Beiyun Technology launches automotive-grade combined navigation unit to support mass production of autonomous driving models

June 18th News Recently, many smart models of many car manufacturers have added high-precision integrated navigation to their autonomous driving systems, and are about to achieve mass production. This may mean that high-precision positioning products represented by integrated navigation will soon become standard in smart car pre-installed applications, and market demand will show exponential growth.

At the just concluded WGDC ​​2021 conference, Beiyun Technology, a developer and manufacturer of high-precision positioning core components, brought its latest automotive-grade combined navigation and positioning unit X2 to the exhibition. Beiyun Technology CEO Mr. Xiang Wei mentioned in his speech that "the application of high-precision combined navigation in smart cars is already a general trend."

The so-called integrated navigation refers to a comprehensive navigation system that combines multiple systems. At present, in the automatic driving of smart cars, the main application is the integrated navigation solution that combines high-precision satellite positioning and IMU (inertial navigation unit).

The author learned that high-precision integrated navigation has become the optimal solution to the problem of high-precision positioning of automobiles, which is particularly important for the development of future smart cars and autonomous driving. In fact, almost all of the high-level autonomous driving solutions exhibited by major manufacturers at this year's Shanghai Auto Show include high-precision integrated navigation.

Specially customized for smart car pre-installation

As one of the earliest technology companies in China to focus on high-precision positioning, Beiyun Technology launched the X1 combined navigation system at the beginning of last year, which was very popular in the smart car aftermarket market. It won wide reputation for its high cost-effectiveness and high performance, and won the "WGDC 2021 Best Word-of-Mouth Product Award". Beiyun Technology took advantage of the strong momentum of its development in the aftermarket and released the new automotive-grade combined navigation and positioning unit X2 this year, intending to further promote the mass production process of major vehicle manufacturers and autonomous driving companies.

Beiyun Technology's automotive-grade deep-coupled integrated navigation and positioning unit X2

It is understood that X2 is based on the GNSS/INS deep coupling integrated navigation technology architecture, and can output absolute centimeter-level position information at more than 200Hz in harsh scenes such as urban canyons, tunnels, viaducts, elevated auxiliary roads, dense fog, rain, snow, dust and severe weather, traffic jams, neon night markets, lane line wear, and open roads without feature points, which can make up for the shortcomings of sensors such as lidar and cameras in these harsh scenes. It can also integrate odometers to further improve the accuracy and stability of combined positioning.

At the same time, X2 has added more interfaces, not only supporting in-vehicle Ethernet and GPTP (Precision Time Protocol), but also adding L-band signal reception and PPP/PPP-RTK functions for areas with poor N-RTK service coverage and overseas users, as well as seamless switching of RTK/PPP modes. In an environment without mobile signals, it can still provide high-precision positioning through satellite-based augmented signals.

X2 Deeply Coupled Integrated Navigation System Architecture

Xiang Wei said that since X2 is mainly aimed at mass production customers, the price of a single product will be greatly reduced. As for how low the price can go, Xiang Wei did not specify. The official slogan of X2 reads: "RTK price, professional-level integrated navigation performance", which gives us a glimpse of it.

Professional integrated navigation performance on par with international standards

At present, in the field of global integrated navigation products, after years of competition, domestic and foreign manufacturers have become relatively close in RTK algorithms, with little difference. Now, everyone is competing in integration and integrated navigation algorithms.

Trimble, Novatel and domestic Beiyun Technology, which started out as a satellite positioning manufacturer, all make integrated navigation products based on their own RTK chips, so they have more advantages in terms of integration. Beiyun Technology's new X2 automotive-grade integrated navigation product is based on Beiyun Technology's self-developed RTK chip. Through the design of a single board, it realizes the underlying integration of satellite positioning and IMU, making the overall size of X2 similar to that of an ID card.

From a deeper underlying algorithm level, the current combined navigation algorithms are divided into three types: loose coupling, tight coupling and deep coupling, and the difficulty of algorithm implementation increases successively.

