AT&T Precision Location Records: What Courts Are Actually Getting

Standard CDR records identify which cell tower sector a phone connected to at the time of a call, text, or data session. AT&T Historical Precision Location records provide latitude and longitude coordinates derived from network-side measurements including NELOS, PCMD, and RTT data. The precision record also includes a stated accuracy threshold in meters, which CDR tower records do not. These are fundamentally different evidence types and should not be conflated in litigation.

Each AT&T Precision Location record includes a statement such as accuracy likely better than 2500 meters. This is a probabilistic upper bound, not a confirmed radius. AT&T states in the report header that location data is sourced from various databases and may be less than exact. A 2500-meter threshold means the phone was estimated to be within a 2500-meter radius of the reported coordinate, which at that scale can encompass many city blocks or multiple neighborhoods and is insufficient to place a device at a specific address.

NELOS, or Network Event Location System, is AT&T's internal platform that aggregates location-relevant measurements from network infrastructure and produces estimated geographic coordinates. It does not require the phone to be in an active call. NELOS draws from multiple signal sources and applies weighting algorithms. The resulting coordinate is a best estimate, not a GPS fix, and carries the accuracy threshold documented in the AT&T report. A forensic examiner must assess which measurement source underlies each record before interpreting its probative value.

Only when the accuracy threshold is sufficiently tight, typically 50 to 200 meters, and the reported coordinate falls consistently near a single address across multiple records. Records carrying thresholds of 1500 to 10000 meters cannot reliably place a device at a specific address and should not be used for that purpose without additional corroborating evidence. Courts have increasingly required expert testimony to contextualize accuracy thresholds before such records are admitted for location-specific inferences.

Defense attorneys should first request the underlying data source documentation for each record to determine whether the coordinate was derived from NELOS, PCMD, RTT, or GPS handoff. Second, they should retain a qualified expert to map accuracy thresholds against the claimed location. Third, they should examine whether any records with wide thresholds are being used to support address-level inferences that the data cannot sustain. Daubert and Frye challenges may be appropriate when the government's expert fails to account for stated accuracy limitations.

PCMD, or Per Call Measurement Data, is a carrier-level dataset capturing signal timing and power measurements during active connections. In the AT&T context, PCMD-derived coordinates tend to carry tighter accuracy thresholds than records sourced from passive network polls. When available, PCMD records can provide more granular location resolution than standard CDR tower sector data. Attorneys should specifically request PCMD records in discovery when precise location at the time of a call or data event is contested.

GPS data extracted directly from a phone via forensic tools reflects the device's own satellite-based position fix, typically accurate to 5 to 15 meters. AT&T Precision Location records are network-side estimates that do not require the device to have GPS enabled. When a phone reports GPS coordinates to the network, those values may be incorporated into the precision record, producing tighter accuracy thresholds. The distinction matters because network-side estimates carry inherent uncertainty that device-side GPS data does not.

AT&T retains Historical Precision Location data for a limited period, typically seven years for law enforcement requests under federal record retention standards. The availability and granularity of records varies by time period, network generation, and geographic coverage. Older records may reflect fewer data sources and wider accuracy thresholds. Attorneys handling post-conviction matters should move quickly to subpoena or preserve these records, as retention windows are finite and data may be purged in the ordinary course of business.