Page | 1 January 23, 2017
APN-074 Rev A
APN-074
NTRIP on NovAtel OEM6®/OEM7
Page | 2 January 23, 2017
NTRIP on NovAtel OEM6/OEM7
Table of Contents
NTRIP Overview ............................................................................................................................................ 3
Receiver Model Requirements ................................................................................................................. 4
NTRIP Client Mode ........................................................................................................................................ 5
Setup of the Ethernet Connection ............................................................................................................ 5
Connecting to an NTRIP Caster as an NTRIP Client ................................................................................... 5
Example ..................................................................................................................................................... 6
NTRIP Server Mode ....................................................................................................................................... 8
Connecting to an NTRIP Caster as an NTRIP Server .................................................................................. 8
Example 1: Lefebure NTRIP Caster............................................................................................................ 8
Example 2: SNIP NTRIP Caster ................................................................................................................ 12
TCP/IP Considerations ................................................................................................................................. 16
Support ....................................................................................................................................................... 16
Table of Figures
Figure 1 - OEM6 Model Options ................................................................................................................... 4
Figure 2 - OEM7 Model Options ................................................................................................................... 4
Figure 3 Lefebure Caster Mount Points List ............................................................................................... 9
Figure 4 Lefebure Caster User List ............................................................................................................. 9
Figure 5 Lefebure Caster Event Log ......................................................................................................... 10
Figure 6 Lefebure Caster Event Log, Server Connected ........................................................................... 11
Figure 7 Lefebure Caster Connections Overview ..................................................................................... 11
Figure 8 - SNIP Client Management ............................................................................................................ 12
Figure 9 - SNIP User List .............................................................................................................................. 13
Figure 10 - SNIP Caster Overview ............................................................................................................... 13
Figure 11 - SNIP Pushed Streams ................................................................................................................ 14
Figure 12 - SNIP NTRIP Server Password ..................................................................................................... 14
Figure 13 - SNIP Active Pushed Server Streams .......................................................................................... 15
Page | 3 January 23, 2017
NTRIP Overview
NTRIP (Networked Transport of RTCM via Internet Protocol) is a protocol for streaming DGNSS
correction data over the internet. NTRIP capable devices can have one or more designated “NTRIP
roles”, which are listed below.
The NTRIP server is a device providing DGNSS correction data to an NTRIP caster over an internet
connection. It is actually not a server in the “classic” definition since it is not serving data directly to any
clients.
The NTRIP client is a device which is using DGNSS correction data provided by an NTRIP caster over the
internet.
The NTRIP caster is a device which is receiving DGNSS correction data streams from one or more
connected NTRIP servers and is distributing or relaying the DGNSS correction data to one or more
connected NTRIP clients. The NTRIP caster itself is not generating or providing any DGNSS correction
data.
An RTK base station would be a typical NTRIP server, while an RTK rover receiver would be a typical
NTRIP client. The RTK base station may have built-in NTRIP caster functionality, but often an NTRIP
caster is a dedicated program running on a computer or server connected directly to the internet over a
high-speed data connection. Since an NTRIP caster may be getting data from a large number of NTRIP
servers and may be serving data to a large number of clients, a mobile connection to the internet may
be less suitable for an NTRIP caster.
NovAtel OEM628, OEM638and OEM7 receiver boards (except for the OEM719™), and the receivers
containing one of these receiver boards, all natively support both the NTRIP server and NTRIP client
roles. NovAtel OEM6 and OEM7 boards do not have on-board NTRIP caster functionality, so a separate
NTRIP caster program is always needed in order to use an OEM6 or OEM7 receiver as an NTRIP-enabled
RTK base station.
Page | 4 January 23, 2017
Receiver Model Requirements
Any NTRIP connectivity (server or client) requires a receiver model that supports NTRIP. For an OEM6
receiver, the 9
th
position in the model name should be either “N” or “R”.
Figure 1 - OEM6 Model Options
For an OEM7 receiver, the 4
th
position in the model name should be “L”, “P” or “R”.