Loose coupling uses RTK positioning results + IMU raw data to achieve fusion. It is equivalent to tight coupling and deep coupling in scenarios where there are no satellite signals, such as tunnels and underground garages. However, in scenarios where there are satellite signals but the signals are blocked, such as urban canyons, the positioning effect is not as good as tight coupling and deep coupling.

Tight coupling uses RTK positioning results + GNSS raw data + IMU raw data. It can effectively use satellite observation data in signal-blocked environments to improve positioning results. The implementation of the tight coupling algorithm requires manufacturers to have both RTK positioning algorithm and combined navigation algorithm research and development capabilities.

However, the tightly coupled algorithm still cannot achieve the best results when the quality of GNSS raw data is poor. In fact, in harsh environments such as shaded trees and building occlusions, GNSS is prone to frequent loss of lock, observation jumps and other abnormal phenomena, which can easily cause positioning anomalies. The deeply coupled integrated navigation algorithm can effectively solve this problem.

Based on the tight coupling algorithm, the deep coupling algorithm uses IMU raw data to assist GNSS signal acquisition and tracking, and assists the carrier tracking loop through the accurate relative Doppler change information of the IMU, thereby improving the accuracy of Doppler estimation in harsh environments, thereby improving the accuracy and continuity of observations such as carrier phase and pseudorange in harsh environments, reducing observation interruptions and jumps, and effectively improving the accuracy and reliability of integrated navigation. In addition, the deep coupling algorithm can also effectively detect deceptive signals and protect integrated navigation equipment from interference.

The deep coupling algorithm is the most difficult to implement, and it also has the best positioning effect in urban canyons. In addition to the ability to develop tightly coupled algorithms, the implementation of deep coupling algorithms also requires GNSS radio frequency and baseband reception capabilities. Currently, only companies that develop their own RTK chips can do this. Beiyun Technology's automotive-grade combined navigation unit X2 is a product based on its own RTK positioning chip and incorporates a deep coupling combined navigation algorithm. Actual test results show that deep coupling can increase positioning accuracy by 3 to 7 times compared to ordinary loose coupling, and by 2 to 5 times compared to tighter coupling.

In the industry, currently only a very small number of companies with self-developed RTK chips have mastered this technology, and most combined navigation manufacturers mainly use loosely coupled technology.

Advantages of deep coupling measurement

For road sections, the proportion of fixed solutions is 15.18%, the proportion of available satellites being no less than two is 76.34%, and loose coupling mainly uses fixed solutions, while deep coupling can use data with more than two available satellites.

Actual measurements show that in harsh environments such as elevated roundabouts, the error of deep-coupled positioning is reduced by 3-7 times compared to loose-coupled positioning.

Costs have dropped to the stage where mass production is possible

In the interview, Xiang Wei believes that integrated navigation has great potential in the field of smart cars, but in order to enter the smart car market on a large scale, integrated navigation needs to further reduce costs. There are currently three main ways to reduce costs: first, independent research and development of key chips and components to gain BOM cost advantages; second, automated production to improve process quality and expand unit man-hour production capacity; third, scale up production to share R&D costs.

Beiyun Technology already has two high-precision positioning chips that are independently developed and mass-produced, and has obtained two integrated circuit layout design registration certificates and more than 30 national invention patents.

Apple's use of self-developed chips reduces the cost by three quarters compared to purchasing Intel chips, which shows that mastering the independent research and development of key chips and devices is crucial to cost control. At the same time, Beiyun Technology's next-generation integrated navigation chip with higher integration is about to be mass-produced, which will further improve performance and reduce costs.

Secondly, Beiyun Technology has introduced ISO26262, ASPICE, and AECQ certifications. The high-precision combined navigation and positioning products based on self-developed chips have passed the German Rhine IATF16949 automotive-grade certification, CE certification, FCC certification, RoHS certification, and German SGS comprehensive testing and certification. It has also invested heavily in building a fully automated production line with a production capacity of 200,000 sets/line/year, and can quickly expand the production capacity to 3 million sets/year in 3 months. Fully automated production can effectively improve product technology and quality, expand unit man-hour production capacity, and significantly reduce labor costs.