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Gladys West and the World Positioning System – Information

Girls’s Historical past is being celebrated all month, and we now have one other story about an influential girl in science for you! Gladys West is an American mathematician who made vital contributions to the event of the World Positioning System (GPS) by creating satellite tv for pc geodesy fashions. Be taught extra about her right here!




Gladys West is an American mathematician who made vital contributions to the event of the World Positioning System by creating a fancy mannequin of the Earth, and you might not have heard of her although you utilize the know-how she helped develop every single day.

West was born on October 27, 1930, in Sutherland, Virginia and was one among seven siblings. Her household owned a small farm that she labored on as a baby, and he or she knew rising up that training can be her ticket to a world exterior farming. Her household could not afford school tuition, however she graduated valedictorian of her highschool in 1948 and obtained a full-ride scholarship to Virginia State School (now referred to as Virginia State College), a traditionally black public college. West graduated in 1952 with a Bachelor’s of Science in arithmetic, and got here again to finish her Grasp’s in arithmetic in 1955 after educating math and science for a couple of years.

Supply: Hackaday

Starting in 1956, West labored at what’s now referred to as the Naval Floor Warfare Heart in Dahlgren, Virginia. When she was employed, she was the second black girl ever employed and one among solely 4 black staff. All through her time there, the Civil Rights motion was in full swing and he or she encountered many hardships due to racism, primarily seen within the lack of recognition she obtained for her work, whereas her white colleagues obtained reward and extra privileges.

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Dr. Gladys Mae West and her husband, Ira West, one of many different few black colleagues she labored with at Dahlgren. Supply: U.S. Navy

She labored within the Dahlgren Division as a programmer for large-scale computer systems and managed tasks that analyzed information from satellites. She labored on quite a lot of cutting-edge mathematical issues there, from proving the regularity of Pluto’s moon Charon relative to Neptune to engaged on the primary satellite tv for pc that would remotely sense oceans. It was right here that she did the work that will result in the World Positioning System.

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Gladys West and Sam Smith look over information from the World Positioning System at Dahlgren in 1985

Like quite a lot of technological improvements in American (and world) historical past, GPS was born with navy functions in thoughts. Earlier programs for navigation weren’t exact sufficient, and whereas sure technological predecessors like LORAN and Transit have been getting used within the Nineteen Sixties, the Division of Protection wanted one thing that labored shortly and precisely.

GPS works through the use of a community of satellites orbiting the Earth to find out the placement of a GPS receiver. The GPS receiver sends a sign to the GPS satellites in view, asking for his or her present time and placement. The satellites every ship again a sign containing that information. The receiver makes use of the indicators from a number of satellites to trilaterate its exact place on the Earth’s floor by calculating the time variations between the indicators.

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Trilateration makes use of three distances to pinpoint a precise location. Supply: GISGeography

To ensure that this technique to work correctly, there are two large obstacles the creators wanted to deal with. First, relativity. Up in center Earth orbit, these satellites are shifting at excessive speeds of round 13,900 kilometers per hour (8,600 mph), the place time dilation could cause sizable errors. In the meantime, these of us on Earth’s floor are shifting together with its rotation, which ranges from round 1,670 km/hr (1,040 mph) on the equator all the way in which all the way down to zero on the poles. Although these relative speeds are sluggish in comparison with the pace of sunshine, even one thing as small as a miscalculated microsecond within the sign’s arrival time can result in an error within the calculated place by a couple of hundred meters!

As well as, house curvature lessens as distance from a mass will increase, so the satellites are in a weaker gravitational area and experiencing time in a different way resulting from basic relativity. The mixture of those relativistic results means the clocks on board these satellites ought to be ticking sooner than these on Earth by about 38 microseconds every day, which may add as much as large errors after a short while. With a view to account for this, GPS satellites are outfitted with extremely correct atomic clocks and microcomputers that calculate time dilation for the satellites.

