Chinese drone giant DJI has filed a lawsuit against its crosstown rival Insta360 for alleged patent infringement, a move that was made public three days ahead of the launch of DJI’s first 360-degree drone, a niche pioneered by its smaller competitor.

The lawsuit, filed recently with the Shenzhen Intermediate People’s Court in the southern tech hub where both companies are based, involved six patents covering critical technologies including drone flight control, structural design and image processing, according to reports by Chinese media on Monday.

DJI claimed that some of the patents were based on inventions made by one or more former employees within one year of their departure from the company, according to reports from government-backed outlets including Jiemian and Securities Times.

Under China’s intellectual property laws, innovations created within one year of an employee’s retirement or departure – if related to their previous regular duties – are legally considered to have been created for the original organisation.

Insta360 founder and CEO Liu Jingkang said on Weibo on Monday that, after an internal review of the concerned patents, “the available evidence indicates that these are all ideas and innovations generated within Insta360”.

DJI did not immediately responded to a request for comment on Monday. The Shenzhen court could not be reached for comment.