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公开(公告)号：US20240262538A1
公开(公告)日：2024-08-08
申请号：US18558021
申请日：2022-05-03
Applicant: Kerri Cahoy , Christian Haughwout , Paul Serra , Ruonan HAN , Anantha CHANDRAKASAN , Massachusetts Institute of Technology
Inventor： Kerri Cahoy , Christian Haughwout , Paul Serra , Ruonan HAN , Anantha CHANDRAKASAN
Abstract: Femto-satellites are very small satellites that can be deployed in constellations from a larger mothership satellite for distributed measurement. They are too small to accommodate the GNSS receivers that many satellites use for navigation, but they can be located with an electromagnetic beam from the mothership satellite. The mothership satellite scans this beam across a constellation of femto-satellites. When the beam scans across a particular femto-satellite, the femto-satellite transmits an acknowledgement to the mothership satellite, e.g., by retroreflecting the beam or via a separate radio link. The beam can be modulated with commands for the femto-satellite, such as to make a measurement or transmit previously acquired data, as well with commands for determining the femto-satellite's location, such as a time stamp or beam pointing information. The femto-satellite can determine its location from the information modulated onto the beam or transmit the time stamp to the mothership satellite for localization.
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公开(公告)号：US11296787B2
公开(公告)日：2022-04-05
申请号：US17187726
申请日：2021-02-26
Applicant: Massachusetts Institute of Technology
Inventor： Kerri Cahoy , Paul Serra , Ondrej Cierny
Abstract: A monostatic, beaconless fiber transceiver for free-space optical links infers fine tracking information using receiver optoelectronics and an injected pointing dither (nutation). A MEMS steering mirror fine-points the beams and injects the nutation. While this may disturb fiber coupling and transmit beam pointing, link loss becomes negligible for sufficient SNR. The SNR for links without point-ahead correction is about 35 dB to keep dither loss below 0.1 dB and RMS spatial tracking noise below a tenth of the beam divergence. Since the pointing and tracking bandwidth is much smaller than the receiver communication bandwidth, this SNR is achievable with appropriate filtering. For point-ahead correction, a single-mode fiber transceiver can reach up to about 1 beamwidth of correction, while a few-mode fiber transceiver can reach up to about 1.75 beamwidths due to improved coupling sensitivity at higher point-ahead offsets. Using a double-clad fiber with a secondary detector further reduces the incurred coupling loss.
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公开(公告)号：US20250074629A1
公开(公告)日：2025-03-06
申请号：US18951856
申请日：2024-11-19
Applicant: Massachusetts Institute of Technology
Inventor： Kerri Cahoy , Christian Haughwout , Paul Serra , Ruonan HAN , Anantha CHANDRAKASAN
Abstract: Femto-satellites are very small satellites that can be deployed in constellations from a larger mothership satellite for distributed measurement. They are too small to accommodate the GNSS receivers that many satellites use for navigation, but they can be located with an electromagnetic beam from the mothership satellite. The mothership satellite scans this beam across a constellation of femto-satellites. When the beam scans across a particular femto-satellite, the femto-satellite transmits an acknowledgement to the mothership satellite, e.g., by retroreflecting the beam or via a separate radio link. The beam can be modulated with commands for the femto-satellite, such as to make a measurement or transmit previously acquired data, as well with commands for determining the femto-satellite's location, such as a time stamp or beam pointing information. The femto-satellite can determine its location from the information modulated onto the beam or transmit the time stamp to the mothership satellite for localization.
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公开(公告)号：US12179942B2
公开(公告)日：2024-12-31
申请号：US18558021
申请日：2022-05-03
Applicant: Massachusetts Institute of Technology
Inventor： Kerri Cahoy , Christian Haughwout , Paul Serra , Ruonan Han , Anantha Chandrakasan
Abstract: Femto-satellites are very small satellites that can be deployed in constellations from a larger mothership satellite for distributed measurement. They are too small to accommodate the GNSS receivers that many satellites use for navigation, but they can be located with an electromagnetic beam from the mothership satellite. The mothership satellite scans this beam across a constellation of femto-satellites. When the beam scans across a particular femto-satellite, the femto-satellite transmits an acknowledgement to the mothership satellite, e.g., by retroreflecting the beam or via a separate radio link. The beam can be modulated with commands for the femto-satellite, such as to make a measurement or transmit previously acquired data, as well with commands for determining the femto-satellite's location, such as a time stamp or beam pointing information. The femto-satellite can determine its location from the information modulated onto the beam or transmit the time stamp to the mothership satellite for localization.
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