Ephemeris and Navigation Data Files

During some sensor trajectory processing LP360, two ephemeride files are obtained as part of the “Auto download” step on the Ephemeris Settings page of the wizard: an ephemeris (sp3) file and a broadcast (brdc*.YYn) navigation file. LP360 allows both files to be browsed or auto downloaded.

If the navigation file isn’t specified or downloaded, LP360 uses the rover navigation file (e.g. 20180119192120.18P, created from the rover GNSS file). If the system was on for too short a time (typically less than 15-18 minutes) due to a short flight, you may fail to get a fixed trajectory solution. You may browse to the navigation file from your base station (either .18N or .18P files), or you may download a broadcast navigation file using one of the links below.

If the ephemeris file isn’t specified or downloaded, use one of the links below to obtain them. You’ll need to know the GPS week and day (0-6, where 0 is Sunday and 6 is Saturday) for ephemeris files. For navigation files, you’ll need to know the Julian Date or day of the year (e.g. 1-365).

Note: Some GNSS providers now distribute broadcast navigation files using modern “long format” RINEX 3/4 filenames (e.g., BRDC00IGS_R_20241230000_01D_MN.rnx.gz) instead of the legacy brdc###0.YYn format described below. LP360 supports both formats.

Ephemeris Files

• https://cddis.nasa.gov/archive/gnss/products/
• https://cddis.nasa.gov/archive/glonass/products/
• ftp://igs.ensg.ign.fr/pub/igs/products/
• ftp://gssc.esa.int/gnss/products/
• ftp://lox.ucsd.edu/pub/products/

Note: In addition to the legacy naming conventions shown below (e.g., iguWWWWD_HH.sp3.Z), many providers now distribute precise ephemeris files using modern long-format filenames (e.g., IGS0OPSFIN_20240190000_01D_15M_ORB.SP3.gz). LP360 supports both formats.

Ultra-rapid Solution (OPSULT / formerly IGU)

GNSS orbit combination solutions (ultra-rapid solution) produced by the International GNSS Service (IGS). These sub-daily files of satellite ephemerides are useful for real-time and near real-time applications; the ultra-rapid solution includes both observed and predicted satellite orbits. The solutions are released four times per day, at 03:00, 09:00, 15:00, and 21:00 UTC. At the time of release, the observed orbits have an initial latency of 3 hours. More information on this product can be found at https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/gnss_igsuorb.html

First, pick the GPS week folder (e.g. 1984). Then find as many as 4 .sp3 files: igu<week#><day#>_00, or _06, or _012, or _018.sp3.Z. Always get the “highest one available for that day”. For Friday of week 1984, that is igu19845_18.sp3.Z. If that one isn’t available, next is igu19845_12.sp3.Z, and so on. Download and unzip, then browse to the file.

WWWW/iguWWWWD_HH.sp3.Z

as described in the table below.

Modern equivalent example:

IGS0OPSULT_20240190000_01D_15M_ORB.SP3.gz

This corresponds to the same type of product as:

iguWWWWD_HH.sp3.Z

Instead of decoding GPS week/day, the modern filename directly encodes:

• 2024 → Year
• 019 → Day of year
• OPSULT → Ultra-rapid solution

Rapid Solution (OPSRAP / formerly IGR)

GNSS orbit combination solutions (rapid solution) produced by the International GNSS Service (IGS). These daily files of satellite ephemerides contain 24 hours (from 00:00 to 23:45 UTC) and are provided in 15-minute intervals in SP3 format including accuracy codes. This rapid solution has a quality nearly comparable to that of the final IGS products. The solution consists of daily orbit and clock files, generated on a daily basis by rapid combining solutions from individual IGS Analysis Centers, released approximately 17 hours after the end of the UTC day. More information on this product can be found at https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/gnss_igsrorb.html

WWWW/igrWWWWD.sp3.Z

as described in the table below.

Final Solution (OPSFIN / formerly IGS)

Summary file produced by the International GNSS Service (IGS) with the GNSS orbit combination solutions (final solution). The summary file describes the combination process and provides statistics on the analysis. This final solution is the most consistent and highest quality IGS solutions, summarizing the analysis performed for the daily orbit and ERP combination solution, generated on a weekly basis approximately 13 days after the end of the solution week. More information on this product can be found at https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/gnss_igssum.html

Mixed Solution (MGX / formerly IGV)

Contains both GPS and GLONASS

Modern Long-Format Ephemeris Files (SP3)

Modern GNSS providers (IGS, CDDIS, ESA) now commonly distribute precise orbit (ephemeris) files using long-format filenames instead of the legacy iguWWWWD_HH.sp3.Z, igrWWWWD.sp3.Z, and igsWWWWD.sp3.Z formats.

Example:

IGS0OPSFIN_20240190000_01D_15M_ORB.SP3.gz

Structure Breakdown

✅ Mapping to Legacy Products

✅ What to Select

• Final (OPSFIN) → best accuracy, highest latency (~13 days)
• Rapid (OPSRAP) → good accuracy, ~17-hour latency
• Ultra-rapid (OPSULT) → near real-time use

⚠️ Key Differences from Legacy Format

• Uses .gz instead of .Z
• Includes explicit duration and sampling interval
• No GPS week/day decoding required
• LP360 fully supports both naming conventions

Broadcast Navigation Files

https://cddis.nasa.gov/archive/gnss/data/daily
ftp://igs.ensg.ign.fr/pub/igs/data/

Select the year folder, then the day folder (Jan 19th is 019), then pick the 18n folder to find legacy files such as: brdc0190.18n.Z (note the extra ‘0’ at the end—that’s expected), or long-format files such as BRDC00IGS_R_*.rnx.gz depending on the archive view. Download, unzip, then browse to the file.

Modern Long-Format Navigation Files (RINEX 3/4)

In addition to the legacy brdc###0.YYn format, many providers (CDDIS, IGS) now distribute broadcast navigation files using a long-format naming convention.

Example:

BRDC00IGS_R_20240190000_01D_MN.rnx.gz

Key differences:

• Includes full timestamp and duration (e.g., 01D = 1 day)
• Identifies source (e.g., IGS)
• Indicates constellation type (e.g., MN = Mixed GNSS)
• Typically distributed as .rnx.gz instead of .Z

Structure Breakdown

✅ What to Select

• Prefer BRDC*_MN.rnx.gz for standard processing (multi-GNSS)
• Ensure the file date matches your flight/session
• Extract the file before use if compressed

Alternate Sites

Other locations for ephemeris and broadcast navigation files may be found at:
https://kb.igs.org/hc/en-us/articles/202054393-IGS-FTP-Sites