Overview
Introduction
The u-blox PointPerfect Flex 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 Flex 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 Flex SPARTN over NTRIP Distribution
- PointPerfect Flex Service Description
- PointPerfect Flex Getting Started
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Do's & Don'ts: Best Practices and Common Pitfalls
Do's:
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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.)
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Verify your NTRIP credentials: Double-check that your endpoint, mount point, and credentials (username, password) match with what is within your Thingstream portal.
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Keep your NTRIP Client up to date: Outdated NTRIP Clients can face connection issues with the NTRIP Server.
Don'ts:
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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.
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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.
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Don't share NTRIP credentials: Sharing your login credentials may lead to unauthorized access, disruptions in service, or potential account suspension.
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NTRIP Protocol Versions and Secure Delivery
PointPerfect Flex supports both NTRIP protocol versions 1.0 and 2.0, automatically detecting which version is used by the GNSS receiver’s NTRIP client. Secure connections using TLS encryption are also supported and recommended as long as the receiver’s NTRIP client is compatible with TLS.
Here is a diagram describing the communication of RTCM via NTRIP:
Configuration
Each Thingstream PointPerfect Flex 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 Flex 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 Flex tab and choose “Add a PointPerfect Flex 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 Flex Thing.
From the list of plans listed on the next screen choose the plan you wish to apply.
Note: If you choose to Skip this part of the process, please remember to select a valid plan before using the new Thing
To enable PointPerfect Flex 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 Flex u-center guide to complete the setup.
For more information on provisioning and obtaining the connection parameters and credentials see the Creating a Thing page.
Service to Service
For service to service (S2S), the user is responsible for distributing the localized corrections data, this requires additional configuration at the user backend to redistribute the service data to the devices.
To access the service via service-to-service approach, please contact us at services-support@u-blox.com
RTCM messages
The following is the list of RTCM messages that are provided:
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1005 --> station description
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1032 --> physical reference station position
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1033 --> receiver and antenna description
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MSM4
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1074 (GPS)
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1094 (GAL)
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1084 (GLO)
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1124 (BDS)
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Still need help?
If you need more help or have any questions, please send an email to services-support@u-blox.com.
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