{"id":2637,"date":"2016-12-17T01:42:03","date_gmt":"2016-12-17T01:42:03","guid":{"rendered":"\/kb\/?post_type=ht_kb&#038;p=2637"},"modified":"2016-12-17T01:43:26","modified_gmt":"2016-12-17T01:43:26","slug":"does-my-rinex-file-have-carrier-data-in-it","status":"publish","type":"ht_kb","link":"https:\/\/www.use-snip.com\/kb\/knowledge-base\/does-my-rinex-file-have-carrier-data-in-it\/","title":{"rendered":"Does my RINEX file have carrier data in it?"},"content":{"rendered":"<p style=\"text-align: left;\"><em><strong>Background<\/strong><\/em>:\u00a0 Without both <em>code<\/em> and <em>carrier<\/em> data, RTK and PPP navigation methods are not possible.\u00a0 While it is routine to have both (as well as other signals) in better modules and chips, some very low end chip sets <span style=\"text-decoration: underline;\">do not<\/span> provide a carrier output.\u00a0 This basically kills any ability to use such a chip set for RTK or PPP style navigation.\u00a0 Avoid them if you need sub-meter accuracy. If you look at the RINEX files for any system you can easily tell if carrier data is present.<\/p>\n<p style=\"text-align: right; padding-left: 30px;\"><strong><span style=\"color: #008000;\">Hint<\/span>:<\/strong>\u00a0 <strong>RINEX<\/strong>, or the Receiver Independent Exchange Format,is the preferred human readable data interchange format used to exchange various types of GNSS measurements.<\/p>\n<p>The carrier field in any RINEX file is the &#8220;<strong>L<\/strong>&#8221; (as in <strong>L1<\/strong> or <strong>L2<\/strong> etc.), if you do not see that field in the file header then you do not have carrier data.\u00a0 The code (pseudorange) is the <strong>C<\/strong>, Doppler is <strong>D<\/strong> (not found in all systems) and <strong>S<\/strong> is the SNR (C over No).\u00a0 Most converter tools have some options to suppress unused fields, so check to make sure the convert step did not removed the carrier data by mistake.<\/p>\n<p>Below is a fragment from\u00a0 a uBlox 6T (an L1 only device) for one epoch (one measurement set).<\/p>\n<p>The first 4 lines are part of the file header and serve to lay out the format of the data to follow in the file (this is fixed for the entire file). The next line is the time stamp of the measurement epoch (accurate to ~100nS). It also tells us that 12 more lines will follow for the 12 SVs that have measurements at that time and then enumerates the order of the SVs (which can change with each measurement epoch).\u00a0 This is a version 2 file style; version 3 differs in some ways.<\/p>\n<p>There is code, carrier, Doppler and and SNR for all of these measurements but for one.\u00a0\u00a0 You can see that the carrier for SV &#8220;<strong>G20<\/strong>&#8221; was missing in this data set. The RINEX format allows blank spaces to stand in for zeros.\u00a0 FYI about this SV:\u00a0 One can also see that this SV was low on the horizon and dropping out of view as the high negative Doppler rate and low SNR shows, which is the typical time carrier tracking is lost.<\/p>\n<p style=\"text-align: center;\"><strong>RINEX Fragment<\/strong><\/p>\n<pre> <tt>\u00a0\u00a0\u00a0\u00a0 4\u00a0\u00a0\u00a0 C1\u00a0\u00a0\u00a0 L1\u00a0\u00a0\u00a0 D1\u00a0\u00a0\u00a0 S1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 # \/ TYPES OF OBSERV <\/tt><tt>\r\n <\/tt><tt>\u00a0 2016\u00a0\u00a0\u00a0\u00a0 6\u00a0\u00a0\u00a0\u00a0 7\u00a0\u00a0\u00a0 17\u00a0\u00a0\u00a0 42\u00a0\u00a0 46.0000781\u00a0\u00a0\u00a0\u00a0 GPS\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 TIME OF FIRST OBS\u00a0\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 2016\u00a0\u00a0\u00a0\u00a0 6\u00a0\u00a0\u00a0\u00a0 7\u00a0\u00a0\u00a0 18\u00a0\u00a0\u00a0\u00a0 3\u00a0\u00a0 27.0000781\u00a0\u00a0\u00a0\u00a0 GPS\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 TIME OF LAST OBS\u00a0\u00a0\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 END OF HEADER\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a016\u00a0 6\u00a0 7 17 42 46.0000781\u00a0 0 12G 7G 8G26G20G21G15G16G27G18G10S20G 4<\/tt><tt>\r\n <\/tt><tt>\u00a0 24315075.481\u00a0\u00a0 127776517.3292\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 448.410\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 29.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 22629267.575\u00a0\u00a0 118917537.1101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2271.698\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 32.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 21895722.936\u00a0\u00a0 115062756.905\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -3156.582\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 42.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 25179786.705\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -3549.886\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 20.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 23308387.593\u00a0\u00a0 122486312.002\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -2759.055\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 46.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 25514482.824\u00a0\u00a0 134079506.961\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 333.453\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 33.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 20601440.208\u00a0\u00a0 108261249.8101\u00a0\u00a0\u00a0\u00a0\u00a0 -1454.798\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 43.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 20620768.706\u00a0\u00a0 108362926.6981\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 797.603\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 40.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 22056801.307\u00a0\u00a0 115909274.4371\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -833.425\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 46.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 21617601.357\u00a0\u00a0 113601266.278\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1698.172\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 47.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 37871568.996\u00a0\u00a0 199016439.7911\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -286.053\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 29.000\u00a0 <\/tt><tt>\r\n <\/tt><tt>\u00a0 23186586.975\u00a0\u00a0 121846252.716\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -3871.296\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 40.000\u00a0 <\/tt><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Background:\u00a0 Without both code and carrier data, RTK and PPP navigation methods are not possible.\u00a0 While it is routine to have both (as well as other signals) in better modules and chips, some very low end chip sets do not provide a carrier output.\u00a0 This basically kills any ability to [&hellip;]<\/p>\n","protected":false},"author":13,"comment_status":"open","ping_status":"open","template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"ht-kb-category":[112],"ht-kb-tag":[264],"class_list":["post-2637","ht_kb","type-ht_kb","status-publish","format-standard","hentry","ht_kb_category-general","ht_kb_tag-rinex"],"_links":{"self":[{"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/ht-kb\/2637","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/ht-kb"}],"about":[{"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/types\/ht_kb"}],"author":[{"embeddable":true,"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/comments?post=2637"}],"version-history":[{"count":1,"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/ht-kb\/2637\/revisions"}],"predecessor-version":[{"id":2638,"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/ht-kb\/2637\/revisions\/2638"}],"wp:attachment":[{"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/media?parent=2637"}],"wp:term":[{"taxonomy":"ht_kb_category","embeddable":true,"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/ht-kb-category?post=2637"},{"taxonomy":"ht_kb_tag","embeddable":true,"href":"https:\/\/www.use-snip.com\/kb\/wp-json\/wp\/v2\/ht-kb-tag?post=2637"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}