Figure 2 - OEM7 Model Options
- -
N
NTRIP
R
Omni STAR/NTRI P
(Obs ol ete)
char[7]
char[8]
char[9]
char[1]
char[2]
char[3]
char[5]
char[6]
Psuedorange
Positioning
Measurement
Output Rate
(Hz)
Position Rate
(Hz)
Correction
Service
Channel Configuration
Positioning Options
Logging Rates and COMS
Constellation
Frequency
Other Systems
Other
Positioning
-
L
Low End Positioning
P
L + Unres tri cted PPP
R
P + RTK
Positioning Options
CORRECT
Positioning
Heading
Reserved
char[4]
char[5]
char[6]
Channel Configuration
Constellation
Frequency
Reserved
char[1]
char[2]
char[3]
Page | 5 January 23, 2017
NTRIP Client Mode
In NTRIP client mode, the receiver is able to connect to an existing NTRIP caster in order to stream DGPS
or RTK correction data from the internet to the receiver. These correction data can be used by the
receiver to improve the quality of its position solutions. A typical example would be connecting to an
RTK network using a mobile internet connection.
Setup of the Ethernet Connection
Before the receiver can connect to the internet, the Ethernet functionality has to be enabled. This can
be done by sending the following command:
ETHCONFIG ETHA AUTO AUTO AUTO AUTO
The receiver will now try to obtain a DHCP-assigned IP address from the network’s DHCP server. Once
the receiver has obtained a valid IP address, it is able to connect to IP addresses on the internet.
To verify the receiver has actually obtained a valid IP address, send the following command:
LOG IPSTATUS ONCE
The receiver will respond with a message similar to the one below:
<IPSTATUS USB1 0 74.0 FINESTEERING 1921 488532.101 00000000 7fe2 14039
< 2
< ETHA "192.168.13.130" "255.255.255.0" "192.168.13.200"
< SERPPP "" "" ""
< 1
< "192.168.13.200"
The numbers on the third line (the line starting with “ETHA”) show the receiver’s current IP address,
subnet mask and the network’s gateway IP address. The numbers on the last line show the IP address of
the network’s DNS server, the device that translates internet names (like www.novatel.com
) to their
corresponding IP addresses.
Connecting to an NTRIP Caster as an NTRIP Client
Before a connection to an NTRIP caster can be established, you would need to know the NTRIP caster’s
IP address or internet name and the caster port. Both can be provided by the owner of the caster. Most
casters nowadays require a user name and password to login to the caster as well. The last piece of
information needed is the mount point. Different mount points usually provide different correction data
streams. If you do not know which mount points are available on an NTRIP caster, the receiver can
request the mount point table from the caster, in which all available mount points on the caster are
listed.
Page | 6 January 23, 2017
Example
The example below will use the following data:
The NTRIP caster is located at IP address 192.168.13.113
The NTRIP caster port for initial connection is 2101
The user name to log in to the caster is “flex6”
The password to log in to the caster is “Fl3x6”
To establish a connection, a mount point is mandatory, but since no mount point is given, it must be
requested and downloaded from the server. To do this, just send the following commands to the
receiver:
NTRIPSOURCETABLE 192.168.13.113:2101
LOG SOURCETABLE
The receiver will respond with a message similar to the one below:
<SOURCETABLE USB1 4 68.0 FINESTEERING 1921 491529.380 00100000 71dd 14039
< "192.168.13.113:2101" 0 0 "SOURCETABLE 200 OK;Server: SubCarrier Systems Corp SNIP
simpleNTRIP_Caster_R1.0.0/of:Oct 17 2016;Date: Fri, 04 November 2016 16:31:52 UTC;Content-Type:
text/plain;Content-Length: 181"
<SOURCETABLE USB1 3 68.0 FINESTEERING 1921 491529.380 00100000 71dd 14039
< "192.168.13.113:2101" 0 0 "STR;CMR;;Raw;Unknown;;;SNIP;XXX;;;0;0;sNTRIP;None;B;N;0;"
<SOURCETABLE USB1 2 74.5 FINESTEERING 1921 491529.380 00100000 71dd 14039
< "192.168.13.113:2101" 0 0 "STR;RTCM;;Raw;Unknown;;;SNIP;XXX;;;0;0;sNTRIP;None;B;N;0;"
<SOURCETABLE USB1 1 74.5 FINESTEERING 1921 491529.380 00100000 71dd 14039
< "192.168.13.113:2101" 0 0 "STR;RTCM_31;;Raw;Unknown;;;SNIP;XXX;;;0;0;sNTRIP;None;B;N;0;"
<SOURCETABLE USB1 0 74.5 FINESTEERING 1921 491529.380 00100000 71dd 14039
< "192.168.13.113:2101" 0 0 "ENDSOURCETABLE"
The mount points in the above listing have been marked in red. As can be seen, this particular NTRIP
caster is providing three different mount points (and therefore likely three different data streams). For
this example, the mount point “RTCM_31” (with correction data in RTCM version 3.1) will be used.
