This activity is intended to investigate the Grazing Angle (GA) Carrier Phase Altimetry (CaPA) using signals transmitted by the Global Navigation Satellite Systems (GNSS). The CaPA technique requires that the electromagnetic signal reflects coherently rather than in a diffuse regime. The hypothesis is that GA geometries enhance the likelihood of coherence scattering. It was also hypothesized that the combination of signals at slightly different frequency bands could expand the coherence conditions (widelane techniques, WL).

The Doherty concept has proven to be a very effective technique for designing amplifiers, which maintain a high efficiency over a wide range of operating conditions. This technique is extensively used in terrestrial applications like base stations where power efficiency is getting more and more attention. Power efficiency is also of concern for space and the Doherty concept could certainly help in designing more efficient PAs. Ka-band is now being considered for mobile services that could offer very high capacity as compared to the existing ones at L-band.

With the increased frequency of shipping activities, such as tourism and freight’s transport, navigation safety has become a major concern, especially when human casualties, environmental issues and economic losses are considered. Even if new technologies have already supplied aids to pilots for the navigation risk reduction, the International Maritime Organization (IMO) reports that the majority of accidents could have been avoided by providing suitable input to the navigation decision-making process.

Background and justification:

•The railway simulation testbed is an essential tool / capability needed to support validation of GNSS receiver technologies / techniques / integrity algorithms for safety-related applications in railway

•Testbed complements field testing allowing conditions that are statistically unlikely to be observed in the field to be simulated in a highly controlled and repeatable environment

Achievements and status:

More and more applications rely on the Position and Time solution provided by a GNSS equipment to enable services of critical nature.

Currently, GNSS is the backbone of most Position, Navigation and Timing (PNT) solutions, in providing 24/7 continuous, all-weather, global coverage to an unlimited number of receiver-equipped users. There is an increasing dependency on the availability and reliability of GNSS. However, GNSS is widely known to be vulnerable to an evolving range of threats (natural and man-made, unintentional and deliberate).

The E.Inspector mission objectives are to:* Image an ESA owned space debris in its current status * Use obtained images for the verification and validation of the e.deorbit or space tug GNC sensorsFollowing a successful ESA internal CDF study, the mission is now proposed to go to phase A to be studied by industry.Several drivers make this mission design challenging:* A possible long and large (delta-V) transfer to the target* Compliance to Space Debris Mitigation guidelines from possibly high altitude* A close RDV while maintaining keep-out zones and ensuring passively safe trajectories* Tr