Due to their ability to sense at great distances, to sense in a non line-of-sight manner, and the relatively low bandwidth required for transmitting sensor telemetry data, systems deployed for law enforcement, public safety and homeland security in the United States have primarily been based on acoustic techniques.
Optical and electro-optical systems have seen success in military environments where immediacy of response is critical and because they generally do not need careful location registration as is generally the case for more permanently installed "Civil" crime fighting systems.