Now that all the required information is available, the connection to the caster can be established by
sending the following commands:
NTRIPCONFIG NCOM1 CLIENT V1 192.168.13.113:2101 RTCM_31 flex6 Fl3x6
INTERFACEMODE NCOM1 RTCMV3 NONE OFF
The first command establishes the connection to the caster and requests data from the mount point
“RTCM_31”. The second command tells the receiver to handle the incoming data as RTCM version 3
correction data and not to send anything back to the NTRIP caster.
Page | 7 January 23, 2017
The settings above will work for any NTRIP caster that is providing correction data from just one
reference station or a small number of reference stations, where the rover is selecting the reference
station by selecting a specific NTRIP mount point.
If a connection to an RTK network is made, the network usually either selects the nearest physical base
station or it creates a virtual reference station for the rover’s position. In these cases, the network needs
to know the position of the rover before any RTK corrections can be provided, so the rover needs to
send its own position back to the network periodically, usually as an NMEA GGA message.
A connection to an RTK network can be established by sending the following commands:
NTRIPCONFIG NCOM1 CLIENT V1 192.168.13.113:2101 RTCM_31 flex6 Fl3x6
INTERFACEMODE NCOM1 RTCMV3 NOVATEL OFF
LOG NCOM1 GPGGA ONTIME 5
The first command establishes the connection to the caster and requests data from the mount point
“RTCM_31”. The second command tells the receiver to handle the incoming data as RTCM version 3
correction data and to send any messages back to the NTRIP caster in clear text. The third command
sends the receiver’s position back to the caster once every 5 seconds. This will allow the RTK network to
provide the most suitable correction data to the receiver at all times.
To verify that the receiver is actually using the incoming correction data, send one of the following
commands to the receiver:
LOG GPGGA ONCE
LOG BESTPOSA ONCE
The possible replies will be similar to:
$GPGGA,170244.00,5201.7048514,N,00441.4288544,E,4,16,0.7,6.634,M,43.40,M,01,00
13*55
#BESTPOSA,USB1,0,68.5,FINESTEERING,1921,493424.000,00000000,b1f6,14039;SOL_COM
PUTED,NARROW_INT,52.02841415871,4.69048086004,6.6410,43.4000,WGS84,0.0192,0.01
58,0.0403,"13",1.000,0.000,16,16,16,16,00,21,00,33*1987b852
In the $GPGGA message, the (highlighted above) GPS status type “4” indicates the receiver is currently
in RTK FIX mode (the most accurate mode available). The “NARROW_INT” indication in the #BESTPOSA
message also indicates the most accurate operation mode.
Page | 8 January 23, 2017
NTRIP Server Mode
A receiver which is setup as a base station (using a fixed, known, position) can connect to an NTRIP
caster as an NTRIP server, streaming correction data to the caster instead of receiving correction data
from the caster. Multiple servers can feed data to one caster, which in turn can distribute the correction
data from the base stations (NTRIP servers) to all connected NTRIP clients.
Connecting to an NTRIP Caster as an NTRIP Server
As with the NTRIP client mode, the receiver must have a working Ethernet connection and a valid IP
address before the connection with the NTRIP caster can be established, see the “Setup of the Ethernet
connection” section on page 5. The way to connect is very similar, but there is one big difference: most
NTRIP casters will require both a user name and password for any connecting client, but they will usually
only require a password for a connecting server. Furthermore, the NTRIP configuration of the receiver
will specify “server” instead of “client”.
Since it would be impossible to describe in detail how to connect a NovAtel receiver as NTRIP server to
every possible NTRIP caster, the two examples below will be limited to two relatively simple NTRIP
caster programs that can be downloaded from the internet and used for free. Both programs feature a
built-in NTRIP server as well, to connect correction streams over a serial (RS-232) connection, but the
examples will only cover a connection from the receiver to the caster over a TCP/IP network. Please
note that NovAtel support are not promoting the use of either caster program and that support for
these programs lies solely with the manufacturer/provider of the programs. The examples below are
purely to demonstrate the mechanics of connecting a NovAtel receiver as an NTRIP server to an NTRIP
caster.
