Deep space Ka-band link management and Mars Reconnaissance Orbiter: long-term weather statistics versus forecasting

SUMMARYOn-going development of Ka-band capability for the Deep Space Networks (DSN) will radically increase the bandwidth available to support advanced mission concepts envisioned for future robotic as well as human exploration of Mars and beyond. While Ka-band links can operate at much higher data rate than X-band, they are much more susceptible to fluctuating weather conditions and manifest a significant tradeoff between throughput and availability. If the operating point is fixed, the maximum average throughput for deep space Ka-band link is achieved at about 80% availability, i.e. weather-related outages will occur about 20% of the time. Low availability increases the complexity of space mission operation, while higher availability would require additional link margins that lowers the overall throughput. To improve this fundamental throughput-availability trade-off, data rate adaptation based on real-time observation of the channel condition is necessary.In this paper, we model the Ka-band channel using a Markov process to capture the impact of the temporal correlation in weather conditions. We then develop a rate adaptation algorithm to optimize the data rate based on real time feedback on the measured channel conditions. Our algorithm achieves both higher throughput and link availability as compared to the constant rate scheme presently in use.

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“…where a encapsulates the rest of the terms in Equation (2). For a transmission at rate R to be successful, we must have…”

Section: Link Margin Analysismentioning

confidence: 99%

Ka‐band link optimization with rate adaptation for Mars and lunar communications

Sun

Gao

Shambayati

et al. 2007

Satell Commun Network

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“…Let us examine the case of a regenerative transponder on board the satellite, and compare its PðeÞ with that obtainable in the 1-hop downlink, the latter given by (9), (10) and (3). In this case the probability of bit error in the 2-hop downlink, for statistically independent errors and small with…”

Section: -Hop Downlink With Regenerative Transpondermentioning

confidence: 99%

Deep‐space communications with a 2‐hop downlink with high link‐availability

Matricciani

2005

Satell Commun Network

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SUMMARYWe recall and discuss the theory of a 2-hop downlink in deep-space communications. The first hop (length d 1 ) links the deep-space spacecraft to either a geostationary satellite or to a low Earth orbiting satellite. The second hop (length d 2 ; with d 2 {d 1 ) links the satellite to the Earth receiver through a transparent or regenerative transponder, in slant paths affected by troposphere attenuation. If we adopt a BPSK or QPSK modulation scheme and the same carrier frequencies in the two hops with a transparent transponder, a particular value of the carrier frequency makes the noise-to-signal ratio minimum. A better choice is to assign a low carrier frequency (X-band) to the second hop and a high one (W-band) to the first hop. A 2-hop downlink is superior to a 1-hop downlink with a large power gain proportional to ðd 1 =d 2 Þ 2 c1 at high microwave frequencies and large troposphere attenuation (high link-availability). Shannon's capacity theorem provides the same large gain independently of the choice of the carrier frequencies in the two hops, if we use a regenerative transponder. The carrier frequencies of a 2-hop downlink need not be those reserved to deep-space communication, because the spacecraft could communicate as if it were transmitting 'from the Earth' through a conventional satellite connection. We have applied the theory to a first-order design in the frequency range 10-100 GHz, slant path elevation angles 308; 458 and 908 at Gera Lario or Fucino (Italy), and downlinks form Mars and Saturn, although the general findings and methodology are of global applicability.

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“…MRO will add a new Electra reprogrammable UHF relay radio [5] and a K a -band deep space link [6] to the Mars Network. JPL is also managing the development of Mars Telecommunications Orbiter (MTO), the first interplanetary mission whose principal function is to support other missions [7].…”

Section: Introductionmentioning

confidence: 99%

“… 6. A spacecraft, astronaut, rover, base station, lander or orbiter in the vicinity of the Earth's moon.…”

mentioning

confidence: 99%

Integrated network architecture for sustained human and robotic exploration

Noreen

Cesarone

Deutsch

et al. 2005

2005 IEEE Aerospace Conference

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The National Aeronautics and Space Administration (NASA) Exploration Systems Mission Directorate is planning a series of human and robotic missions to the Earth's moon and to Mars. These missions will require telecommunication and navigation services. This paper 1 sets forth presumed requirements for such services and presents strawman lunar and Mars telecommunications network architectures to satisfy the presumed requirements. The paper 2 suggests that a modest ground network would suffice for missions to the near-side of the moon. A constellation of three Lunar Telecommunications Orbiters connected to a modest ground network could provide continuous redundant links to a polar lunar base and its vicinity. For human and robotic missions to Mars, a pair of areostationary satellites could provide continuous redundant links between a midlatitude Mars base and Deep Space Network antennas augmented by large arrays of 12-m antennas.

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Deep space Ka-band link management and Mars Reconnaissance Orbiter: long-term weather statistics versus forecasting

Cited by 40 publications

References 4 publications

Ka‐band link optimization with rate adaptation for Mars and lunar communications

Ka‐band link optimization with rate adaptation for Mars and lunar communications

Deep‐space communications with a 2‐hop downlink with high link‐availability

Integrated network architecture for sustained human and robotic exploration

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