José Carlos Rodríguez

Instituto Geográfico Nacional, España · Geodesy

All-sky cameras imagery is employed in Satellite Laser Ranging (SLR) stations during operations to gather information about the observing conditions, typically as an sky awareness tool for operators. Due to the emission of laser light towards the sky in the SLR technique, it is a priority to ensure aerial safety prior to and during operations. For...

First results for the determination of the centre of mass corrections for LARES-2 following the same methodology applied previously for other geodetic spheres.

Here I go about some developments I was involved with at Yebes Observatory, related to auxiliary equipment for the SLR station being built at the time. Specifically, an ADS-B receptor and an all-sky camera. It's in Spanish, though.

Some observations on the thorny issues of range biases, satellite laser target signatures, and the way we handle these at the ILRS.

All-sky cameras are a staple of astronomical and SLR observatories. They are normally employed as environmental awareness tools, showing cloud presence, illumination conditions, and the laser beam direction. For actual positional tasks requiring certain degree of accuracy, these cameras require a star calibration to correct for their physical orien...

The National Geographic Institute of Spain (IGN Spain) develops, operates, and exploits the Spanish national geodetic networks and their associated infrastructure. This includes the permanent networks of reference GNSS (Global Navigation Satellite System) receivers, VLBI (Very Long Baseline Interferometry) telescopes, and a new SLR (Satellite Laser...

The development of the Satellite Laser Ranging station in Yebes, YLARA (ERDF co-financed), is proceeding apace, with an estimated completion of the project in mid-2023. The station will be a modern system that will become part of the ground network of the International Laser Ranging Service (ILRS) and make of Yebes Observatory, together with its VL...

What are the absolute top priorities for stations from the point of view of data analysts?

Absolute gravity measurements taken on a near-weekly basis at a single location is a rarity. Twelve years of data at the UK’s Space Geodesy Facility (SGF) provides evidence to show that the application of results from international comparisons of absolute gravimeters should be applied to data and are critical to the interpretation of theSGF gravity...

Satellite laser ranging (SLR) began as a concept in 1962 when Plotkin of the Goddard Space Flight Center in Maryland, USA, first proposed the development of accurate laser ranging to retroreflectors on orbiting spacecraft in order to improve geodetic information (Plotkin 1964). At that time optical and radar tracking of satellites was being used to...

Satellite laser ranging orbital solutions, using observations of satellites LAGEOS and LAGEOS-2 collected from 2000 to 2017, were used to test the performance of two reference frame realisations, ITRF2014 and DTRF2014. We compare the post-fit residuals from solutions where only initial conditions and orbit parameters were solved for, leaving aprior...

The satellite laser ranging (SLR) technique has the potential to make extremely precise measurements to retroreflector arrays on orbiting satellites, with normal point range precision at a level of 1 mm for the core tracking stations of the International Laser Ranging Service (ILRS). The main limitation to achieving a similar level of range accurac...

We present improved modelling to compute centre of mass (CoM) offsets for spherical geodetic satellites and derive new values for the spacecraft LAGEOS, LAGEOS-2, Etalon-1/2, Starlette, Stella, LARES, and Ajisai for all system configurations of the laser ranging network, past and present. The updated CoM values, i.e. the average distances between t...

Discussion on several corrections required in the analysis of SLR data (troposphere, centre of mass, Shapiro delay) and demonstration of their importance in the quality of POD.

In the latest official ITRF release, ITRF2014, the scale difference between the VLBI and SLR contributions was estimated to be 1.37 (0.1) ppb. Approximately half of this difference can be accounted for by the presence of systematic errors both in the SLR observations and in their treatment, as evidenced by our previous work on estimation of range e...

CoM modelling for geodetic SLR targets, with focus on possible error sources and sensitivity analysis.

The TOPEX/Poseidon (T/P) altimetry mission operated for 13 years before the satellite was decommissioned in January 2006, becoming a large space debris object at an altitude of 1,340 km. Since the end of the mission, the interaction of T/P with the space environment has driven the satellite’s spin dynamics. Satellite Laser Ranging (SLR) measurement...

An observation policy employed by some SLR stations is the so-called single photon ranging. This consists in controlling the intensity of the retroreflected laser pulses so that, on average, no more than a single photon per returned pulse can generate a detected photoelectron. This ensures that the optical spread distribution of the laser light, ca...

Present-day Satellite Laser Ranging (SLR) systems are in principle capable of providing ranges with an accuracy and precision approaching the millimetre level. This capability is best utilised if the error budget contributions of the multiple factors affecting the laser observations are minimised and do not exceed the inherent accuracy of the rangi...

Satellite laser ranging (SLR) to the geodetic satellites LAGEOS and LAGEOS-2 uniquely determines the origin of the terrestrial reference frame and, jointly with very long baseline interferometry, its scale. Given such a fundamental role in satellite geodesy, it is crucial that any systematic errors in either technique are at an absolute minimum as...

Geodetic sites for global reference frame determination are ideally equipped with multiple co-located techniques located on stable ground, with well defined inter-technique local ties and demonstrably negligible relative motion, providing high quality data regularly. At SGF, a campaign of digital levelling surveys began in 2010 to monitor the relat...

In this paper we describe a novel combination of Raman spectroscopy, isotope editing and X-ray scattering as a powerful approach to give detailed structural information on aromatic side chains in peptide fibrils. The orientation of the tyrosine residues in fibrils of the peptide YTIAALLSPYS with respect to the fibril axis has been determined from a...

We introduce the SLR double-difference approach of space geodesy. With real and simulated SLR measurements it is shown how common SLR biases are removed by forming SLR double-differences, i.e. station range biases, common retro-reflector effects and orbit errors (GNSS) for baselines up to e.g. 5000 km. In this way we obtain SLR observables of utmos...

A novel combination of site-specific isotope labelling, polarised infrared spectroscopy and molecular combing reveals local orientational ordering in the fibril-forming peptide YTIAALLSPYSGGRADS. Use of (13)C-(18)O labelled alanine residues demonstrates that the N-terminal end of the peptide is incorporated into the cross-beta structure, while the...

New technical challenges placed on ground-based geodetic observatories by the scientific goals of IAG's GGOS initiative have led the Space Geodesy Facility (SGF) in Herstmonceux UK to carry out a programme of hardware upgrade and capability expansion. In recent years the SGF Satellite Laser Ranger has been upgraded to operate at kHz rates, and both...

We report the use of molecular combing as an alignment method to obtain macroscopically oriented amyloid fibrils on planar surfaces. The aligned fibrils are studied by polarized infrared spectroscopy. This gives structural information that cannot be definitively obtained from standard infrared experiments on isotropic samples, for example, confirma...

The alignment of model amyloid peptide YYKLVFFC is investigated in bulk and at a solid surface using a range of spectroscopic methods employing polarized radiation. The peptide is based on a core sequence of the amyloid beta (Abeta) peptide, KLVFF. The attached tyrosine and cysteine units are exploited to yield information on alignment and possible...

In certain applications copolymer P123 (E21P67E21) is dissolved in water-ethanol mixtures, initially to form micellar solutions and eventually to gel. For P123 in 10, 20, and 30 wt % aqueous ethanol we used dynamic light scattering from dilute solutions to confirm micellization, oscillatory rheometry, and visual observation of mobility (tube invers...