The two examples below will use the following data:
The NTRIP caster is located at IP address 192.168.13.113
The password to log in to the caster is “novatel”
A user name is not required for the server connection and will be left blank.
Example 1: Lefebure NTRIP Caster
The Lefebure NTRIP Caster is a small and lightweight program, allowing for one serial (RS-232)
connection and an “unlimited” number of TCP/IP connections. The program does have its limitations
when multiple clients are connected (for more details, please see the Lefebure website at
http://lefebure.com/software/ntripcaster/
) and the caster port is fixed to 5000. This port number
cannot be changed.
Page | 9 January 23, 2017
Figure 3 – Lefebure Caster Mount Points List
Before a server can connect to the caster, at least one mount point has to be defined on the “Mount
Points” tab. The mount point name must be unique (which it automatically is when only one mount
point is defined). Although the caster will accept a mount point without password, for security reasons it
is highly recommended to use one. All other fields are optional, but it is recommended to provide as
much information as possible, so clients can use this information to choose the correct data stream.
To enable users to connect to the caster once the server is connected, make sure to define at least one
user on the “Users” tab (user name and password):
Figure 4 – Lefebure Caster User List
Page | 10 January 23, 2017
Lastly, verify the NTRIP caster is actually running and listening for incoming data requests by clicking the
“Event Log” tab:
Figure 5 – Lefebure Caster Event Log
Now that the NTRIP caster program is set up correctly, the following commands sent to the NovAtel
receiver will establish a connection with the caster and start streaming RTCMv3 data to the mount point
called “RTCM31”:
FIX POSITION <antenna latitude> <antenna longitude> <antenna MSL height>
NTRIPCONFIG NCOM1 SERVER V1 192.168.13.113:5000 RTCM31 "" novatel ALL
INTERFACEMODE NCOM1 NOVATEL RTCMV3 OFF
LOG NCOM1 RTCM1004 ONTIME 1
LOG NCOM1 RTCM1012 ONTIME 1
LOG NCOM1 RTCM1006 ONTIME 10
LOG NCOM1 RTCM1008 ONTIME 10
LOG NCOM1 RTCM1033 ONTIME 10
Note the two double quotation marks in the second line to indicate a blank user name. Please provide
the antenna latitude, longitude and height as accurately as possible. Any deviation from the “real”
antenna position here will have a direct effect on the quality of the DGPS/RTK solution of the connected
rover receivers.
To verify the NTRIP server is indeed connected to the caster, first check the Event Log tab again. Upon
successful connection, an entry will be added with the IP address of the server and the name of the
mount point it is streaming correction data to.
Page | 11 January 23, 2017
Figure 6 – Lefebure Caster Event Log, Server Connected
The “Connections” tab will also show the connected server(s) and connected clients (if any). A server will
by default show “-SERVER-” as the user name:
Figure 7 – Lefebure Caster Connections Overview
To close the connection to the caster from the server side, send the following command to the NovAtel
receiver:
NTRIPCONFIG NCOM1 DISABLED
This command will “gracefully” disconnect the server, removing it from the caster’s “Connections” tab. If
the server is just switched off, the caster will not disconnect the server, which might cause problems
and/or hangups at the caster and connected clients.
Page | 12 January 23, 2017
Example 2: SNIP NTRIP Caster
The SNIP NTRIP caster (www.Use-SNIP.com) has a number of configuration options and will allow a mix
of serial and TCP/IP streams, up to the maximum number of input streams allowed by the registered
license of the caster. The free version is limited to 3 different input streams. Both the caster port and
the caster IP address (in case the computer on which the caster program runs has more than one IP
address) can be selected by the user.
When a receiver is connected over a serial (RS-232) connection, the user has to define a mount point
during setup of the connection. For connections over TCP/IP, the NTRIP server will define the mount
point.
Although SNIP allows anonymous access to the caster, it is recommended to define at least one user and
disable anonymous access to the caster. To create a user entry, open the “Caster and Clients” tab, then
click the “Manage Users” button.
Figure 8 - SNIP Client Management
The “Registered Users” window will open. Any existing users, with passwords, along with the maximum
number of simultaneous connections allowed for this user will be shown.
Page | 13 January 23, 2017
Figure 9 - SNIP User List
To add a new user, click the “Add User” button, enter the new user name and password and adjust the
number of simultaneous connections if required, then click the “OK” button. Before closing the
“Registered Users” window, make sure to unmark the “Allow Anonymous Access for Users” checkbox.
