PointPerfect RTCM Distribution

Overview

Introduction

The u-blox PointPerfect service provides high-precision GNSS correction data to improve positioning accuracy. It delivers corrections in the SPARTN or RTCM format. This guide covers how to receive PointPerfect corrections in RTCM 3.3 format via NTRIP, a standard protocol supported by many high-precision GNSS receivers. RTCM, developed by the Radio Technical Commission for Maritime Services, defines the format and communication method for delivering differential GNSS data.

For details on SPARTN over NTRIP or other delivery options, refer to:

• PointPerfect SPARTN over NTRIP Distribution guide

• PointPerfect Getting Started guide

• PointPerfect Service Description page

                               -------------------------------------------------------------------------------------------

Do's & Don'ts: Best Practices and Common Pitfalls 

Do's: 

• Send GGA messages every 10 seconds: The NTRIP server needs a current GGA message from the rover to ensure correct localized corrections. Most NTRIP Clients are set to send GGA every 10 seconds. (The NTRIP server disconnects if no GGA is sent within 30 seconds.) 

• Verify your NTRIP credentials: Double-check that your endpoint, mount point, and credentials (username, password) match with what is within your Thingstream portal. 

• Keep your NTRIP Client up to date: Outdated NTRIP Clients can face connection issues with the NTRIP Server. 

Don'ts: 

• Don’t use SPARTN for 3rd party receivers: Only u-blox receivers, such as the F9 or X20 series, can benefit from SPARTN over NTRIP. Third-party receivers are not compatible with the SPARTN format and will need to use RTCM over NTRIP distribution. 

• Don’t send inaccurate GGA messages: Some NTRIP Clients send fixed or “baked” GGA messages that don’t reflect the rover’s real-time position. This can lead to DGNSS or Float problems. Always ensure GGA messages reflect the rover’s current location. 

• Don't share NTRIP credentials: Sharing your login credentials may lead to unauthorized access, disruptions in service, or potential account suspension. 

                               -------------------------------------------------------------------------------------------

Configuration

Each Thingstream PointPerfect device (‘Thing’) is provided with unique username and password credentials for the RTCM/NTRIP service.  These credentials are exclusive to one simultaneous NTRIP client connection.  If a second device attempts to connect using the same credentials, the first device will be disconnected.

Our NTRIP service requires a valid NMEA-GGA (GxGGA) message to be sent regularly to the caster in order to maintain connectivity. If no valid NMEA message is sent within 30 seconds, the connection will be dropped. To prevent a hard disconnect at the 30-second interval, we recommend sending this NMEA-GGA message every 10 seconds.  A valid NMEA-GGA message must be within the expected time/location range, contain at least 4 satellites, must be presented in the right format, and the checksum must pass.