Il Nuovo Cimento C

, Volume 13, Issue 1, pp 169–176 | Cite as

Spacecraft Doppler tracking with a VLBI antenna

  • G. Comoretto
  • L. Iess
  • B. Bertotti
  • J. P. Brenkle
  • T. Horton
  • G. Grueff
Article

Summary

Accurate measurements of the Doppler shift of the Voyager 2 spacecraft (26 A. U.) have been performed in the period 23/7/88-12/8/88 with the 32m VLBI antenna at Medicina (BO). The device which allows the use of VLBI instrumentation for precision Doppler tracking is basically an open-loop receiver and is called digital tone extractor (DTE). Simultaneous measurements were performed at NASA's Deep Space Network (DSN) stations of the Madrid complex, using a different technique (closed loop). In the most interesting tracking configuration, the signal was transmitted inS-band (2.1 GHz) from the 70 m DSN station at Canberra (Australia), retransmitted back coherently from the spacecraft inX-band (8.4 GHz–19 W) and received 7h 6min later at Medicina and Madrid. The main purpose of the experiment was to test the capabilities of this new system and to characterize its performances. This taks has been successfully accomplished with the acquisition of high-quality data, which are presently under analysis. We plan also to compare and correlate the data with the ones acquired at Madrid stations, in order to separate out different noise contributions to the measured signal. The use of Medicina antenna as a listen-only station is planned for the gravitational wave experiment of the Ulysses spacecraft (ESA), in 1992.

PACS 95.55.Sh

Auxiliary and recording instruments 

PACS 95.55.Wk

Other instrumentation and techniques 

PACS 95.55.Pe

Lunar planetary and deep-space probes 

Riassunto

Misure di precisione dello spostamento Doppler del satellite Voyager 2 (26 U.A.) sono state effettuate dal 23-7-88 al 12-8-88 utilizzando l'antenna VLBI da 32m di Medicina (BO). Il dispositivo che permette di convertire una stazione VLBI all'inseguimento Doppler di satelliti interplanetari, chiamato estrattore digitale di tono (DTE), è stato provato con successo e ha permesso l'acquisizione di dati di buona qualità. Misure simultanee sono state effettuate dalle antenne della stazione di Madrid del Deep Space Network (NASA). L'uso dell'antenna VLBI di Medicina, equipaggiata con un DTE, è previsto durante l'esperimento di onde gravitazionali del satellite europeo Ulysses.

Резюме

В период с 23.07.88 по 12.08.88 с помошью 32 м антенны VLBI в Медичине были проведены измерения доплеровского сдвига для спутника Вояджер-2. Прибор, который позволяет использовать VLBI антенну для точного прослеживания доплеровоского сдвига, представляет приемник с открытым контуром и называется DTE. Используя разичную технику, были проведены одновременные измерения на станциях НАСА комплекса в Мадриде. Предлагается использовать VLBI антенну Медичины, снабженную DTE, в эксперименте по детектированию гравитационных волн на европейском спутнике ULYSSES в 1992 г.

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Copyright information

© Società Italiana di Fisica 1990

Authors and Affiliations

  • G. Comoretto
    • 1
  • L. Iess
    • 2
  • B. Bertotti
    • 3
  • J. P. Brenkle
    • 4
  • T. Horton
    • 4
  • G. Grueff
    • 5
  1. 1.Osservatorio Astrofisico di ArcetriFirenze
  2. 2.Istituto di Fisica dello Spazio InterplanetarioCNRFrascati (Roma)
  3. 3.Dipartimento di Fisica Nucleare e TeoricaUniversità di PaviaPavia
  4. 4.Jet Propulsion LaboratoryPasadenaUSA
  5. 5.Dipartimento di FisicaUniversità di BolognaBologna

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