Mobile App

In support of the USNG Emergency Location Marker (ELM) system, a FREE browser based application has been developed which uses the GPS chip of late model smartphones and hand-held computers (models since about the start of 2011) to generate a USNG position display. Because the program is browser based, it can be used with ANY operating system.*

Provided the URL has been saved in the mobile platform’s browser, the display will operate dynamically and does not require an Internet connection. Per the graphic to the left, the generated location display will closely mimic the appearance of an USNG ELM. And, so long as the mobile platform’s browser is left open, the location display will be continuously updated, just as would be the case with a GPS unit.


To download and use the application, use the following steps.

1.)  As needed, refer to your user manual to ensure the GPS feature of your smartphone or hand-held is turned “On”.

2.)  As needed,  refer to your user manual to ensure the browser on your smartphone or hand-held is “allowed” to see the location information provided by the GPS feature.

3.)  Enter the following URL in the browser of your mobile platform:

4.)  When that page opens, save it as a “favorite” in your browser.

5.)  The ability of the GPS chip to accurately determine location can be determined one of two ways – by the number of large digits displayed in the white space of the display (eight digits is 10 meter accuracy, six is 100 meter, four is 1000 meter, and two is 10,000 meter), and by an orange colored “Status” accuracy readout in the lower left-hand corner of the display.

6.)  So long as you do not turn off your browser, you can turn off your hand-held and the USNG location application will be always available when the hand-held is turned back on by simply clicking the appropriate “favorite” link, whether or not there is Internet connectivity.

7.)  Should your browser get turned off, simply “hitting” the above URL again when you have Internet connectivity will refresh the application and once again generate an USNG  location display on your hand-held.

* Note: Some older versions of iOS may have font resize issues when the device is switched between  horizontal and vertical orientation.

* Note: As of September 2017, also available as an Android app on Google Play.

Attention App Developers: We’re looking for a volunteer to convert this web-based app to an iOS app. Please contact us if you are interested.

See a printable version of these USNG App Instructions.

Download USNG App Instructions