Multipath tests on 64-m antennas using the Viking Orbiter-1 and -2 spacecraft as far-field illuminators

摘要

Far field multipath tests were performed on the 64-m antennas at Goldstone, DSS 14, and Madrid, DSS 63, by use of the transponders on the Viking Orbiter-1 and -2 spacecrafts. At the time of the tests, Viking Orbiter-1 and -2 spacecrafts were in their interplanetary orbits to Mars and were respectively about 21.9 million and 13.9 million km from Earth. The test results showed that the effects of multipath in the far field of the 64-m antenna were to cause less than a 5-ns peak-to-peak variation on two way range and 0.1-db peak-to-peak variations on received signal level. The multipath signal level was calculated to be approximately 40 db weaker than the primary signal in the far field main beam direction.