GVX: The GNSS Vector Exchange File Format


Background

GVX aims to provide a standard file format for exchanging GNSS vectors derived from varying GNSS survey methods and manufacturer hardware. The file format includes all of the necessary data of a GNSS vector for inclusion in a survey network for least squares adjustment, as well as crucial metadata. The format is meant for any type of GNSS vector, whether it was derived in a real-time kinematic (RTK) survey or from baseline post-processing. One goal for developing GVX is so that vector data can be uploaded to OPUS-Projects. NGS requests feedback on this file format. Please send comments to NGS.Feedback@noaa.gov.

The Receiver Independent Exchange format (RINEX) was developed three decades ago as a means for sharing static GNSS data. Unfortunately, a similar, standard file format for GNSS vectors does not currently exist. A GNSS vector is a mathematical representation of the processing and differencing of raw GNSS data collected by two receivers, one at each end of a baseline. Such vectors are commonly put in a survey network for least squares adjustment; however, vector file formats are largely technique and vendor specific. To this end, NGS is proposing the GVX file format for exchanging all types of GNSS vectors, whether derived as part of a real-time kinematic (RTK) survey or from baseline post-processing.

GVX Contents

The links below provide detailed documentation on all of the elements and data types in the GVX file format, an example GVX file, and a schema with information on restrictions, optional elements, and more.

GVX elements include (but are not limited to) the following:

  • Mark-to-mark Earth-Centered, Earth-Fixed (ECEF) vector components
  • Variances and covariances of vector components
  • Reference frame information
  • Start and stop time of the observation
  • A-priori coordinates for the end points of each vector
  • Receiver and antenna types
  • RTK and real-time network (RTN) settings, if applicable
  • Quality control metadata (e.g., PDOP, number of satellites used, orbit type, etc.)

Feedback
Tell us what you think!

Ultimately, the goal is for industry and academia to adopt GVX for storing and sharing GNSS vector data, in a similar manner to how RINEX has been adopted for static GNSS data. Thus, NGS is requesting comments and feedback from all interested parties, which can be emailed to NGS.Feedback@noaa.gov.

NGS is interested in feedback on the following:
  • Important data that is missing in the proposed format
  • Extraneous or unnecessary data that is currently in the format
  • Similar standard file formats that may already be available for use