo de la velocidad de la computadora, y posibilitándose el procesamiento en tiempo real o en línea de los datos digitalizados, en una suerte de compartición de tiempo (Time Sharing).Item Open Access Interfase y controlador para un sistema de despliegue visual (Display X-Y)(AEP, Asociación Electrotécnica Peruana, 1974) Woodman Pollitt, Ronald Francisco; González, CésarComo resultado de un Proyecto elaborado en el Radio Observatorio de Jicamarca (ROJ) se tiene el presente escrito. El ROJ dispone de un Centro de Cómputos alrededor del cual, paulatina y sistemáticamente se están enlazando otros Sistemas a modo de Unidades Periféricas. Gran parte del diseño se realiza aquí complementándose con equipo comercial. El diseño del Controlador para una Unidad de éstas es tema de este trabajo.Item Open Access Las ciencias y tecnologías espaciales en el Perú(Comisión Nacional de Investigación y Desarrollo Aeroespacial, 1974) Woodman Pollitt, Ronald FranciscoLo función de este informe es le de hacer un análisis de los actividades espaciales, las actividades directamente conectadas o ellos, y los campos en que pueden ser aprovechados, pero proporcionar a la Comisión elementos de juicio que le permiten delimitar y programar sus actividades y tomar los decisiones necesarios a la brevedad posible.Item Open Access Programación de la transformada rápida de Fourier de base 4 y 8 para procesamiento en tiempo real(Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 1975-01) Hoz, César La; Woodman Pollitt, Ronald FranciscoSe informa sobre la implementación de la transformada Rápida de Fourier para su aplicaci6n en el estimado de funciones de densidad espectral de ecos ionosféricos en tiempo real. Se hace una descripción del algoritmo básico mostrándose que la eficiencia de la TRF es proporcional por lo menos a NlogrN en lugar de N Se describen los criterios que conducen a una estructura óptima del programa, estableciéndose las relaciones que dan el número de operaciones exactas en el cálculo de la TRF de base arbitraria, Se informa que el programa de base 8 admite un ancho de banda en tiempo real de 6 kHz, ó el procesamiento espectral de 15 al turas de ecos ionosféricos con un periodo entre-pulsos de 2.5 mseg.Item Open Access A proposed VHF radar experiment in relation to stratospheric pollution problems(Instituto Geofísico del Perú, 1976-06-01) Woodman Pollitt, Ronald FranciscoThere is no need to stress here the importance of current stratospheric research motivated by possible man-made disturbances of the natural chemical equilibrium state of ozone in the stratosphere. The subject is discussed not only in the technical literature but in newspapers, magazines and television programs. This includes the effects of high flying aircraft, fluor carbon releases from aerosol cans and airconditioning units and more recently the effects of enhanced soil production of N20 as a consequence of the use of artificial fertilizers.Item Open Access Digital filtering, calibration and correlation analysis of radar-echoes from the tropo and stratosphere(Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 1978) Rüster, R.; Woodman Pollitt, Ronald FranciscoVHF-radars have been successfully used for remote sensing of the lower and middle atmosphere. The received radar-echoes are digitized and these raw data are processes in several sequential steps. By digitally filtering the raw data which is equivalent to a compression or a coherent integration, the amount of data is reduced and at the same time the signal-to-noise ratio is increased. After this preintegration procedure the compressed data are calibrated and digitally corrected. Using correlation methods the spatial and temporal variations of the echo-power as well as the velocity of the reflecting or backscattering medium are determined. Results of measurements using the Jicamarca radar facility and the SOUSY-VHF-radar are presented.Item Open Access Die prozebsteuerung und datenerfassung der SOUSY-VHF-Radaranlage(Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 1978) Kugel, R.P.; Shmidth, G.; Woodman Pollitt, Ronald FranciscoCentral unit of the radar control and data acquisition is a 21M08 hewlett packard minicomputer with a real-time-II and file-manager execute system. Together with standard periphery and analog-digital converter, a radar controller controls the preprocessor, and the antenna control are connected to the computer. The radar controller controls the synchronous radar cycle and can generate phase-coded signals. The processor reduces the data rate of 4 MW/s from the AD-converter by a factor of thousand by averaging the signals. In addition the preprocessor can decode phase-coded signals. He averaging has the effect of a combfilter.Item Restricted Synchronous programmable sequencer (SPS)(Instituto Geofísico del Perú, 1978-09) Tobaja, E.; Woodman Pollitt, Ronald Francisco; Haseltine, D.The purpose of this document is lo provide the user, the maintenance engineer, and the system programmer with the necessary information for its maintenance and use. The document provides more information than would normally be required by the average experimental user. The latter may want to limit himself to reading the following "Short. Description" and taking a quick look at the rest of the document. The SPS has been implemented on a Harris universal interface wire wrap card. This card, bought from Harris, contains all the interface element’s needed to communicate to and from the computer. They are mounted in wire wrap IC sockets and wired lo their respective pins in the channel communications cable connectors. Since the card also contains a number of 16 and 14 pins wire wrap IC sockets, the SPS logic is implemented here by populating these sockets and interconnecting them.Item Open Access El Radio Observatorio de Jicamarca(Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 1980) Woodman Pollitt, Ronald FranciscoEl Radio Observatorio de Jicamarca es esencialmente un radar científico gigantesco diseñado y construído para observar desde tierra las propiedades de la atmósfera superior. El radar es uno de la media docena de radares similares existentes en diferentes partes del mundo, cada uno de ellos a un costo de varias decenas de millones de dólares. Fue el primero de su género en construirse. Sus transmisores son capaces de producir 6,000,000 de watios de potencia, y su antena - la más grande de todos los radares del mundo - consta de cerca de 10,000 elementos, cubriendo una área de 100,000 metros cuadrados. En él se efectuan estudios desde los 15 hasta los 10,000 kms. de altura.