Next, check the “Caster Management” part of the Caster and Clients window. It will tell you which IP
address and which caster port the caster is currently listening on. If you would like to change any of
these settings, click “Disconnect”, change the IP address and/or caster port, then click “Connect”.
Figure 10 - SNIP Caster Overview
Make sure to note down the caster IP address and caster port, since the server needs this information to
be able to connect to the caster.
To define the password for server connections to the caster, click the “Pushed Streams” tab, then click
the “Set Up” button.
Page | 14 January 23, 2017
Figure 11 - SNIP Pushed Streams
Figure 12 - SNIP NTRIP Server Password
Enter the connection password, or alternatively click the “Generate” button to have the program
generate a password, then click “OK”.
Now that the NTRIP caster program is set up correctly, the following commands sent to the NovAtel
receiver will establish a connection with the caster and start streaming one data stream in RTCMv3
format to a (server-defined) mount point called “RTCM_31” and another data stream in CMR format to
a (server-defined) mount point called “CMR”:
FIX POSITION <antenna latitude> <antenna longitude> <antenna MSL height>
NTRIPCONFIG NCOM1 SERVER V1 192.168.13.113:2101 RTCM_31 "" novatel ALL
INTERFACEMODE NCOM1 NOVATEL RTCMV3 OFF
LOG NCOM1 RTCM1004 ONTIME 1
LOG NCOM1 RTCM1012 ONTIME 1
LOG NCOM1 RTCM1006 ONTIME 10
LOG NCOM1 RTCM1008 ONTIME 10
LOG NCOM1 RTCM1033 ONTIME 10
NTRIPCONFIG NCOM2 SERVER V1 192.168.13.113:2101 CMR "" novatel ALL
INTERFACEMODE NCOM2 NOVATEL CMR OFF
LOG NCOM2 CMROBS ONTIME 1
LOG NCOM2 CMRGLOOBS ONTIME 1
LOG NCOM2 CMRREF ONTIME 10
Page | 15 January 23, 2017
Note the two double quotation marks in both “NTRIPCONFIG” lines to indicate a blank user name.
Please provide the antenna latitude, longitude and height as accurately as possible. Any deviation from
the “real” antenna position here will have a direct effect on the quality of the DGPS/RTK solution of the
connected rover receivers. Also note that the server is connecting to the same caster port (2101) for
both data streams. This is also the port to which all clients will initially connect. Once the connection has
been established, the caster will negotiate and assign a different port over which the communication
will be routed.
The Pushed Streamstab will now show the two data streams from the server to the caster:
Figure 13 - SNIP Active Pushed Server Streams
When an NTRIP client is connected to a specific data stream, it will be shown in the “Clients” field of the
data stream.
To close the connections to the caster from the server side, send the following commands to the
NovAtel receiver:
NTRIPCONFIG NCOM1 DISABLED
NTRIPCONFIG NCOM2 DISABLED
This command will “gracefully” disconnect the server, removing the data streams from the caster’s
“Pushed Streams” tab. If the server is just switched off, the caster will not disconnect the server but will
show the server as being “Down”. The mount point and data stream on the caster side will be kept alive,
even though the connected clients are not receiving any data, which might trigger them to
disconnect/reconnect endlessly until the data stream becomes available again.
A data stream that is down/dead may be forcibly closed by right clicking the mount point name and
selecting “Disconnect” from the drop down menu. This will also disconnect any clients connected to this
data stream.
Page | 16 January 23, 2017
TCP/IP Considerations
The above examples are “simplified” examples in that both the NTRIP server and the PC which is running
the NTRIP caster are both on the same network (LAN). When setting up an NTRIP caster with server(s)
and/or client(s) located outside the caster network, please make sure to configure the modem/router in
such a way that a built-in firewall will allow the incoming connections to the caster port and the caster
port is routed (NAT/PAT) from the external IP address of the modem to the “internal” IP address of the
caster.
Any servers or clients not connected to the same LAN as the NTRIP caster will have to connect to the
external IP address of the modem and the modem port that has been forwarded to the caster, instead
of the “internal” IP address and port of the caster directly.
Support
Although this document was written to cover the most common NTRIP setup scenarios, it is possible
your situation is not (fully) covered by its contents. If you need assistance setting up your receiver,
please don’t hesitate to contact NovAtel support by sending an email to support@novatel.com