Study of radiation-induced frequency shifts in quarz crystal oscillators

The use of commercially available components in satellite design has become more predominant in recent years. The Phoenix GPS receiver family, developed by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR), is based on a commercial off-the-shelf hardware platform. During campaigns in the laboratory as well as during satellite operation in low-earth orbit a frequency shift of the crystal oscillator which supplied the clock signal for the system was observed.We present the results of a detailed study on the effects of ionizing radiation on commercial crystal oscillators, including those used in the Phoenix GPS system, and how they can be used to estimate the total ionizing dose accumulated by on-board electronics.