Gravity science (Juno)

[1][4] These components work together to detect minute changes in radio frequency (Doppler shift) to measure the spacecraft's velocity over time.

[5] The KaTS box was funded by the Italian Space Agency and overseen by professor Luciano Iess from University La Sapienza in Rome.

[4] KaTS detects signals coming from the DSN on Earth, and then sends replies in a very precise way that allows the velocity of Juno to be determined to within 0.001 millimeters per second.

[9] It was possible to use the data from the observations, and from just the first two Perijoves the accuracy of Jupiter's gravity field record was increased by factor of five according to one report.

[9] Additional data collections refined by understanding of the early recordings is planned for the experiment.

The gravity science experiment for Juno involves using communication hardware on Juno and Earth. Deep Space Network antenna shown here.
The Juno gravity experiment makes use of spacecraft's antenna, which are used to send radio signals to Earth with precise timing. This allows the Doppler effect to be recorded, which in turn allows the calculation of the gravity field around Jupiter.
Jupiter shown in the image 'Jupiter Marble' as recorded by Juno