This is a follow-up question to: What is the lowest power signal that the DSN can detect?
Essentially, I have determined that the asteroid Bennu (ranging from 25 to 350 million kilometers from Earth) is in view of 2 DSN dishes for 5 hours, followed by another 2 hours, per day.
I have also found that the power received from a copy of the MarCO CubeSat by a 34 meter dishes varies from about -95.7 to -118.6 dBW (these were calculated using the equation and values found in my comment below). The power sent, for reference, is about 35 dBW including transmitter gain, excluding receiver gain and distance losses.
The transponder being used is an Iris v2 (Spec sheet: https://www.jpl.nasa.gov/cubesat/pdf/Brochure_IrisV2.1_201611-URS_Approved_CL16-5469.pdf). According to the spec sheet, the maximum bandwidth available for X-band using the Iris v2 transponder is about 0.05 GHz.
The goal is purely to estimate Bennu's position by performing a differenced doppler with a MarCO CubeSat in orbit around Bennu (https://solarsystem.nasa.gov/basics/chapter13-1/). No extra information, such as sending back images, is necessarily required, though may be useful if possible. Telemetry is not critical, and can be automated on-board. How can I go about finding the ideal SNR, and verifying a successful reading? What rough data rate should be required for an accurate differenced doppler reading? How long should a signal be sent to Earth to get an accurate reading of the doppler shift?
Let me know if I need to specify or clarify anything else. Thank you.