# Resources

This section includes a list of resources related to GNSS data that you might find useful, should you require further information.

## Glossary

term | definition |
---|---|

broadcast ephemeris | is the set of data delivered by the GNSS satellite such as satellite orbits and clocks that are required to compute the position |

convergence time | time that the navigation filter needs to reach a target accuracy in the position solution |

formal error | error estimate of the navigation filter |

GNSS raw measurements | The set of measurements (pseudorange and carrier phase) generated by a GNSS receiver, used to compute the navigation solution |

navigation filter | is the mathematical engine that implements a given strategy in order to estimate the |

## External links

There is a list of external links and references you might find handy:

- ESA's Navipedia page.
- UPC's gAGE Course on GNSS data processing
- GPS service daemon software gpsd
- RTKlib, an open-source GNSS data processing software
- UNAVCO's teqc Rinex pre-processing tool

We'd rather have you using our service to compute position, but should you want to explore other services, here there is a list of them, that perform PPP, in case you want to try them out:

- JPL's Automatic Precise Positioning Service
- NRCan's PPP service
- Geoscience Australia positioning service
- GMV's magicGNSS service
- Trimble CenterPoint RTX Post-processing service