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One of the assumptions leading to the ‘observed’
anomalous acceleration of Pioneer 10 toward the Sun was the earthsite motions of the sending and receiving stations That is, the predicted Doppler shifted frequency of a radar frequency sent to the spacecraft and returned to earth two light times later were used to check successive Newtonian positions and velocities of the spacecraft as it moved away from the Earth. That is, the launch and subsequent velocities imparted to the craft and calculations of the gravitational effects of Earth, Jupiter, the Sun etc were combined since the launch in 1973 to produce craft positions and velocities for each minute since the launch. Marquardt has said that there were problems in determining the craft trajectory when in this way when P10 was near Jupiter and the other planets in the first years after launch which suggests that the Doppler corrected Newtonian predictions were even more different then from the observed frequencies than accounted for by the anomalous acceleration toward the Sun. If something is wrong with the assumption as to which earthsite motions to use to obtain the Doppler shifted frequencies, the result could be continual errors, eg accelerative or decelerative trends in the discrepancy between the predicted and observed frequency. That is, a comparison of the tracking data, ie the radar frequency, constantly sent from or to and from the moving spacecraft, to the observed frequency, assuming specific earthsite motions during transmission and reception, showed unexplained discrepancies. Presumably the positions and velocities of the craft were altered to make them consistent with this tracking data. Then Newtonian calculations of the new position and velocity of the craft were made and the process repeated. It appears that at some point in time, the readjustment of the Newtonian calculated positions and velocities ceased and the ephemeris positions were based only on Newtonian calculations from this time forward. Thus at any point in time, one can look at the tracking data given minute by minute in the UTC or GMT time system and compare this to the predicted frequency given the earth site motions at the corresponding time in the CT time system. That is one can adjust the position and or velocity of the craft to make the observed frequency equal the predicted frequency,assuming specific transmission and reception earth site motions, for any specific reception time. The subsequent position and velocity of the craft based on this and the gravitational effects of the sun etc would determine the next position and velocity. A credible trajectory would be one where there were no accelerative or decelerative trends and the variation of the discrepancy between predicted and observed was small and uniformly distributed. For example: 1)Project the Madrid earthsite velocity wrt sun,V=(v1(t),v2(t),v3(t)),a vector starting at Madrid at a specific time( eg t=21:23 Oct 7 1987) onto the line between Madrid and the craft position at this same time based on an the above estimation procedure and conventional earth site motions assumptions. However we will assume in obtaining the next position and acceleration, the nearly instantaneous light delay model.v1(t)=(x(t)-x(t-1))/60sec., etc. (in this example the earthsite velocity is roughly V=30km/sec and the projected velocity on the simulataneous Madrid-craft line is roughly W= 25km per second, more exactly at this time,V=30.02755,W=25.42127). Note the projection magnitude is the sum of the cross products of the velocity components times the corresponding Madrid-craft vector components divided by the Madrid-craft distance. The angle of projection is arcos(0.879900957)= 28.36958169 deg. 2)Note that if we change the magnitude of the projected earthsite velocity at Madrid by trial and error in the spreadsheet to 24.780755, the predicted frequency minus the observed frequency is .008… Hz. This means that if the craft position is at a slightly larger angle of projection,namely arcos(24.780755/30.02755)= 34.38440, or about six degrees more, the motion of the earthsite to the craft would be reduced enough so that when the craft velocity away from the earth assumed to be the same is, subtracted, the net velocity of the earth to the craft is smaller and enough smaller to make the predicted frequency match the observed frequency to within .004Hz. Of course we could also assume a slightly larger velocity of the craft away from the earth and a smaller increase in the angle of projection of the earthsite velocity onto the line between the earthsite and the new craft position.. In this example the positions of the earth sites given by the ephemeris are 55 seconds later than the times for the frequencies in the tracking data. Thus the change in position of the Madrid earthsite wrt the Sun from 21:23 to 21:24 divided by 60 seconds and associated with the spreadsheet time, 21:24, represents the average velocity during this minute in the CT time system but in the GMT time system this is the average velocity from 21:22 to 21:23 and this produces the Rx frequency in the tracking data recorded at 21:23 etc. So we compare the spreadsheet predicted frequency for 21:24 with the observed frequency for 21:23 etc. |
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