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MORE Review of Requirements. L. Iess. With WVR. Dish deformations not included. Proposed configuration of the onboard radio system. DST. XTWTA. 8.4 GHz. 7.2 GHz. KaTWTA. 32.5 GHz. MORE. KAT+SSA. 34.3 GHz. 32.5 GHz. X Ka. X Ka.
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MOREReview of Requirements L. Iess
With WVR Dish deformations not included
Proposed configuration of the onboard radio system DST XTWTA 8.4 GHz 7.2 GHz KaTWTA 32.5 GHz MORE KAT+SSA 34.3 GHz 32.5 GHz X Ka X Ka • No intermodulation, larger output power, larger data rate • Simpler testing procedures • Onboard range delay calibration • Simpler interfaces Target accuracy: Df/f = 10-14 at 103-104s Dr= 10 cm y(1000s)=10-141.5 micron/s 1.5 mm in 1000 s
Plasma noise cancellation Multi-frequencyradio link (two-way) Target accuracy: Df/f = 10-14 at 103-104s Dr= 10 cm y=10-14 is equivalent to a one-way range rate of 1.5 micron/s The corresponding one-way displacement in 1000 s is 1.5 mm X Ka X Ka DST XSSA 8.4 GHz 7.2 GHz KAT KaTWTA 34.3 GHz 32.5 GHz Original configuration – MORE EID-B
X/X Doppler/range observable X/Ka Doppler/range observable Ka/Ka Doppler/range observable • Three unknown quantities: • non-dispersive term ( ) • uplink plasma ( ) • downlink plasma ( ) Cancellation of plasma noise with a multifrequency link [Bertotti, Comoretto, Iess, 1993]
Cancellation of plasma noise (cont.) Conclusion: The Ka/Ka link provides the crucial observable and needs the highest accuracy.