Characterization of Chip-Scale Atomic Clock for GNSS navigation solutions

Chip Scale Atomic Clocks are a recently developed technology, that used together with a GNSS receiver helps to improve the performance of GNSS navigation solutions in some particular conditions [1]. Current GNSS receivers include a Temperature Compensated Cristal Oscillator (TCXO) clock which is characterized by a short term stability (τ = 1 second) of 2·10-9 seconds that leads to an error of 0.6 meters in pseudorange measurements. While a Chip Scale Atomic Clock (CSAC) [1] has a stability (τ = 1 second) of 2.5·10-10 seconds that implies a range error of 0.075 meters. The use of TCXO forces the inclusion of a time parameter in the navigation algorithms, which reduces the positioning performance in poor satellite constellation conditions, reflected in the Dilution of Precision (DoP) values [2]. The aim of the study presented on this paper is to characterize the impact of the Cesium Atomic clocks technology, specifically a CSAC clock, in high-grade GNSS receivers by evaluating the position scattering and the holdover.