Metrology on-board PROBA-3: The shadow position sensors subsystem

Loreggia, D.; Capobianco, Gerardo; Fineschi, Silvano; Бемпорад, А.; Casti, Marta; Buckley, Steven; Romoli, M.; Focardi, M.; Belluso, M.; Thizy, Cédric; Hermans, Aline; Galano, Damien; Versluys, Jorg

doi:10.1016/j.asr.2020.08.004

Cited by 2 publications

(6 citation statements)

References 20 publications

(24 reference statements)

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“…At the nominal alignment conditions, at ISD=144m, we expect to have an SPS readout around 1037 DN so the error expected is about 1.0-1.5DN (1σ). From the qualification of the electronic chain [9], we know that the relation between DN and corresponding lateral shift is 10μm/DN so the contribution of the temporal stability of the SPS readout, within the requirement box (sec.2), remains of the order of 15μm. This contribution is in good agreement with the results obtained by performance analysis and it will be included in the overall error budget to confirm the final error, with the contribution of the electronics and of the numerical calculation (algorithm).…”

Section: Time Stability Test Resultsmentioning

confidence: 99%

“…In order to achieve the formation-flying objectives, a suite of metrology systems will provide continuous measurements of the satellites relative and absolute position down to sub-millimetre precision [6]. Among these, the Shadows Position Sensors (SPS) is expected to return the position measurement with the highest accuracy [7]. The SPS unit consists of a mechanical flange mounted in front of the ASPIICS telescope boom, hosting an electronic board where a set of eight silicon photo-multipliers (SiPMs), positioned along a circumference concentric with the telescope entrance pupil, will measure the solar penumbra irradiance as projected by the external occulter.…”

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

“…The eight SiPMs are grouped in two sets that are used separately: the set A (nominal), composed by SiPMs 1, 3, 5, 7, and the set B (redundant), composed by SiPMs 2, 4, 6, 8, as shown in figure 2 where the distribution of the SiPMs with respect to the pupil, as mounted on the telescope and respect to the penumbra, is shown. During standard operations the set A (nominal) will be operated while the set B (redundant) will be used only for calibration, or in case the nominal one will go failed [7]. Moreover, due to the need for a precise in-flight calibration, the full Sun will be used as reference source and the nominal SPS set will be permitted to observe directly the Sun through a set of neutral density filters mounted in front of each diode on the front door when closed.…”

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

“…The FF alignment measurement accuracy required to the SPS is 500μm (3σ) for lateral movements out of the control loop, 2mm within the control loop, and 50 mm (3σ) for longitudinal movements, within a 3D FF requirement box of (20x20x200)mm 3 . Besides, the SPS should be able to return a position estimation on a wider 3D goal box of (200x200x2000)mm 3 without any accuracy specification [7]. The SiPMs generate a current proportional to the received irradiance.…”

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

“…The SiPMs generate a current proportional to the received irradiance. The currents are then converted in voltage by the proximity electronics and amplified by a 2-stage amplification chain [9]. Finally, the signals are digitized by 12-bit ADCs.…”

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

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Laboratory testbed for the calibration and the validation of the shadow position sensor subsystem of the PROBA3 ESA mission

Loreggia¹,

Zangrilli²,

Capobianco³

et al. 2021

International Conference on Space Optics — ICSO 2020

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The PROBA3 mission of the European Space Agency is the first formation flying (FF) mission that will be flown in high elliptic geocentric orbit aiming at verifying and validating different metrology control systems and algorithms in order to realize and maintain the formation of two independent spacecraft, in total autonomy. The final target accuracy for the relative and absolute alignment of the two satellites is of about 2mm over an inter satellite distance of 144.3m. During the FF, the two spacecraft will realize a giant coronagraph with the external occulter on one payload and the telescope on the other one. The Sun Corona observation will be the scientific tool for the FF validation. Between the different metrology systems that will be tested, the Shadow Position Sensor (SPS) is the most challenging one, aiming at returning the relative and absolute position of the formation with the finest accuracy: 0.5mm out of the guidance and navigation and control loop and 2mm within the loop. The mission program is now in the Phase D with the realization and the testing of the flight model. Due to the high expected performance, a fine calibration of the SPS subsystem is mandatory. In this paper, we discuss the radiometric and spectral calibration plan, the algorithm validation procedure, and the laboratory test-bed realized to reproduce the in-flight observation conditions of the SPS by using a set of calibrated LED and a mechanical set-up equivalent to the SPS system. Preliminary results are also reviewed.

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Section: Time Stability Test Resultsmentioning

confidence: 99%

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

Section: Proba3 Mission and The Shadow Position Sensors (Sps)mentioning

confidence: 99%

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Laboratory testbed for the calibration and the validation of the shadow position sensor subsystem of the PROBA3 ESA mission

Loreggia¹,

Zangrilli²,

Capobianco³

et al. 2021

International Conference on Space Optics — ICSO 2020

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Formation flying performances simulator for the shadow position sensors of the ESA PROBA-3 mission

Capobianco

Amadori

Fineschi

et al. 2021

International Conference on Space Optics — ICSO 2020

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PROBA-3 (PRoject for OnBoard Autonomy) is an ESA mission to be launched on beginning of 2023 where a spacecraft is used as an external occulter (OSC-Occulter Spacecraft), to create an artificial solar eclipse as observed by a second spacecraft, the coronagraph (CSC-Coronagraph Spacecraft). The two spacecrafts (SCs) will orbit around the Earth, with a highly elliptic orbit (HEO), with the perigee at 600 km, the apogee at about 60530 km and an eccentricity of ≈ 0.81. The orbital period is of 19.7 hours and the precise formation flight (within 1 mm) will be maintained for about 6 hours over the apogee, in order to guarantee the observation of the solar corona with the required spatial resolution. The relative alignment of the two spacecrafts is obtained by combining information from several subsystems. One of the most accurate subsystems is the Shadow Position Sensors (SPS), composed of eight photo-multipliers installed around the entrance pupil of the CSC. The SPS will monitor the penumbra generated by the occulter spacecraft, whose intensity will change according to the relative position of the two satellites. A dedicated algorithm has been developed to retrieve the displacement of the spacecrafts from the measurements of the SPS. Several tests are required in order to evaluate the robustness of the algorithm and its performances/results for different possible configurations. A software simulator has been developed for this purpose. The simulator includes the possibility to generate synthetic 2-D penumbra profile maps or analyze measured profiles and run different versions of the retrieving algorithms, including the "on-board" version. In order to import the "as-built" algorithms, the software is coded using Matlab. The main aspects of the simulator, such as the results of the simulations, with the inclusion of some specific case studies, will be reported and discussed in this paper.

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Metrology on-board PROBA-3: The shadow position sensors subsystem

Cited by 2 publications

References 20 publications

Laboratory testbed for the calibration and the validation of the shadow position sensor subsystem of the PROBA3 ESA mission

Laboratory testbed for the calibration and the validation of the shadow position sensor subsystem of the PROBA3 ESA mission

Formation flying performances simulator for the shadow position sensors of the ESA PROBA-3 mission

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