Enabling Affordable Communications for the Burgeoning Deep Space Cubesat Fleet

Abraham, Douglas A.; MacNeal, B.E.; Heckman, D.

doi:10.2514/6.2016-2625

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…In this paper, we leverage on prior work [6] that focuses on simultaneous command and telemetry links, and introduces a new flight-ground collaborative architecture that provides simultaneous Doppler and ranging for multiple spacecraft in the Mars vicinity. We assume that 2-way ranging is done in X-band, which also supports low-rate command and telemetry.…”

Section: Simultaneous 2-way Doppler/ranging For Multiple Spacecraftmentioning

confidence: 99%

In-Situ Navigation and Timing Services to prepare for a Human Mars Landing Site

Cheung

Lee

2018

2018 SpaceOps Conference

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In a previous paper, we described the system concept of a proposed Mars Regional Navigation Satellite System (MRNSS) that is built upon a number of notional Mars orbiting and surface missions in the human exploration era of Mars. We assume two areostationary Mars relay orbiters that have continuous line-of-sight visibility with the Mars landing site, a Deep Space Habitat (DSH) in an inclined 48-hour circular orbit, and a surface communication lander that could serve as the reference point. These orbiting and surface infrastructure elements broadcast GPS-like ranging signals and other ephemeris information to the mission users. With one or more additional orbiters in areosynchronous orbits that trace around a figure-8 path, a regional navigation satellite system can be realized that provides in-situ course absolute localization and precision relative localization and timing services to the users in the vicinity of a Mars landing site.We also introduced a new geometric trilateration method that simultaneously performs absolute positioning and relative positioning. The relative position is derived from a "differencing" function of two raw-range measurements between a known reference point and of the target from a navigation satellite, thereby eliminating most of the common errors like atmospheric delays, ephemeris errors, and instrument delays in real-time. In the Mars environment, this "error-cancellation" function greatly reduces the need to perform extensive orbit determination (OD) of the navigation satellites like the Earth's GPS, and only requires occasional tracks from the Earth's large-aperture deep space antennas to perform OD's.In this paper, we provide detailed simulations on both the absolute positioning scheme and the relative positioning scheme, and show that the relative positioning scheme provides 200 -400 times improvement in localization accuracy.On the ground side, we discuss new approaches that simultaneously perform 2-way Doppler/ranging, and re-introduce the method of Same Beam Interferometry (SBI) for the Mars navigation orbiters. This helps to further reduce the tracking burden of the ground antennas required to support the OD of the Mars orbiters, making the concept of MRNSS more realizable.

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Section: Simultaneous 2-way Doppler/ranging For Multiple Spacecraftmentioning

confidence: 99%

In-Situ Navigation and Timing Services to prepare for a Human Mars Landing Site

Cheung

Lee

2018

2018 SpaceOps Conference

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“…In [2], we leveraged on prior work [3] that focus on simultaneous command and telemetry links and introduced a new flight-ground collaborative architecture that provides simultaneous Doppler and ranging for multiple spacecraft in the Mars vicinity. We assumed that 2-way ranging is done in X-band, which also supports low-rate command and telemetry.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous 2-Way Doppler and Ranging for Multiple Spacecraft at Mars

Cheung

Bryant

Lee

2018

2018 SpaceOps Conference

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Mars exploration requires multiple orbiters and surface infrastructures on Mars. Location determination is essential to support various human and robotic activities on the Mars surface and in orbits. Robust communication coverage is required for data transmission between assets on Mars surface and orbiters in addition to the communication between orbiters andEarth. We proposed a notional Mars Regional Navigation Satellite System (MRNSS) that provides continuous or near-continuous in-situ navigation and timing services for the robotic and human missions in the vicinity of a Mars landing site. For such a system, the Earth's deep space stations have to perform orbit determination (OD) for the Mars orbiters so that their locations are known to a reasonable degree of accuracy. This provides the surface and orbiting user vehicles the ability to estimate their locations using the orbiter-vehicle range measurements. Two important inputs for accurate OD are 2-way Doppler and ranging measurements derived from the transmitted and received radio signals. We also introduced a new flight-ground collaborative architecture that provides simultaneous Doppler and ranging measurements for multiple spacecraft in the Mars vicinity, using an example of the Mars landing site Utopia Planitia and four Mars orbiters, all communicating with Earth via twoway communications in the X-band frequency range. One key component of this architecture is that each spacecraft uses a smart frequency sweeping algorithm that acquires and tracks the uplink signals with high Doppler and Doppler rate residuals. In this paper, we simulate the Doppler and Doppler rate profiles of the Mars orbiters of the MRNSS and assessed the acquisition and tracking performances.

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