Nav: Home

'GPS in space': NPL and Leicester bring autonomous interplanetary travel closer to reality

August 04, 2016

  • Pulsars can be used to obtain position along a particular direction in space to an accuracy of 2km
  • Current large ground-based technology is limited by cost and number of spacecraft it can track
  • New method operates autonomously, increasing the number and capabilities of space missions
An accurate method for spacecraft navigation takes a leap forward today as the National Physical Laboratory (NPL) and the University of Leicester publish a paper that reveals a spacecraft's position in space in the direction of a particular pulsar can be calculated autonomously, using a small X-ray telescope on board the craft, to an accuracy of 2km. The method uses X-rays emitted from pulsars, which can be used to work out the position of a craft in space in 3D to an accuracy of 30 km at the distance of Neptune. Pulsars are dead stars that emit radiation in the form of X-rays and other electromagnetic waves. For a certain type of pulsar, called 'millisecond pulsars', the pulses of radiation occur with the regularity and precision of an atomic clock and could be used much like GPS in space.

The paper, published in Experimental Astronomy, details simulations undertaken using data, such as the pulsar positions and a craft's distance from the Sun, for a European Space Agency feasibility study of the concept. The simulations took these data and tested the concept of triangulation by pulsars with current technology (an X-ray telescope designed and developed by the University of Leicester) and position, velocity and timing analysis undertaken by NPL. This generated a list of usable pulsars and measurements of how accurately a small telescope can lock onto these pulsars and calculate a location. Although most X-ray telescopes are large and would allow higher accuracies, the team focused on technology that could be small and light enough to be developed in future as part of a practical spacecraft subsystem. The key findings are:
  • At a distance of 30 astronomical units - the approximate distance of Neptune from the Earth - an accuracy of 2km or 5km can be calculated in the direction of a particular pulsar, called PSR B1937+21, by locking onto the pulsar for ten or one hours respectively
  • By locking onto three pulsars, a 3D location with an accuracy of 30km can be calculated

This technique is an improvement on the current navigation methods of the ground-based Deep Space Network (DSN) and European Space Tracking (ESTRACK) network as it:
  • Can be autonomous with no need for Earth contact for months or years, if an advanced atomic clock is also on the craft. ESTRACK and DSN can only track a small number of spacecraft at a time, putting a limit on the number of deep space manoeuvres they can support for different spacecraft at any one time.
  • In some scenarios, can take less time to estimate a location. ESTRACK and DSN are limited by the time delay between the craft and Earth which can be up to several hours for a mission at the outer planets and even longer outside the solar system.
Dr Setnam Shemar, Senior Research Scientist, NPL, said:

"Our capability to explore the solar system has increased hugely over the past few decades; missions like Rosetta and New Horizons are testament to this. Yet how these craft navigate will in future become a limiting factor to our ambitions. The cost of maintaining current large ground-based communications systems based on radio waves is high and they can only communicate with a small number of craft at a time. Using pulsars as location beacons in space, together with a space atomic clock, allows for autonomy and greater capability in the outer solar system. The use of these dead stars in one form or another has the potential to become a new method for navigating in deep space and, in time, beyond the solar system."

Dr John Pye, Space Research Centre Manager, University of Leicester, concludes:

"Up until now, the concept of pulsar-based navigation has been seen just as that - a concept. This simulation uses technology in the real world and proves its capabilities for this task. Our X-ray telescope can be feasibly launched into space due to its low weight and small size; indeed, it will be part of a mission to Mercury in 2018. NPL's timing analysis capability has been developed over many years due to its long heritage in atomic clocks. We are entering a new era of space exploration as we delve deeper into our solar system, and this paper lays the foundations for a potential new technology that will get us there."
-end-
Press contacts

Alex Cloney / David Cohen / Fareha Lasker
npl@aprilsixproof.com

About the National Physical Laboratory

The National Physical Laboratory (NPL) is the UK's National Measurement Institute and one of the UK's leading science facilities and research centres. It is a world-leading centre of excellence in developing and applying the most accurate standards, science and technology available.

NPL occupies a unique position as the UK's National Measurement Institute and sits at the intersection between scientific discovery and real world application. Its expertise and original research have underpinned quality of life, innovation and competitiveness for UK citizens and business for more than a century.

Based in Teddington, Middlesex, it is a global centre of excellence in measurement and materials science. Established in 1900, has been home to a number of world-leading figures from science and engineering, including Alan Turing, recognised as the father of modern computing; Robert Watson-Watt, the inventor of radar; Donald Davies, who developed packet-switching, the basis of modern computer communications and Louis Essen who developed the world's first atomic clock. NPL continues this great tradition and is currently home to the world's most accurate clock (NPL-CsF-2), which is accurate to one second in 158 million years; and is leading thinking in areas such as graphene and carbon metrology.

http://www.npl.co.uk

About the University of Leicester

The University of Leicester is led by discovery and innovation - an international centre for excellence renowned for research, teaching and broadening access to higher education. The University of Leicester is ranked among the top one per cent of universities in the world by the THE World University Rankings and also among the top 100 leading international universities in the world. It is among the top 25 universities in the Times Higher Education REF Research Power rankings with 75% of research adjudged to be internationally excellent with wide-ranging impacts on society, health, culture, and the environment.

Find out more: https://le.ac.uk/about-us

University of Leicester

Related Solar System Articles:

From rocks in Colorado, evidence of a 'chaotic solar system'
Plumbing a 90 million-year-old layer cake of sedimentary rock in Colorado, a team of scientists from the University of Wisconsin-Madison and Northwestern University has found evidence confirming a critical theory of how the planets in our solar system behave in their orbits around the sun.
Why are there different 'flavors' of iron around the Solar System?
New work from Carnegie's Stephen Elardo and Anat Shahar shows that interactions between iron and nickel under the extreme pressures and temperatures similar to a planetary interior can help scientists understand the period in our Solar System's youth when planets were forming and their cores were created.
Does our solar system have an undiscovered planet? You can help astronomers find out
ASU's Adam Schneider and colleagues are hunting for runaway worlds in the space between stars, and citizen scientists can join the search with a new NASA-funded website.
Rare meteorites challenge our understanding of the solar system
Researchers have discovered minerals from 43 meteorites that landed on Earth 470 million years ago.
New evidence on the formation of the solar system
International research involving a Monash University scientist is using new computer models and evidence from meteorites to show that a low-mass supernova triggered the formation of our solar system.
Planet Nine could spell doom for solar system
The solar system could be thrown into disaster when the sun dies if the mysterious 'Planet Nine' exists, according to research from the University of Warwick.
Theft behind Planet 9 in our solar system
Through a computer-simulated study, astronomers at Lund University in Sweden show that it is highly likely that the so-called Planet 9 is an exoplanet.
Studying the solar system with NASA's Webb Telescope
NASA's James Webb Space Telescope will look across vast distances to find the earliest stars and galaxies and study the atmospheres of mysterious worlds orbiting other stars.
'This solar system isn't big enough for the both of us.' -- Jupiter
It's like something out of an interplanetary chess game. Astrophysicists at the University of Toronto have found that a close encounter with Jupiter about four billion years ago may have resulted in another planet's ejection from the Solar System altogether.
IBEX sheds new light on solar system boundary
In 14 papers published in the October 2015 Astrophysical Journal Supplement, scientists present findings from NASA's Interstellar Boundary Explorer, or IBEX, mission providing the most definitive analyses, theories and results about local interstellar space to date.

Related Solar System Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...