WebPPP

PRECISE POINT POSITIONING

WebPPP – is a free online service for a posteriori processing of GNSS observations.

The service provides high-precision coordinate estimation using Precise Point Positioning (PPP) from RINEX observation files and includes a detailed analysis of the resulting positioning solution.

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SATELLITE SYSTEMS

Satellite constellations used in the positioning solution.

  • GLONASS
  • GPS
  • Galileo
  • QZSS
  • Beidou

REFERENCE FRAMES

Reference frames that can be selected as output.

  • ITRF-2020
    PZ-90.11
  • ITRF-2014
    PZ-90.02
  • ITRF-2008
    PZ-90
  • ITRF-2005
    GSK-2011
  • ITRF-2000

ELLIPSOIDS

Reference ellipsoids for which coordinates can be computed for the
receiver.

  • WGS-84
  • GSK-2011
  • PZ-90.11
  • GRS80
  •  

GEOIDS AND QUASIGEOIDS

Earth gravity field models from which orthometric and normal heights can be obtained

  • EGM-2008
  • EGM-96
  • GAO-2012
  • EIGEN-6C4
  • GECO
Processing in static and kinematic modes
Detailed report with positioning results
Visualization of the receiver trajectory
Solution at a selected epoch
Application of ocean tide loading (OTL) corrections
Single-frequency and dual-frequency solutions
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Service Features

Observation upload form with many settings

Solutions for stationary and moving objects
Single-frequency or dual-frequency solution
Select the epoch to which the output coordinates will be propagated
Support for user-provided ocean tide loading (OTL/BLQ) corrections, ANTEX antenna calibrations, and many other settings

Request history

A dedicated page with trajectory visualization for each file

Solution Analysis

Summary of processing results
Receiver trajectory and axis offsets in the local tangent plane coordinate system
Observed satellites and reasons for their exclusion from the solution
Code multipath profile
Cycle slips and residuals
Details

Observation processing results

Summary of processing results
Receiver coordinates in ITRF-2020
Covariance matrix parameters
Coordinates in the selected reference frame
Coordinates relative to the selected ellipsoid
Orthometric and normal heights
Compatible with RTKPLOT (RTKLIB)
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Observation file processing report

Frequently Asked Questions

General questions on the topic:

PPP (Precise Point Positioning) is a high-precision satellite positioning method that uses precise ephemerides and clock corrections to determine coordinates without requiring data from a base station.

Unlike differential methods (RTK, DGPS), PPP operates globally and can provide millimeter-level positioning accuracy in post-processing.

RTK (Real-Time Kinematic) requires a nearby base station (up to 20–30 km away) to achieve high accuracy.

PPP is independent of base stations, operates globally, and is suitable for remote areas, providing millimeter-level accuracy in post-processing mode.

RINEX (Receiver Independent Exchange Format) is a standardized data-exchange format that stores GNSS observation and navigation data recorded by a receiver and is widely used for post-processing

A detailed description of the current version of the format is available via this link.

Service-related questions:

Currently, the service uses precise ephemeris and clock information (POD products) from three Russian sources — IAC KVNO, SVO ECI, and SDCM.

POD products are classified by latency (and therefore expected accuracy) as Ultra-rapid, Rapid, and Final:

A solution based on Ultra-Rapid products is available on the same day.

A solution based on Rapid products becomes available after 2 days.

A solution based on Final products becomes available after 4–5 days.

After registration, the service lets you check POD products availability and download the files used in the positioning solution.

Yes. WebPPP can process observations in both static and kinematic modes (e.g., from drones, cars, etc.).

A public API is available to automate observation file processing.

The WebPPP service has a number of requirements for submitted observation files:

- A RINEX file (versions 2.01–4.02) or Hatanaka-compressed RINEX (CRX)

- Static and kinematic observations at one or more frequencies are supported

- Multi-day observation files and arbitrary sampling intervals are supported

- File size up to 350 MB

- Uploading archived files is allowed

The recommended minimum observation duration for a static site is 60 minutes.

The accuracy of the estimated coordinates can depend on many factors, including:

- The selected type of ephemeris and clock information — Ultra-Rapid, Rapid, or Final

- The amount and quality of observations

- The number of observed satellites and their geometry

- The availability of multi-frequency observations

- The quality of the regional ionospheric model/grid (for single-frequency solutions)

- Applying ocean tide loading (OTL/BLQ) corrections

- Using antenna calibration files in ANTEX format

- The accuracy of correction products (Rapid vs Final)

- Multipath and other types of interference

The service supports user-provided ocean tide loading (OTL) correction files in BLQ format.

Applying these corrections can improve positioning accuracy, especially in coastal areas.

The service supports user-provided antenna calibration files in ANTEX format (.atx).

The ANTEX format is used to store information on the characteristics and phase center offsets of satellite and receiver antennas.

Yes. By default, the service returns coordinates at the observation epoch.

However, you can select an epoch to which the estimated coordinates will be propagated.

Epoch propagation is performed using the ITRF2020-PMM plate motion model and GSRM v2.1.

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