Seeing a bright picture of Chinese drones in the global market, aviation experts said people should be reminded that China still lags behind in many aspects in the UAV industry.

China is still unable to produce an unmanned aerial vehicle that can rival the United States' RQ-4 Global Hawk, according to Wang Yangzhu, deputy director of the Unmanned Aircraft System Institute under Beijing University of Aeronautics and Astronautics.

"If we rank the automation capabilities of UAV with 10 being the highest score, China can only get five or six," he said.

"The capability of a UAV should not be judged merely by its speed and altitude, its ability in performing varied missions makes more sense."

Wang's institute is one of the three academic institutes in China that specialize in UAVs. The other two are in Nanjing University of Aeronautics and Astronautics in Jiangsu province and Northwestern Polytechnical University in Shaanxi province.

He said China's efforts to develop advanced drones are being haunted by a long-time inability in resolving some key technologies including engines and data links, noting the country's aviation industry needs to solve a host of technical blocks.

"Though we are able to manufacture UAVs on our own, we can't produce those as advanced as the RQ-4 Global Hawk, which is now the top drone before the Northrop Grumman X-47B enters into service. The most outstanding obstacle confronting us remains the engine problem."

He explained that the data link and airborne electronic devices used on Chinese drones still lag behind those of their US counterparts.

In contrast to Wang's words, many foreign military observers said Chinese drones are fairly competitive in the international market in terms of technical characteristics, performance and price.

Wendell Minnick, Asia bureau chief at Defense News, said in an earlier report on VOA's website that Chinese drones, many of which are specifically produced for the export market, are very attractive for many developing nations.

"(The US) drone exports are very expensive platforms, very sophisticated. The Chinese produce a much cheaper variety that basically does the same job," said Minnick. "The Chinese ... are looking at an export market that's growing."

"China has ramped up research in recent years faster than any other country. It displayed its first unmanned system model at the Zhuhai air show five years ago, and now every major manufacturer for the Chinese military has a research center devoted to unmanned systems," a report published in July by the Defense Science Board, an experts panel charged with advising the US Department of Defense on scientific and technical issues, was quoted by The New York Times as saying.

"(China) could ... rapidly close the technology gaps and become a formidable global competitor in unmanned systems."