Global Positioning System

This article provides an overview of the Global Positioning System (GPS), including its history, research, and applications. It explains how GPS works, its reliability and validity, and its use in sports and navigation. The article also discusses the advancements in GPS technology and its potential for future developments.

Global Positioning System
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Introduction
The U.S. Department of Defense owns and invented the Global Position System2. The GPS is a
satellite system used for navigation, designed by scientists in the Sputnik era at a time scientist
could track satellites with shifting radio signals well identified as “Doppler Effect.”
Brief History
With the atomic clock invention in the year 1944, the US Navy managed to perform GPS
experiments on satellite navigation during the mid-1960s for the aim of tracking their submarines
carrying nuclear weapons2. They observed the Doppler changes in pinpointing the submarine
location.
Reaching the 1970's, the U.S.A satellite defence system supported the proposed navigational
system and in 1978 founded the NAVSTAR (Navigation System with Timing and Ranging)
satellite. It used 24 satellite and was not until 1993 that it got fully operational. Recently, the
GPS is multi-purposely used other than for navigation by all, but with restrictions2.
Research and Applications
The atomic clock in GPS allows precise measurement of time and calculation of the time taken
by radio signals travelling from satellites to the Earth-based GPS receiver2. Hence, allowing the
travelled distance to be calculated, and, if four satellites or more communicate with the receiver,
the receiver’s location can be accurately triangulated. Knowing the position allows calculation of
a movement’s velocity within a given epoch and at this point, the coaches, scientist and engaged
athletes within sports become interested.

Modern GPS devices have low costs, good data storage ability and are portable, good for sports
venues' match analysis. Take the MinimaX Team Sports v4.0, it allows easy data collection, has
a 4-hour storage capacity, weighs 97 gms and is small. Through Time-Motion Analysis
application that describes an athlete’s activity profile, GPS applied in various sports are used in
comparing sports’ activity profiles. Also, players’ training activity profile can be tailored for
matching and adapting to the matches’’ activity profiles4.
Reliability and Validity of using GPS
Invalidating the use of GPS systems in sports, the paper uses the GPSports SPI-10 system that
was validated against the CBT (Computer-Based Tracking systems) 4. For a series circuit
distance measurement, the GPS results were compared with a calibrated trundle wheels
producing a systematic distance overestimation of about 5% by the GPS despite an r = 0.998
high correlation while the CBT had a 6% correlation to the trundle wheels’ distance1.
On the other hand, as the movement’s velocity increased, the GPS reliability decreased. Take an
athlete who was investigated to walk 8,800 m, produce a 1.4-2.6% CV using a 5 Hz GPS but
produced a 19.7-30.0% CV when sprinting 20 m1.
Conclusion
The Global Positioning System, used for navigational analysis, has been advancing allowing
extensive reliability and validation testing completions leading to its application in team sports3.
Additionally, GPS has allowed relationship investigation by scientists on match performances
and physical capacity. An integration of this data and other technologies is seen to greatly
increase the knowledge body within field sports activities in recent years as well as the future4.

References
1. Clemente FM, Sequeiros JB, Correia AF, Silva FG, Martins FM. Computational Metrics for
Soccer Analysis: Connecting the dots. 1st ed. Springer; 2017.
2. Kaplan ED, Hegarty C. Understanding GPS/GNSS: Principles and Applications, Third
Edition. 1st ed. Sydney: Artech House; 2017.
3.Sun J, Liu J, Yang Y, Fan S, Yu W. China Satellite Navigation Conference (CSNC) 2017
Proceedings: Volume 1. 1st ed. Darwin: Springer; 2017.
4. Vermaat M, Sebok S, Freund S, Frydenberg, M, Campbell J. Enhanced Discovering
Computers ©2017. 1st ed. Melbourne: Cengage Learning; 2019.