Deep space acquisition and tracking with single photon detector arrays

Farr, William H.; Sburlan, Suzana; Sahasrabudhe, Adit; Birnbaum, Kevin

doi:10.1109/icsos.2011.5783654

Cited by 10 publications

(5 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The EM testbed tests provided further confidence to execute this protocol in flight operations. The uplink signal centroid was calculated from PCC images using the modified square-law (MSQ) calculation [7,8,9].…”

Section: Testbed and Flight Data Comparisonmentioning

confidence: 99%

Deep space optical communications technology demonstration pre-launch validation and performance tests with the laser test evaluation station (LTES)

Velasco,

Allmaras,

Kovalik

et al. 2024

Free-Space Laser Communications XXXVI

View full text Add to dashboard Cite

The Deep Space Optical Communications (DSOC) project launched in October 2023 hosted by the Psyche spacecraft. The DSOC flight laser terminal will be periodically closing links starting a few weeks after launch and extending out to Mars ranges. The DSOC engineering model (EM) flight laser transceiver terminal was built to serve as a replica of the flight terminal in space to be integrated into an EM testbed at JPL. The EM testbed characterized the EM flight laser transceiver terminal under test conditions emulating deep space. These tests helped to understand acquisition, tracking, pointing and the bi-directional communications performance. The EM testbed includes a gravity offload structure and the Laser Test Evaluation Station (LTES) testbed that emulates the ground transmitter and receiver. The LTES testbed was developed at NASA/JPL to serve as a pseudo transmitter and receiver ground station for deep-space flight terminals. This paper will describe the EM testbed capabilities that provide calibrated uplink irradiances overfilling the 22 cm aperture, provides a zero-gravity environment, and characterizes the downlink beam. Atmospheric fading and additive background noise can be injected, while performing uplink/downlink communications characterization. The gravity offload is capable of injecting a disturbance spectrum with a hexapod system allowing for a range of spacecraft environments to be emulated. The LTES architecture can be expanded to allow for multiple flight terminals to be tested in parallel for future projects. Key DSOC validation and performance tests with the EM testbed are reported in this paper.

show abstract

Section: Testbed and Flight Data Comparisonmentioning

confidence: 99%

Deep space optical communications technology demonstration pre-launch validation and performance tests with the laser test evaluation station (LTES)

Velasco,

Allmaras,

Kovalik

et al. 2024

Free-Space Laser Communications XXXVI

View full text Add to dashboard Cite

show abstract

“…The low rate uplink data channel (mode 1) uses binary pulse-position modulated (2-PPM), transmitting data at 1.8 kbps. In combination with two additional trailing inter-symbol guard time (2-ISGT) slots, the time-averaged envelope of this modulation is a square wave whose alternating intensity pattern serves as a beacon signature that is exploited by the flight terminal signal processing for spatial acquisition, tracking, and pointing 5,6,7 . When channel conditions do not support uplink data decoding on the flight terminal, the ULDF switches to mode 2, in which a non-data-bearing 50% duty cycle square wave pulse train is used to modulate the uplink laser, preserving the functionality of the flight terminal beacon tracking algorithms.…”

Section: Uplink Data Formatter (Uldf)mentioning

confidence: 99%

The Deep Space Optical Communications project ground laser transmitter

Srinivasan

Velasco

Wright

et al. 2023

Free-Space Laser Communications XXXV

View full text Add to dashboard Cite

The Deep Space Optical Communication (DSOC) project will conduct its technology demonstration concurrently with NASA's Psyche mission, which hosts the DSOC flight transceiver (FLT) on its spacecraft and will operate it over an approximate range of 0.05 to 3.0 AU. The DSOC Ground Laser Transmitter (GLT), located at the Jet Propulsion Laboratory's Optical Communication Telescope Laboratory (OCTL) near Wrightwood, CA, has been developed to provide a high-power optical uplink beacon that serves as a line-of-sight FLT downlink pointing reference and delivers low rate (1.8 kbps) uplink command data to the FLT. In this paper we present an overview of the completed GLT and its subsystems: (i) the multi-beam Uplink Laser Assembly (ULA) capable of transmitting up to 7 kW of average power, (ii) the Uplink Data Formatter that modulates the ULA, (iii) the GLT Optics Assembly that manages the ULA high power output beams and couples them to the OCTL telescope, (iv) the Uplink Laser Safety Assembly that automatically avoids hazardous laser irradiation by shuttering the laser output, and (v) the custom-developed Monitor and Control software used to test and operate the entire system. We discuss various implementation and operational challenges, and review results from key system performance verification and operational tests, indicating the readiness of the Ground Laser Transmitter station to fulfill the DSOC technology demonstration objectives.

show abstract

“…If the high rate data is not included, then the 2-PPM+2-ISGT with slot duration T, is implemented directly. In either case, the average intensity envelope of the combined modulation layers is a square wave that forms a beacon signal whose alternating pattern may be 65 exploited for background rejection, [3] signal acquisition and tracking. Here, it is assumed that the higher rate data channel is not implemented.…”

Section: Uplink Beacon Signal Examplementioning

confidence: 99%

“…In order to obtain an unbiased position estimate, our approach is to perform the centroiding on a set of statistics that have been modified to effectively subtract out the contribution from background photons. By alternately incrementing and decrementing two photon arrival counters 35 (up-down counting") that are offset by one-quarter of the square wave period, [3] one or more embodiments of the present invention construct pixel statistics for detecting signal presence in the absence of temporal synchronization of the counters with the received signal. This leads to a faster 40 spatial acquisition and tracking sequence.…”

Section: Algorithmsmentioning

confidence: 99%