Tower triangulation is old news. Law enforcement can now receive real time updates on your near exact coordinates via email with various carrier technologies like NELOS, PCMD, and RTT, all thanks to next generation 9-11 services.
The above image is an alert sent by AT&T of subscriber data from a serving mobile location center, SMLC. AT&T's technology is called NELOS, Network Event LOcation Service.
PCMD, Per Call Data Measurement, is Sprint's method of providing approximate GPS location to law enforcement, and Verizon has the Real Time Tool, RTT (not to be confused with Round Trip Time, a measurement used in cell tower triangulation). Handy quick reference here.
This cellular spiderweb was created to allow service providers to locate 9-11 callers using mobile phones.
But, as described in a product guide for the Pen-link call intercept software, "instead of delivering the data to a call center, the carrier delivers the data to the requesting law enforcement agency."
There's more on these services and how cops use them in the tutorials I published here.