E-OTD (Enhanced Observed Time Difference) is a standard for the location of mobile telephones. The location method works by multilateration. Conceptually, the handset makes an observation of the time difference of arrival of signals from two different base stations.
Relevant NENA Documents
Note: To find and download the document, copy the document number (like NENA-STA-010) from below and search the NENA Standards and Documents page.
NENA-STA-015, NENA Standard Data Formats for 9-1-1 Data Exchange & GIS Mapping