Baidu, one of the earliest movers into autonomous driving, has been in the sector for years now. Its high-definition maps are based on the requirements of Level 3 autonomous driving and are known to have the highest level of refinement, productivity and coverage in the country.

Level 2 means "hands off"－the automated system takes full control of the vehicle, but the driver must monitor the driving and be prepared to intervene immediately at any time. Level 3 refers to "eyes off"－the vehicle will handle situations which require an immediate response, and the driver must still be prepared to intervene within some limited time.

Baidu's archrival AutoNavi, also known as Amap, was acquired by Alibaba in 2014. The firm launched last year an integrated solution for high-precision maps, which enables an accurate mapping with an error range of less than 7 centimeters under normal road conditions, one of the lowest error ranges so far.

Together, Tencent Map, Baidu Map and AutoNavi account for over 80 percent of the domestic mapping sector.

While companies are stepping up efforts in the field, Feng Hanping, chief technology officer of Chinese map provider Kuandeng, said the current phase is "only the beginning".

"For a well-rounded high-definition mapping solution, the very first bar is to have qualifications for surveying and mapping," Feng said.

"That's why, most domestic manufacturers prefer to find one partner that has the qualifications and can provide such maps for mass production," he said.

Some 20 Chinese companies and entities, including Chinese mapping provider NavInfo and the National Geomatics Center of China, have acquired class A qualification of surveying and mapping in the country.

NavInfo said earlier that it expects to finish China's first high-definition map by the end of this year. It also said it leads the domestic standards for making such maps.

The Beijing-based company is also one of the most reliable partners of global carmakers in the Chinese market. In July, BMW China inked a partnership with NavInfo to develop high-precision maps for autonomous driving.

At that time, Gao Le, president and CEO of BMW Group Greater China, said: "High-precision maps have irreplaceable importance in forecasting, driving strategies and safety. This cooperation will greatly promote BMW China's progress in the field of autonomous driving."

With autonomous driving accelerating its steps toward possible commercialization in the coming years, the high-precision mapping industry will be lifted to a new high, experts said. A Goldman Sachs report said the market size of high-definition mapping will grow to over $30 billion by 2030.

Consulting firm McKinsey said China has the potential to become the world's largest market for autonomous vehicles. It estimated that such vehicles will make up more than 40 percent of new vehicle sales in China, the world's largest auto market, by 2040.

"It's widely recognized that by 2025, the Level 3 autonomous cars are expected to account for 12 percent of total and that all the high-end cars will be embedded with Level 3 functions," said Guo Jishun, chief smart driving technology officer at the research department of Guangzhou-based GAC Group.

By that time, Chinese consumers will have a strong willingness to buy autonomous vehicles and have higher demand for such cars, Guo said.

"The higher expectation will drive the high-definition mapping market to grow fast. Related mapping providers should make sure ahead that such maps can offer safe and reliable services to unmanned vehicles."