Extensive cosmic showers detection: the importance of timing and the role of GPS in the EEE experiment.

Extreme Energy Events (EEE) is an extended Cosmic Rays (CRs) Observatory, composed of about 60 tracking telescopes spread over more than 10 degrees in Latitude and Longitude. We present the metrological characterization of a representative set of actually installed EEE GPS receivers, their calibration and their comparison with respect to dual-frequency receivers for timing applications, as well as plans for a transportable measurement system to calibrate the currently deployed GPS receivers. Finally, the realization of an INRIM Laboratory dedicated to EEE, aimed at hosting reference telescopes and allowing timing studies for Particle Physics/Astrophysics experiments, is presented, as well as the possibility of synchronizing already deployed telescopes utilizing White Rabbit Technique, over optical fiber links, directly with the Universal Time Coordinated time scale, as realized by INRIM (UTC(IT)).

Calibration of Galileo signals for time metrology.

Using global navigation satellite system (GNSS) signals for accurate timing and time transfer requires the knowledge of all electric delays of the signals inside the receiving system. GNSS stations dedicated to timing or time transfer are classically calibrated only for Global Positioning System (GPS) signals. This paper proposes a procedure to determine the hardware delays of a GNSS receiving station for Galileo signals, once the delays of the GPS signals are known.

Near real-time comparison and monitoring of time scales with precise point positioning using NRCan ultra-rapid products.

This paper experimentally evaluates the assessment of precise point positioning (PPP) using the Natural Resources Canada (NRCan) Ultra-Rapid GPS products to serve as a short latency time-transfer tool to assist timing laboratories in operational maintenance of frequency standards and time scale dissemination. An automated data exchange and processing system has been set up to serve the international community for efficient, nearly real-time clock comparison and monitoring purposes.

Network time and frequency transfer with GNSS receivers located in time laboratories.

In this paper we investigate a possible network solution, similar to the IGS analysis center solutions, that can be easily managed by a network of timing institutes to solve for all the clock differences (in addition to other quantities) in a unique system to understand the feasibility and the advantages of this approach in time and frequency transfer. The investigation is based on a suite of global navigation satellite system (GNSS) software products that allows the users to perform a wide range of calculations and analyses related to GNSS, from the evaluation of performances at the user level to the computation of precise GNSS orbits and clocks, including the calculation of precise receiver coordinates. The time and frequency transfer capabilities of the network solution (named ODTS) are evaluated and compared with PPP solutions as well as to other time transfer results.

Further characterization of the time transfer capabilities of precise point positioning (PPP): the Sliding Batch Procedure.

In recent years, many national timing laboratories have installed geodetic Global Positioning System receivers together with their traditional GPS/GLONASS Common View receivers and Two Way Satellite Time and Frequency Transfer equipment. Many of these geodetic receivers operate continuously within the International GNSS Service (IGS), and their data are regularly processed by IGS Analysis Centers. From its global network of over 350 stations and its Analysis Centers, the IGS generates precise combined GPS ephemeredes and station and satellite clock time series referred to the IGS Time Scale.