# GNSS Signal Tracking Performance Improvement for Highly Dynamic Receivers by Gyroscopic Mounting Crystal Oscillator

## TL;DR

This paper shows that using a gyroscopic mounting method improves GNSS signal tracking in highly dynamic environments by reducing signal loss and frequency jitter.

## Contribution

The novelty is demonstrating how gyroscopic mounting reduces signal loss and frequency deviation in highly dynamic GNSS receivers.

## Key findings

- Gyroscopic mounting reduces signal loss in high dynamic flight scenarios.
- The method suppresses frequency jitter below the FLL one-sigma threshold during steady-state loads.
- It also reduces disturbances from random vibrations beyond the FLL three-sigma threshold.

## Abstract

In this paper, the efficiency of the gyroscopic mounting method is studied for a highly dynamic GNSS receiver’s reference oscillator for reducing signal loss. Analyses are performed separately in two phases, atmospheric and upper atmospheric flights. Results show that the proposed mounting reduces signal loss, especially in parts of the trajectory where its probability is the highest. This reduction effect appears especially for crystal oscillators with a low elevation angle g-sensitivity vector. The gyroscopic mounting influences frequency deviation or jitter caused by dynamic loads on replica carrier and affects the frequency locked loop (FLL) as the dominant tracking loop in highly dynamic GNSS receivers. In terms of steady-state load, the proposed mounting mostly reduces the frequency deviation below the one-sigma threshold of FLL (1σFLL). The mounting method can also reduce the frequency jitter caused by sinusoidal vibrations and reduces the probability of signal loss in parts of the trajectory where the other error sources accompany this vibration load. In the case of random vibration, which is the main disturbance source of FLL, gyroscopic mounting is even able to suppress the disturbances greater than the three-sigma threshold of FLL (3σFLL). In this way, signal tracking performance can be improved by the gyroscopic mounting method for highly dynamic GNSS receivers.