Episode 48 : Is Your GPS Watch ACCURATE? The Surprising Truth ⌚

Episode 48 : Is Your GPS Watch ACCURATE? The Surprising Truth ⌚💬 Got a question or feedback? Write us at: [email protected]☕ Buy a Gel Caf for Lactate to support the work: ko-fi.com/lactateSummary: You treat the pacing data displayed on your wrist as an absolute, infallible reflection of reality, but it is actually a highly processed statistical probability. While multi-band receivers capture high-frequency radio signals to mitigate multipath interference in urban environments , raw spatial data theoretically overestimates distance due to random point scatter ; to compensate, your watch utilizes a Kalman filter that aggressively smooths curves, ultimately causing consumer devices to consistently underestimate total distance. Furthermore, your own body acts as an obstacle, with high tissue water content absorbing electromagnetic waves , while the pendulum motion of your arm swing introduces continuous Doppler shifts that severely destabilize instant pace calculations. For elite training, you must minimize reliance on real-time micro-pacing during high-intensity intervals, prioritizing manual lapping and utilizing telemetry strictly for post-hoc analysis rather than as a real-time throttle ; amateur athletes should focus entirely on lap pace to absorb spatial scatter and ensure a smoothed moving average that prevents erratic surging. Keep in mind that purely GPS-derived elevation is mathematically weaker and inherently inaccurate without a barometric altimeter , and understand that certified marathon courses are intentionally designed longer than standard to prevent short-course records. Despite the multi-billion-dollar satellite infrastructure, every legitimate marathon on Earth is still measured by an official riding a bicycle equipped with a 1971 mechanical analog device known as the Jones Counter.Keywords: telemetry, gps accuracy, kalman filter, pace, running, dual-band, multipath🎙️ Lactate, the podcast that deciphers science to improve your performance.Key references :Ranacher, P., Brunauer, R., Trutschnig, W., Van der Spek, S., & Reich, S. (2016). Why GPS makes distances bigger than they are. International Journal of Geographical Information Science, 30(2), 316-333. https://doi.org/10.1080/13658816.2015.1086924Johansson, R. E., Adolph, S. T., Swart, J., & Lambert, M. I. (2020). Accuracy of GPS sport watches in measuring distance in an ultramarathon running race. International Journal of Sports Science & Coaching, 15(5-6). https://doi.org/10.1177/1747954119899880Waegli, P., & Skaloud, A. (2009). Optimization of two kinematic trajectory estimation methods. Journal of Applied Geodesy.Tavakoli, M., et al. (2020). Accuracy of sport watches in tracking distance and pace in urban and forest environments. JMIR mHealth and uHealth, 8(6), e17118. https://doi.org/10.2196/17118Zhu, Y., et al. (2021). The effects of human body interference on the performance of a GPS antenna. IEEE Transactions on Antennas and Propagation.Voices generated by artificial intelligence from the scientific report produced by the Lactate team.