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Gladys West and the World Positioning System – Information

Ladies’s Historical past is being celebrated all month, and we’ve 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. Study 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 posh mannequin of the Earth, and it’s possible you’ll not have heard of her although you utilize the know-how she helped develop day-after-day.

West was born on October 27, 1930, in Sutherland, Virginia and was certainly one of 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 outdoors farming. Her household could not afford faculty tuition, however she graduated valedictorian of her highschool in 1948 and obtained a full-ride scholarship to Virginia State Faculty (now often called 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 instructing math and science for a number of years.

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Supply: Hackaday

Starting in 1956, West labored at what’s now referred to as the Naval Floor Warfare Middle in Dahlgren, Virginia. When she was employed, she was the second black girl ever employed and certainly one of 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 knowledge 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 might result in the World Positioning System.

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

Like a variety of technological improvements in American (and world) historical past, GPS was born with army purposes in thoughts. Earlier methods for navigation weren’t exact sufficient, and whereas sure technological predecessors like LORAN and Transit have been getting used within the 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 receives a sign from the satellites containing their present time and placement knowledge. The receiver makes use of the alerts from a number of satellites to trilaterate its exact place on the Earth’s floor by calculating the time variations between the alerts.

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Trilateration makes use of three distances to pinpoint an actual location. Supply: GISGeography

To ensure that this technique to work correctly, there are two massive obstacles the creators wanted to deal with. First, relativity. Up in center Earth orbit, these satellites are transferring at excessive speeds of round 13,900 kilometers per hour (8,600 mph), the place time dilation may cause sizable errors. In the meantime, these of us on Earth’s floor are transferring together with its rotation, which ranges from round 1,670 km/hr (1,040 mph) on the equator all the best way right down to zero on the poles. Regardless that these relative speeds are gradual in comparison with the velocity 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 number of hundred meters!

As well as, area curvature lessens as distance from a mass will increase, so the satellites are in a weaker gravitational subject and experiencing time in a different way as a result of normal relativity. The mix of those relativistic results means the clocks on board these satellites ought to be ticking quicker than these on Earth by about 38 microseconds every day, which may add as much as massive errors after a short while. So as to account for this, GPS satellites are geared up with extremely correct atomic clocks and microcomputers that calculate time dilation for the satellites.

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Because of 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 isn’t 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 heart of mass, are variable distances from the Earth’s floor. This could trigger errors within the GPS calculations and lead to inaccurate location data.

So as 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 stage 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 as a result of 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 shade, shaded aid and vertical exaggeration (10000 scale issue).

Geoid undulation in false shade, to scale.

That is the place Gladys West got here into the image. From the mid-Seventies via the Eighties, West programmed an IBM 7030 Stretch laptop to ship more and more exact calculations to mannequin the form of the Earth; “an ellipsoid with extra undulations, often called 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 data, making it a lot much less helpful for navigation and different purposes.

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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 necessary 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 study 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 girls 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 together 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 Ladies 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 giant scale engineering tasks earlier than the period of digital methods. Her work has impacted the world greater than she knew was potential when she first began again in 1956. She has mentioned “Whenever you’re working day-after-day, you’re not considering, ‘What influence is that this going to have on the world?’ You’re considering, ‘I’ve obtained 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 improvement. For somebody used to trusting their very own calculations on paper, some outdated habits by no means die.

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

Need to study extra about GPS? You are in the fitting 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 need 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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