SETI public: ESA Deep Space Vessel Pulsar Navigation Study

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http://www.esa.int/gsp/ACT/mission_analysis/pulsar.htm

Pulsar Navigation Study

Millisecond pulsars offer the most reliable timing standard known to us.
Hence it appears logical to investigate if navigation in deepspace can
benefit from using this timing information. The possibility of using pulsar
signals for the positioning of spacecraft was reviewed in the Ariadna study
Feasibility study for a spacecraft navigation system relying on pulsar
timing information conducted by the Universitat Politècnica de Catalunya and
Universitat de Barcelona.

Earth-based navigation of deepspace satellites has several drawbacks: The
navigational accuracy is high only along the line-of-sight (this is still
true even if ?VLBI is taken into consideration). During Solar conjunctions
no precision navigation is possible. A remedy could come from two possible
approaches. The first one would be a positioning system based on a network
of deepspace satellites. This solution would be extremely costly. The second
possibility would be autonomous navigation. In order to enable
high-precision autonomous navigation the spacecraft position needs to be
tied to a precisely known natural reference frame. The best currently known
reference frame is set up by the positions of remote millisecond pulsars.

While exhibiting an extremely high timing stability the pulsar signals are
very weak compared to a conventional radio-tracking signal. Hence the
question arises if pulsar signals can effectively be employed for navigation
when the constraints that a deepspace mission poses to the mass and power
consumption of the navigation hardware are taken into account. The study
treated convincingly the characterisation of suitable astrophysical sources
and derived from this the minimal hardware requirements for a positioning
system. This was done for both, radio and x-ray signals. The results are
however not clear cut: A positioning accuracy of 1,000 km is attainable with
a moderate antenna size (10 m2) and a signal integration time of the order
of an hour. However simultaneous observation of several pulsars with
separate antennas seems desirable for a reduced integration time or an
enhanced accuracy. However, this seems to require prohibitively heavy
hardware.

The study report can be downloaded here:

J. Sala, A. Urruela, X. Villares, R. Estalella and J. Paredes: Feasibility
study for a spacecraft navigation system relying on pulsar timing
information.

Page last updated by Andreas Rathke 6-Oct-2004

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