{"id":4024,"date":"2017-08-29T02:54:16","date_gmt":"2017-08-29T02:54:16","guid":{"rendered":"\/kb\/?post_type=ht_kb&p=4024"},"modified":"2018-10-29T16:21:01","modified_gmt":"2018-10-29T16:21:01","slug":"using-strsvr-from-rtklib-with-snip","status":"publish","type":"ht_kb","link":"https:\/\/www.use-snip.com\/kb\/knowledge-base\/using-strsvr-from-rtklib-with-snip\/","title":{"rendered":"Using STRSVR from RTKLIB with SNIP"},"content":{"rendered":"

This article discusses how to set up the RTKLIB<\/a> tool STRSVR\u00a0<\/strong> (aka stream server<\/em>) to send data to a SNIP<\/strong> Caster <\/span><\/a>node on the same, or on a different, machine.<\/p>\n

Many users of OEM boards across the cost spectrum use the STRSVR tool to convert (translate) from a GNSS vendor’s proprietary data stream into industry standard RTCM 3.x messages.\u00a0\u00a0 Many GNSS vendors charge a considerable sum for the direct ability to send RTCM 3.x messages (while RTKLIB is free to use).\u00a0 So this is a very cost effective solution to those users.\u00a0 With a modest amount of DIY effort, a very solid L1\/L2 survey grade Base Station can be assembled for an investment of under $1K US using such methods.<\/p>\n

Aside<\/span><\/strong>: If you plan to attempt this with a patch antenna – please read this note<\/a>.<\/p>\n

Setup for STRSVR\u00a0<\/strong><\/h2>\n

Here is the basic STRSVR dialog screen, showing an input data stream from a serial device and one output data stream.<\/p>\n

\"STRSVR-running\"<\/a><\/p>\n

In this example we have connected to a uBlox 6T board <\/a>over a serial port on com port 10 (using a USB convertor<\/a>) which is sending the proprietary uBlox binary format.\u00a0 The STRSVR tool will convert this to suitable RTCM 3.x messages<\/a> (in this case the 1004 message, the L2 observational elements will be set to zeros).<\/p>\n

\"STRSVR_serialSetUp\"<\/a><\/p>\n

We could have connected to a data stream from any Caster (such as the open one kept at ntrip.use-snip.com:2101<\/a>), or any other valid data source.\u00a0 RTKLIB supports all the normal connection modes in this respect. But it is more typical to connect to a local serial stream<\/em>.\u00a0 In the above image, the Cmd<\/strong> button allows sending setup commands to the device (typical used with a serial device) similar to what SNIP<\/strong> <\/span>allows to setup serial devices<\/a>.\u00a0 As a best practice, always set up your GNSS device settings each time you connect to it.<\/p>\n

Important !
\n<\/strong><\/span><\/p>\n

The key purpose of connecting to STRSVR (rather than directly to SNIP<\/strong><\/span>, see this tab<\/a> to do so) is to allow it to parse and translate<\/strong> the data stream from one message format to another<\/span>.\u00a0 At this time SNIP<\/strong><\/span> does not have a similar translation ability built into it.\u00a0\u00a0 The STRSVR tool can be thought of as a translation<\/em> step between the GNSS device and the Caster.\u00a0\u00a0\u00a0 The STRSVR tool can also be used to redirect the same data stream to as many as three parties, but it is the translate<\/strong> ability that is of greater value to most users.<\/p>\n

Once you have connected to a source<\/em> of data, you must connect it to an output<\/em> and (optionally) translate the data for that output.<\/p>\n

Outputting Data<\/h3>\n

The STRSVR allows up to three<\/span> output streams to be created.\u00a0 One of these should be connected to SNIP<\/strong><\/span> so that SNIP<\/strong><\/span> can service your NTRIP Client<\/a> connections.<\/p>\n

In this context only two connection types make sense, the NTRIP Server<\/strong> and the TCP Client<\/strong>.\u00a0 The NTRIP Server method is to be preferred.<\/p>\n

Aside<\/strong><\/span>: The TCP Server<\/em><\/strong> connection setting is used to instruct the STRSVR tool to be listener<\/em> on a given port and to send the data stream to any connection that appears there.\u00a0 This is simply a brute force TCP\/IP connection, and it does not use the NTRIP protocol.\u00a0 You can in fact connect to it with SNIP<\/strong><\/span> as a Remote Relay<\/a> connection if you wish, but that is not needed.\u00a0 On the whole, leaving ports open on your machine is a security risk to be avoided.<\/p>\n

The dialog box for the NTRIP Server<\/strong> connection [ Output (1) ] is shown below.<\/p>\n

\"STRSVR_PUSH-InSetUp\"<\/a><\/p>\n

Enter the Caster URL, or the machine’s IP\u00a0 (enter your own IP address if the STRSVR tool and SNIP<\/strong><\/span> are on the same machine).\u00a0 Enter the port used (typically 2101).\u00a0 [Please do not enter serv2, as that machine is not open for public use<\/em>]<\/p>\n

Enter the mount point (mountPt) name you wish to see this data stream appear as.\u00a0\u00a0 This needs to be a well-formed mount point<\/a> name, therefore no white space and no odd symbols (!@#$%:; etc..) are allowed.\u00a0 Caution<\/strong><\/span>: STRSVR does not check for ill-formed names.\u00a0 Here we have used PushInAsServer<\/strong> as the mountPt name.<\/p>\n

