NTRIP Client connection settings

If reference station data is distributed in real-time through the Internet using the Ntrip protocol, you can connect to these data streams and use them as data input for your Trimble 4D Control Server system. A main advantage of this connection type is that in a firewall system one does not require more than one port open for connections. Moreover, the Ntrip concept allows data requests from multiple broadcasting networks. A connection configuration using the NTRIP Client type is basically comparable to a TCP/IP client.

Tip - For more information on the basics of the Ntrip concept and its main components (the NtripSources generating data streams, the NtripServer providing the data streams, the NtripCaster making the data streams available using source-tables, and the NtripClients requesting the data streams), see the description of the Trimble NtripCaster. Detailed information on the Ntrip concept is available from igs.bkg.bund.de/ntrip/index.

To configure a connection as an NTRIP Client connection, select the NTRIP Client connection type. It will allow the use of Ntrip protocol standards for the communication between the computers. The properties of the Connection Settings category adjust themselves for the selected connection type.

Caster name: Specifies the name (IP address or Internet host domain name) of the Ntrip Caster computer. Both address formats are allowed. Defaults to localhost (127.0.0.1), when setting up a new connection. Enter a valid address that allows you to request a source-table.

Port: Specifies the IP port number of the caster host. The default port number is 2101, which is registered by IANA (Internet Assigned Numbers Authority) in the list of well known ports for the usage of GNSS data.

SSL/TLS: The Secure Sockets Layer (SSL) protocol and its successor Transport Layer Security (TLS) are encryption protocols which provide secure communication on the Internet. This settings specifies whether (Yes) or not (No) the connection is only built up, if both sides communicate using either SSL v3.0 or any TLS protocol version. If different or multiple versions of encryption protocols are available at the connecting computers, the latest version that is supported by both, the client and the server, will be used. If set to Yes, additional properties become available that specify whether additionally authentication certificates are needed for the local computer to identify itself at the remote side (Select certificate) or for the remote side to be accepted at the local machine (Remote certificate required). If set to Yes, the Ntrip version property cannot be set to Ntrip version 1.0, because this version does not support SSL encryption.

Remote certificate required: Only available, if the SSL/TLS property is set to Yes. Specifies whether or not the remote side has to identify itself using a valid certificate which must be known at the local computer. With the default No selection, the counterpart needs not to identify itself. If you set the property to Yes, the computer hosting this module needs to have a valid client certificate from the counterpart in its Trusted Root Certificates Authorities folder. If such an certificate is not provided or if the counterpart does not identify itself correctly, the connection will not be built up.

Select certificate: Only available, if the SSL/TLS property is set to Yes. Specifies the personal certificate (that is, the certificate that identifies the current user account running the Trimble 4D Control Server system on the local computer). This certificate proves the identity to any counterpart to which you want to connect, if the counterpart has received a copy of your certificate in advance. The Select certificate drop-down list shows all certificates installed on the computer that runs the module under the current user account. Either select the a certificate or the <None> option, if the counterpart does not require an authentication certificate.

NTRIP version: Specifies the version of the Ntrip protocol used to communicate. Ntrip version 1.0 (default) and Ntrip version 2.0 are supported versions. If Ntrip version 2.0 is selected, additional properties become available.

Communication type: Only available, if the Ntrip version property is set to Ntrip version 2.0. Ntrip Version 2.0 is a fully HTTP-compatible Internet protocol standard that works with proxy servers and adds an optional data transport via UDP. Hence, several Ntrip Version 2.0 communication types are selectable:

Automatic reconnect: When the program is running on different computers, a shutdown of one of the computers or a breakdown of the network connection (for example, an unplugged network cable) may cause an attempt to automatically re-connect. If set to Yes, the Reconnect delay setting becomes available.

Reconnect delay: Only available if Automatic reconnect is set to Yes. Specifies a time delay, after which the module will attempt a re-connection to the to the Ntrip caster. Note that in the case of an unplugged network cable, the module will now continuously try to access the Ntrip caster in the specified interval until it succeeds. Default: 10 seconds.

Depending on the module for which the NTRIP Client connection will be used, different properties are available for specifying the caster mountpoint, which identifies the GNSS data stream at the NtripCaster.

Dynamic mountpoint: Only available for modules using station information or added below such a module. With the default setting No, the Mountpoint property becomes available. Use it to specify the caster mountpoint. For setting up several modules of the same type in one step, set the Dynamic mountpoint value to Yes and specify a string that will be added to the station code using the Mountpoint suffix property. Trimble 4D Control Server then will dynamically create mountpoints for each module.

Mountpoint: Available for all NTRIP Client connections. (For modules using station information or added below such a module, only available, if the Dynamic mountpoint property is set to No.) Unique caster mountpoint. Identifies the GNSS data stream at the NtripCaster. To select a mountpoint, set the focus onto the value field and click the browse button. The Select Mountpoint dialog appears automatically starting a request for a source-table from the caster specified in the Caster name setting. One may also edit the value field.

Mountpoint suffix: Only available, if the Dynamic mountpoint property is set to Yes. Specifies a string which will be the second part of the composed mountpoint (that is, the "suffix"). The first part is derived from the station code of the station used by the module or its parent. An underscore will separate the components of the mountpoint string. The following is an example for a Mountpoint suffix value of a Router set up as "_Network1" and its parent GNSS Receiver module based on a station whose code is AB01. In this case, the automatically generated mountpoint for the Router module results in "AB01_Network1".

Authentication: Specifies whether user authentication is necessary. The following authentication modes are available for selection:

Note - Authentication settings may not be available, if the mountpoint does not require user authentication (that is, it is set up with Authentication value None in the source-table).

User: Only available, if Authentication is not set to None. Specifies the user name.

Password: Only available, if Authentication is not set to None. Specifies the password for the user.

Use proxy server: Specifies whether the access to the NtripCaster should be routed via a proxy server or not. A proxy server may be necessary if a firewall blocks the port on which the NtripCaster is running. Default: No.

Proxy server name: Only available, if Use proxy server is set to Yes. Specifies the name (IP address or host name) of the proxy server to use.

Proxy server port: Only available, if Use proxy server is set to Yes. Specifies the IP port number of the proxy server to use. Default: 8080.

Note - When using the proxy server, the NtripClient uses the HTTP commands "GET" to retrieve mountpoint information, and "CONNECT" to establish a proxy tunnel connection for retrieving the data stream from the NtripCaster. It is important that the proxy server is configured to allow the usage of both the "GET" and "CONNECT" commands, otherwise the NtripClient will not be able to retrieve data from the caster.