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Attributable to their excessive speeds and orbits, GPS satellites are affected by relativistic time dilation. Supply: NASA

The opposite impediment confronted by scientists designing the worldwide positioning system was the Earth itself. Whereas it’s typically approximated as such, the Earth is just not an ideal sphere. It is an oblate spheroid form as a result of Earth’s rotation, which causes centripetal forces that push materials away from the axis of rotation, leading to a bulge on the equator and a flattening on the poles. Along with this, oceans, mountains and valleys trigger the Earth’s floor to be something however uniform. This implies the satellites, though a constant distance from the Earth’s middle of mass, are variable distances from the Earth’s floor. This could trigger errors within the GPS calculations and end in inaccurate location info.

With a view to make precise measurements, they wanted to have a correct understanding of altimetry, which incorporates each the peak of the planet’s floor above sea degree and the peak of any orbiting satellite tv for pc above that floor. The Earth’s oceans are large, and their peak modifications with time resulting from tides and different results like temperature and ice soften. Getting an correct mannequin of the oceans was crucial to this mission as nicely.

Geoid undulation in false coloration, shaded aid and vertical exaggeration (10000 scale issue).

Geoid undulation in false coloration, to scale.

That is the place Gladys West got here into the image. From the mid-Seventies by way of the Nineteen Eighties, West programmed an IBM 7030 Stretch pc to ship more and more exact calculations to mannequin the form of the Earth; “an ellipsoid with extra undulations, referred to as the geoid.” These fashions accounted for the Earth’s form being distorted by gravitational, tidal, and different forces. With out these calculations, GPS know-how wouldn’t have the ability to present correct location info, making it a lot much less helpful for navigation and different functions.

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The IBM 7030 Stretch’s console. Supply: Lawrence Livermore Nationwide Laboratory

All through her profession, West was extremely devoted to her work. She was tasked with extremely vital and difficult tasks, and he or she is alleged to have labored lengthy hours optimizing processing algorithms, and reduce her crew’s processing time down by half. She fairly actually wrote the information for the way forward for radar altimeter satellites by stressing the significance of accelerating satellite tv for pc geodesy’s precision with improved know-how (test it out to be taught extra about GEOSAT).

Since her retirement in 1998, Gladys West has continued to be acknowledged for her contributions to GPS know-how and her advocacy for ladies and minorities in STEM fields. After retiring, she accomplished a PhD in public administration. In 2018, she was inducted into the Air Pressure House and Missile Pioneers Corridor of Fame for her contributions to the event of the GPS along with her correct geodetic Earth mannequin. Dr. West was nominated and gained the award for “Feminine Alumna of the Yr” on the Traditionally Black Schools and Universities Awards sponsored by HBCU Digest in 2018 as an alum of Virginia State College. West was chosen by the BBC as a part of their 100 Girls of 2018. In 2021, she was awarded the Prince Philip Medal by the UK’s Royal Academy of Engineering, their highest particular person honor.

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AFSPC Vice Commander Lt. Gen. DT Thompson presents Dr. Gladys West with an award as she is inducted into the Air Pressure House and Missile Pioneers Corridor of Fame.

Throughout her time with the Navy, Gladys West was one of many computer systems who did the maths calculations by hand for these massive scale engineering tasks earlier than the period of digital programs. Her work has impacted the world greater than she knew was potential when she first began again in 1956. She has stated “While you’re working every single day, you’re not pondering, ‘What influence is that this going to have on the world?’ You’re pondering, ‘I’ve bought to get this proper.’ ”

At present, West nonetheless likes to make use of a paper map when she travels regardless of the widespread use of GPS and her integral position in its growth. For somebody used to trusting their very own calculations on paper, some outdated habits by no means die.

Be taught extra about Gladys West from an interview she did with the Navy right here:

Need to be taught extra about GPS? You are in the suitable place.

  • Take a look at a few of our previous weblog posts to go extra in depth on GPS know-how.

Have you ever used GPS? Thank Gladys West! We wish to hear about your work and what ladies have impressed you thru their innovations and exhausting work. Shoot us a tweet @sparkfun, or tell us on Instagram, Fb or LinkedIn.



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