  I perform an independent analysis of radio Doppler tracking data from the
Pioneer 10 spacecraft for the time period 1987-1994. All of the tracking data
were taken from public archive sources, and the analysis tools were developed
independently by myself. I confirm that an apparent anomalous acceleration is
acting on the Pioneer 10 spacecraft, which is not accounted for by present
physical models of spacecraft navigation. My best fit value for the
acceleration, including corrections for systematic biases and uncertainties, is
(8.60 +/- 1.34) x 10^{-8} cm s^{-2}, directed towards the Sun. This value
compares favorably to previous results. I examine the robustness of my result
to various perturbations of the analysis method, and find agreement to within
+/- 5%. The anomalous acceleration is reasonably constant with time, with a
characteristic variation time scale of > 70 yr. Such a variation timescale is
still too short to rule out on-board thermal radiation effects, based on this
particular Pioneer 10 data set.
