Based on the experience acquired early from pioneering work at Stanford University and Thomson-CSF starting in the mid 70s, fiber optic gyro (FOG) R&D began at Photonetics in the late 80s to yield OCTANS, a FOG-based inertial strapdown system providing attitude and gyro compassing, at the end of the 90s. This FOG activity was spun out from Photonetics in October 2000 to create iXsea with only 16 people. The product line was rapidly expanded with PHINS, an inertial-grade INS (Inertial Navigation System) and later with MARINS, a strategic-grade INS, as well as with ASTRIX systems developed for satellites in cooperation with EADS-Astrium (today Airbus Defence & Space). In 2010, iXsea merged with several subsidiaries of its parent company, iXcore, to create iXblue. Among these subsidiaries were iXfiber, a maker of specialty fibers, and Photline, producing lithium-niobate integrated optics, hence allowing iXblue to fully master the key FOG components supply chain. Ten years later, the ‘adventure' is continuing and the former start-up is now quite a significant player in the inertial world, especially for high-grade applications. The cumulated number of high-performance 3-axis systems in service has grown to over 8,000, i.e. more than 25,000 FOG axes, with a bias stability ranging from 30 mdeg/h down to 15 μdeg/h, and an angular random walk (ARW) performance ranging from 8 mdeg/√h down to 40 μdeg/√h depending on the size of their sensing coils (3 m2 to 1000 m2) and on the application!
Planetary seismology is a key technique for imaging the internal structure of planetary objects. It targets some of the most fundamental science objectives, from the formation of planetary systems to the characterization of habitable worlds. However, standard methods suffer from various limitations inherent to planetary missions, first one being that a single station is much easier to settle than an array.
Taking benefit of the latest developments in so-called “rotational seismology”, it appears that a single instrument able to monitor both translations and rotations of planetary surfaces would be a game changer in planetary seismology. Indeed, in addition to perform both seismology and global rotational monitoring of the planetary object, the measurement of 6 Degrees of Freedom (DoF) brings a significantly increased scientific return compared to classical 3-DoF sensors.
Hence, to enter a new realm of planetary exploration with an innovative ground motion instrumentation concept relying on high precision sensors based on optical interferometry, a project named PIONEERS has been submitted (April 2018) and accepted (July 2018) by European Commission through its H2020 program.
Under the leadership of ISAE-SUPAERO, gathering IPGP, ETH-Z, Royal Observatory of Belgium, LMU and iXblue, the PIONEERS team aims to develop two innovative 6-Dof instruments for measuring ground deformation on planetary objects.
The first instrument is a prototype of very low noise 6-Dof sensor dedicated to the imaging of the internal structure of terrestrial planets. The second one is a high TRL CubeSat version of the same instrument concept for exploration of small bodies.
In Lippmann photography, the interference of the image with its reflection onto a mirror in contact with the photographic
emulsion allows, for each pixel of the image, the recording of Bragg gratings. Removing the mirror, processing the plate
and reading out these Bragg gratings with a white light source diffracts the very colours used for recording and thus
reproduces the images in colours. Using Lippmann photography as a data storage technique was proposed in the 1960th:
for a given pixel, and to each recording wavelength is associated one bit of data, several bits being recorded at the same
pixel. In this paper, we revisit this data storage technique and we propose and demonstrate an homodyne detection to
improve the efficiency of Lippmann data storages. The proposed homodyne geometry also presents the advantage to
simplify the architecture: the Lippmann mirror required for recording is kept in place for data retrieving. Such an
homodyne readout could also be applied to enhance the detected signals in other holographic approaches.