This week radio frequency (RF) monitor HawkEye 360 announced it closed its latest investment round, totaling up $14.9 million.  Defense giant Raytheon lead the round, with participation by Sumitomo, Razor’s Edge Ventures, Shield Capital Partners, Space Angels, and Allied Minds.

“This second closing further illustrates the strong demand we’ve experienced from investors to our Series A-3 round fundraising,” said John Serafini, Chief Executive Officer, HawkEye 360. “We are honored to be backed by a diverse group of premier investors, such as Raytheon Company and Sumitomo Corporation of Americas. Investors recognize the valuable insights that HawkEye 360’s advanced analytics will bring to our government and commercial customers.”

Herndon, Virginia-based HawkEye 360 uses a trio of formation-flying nanosatellites to monitor and geo-locate radio frequency transmissions. Precision RF data will be used for applications such as maritime ship monitoring and spectrum mapping and monitoring.

HawkEye’s first three pathfinder satellites are scheduled to launch later this year onboard the Spaceflight SSO-A rideshare mission.  Funding from the A-3 round enables HawkEye 360 to accelerate development of the company’s first commercial cluster with the next launch of satellites targeted for 2019.

In August, HawkEye 360 announced it had secured $9.6 million in funding as the first part of its Series A-3 investment round, with Razor’s Edge, Allied Minds and Shield, along with a “U.S Aerospace and Defense Company” – now announced as Raytheon.   Sumitomo and Space Angels are the new investors participation in the second part.

HawkEye plans to operate a constellation of 30 satellites, providing global coverage with 30 to 45 minute revisits of anywhere on earth.

Defense contractor Raytheon issued a separate press release touting its investment in HawkEye 360, noting its Intelligence, Information and Services business is “collaborating” with HawkEye as part of its effort to provide commercial technology and more precise data to the government sector.  Raytheon will fuse HawkEye 360 geospatial RF data with “other relevant data sources” it provides to U.S. and international customers.

RF monitoring via satellite isn’t unique to HawkEye.  Kleos Space of Luxembourg recently conducted an IPO on the Australian Stock Exchange to raise capital towards a constellation of twenty RF monitoring satellites. France-based UnseenLabs has described a 6U satellite to be launched by the end of 2018 while Sky and Space Global has tested the ability to conduct RF interference monitoring using its trio of pathfinder satellites and software-defined radio technology.