Existing Counter-Sniper Systems

The development and fielding of an effective counter-sniper system has attracted considerable attention in recent years. Several government entities, companies and academic institutions have developed various sniper detection and localization systems that primarily exploit acoustic sensors to detect muzzle blast and the ballistic shockwave. These systems are either soldier portable or vehicle-mounted and typically consist of sensor nodes with different geometry of microphone arrays together with local processing capabilities. Owing to the array structure of these nodes performance is greatly affected by improper and disadvantaged orientation and position of the array which are conditions likely to occur in battlefield, especially for soldier-portable units.

Our Innovation

The emergence of low cost, small-size and low power sensor technologies that possess on-board signal processing and wireless communication capabilities has stimulated great interests in utilization of distributed sensor networks for gunshot detection and localization. The distributed processing allows for better capture of muzzle blast, ballistic shockwave or both and overcome non-line-of-sight and multipath problems common in urban environments. Moreover, they offer stealthy operational capability, simple communication and DSP systems, ability to handle multiple sniper shots, and flexibility to configure a local network depending on the shooter location. Figure below illustrates a distributed sensor network that captures both muzzle blast and shockwave components for more accurate sniper localization.

ISTI has developed novel transient (gunshot or any other transient event) detection and localization system exploiting low-cost distributed sensor network technologies that overcome the short-comings of some of the existing array-based systems. The features and benefits of ISTI's solution are:

• Each sensor node consists of only one microphone together with a field programmable gate array (FPGA) processor, memories, onboard radio, zigbee-based mote (see Products), and a battery pack. Thus, unlike the array-based systems the performance is not dependent on the orientation or position of the microphone.
• Each node detects the transient events, estimates time of arrival (ToA) of muzzle blast and/or shockwave components using a proprietary sensor-level detection system, and then transmit them to the base station, which could be another node in the cluster.
• A robust collaborative method localizes the shooter and estimates the trajectory of the bullet based upon the received ToA's at the base station.
• Simple discriminatory features from muzzle blast and/or shockwave are also extracted at each node which may be transmitted to the base station for weapon classification, if needed.
• The system can be used in fixed-site applications or in portable units.
• A single integrated battlefield transient event assessment picture can be generated based upon the history of occurrence and types of transient events detected, localized and classified.

Figure below shows the localization results of a distributed sensor network consisting of nineteen randomly distributed nodes in an urban setting. The location accuracy of better than 3m in radius is achieved even in non-line-of-sight conditions using muzzle blast only (blank shells). Field testing in other sites with live ammunitions revealed that the proposed trajectory estimation method provides better than 1.5 degree accuracy when the shoot is over the array. For more information on the hardware and software products for other similar applications please contact mo@infsyst.biz.