{"id":225,"date":"2015-12-23T02:07:21","date_gmt":"2015-12-23T02:07:21","guid":{"rendered":"https:\/\/carson.fenimorefamily.com\/?p=225"},"modified":"2016-01-01T17:32:32","modified_gmt":"2016-01-01T17:32:32","slug":"gsm-phone-tracking-methods","status":"publish","type":"post","link":"https:\/\/carson.fenimorefamily.com\/?p=225","title":{"rendered":"GSM Phone Tracking Methods"},"content":{"rendered":"<p>I decided to conduct a few tests with my fona808.  <\/p>\n<ul>\n<li>Battery.  The at+cbc command give you the current charge mode, percent charged, and millivolts.  I found on the adafruit fona808 that the charge mode indicator always gave status 0 (&#8220;not charging&#8221;) even when charged.\n<\/li>\n<li>GSM Location.  This is given by the at+cipgsmloc.  It spits out lat and lon.  I don&#8217;t know where it is getting the data from, but based on the plots I made the location it gives is an estimate based on your location to the nearest cell tower.\n<\/li>\n<li>GPS.  Given by at+cgnsinf.  I found this to be spot-on, always accurate, even with my pea-sized GPS antenna!<\/li>\n<li>DIY cell tower triangulation.  If you put the fona into ENG mode (&#8220;AT+CENG=3&#8221;), it will give you the MNC, MCC, LAC, and CellId for the towers around you (i usually got six reports per &#8220;AT+CENG?&#8221; query).  You can then use a site like cellphonetrackers.org to turn the tower info into a lat\/lon coordinate.  The +CENG messages also given a power level which you can use, in cojunction with the cell tower lat\/lon coordinates, to perform the triangulation.  The method of doing this is described elsewhere, but basically each power level becomes a weight, w_i = rx_i \/ (rx_0+rx_1&#8230;rx_n), which is multiplied by the lat\/lon of the corresponding cell tower item.  You then just add up the weighted lat\/lons, and viola!<\/li>\n<ul>\n<p>My results?  <\/p>\n<ul>\n<li>I found that i lost about 10% power on my 1 hour trip.  This seems terrible &#8211; barely 10 hours per charge, extrapolating.<\/li>\n<li>The GPS info was perfect.  It took about 2 min to acquire<\/li>\n<li>The GSM location was too course, but was actually more clean than my DIY location<\/li>\n<li>DIY location seems crumby.  Im not sure what would fix this. Possible things to look at: 1) Filtering.  Maybe I could throw out the lowest power rating, or smooth out the locations somehow. 2) See if there are better cell tower dbs.  As far as i know, cell tower info isnt public, so any db is most likely based on reported, possibly inaccurate, values\n<\/li>\n<\/ul>\n<p>Here&#8217;s a map with plots of the three localization methods: GPS (magenta), GSM (green), and DIY Triangulation (yellow).<\/p>\n<p><a href=\"\/\/carson.fenimorefamily.com\/wp-content\/uploads\/2015\/12\/gsmtrack.png\" rel=\"attachment wp-att-226\"><img loading=\"lazy\" decoding=\"async\" src=\"\/\/carson.fenimorefamily.com\/wp-content\/uploads\/2015\/12\/gsmtrack-300x117.png\" alt=\"gsmtrack\" width=\"300\" height=\"117\" class=\"alignnone size-medium wp-image-226\" srcset=\"https:\/\/carson.fenimorefamily.com\/wp-content\/uploads\/2015\/12\/gsmtrack-300x117.png 300w, https:\/\/carson.fenimorefamily.com\/wp-content\/uploads\/2015\/12\/gsmtrack-768x299.png 768w, https:\/\/carson.fenimorefamily.com\/wp-content\/uploads\/2015\/12\/gsmtrack-1024x399.png 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>I decided to conduct a few tests with my fona808. Battery. The at+cbc command give you the current charge mode, percent charged, and millivolts. I found on the adafruit fona808 that the charge mode indicator always gave status 0 (&#8220;not charging&#8221;) even when charged. GSM Location. This is given by the at+cipgsmloc. It spits out &hellip; <a href=\"https:\/\/carson.fenimorefamily.com\/?p=225\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">GSM Phone Tracking Methods<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-225","post","type-post","status-publish","format-standard","hentry","category-diy-cell-phone"],"_links":{"self":[{"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=\/wp\/v2\/posts\/225","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=225"}],"version-history":[{"count":3,"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=\/wp\/v2\/posts\/225\/revisions"}],"predecessor-version":[{"id":235,"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=\/wp\/v2\/posts\/225\/revisions\/235"}],"wp:attachment":[{"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=225"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=225"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/carson.fenimorefamily.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=225"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}