Raven Gunshot Detection Technology

The Champaign Police Department has contracted with Flock Group, Inc. to install Raven gunshot detection technology for use in select areas of the community on a trial basis. In total, 33 units were installed in Champaign in the Winter of 2022. The initial authorization for gunshot detection units is for a period of one year. Following a review of the pilot program, Champaign Police discontinued the use of gunshot detection technology on February 12, 2024.

The below resources, including FAQ and policy documents, are provided to give residents a greater awareness of gunshot detection functions and limitations and CPD’s guidelines around use, privacy, and data storage.

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Gunshot Detection: How the Technology Works

Gunshot detection units capture short audio clips of their surroundings, interpret that audio to detect specific sound patterns, and, ultimately, alert an officer when the system has captured the sound of a potential gunshot. The automated process of capture, analysis, and comparison typically takes seconds, and officers are alerted to the vicinity of the gunshots.

The process of gunshot detection works like this:

1. Each Gunshot Detection unit is equipped with a microphone that gathers audio for five seconds at a time.

2. The unit processes the audio to determine if a gun has been fired.

3. Audio suspected to be gunfire is uploaded to Flock Group, Inc. processing systems. These systems reprocess the audio to ensure that the sound was a gunshot and not a similar sound like fireworks or a car backfiring.

4. If the sound is determined to be gunfire, the unit sends an initial detection alert to Champaign Police Officers.

5. Simultaneously, the system cross-references detections from other nearby gunshot detection units. Using calculations based upon the time delays between units hearing the sound, the system is able to determine the approximate location of the incident. The vendor asserts that this automated process determines the location with a 90% accuracy to within 90 feet.

6. As the cross reference is completed, an updated alert is relayed to Champaign Police with a narrowed geographical location, and available officers are immediately dispatched to the specified location to investigate.

Policy and Reports

• CPD Policy and Procedure 41.20: Gunshot Detection

• October 2021 Report to Council: Use of Technology to Address Violent Crime
  • Council Study Session Report
  • Council Video

• December 2021 Council Bill: A Resolution Authorizing the Purchase and Installation of Automated License Plate Readers, Gunshot Detection, and Related Equipment from Flock Group, Inc.
  • Council Bill & Report to Council
  • Council Video

• November 2023 Report to Council: Automated License Plate Reader Update and Public Safety Technology Implementation
  • Council Study Session Report
  • Council Video