8

These maps were produced with doppler-delay imaging, which uses a combination of range and motion to identify the radar return from each specific point on the surface and build a map. Longitude is determined from doppler shift - as Venus rotates, one side of the planet is moving towards Earth while the other is moving away. Latitude is calculated from the ...


4

The DDM term is mostly used in the GNSS Reflectometry (GNSS-R) scope, but is conceptually equivalent to the radar ambiguity function. In fact, a GNSS-R system can be understood as a bistatic radar, that is to say, a configuration in which the transmitter (the GPS/Galileo/GLONASS/Beidou satellite) and the receiver (which receives the reflected signal) are ...


3

Yes, and yes. The standard Doppler data type on deep-space spacecraft is X-band to X-band, and transmit and receive are on the same antenna. Most deep-space spacecraft only have X-band transceivers. A few have more than one band, usually for either radio science reasons and/or higher data rate on Ka (accepting some added risk of weather interference). S-band ...


3

Three-way Doppler tracking was developed for when the spacecraft (specifically Voyager) is so danged far away, that by the time the round trip signal gets back to Earth the original transmitting complex has rotated out of view. Then the signal is being received at a different complex. Then there needs to be a third link between the two complexes for a phase ...


2

The DDM measures both the delay that a reflected signal takes to get back to you and the doppler (frequency) shift of that signal. In your left most figure, what you are looking at is a picture of how a GPS signal reflected off of the ocean. The bright red spot is the point of "maximum specular reflection", that is, the point directly underneath the ...


2

The two antennas need to point at Earth during morning and evening on Mars. They are oriented in opposite directions so that one can be used in the morning and one in the evening. The science goal requires continuous contact over several years, so all the relative orientation changes of the antennas due to the movement of Mars need to be taken into account. ...


2

The landing systems seem to be the key. In this paper The Rotation and Interior Structure Experiment on the InSight Mission to Mars (Folkner, W.M., Dehant, V., Le Maistre, S. et al. Space Sci Rev (2018) 214: 100. https://doi.org/10.1007/s11214-018-0530-5), it refers to using the Insight's landing system. The InSight landing system will control its azimuth ...


2

Evidently the DSS-14 does rely on separate periods of transmitting and receiving, but it is able to switch between the transmitting and receiving modes rapidly using a "quasi-optical switch". Per Perez and Bhanji 1997, Due to the large antenna to target distances, involving round - trip light times of up to several hours, duplexing in this radar system ...


1

This is probably a partial answer because I don't understand it that well myself, but the source document is so incredibly detailed that you can probably build a TDRS yourself from it, so I'm going to post an answer for those who have an interest. From TRACKING AND DATA RELAY SATELLITE SYSTEM (TDRSS) RANGE AND DOPPLER TRACKING SYSTEM OBSERVATION MEASUREMENT ...


1

Scientists routinely use the onboard transponders of deep space missions to return signals from the Deep Space Network in order to determine their distance from earth. This is briefly described in this Scientific American article. Since the furthest object ever visited by a deep space mission is Ultima Thule by the New Horizon's spacecraft, it stands to ...


1

According to the list at Wikipedia's article on Radio Astronomy, the furthest object that's been measured was probably Saturn's rings; Titan may have been further, depending on where in its orbit it was. Other radar observations of note have involved making elevation maps of Mercury and Venus, and since you asked about distance, high-precision distance ...


1

Monostatic just means the transmitter and receiver are in the same place (DSS-14), as opposed to bistatic radar where they are separate (DSS-13 transmitter, Green Bank receiver). No klystron means they don't have a functioning radar transmitter. DSS-13 will be used as the transmitter, while Green Bank will receive the radar echo. Monostatic radar requires a ...


1

It is an NHATS object. I found it on there but first I had to select 'Use Unconstrained Settings'. The default view restricts on some parameters. DeltaV is over 10 km/s. On question over the Goldstone planning info, H=26.7 is the absolute magnitude of the object. This relates to the size and reflectivity (albedo) of the object itself and is not specific to ...


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