1. The vehicle DVR, along with cameras, pickups, microphones, car amplifiers, displays, alarm buttons, sirens, and other devices, together form the operating environment. GPS satellites are used to obtain positioning information, and the monitoring video and other data collected by the vehicle DVR are sent to the monitoring platform (Public Security Command and Dispatch Center) through a wireless network link (3G/GPRS/CDMA) via a data exchange center. It can achieve functions such as four-way real-time audio and video monitoring and recording, vehicle linkage alarm, remote video monitoring, GPS positioning, network access, and real-time information bidirectional transmission.
2. The vehicle mounted DVR is installed on the police patrol vehicle and can be equipped with a vehicle mounted PTZ DVR control keyboard, vehicle mounted display, laptop, siren and other devices to form a powerful monitoring system. During police patrols, footage along the way can be captured and recorded on DVR. Police officers can conduct real-time monitoring and control the pan tilt zoom camera in the vehicle, and if necessary, make emergency alarms or manually record and capture videos. The police center can remotely observe the surrounding conditions of police cars and call for video recordings, as well as timely obtain vehicle alarm information and issue commands for dispatch and response.
3. The video data is managed through a removable hard drive, and can be overlaid with video loading time, vehicle number, GPS information, and watermark information, becoming a powerful basis for law enforcement.

Figure 1: System architecture diagram

Figure 2: Law Enforcement Vehicle Video Surveillance System