Enter the password for the SNIP<\/strong><\/span> Caster you will connect to.\u00a0 If you are using a reservation<\/em> on SNIP<\/strong><\/span>, it will have its own password.\u00a0 If not, it will use the same password as other PUSH-In<\/strong> streams on your copy of SNIP<\/strong><\/span>.\u00a0 If the receiving Caster is not under your control, ask the operator what password is to be used.<\/p>\n

Finally, if you are knowledgeable about NTRIP Caster table entries, enter the table entry (except for the mount point name itself) into the line called “String.<\/strong>”\u00a0\u00a0\u00a0 Hint<\/strong><\/span>: Most users simply leave this blank, letting SNIP<\/strong><\/span> handle it.\u00a0 One of the advantages of SNIP <\/strong><\/span>is that it understands the RTCM3 message flow (when the data stream is parsed) so it will simply fill in the correct data for you once the stream connects.\u00a0\u00a0 If in doubt, please leave this field empty.
\n<\/strong><\/p>\n

 <\/p>\n

Translating, the Conv dialog<\/h3>\n

The Conv…<\/strong> button brings up a critical dialog for this setup.\u00a0 You can set a different set of Conv values for each output stream you create. Here we only create one.<\/p>\n

\"STRSVR_Translate_SetUp\"<\/a><\/p>\n

To translate<\/strong> from a GNSS vendor to RTCM 3.x, set the controls as shown.\u00a0 The Message Types<\/strong> line is required to tell STRSVR exactly what message contents you want to be output.\u00a0 If you have a GPS L1\/L2 data source a line like “1004(1)” would be typical. Some people will use “1002(1)” for L1 only systems; others will use “1004(1)” because it is more commonly understood.\u00a0 [When SNIP<\/strong><\/span> completes the Caster table entry, it will adjust for the present of L1\/L2 automatically.]<\/p>\n

You might want to added orbital messages as well.\u00a0 Read the RTKLIB manual for further setup details.\u00a0 Be sure to set a value and add an EFEF location message every few seconds, such as “1005(10)” as well, unless your end users will know it by other means.<\/p>\n

So a full message type string for legacy GPS+GLO might look like this: “1004(1), 1005(10), 1012(1)”\u00a0 If you wished to use MSM messages, the string might be this: “1005(10), 1077(1), 1087(1)”\u00a0 etc.<\/p>\n

You can read more about Caster String controls in RTKLIB in this article<\/a>.<\/p>\n

Aside<\/strong><\/span>: The STRSVR tool is adept at translating proprietary GNSS formats to the common\u00a0 rtcm_t <\/strong>data structure defined in RTKLIB, and then exporting that into RTCM 3.x messages.\u00a0 It is not at all adept in handling RTCM 2.x messages<\/a> and it cannot even create RTCM 2.x messages.\u00a0\u00a0 Hence, it cannot be used to “convert” from RTCM 2 to 3 or in the reverse direction.\u00a0 The combo box choices seem to imply this ability to some users.\u00a0 We note that detail here because the question seems to come up fairly often.\u00a0 If this is a need you have, please contact us for support.<\/p>\n

Aside Number 2<\/strong><\/span>: If the STRSVR tool is told to translate a GNSS format, you must<\/strong> then tell it what the new message types and sending rates need to be.\u00a0 AND you must provide it with a suitable ECEF value to send.\u00a0 People often forget to set the ECEF value and then STRSVR cannot send a valid Base Station location, making the stream useless.<\/p>\n

Once this is set up, you now have a stream of Base Station data suitable to be shared with others and the next step is to forward that to your copy of SNIP<\/strong><\/span> for mass distribution.<\/p>\n

You could press Start<\/strong> at this point, but it is likely there are a few things to set up on the SNIP<\/strong><\/span> side as well.<\/p>\n

Setup for SNIP<\/strong><\/span><\/h2>\n

Sending data to SNIP<\/strong><\/span> as outlined above results in a new PUSH-In<\/strong> connection.\u00a0 The STRSVR tool is acting like an NTRCIP Server, while SNIP<\/strong><\/span> is acting like an NTRIP Caster in the normal way.<\/p>\n

When Sending Data without a reservation<\/h3>\n

The sender simply has to follow the master password<\/a> established for that Caster.\u00a0 See the button Set Up..<\/strong>\u00a0 on the Pushed-In Streams<\/strong><\/em> tab.\u00a0 Here you can tell (or reset) the password to be used.\u00a0 Be sure to inform any other data sender when you change this value.<\/p>\n

When Sending Data with a reservation<\/h3>\n

In this case, the sender follows the password previously established for that reservation<\/a>. Other values for the reservation are then applied as well, such as parsing and logging and even limiting what the connection IP is allowed to be.\u00a0\u00a0 This connection method is more secure. A right mouse click in the window Reserved MountPts<\/strong>\u00a0 (in the Pushed-In Streams<\/strong><\/em> tab) will bring up menu options to add\/edit\/remove reservations.<\/p>\n

When it connects…<\/h3>\n

\"STRSVR-with-SNIP\"<\/a><\/p>\n

When the PUSH-In<\/strong> stream from the STRSVR tool connects to your SNIP<\/strong><\/span> node, you will see the new slot as an image in the tab similar to this.<\/p>\n

The STRSVR app is shown below it in the area where the console log appears.<\/p>\n

How can I tell if it is working?<\/h2>\n

Several ways, all practical and easy.
\nYou can tell by:<\/p>\n