What impact do atmospheric conditions have on GPS signals?

Atmospheric conditions significantly influence GPS signals, particularly through the ionosphere and troposphere. These layers of the atmosphere can cause signal delays that affect the accuracy of positioning. The ionosphere can introduce delays due to variations in electron density, while the troposphere impacts signal travel time because of changes in temperature, pressure, and humidity. These delays can result in errors in the estimated position, causing inaccuracies in the geographic coordinates determined by the GPS system. As a result, understanding and compensating for these atmospheric delays is crucial for achieving precise GPS measurements.