Chip-grade Multi-Band Multi-GNSS RTK and Attitude Determination with Low Cost Dual Antennas for Mass Market Applications

Abstract

This paper is dedicated to Allystar’s new generation GNSS system-on-a-chip (SoC) for introducing its basic Cynosure III architecture, hardware layout and firmware framework of built-in real-time kinematic (RTK) and attitude determination engines by a module with two fully integrated GNSS SoC inside, and preliminary testing results of RTK and attitude determination functions. The motivation and objective of launching this module is providing a desirable solution to mass-market for meeting their requirements. Besides providing both accurate and precise position and attitude information, the size, cost and power consumption of this solution are taken into consideration as well. Furthermore, the fully integrated GNSS SoC is capable of tracking all legacy and modernized civil signals (in L1, L2, L5 and L6 band) transmitted by all satellite navigation systems (GPS, BDS, GLONASS, Galileo, QZSS, NAVIC and SBAS) concurrently. In addition to provide standard positioning service (SPS) with multi-band multi- constellation GNSS signals, it also provides built-in RTK engine with centimeter-level positioning accuracy and attitude determination engine in conjunction with low-cost dual-antenna. Hence it enables any kind of high-precision integrations and applications, such as wearable devices, GIS data collection, precision agriculture, intelligent logistic, intelligent driving, surveying and mapping, and so forth. According to preliminary testing results, the proposed solution is equal to satisfy mass-market application by providing both position and attitude information with high accuracy, precision and availability, and the advantage of small size, low power consumption and low cost. For manufacturing processes, the GNSS SoC adopts TSMC’s 40 nm process and incorporates a variety of advanced low-power design technologies, making it extremely attractive in terms of size and power consumption. The chip die of Cynosure III architecture is mounted in a 5.0 mm by 5.0 mm quad-flat no-lead (QFN) package, which allows customers to reduce printed circuit board (PCB) and bill of materials (BOM) cost while reducing the number of peripheral devices. The distinguishing characteristic of Cynosure III architecture is that only an analog GNSS radio-frequency (RF) front-end, a digital GNSS baseband, and an ARM Cortex-M4 microcontroller are integrated for tracking multi-band multi-constellation GNSS signals. