5.2 Progress on Pulsar Navigation
279
In summary, although the navigation concept using the radio pulsars was presented
in the 1970s, the XPNAV technology was proposed only 15 years ago, using the idea
of arrival-time ranging of the navigation satellite system, and increasingly attracted
the attention to the major space countries in the world. At present, the XPNAV is in
the stage of key technology research and space flight test. From the in-orbit flight
tests, the feasibility of the XPNAV system has been demonstrated preliminarily.
5.2.2 Relevant Development Programs
In 2004, the U.S. Defense Advanced Research Projects Agency (DAPAR) was
delving into creation of a “Pulsar Network” for satellite to know their exact whereabouts in space and time, also known as “military eyes pulsar navigation network”.
The idea was to create a celestial seasoning of sorts, adding a little pizzazz to the GPS
constellation of satellites in the Earth orbit. The effort was dubbed X-ray Sourcebased Navigation for Autonomous Position Determination (XNAV) Program and was
being spearheaded under the DAPAR’s tactical technology work [14]. “We’re on our
way… basically creating a pulsar network”, said Tony Tether, Director of the then
DAPAR during opening remarks at the Small Satellites: Complimentary or Disruptive Technology Conference, being held at Utah Sate University in August 2004. In
the GPS world there is a term called “Dilution of Precision (DOP)”, a measure of
the quality of the GPS data being received from the satellites. “I don’t think we’ll
have that problem with pulsars”, Tether said. “First of all, there’s lots of pulsars”,
Tether said. “What hasn’t been done is that they haven’t been characterized. It would
be useful for anywhere in the solar system… a great way to navigate around, all
over space”. The XNAV is a research and development to look into an autonomous
position, attitude and time determination system using celestial sources in the X-ray
band of the electromagnetic spectrum. The goal of the Program is to prove the feasibility and viability of the use of celestial sources, pulsars as well as neutron stars for
position, attitude and time determination of low Earth orbiting spacecrafts. Such a
capability would provide an autonomous backup system to military navigation and
communication satellites. Using the XNAV, a satellite in space would be able to find
where it is using pulsars.
The XNAV project was contracted to two research teams: one is a research team led
by Ball Aerospace & Technologies Corporation, in collaboration with Los Alamos
National Laboratory, Applied Physics Laboratory of Johns Hopkins University, and
National Institute of Standards and Technology (NIST), carried out the research
work in the project’s overall design, device development and system integration;
the other is a research team led by the NRL, which cooperated with Massachusetts
Institute of Technology (MIT) and Brookhaven National Laboratory, carried out the
studies on navigation database and X-ray detector technology. The ultimate goal of
the XNAV Program is to establish a pulsar navigation network that can provide the
279
In summary, although the navigation concept using the radio pulsars was presented
in the 1970s, the XPNAV technology was proposed only 15 years ago, using the idea
of arrival-time ranging of the navigation satellite system, and increasingly attracted
the attention to the major space countries in the world. At present, the XPNAV is in
the stage of key technology research and space flight test. From the in-orbit flight
tests, the feasibility of the XPNAV system has been demonstrated preliminarily.
5.2.2 Relevant Development Programs
In 2004, the U.S. Defense Advanced Research Projects Agency (DAPAR) was
delving into creation of a “Pulsar Network” for satellite to know their exact whereabouts in space and time, also known as “military eyes pulsar navigation network”.
The idea was to create a celestial seasoning of sorts, adding a little pizzazz to the GPS
constellation of satellites in the Earth orbit. The effort was dubbed X-ray Sourcebased Navigation for Autonomous Position Determination (XNAV) Program and was
being spearheaded under the DAPAR’s tactical technology work [14]. “We’re on our
way… basically creating a pulsar network”, said Tony Tether, Director of the then
DAPAR during opening remarks at the Small Satellites: Complimentary or Disruptive Technology Conference, being held at Utah Sate University in August 2004. In
the GPS world there is a term called “Dilution of Precision (DOP)”, a measure of
the quality of the GPS data being received from the satellites. “I don’t think we’ll
have that problem with pulsars”, Tether said. “First of all, there’s lots of pulsars”,
Tether said. “What hasn’t been done is that they haven’t been characterized. It would
be useful for anywhere in the solar system… a great way to navigate around, all
over space”. The XNAV is a research and development to look into an autonomous
position, attitude and time determination system using celestial sources in the X-ray
band of the electromagnetic spectrum. The goal of the Program is to prove the feasibility and viability of the use of celestial sources, pulsars as well as neutron stars for
position, attitude and time determination of low Earth orbiting spacecrafts. Such a
capability would provide an autonomous backup system to military navigation and
communication satellites. Using the XNAV, a satellite in space would be able to find
where it is using pulsars.
The XNAV project was contracted to two research teams: one is a research team led
by Ball Aerospace & Technologies Corporation, in collaboration with Los Alamos
National Laboratory, Applied Physics Laboratory of Johns Hopkins University, and
National Institute of Standards and Technology (NIST), carried out the research
work in the project’s overall design, device development and system integration;
the other is a research team led by the NRL, which cooperated with Massachusetts
Institute of Technology (MIT) and Brookhaven National Laboratory, carried out the
studies on navigation database and X-ray detector technology. The ultimate goal of
the XNAV Program is to establish a pulsar navigation network that can provide the