PointPerfect RTCM Distribution

Overview

Introduction

The u-blox PointPerfect service offers GNSS correction data services that enable high-precision positioning. This data is provided in either SPARTN or RTCM data formats.  


This document describes only how to receive PointPerfect corrections in an RTCM data format using the NTRIP protocol. More information about SPARTN data via NTRIP or other delivery options can be found in the PointPerfect Service Description page or the PointPerfect Getting Started guide. 


We also provide a SPARTN/NTRIP corrections service, information about this service is available on the following page: PointPerfect NTRIP Distribution

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

 

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Don'ts: 

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RTCM data format

The RTCM data format applies a standard for the network communication and encoding of GNSS data.  It was the first published standard by the Radio Technical Commission for Maritime Services for Differential GNSS and is used today by many high-precision GNSS receivers.  

PointPerfect delivers RTCM 3.3 via NTRIP when a user selects an RTCM plan.

NTRIP versions

PointPerfect supports both NTRIP protocol versions 1.0 and 2.0, automatically identifying the version used by the GNSS receiver device's NTRIP client. 

TLS encryption

Secure NTRIP connections using TLS encryption are supported and recommended, provided the GNSS receiver device’s NTRIP client supports TLS. 

Here is a diagram describing the communication of RTCM via NTRIP:

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.

Prerequisites for using the RTCM service

The ability to create a PointPerfect Location ‘Thing’ should be enabled on your Thingstream domain when this page was shared with you.  If you find any of the steps below are not available to you, please send us a message.

IMPORTANT: User credentials for each Location ‘Thing’ include a 36-character username, but some NTRIP clients require a shorter length username.  Please check the username requirements of your NTRIP client before creating your RTCM device on your domain. If your NTRIP client cannot accept our current username length, submit a request with your Thingstream domain name and the desired length of your username credentials. This length can be between 6-20 characters, and we recommend for security purposes using the maximum length allowed by your client.

Create a new RTCM Thing

On your domain, go to Location Services > Thing List > Add Location Thing.  Select the PointPerfect tab and choose “Add a PointPerfect Thing” 

You will be prompted to enter a friendly Thing name, and to select the Format of the data corrections provided for this device - choose the RTCM option. 

IMPORTANT NOTE: The Format cannot be changed for your device once it has been created.  If you wish to use the SPARTN format you must create a new PointPerfect Thing.

Choose the plan you wish to apply - for example the Developer plan as shown in the example screen shot below.   

Note: If you choose to Skip this part of the process, please remember to select a valid plan before using the new Thing 

Configure your NTRIP Client 

Each Thingstream PointPerfect device (‘Thing’) is provided with unique credentials (username and password) for the RTCM/NTRIP service.  You will find these under the Credentials tab of your Thing Details.   

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. 

NOTE: If your NTRIP client does not accept the length of the username, please send a request specifying the username length required and we will update your domain.  New devices created after this adjustment will apply your new username length.  Simply deactivate any Thing that you will not use to stop any billings from it.   

To enable PointPerfect RTCM over NTRIP on the F9 module, you will need to connect your receiver’s client to the NTRIP caster and stream. Follow the steps in the PointPerfect u-center guide to complete the setup. 

RTCM messages

The following is the list of RTCM messages that are provided:

Reference Documentation

[1] ZED-F9P Integration manual, UBX-18010802
 [2] u-center User guide, UBX-13005250
 [3] u-blox F9 HPG 1.32 Interface description, UBX-22008968
 [4] C099-F9P application board User guide, UBX- 18063024
[5] EVK-F9P-01 evaluation kit User guide, UBX-22038408  
 [6] Thingstream Knowledge Base – Services Support
[7] u-blox information on positioning and location technologies - What is NTRIP