That technology is widely available. The ping is usually a so called "silent SMS". The response from the phone leaves data about the call (e. g. ID, signal strength, sector and cell station) from that it´s just simple geometry. Depending on coverage the accuracy can be between 10m and 50m. In Germany it´s sometimes used to locate missing people or bad guys. Police has so called IMSI catchers to get their own data. I am sure intelligence services have it too.
_________________________
If it isn´t broken, it doesn´t have enough features yet.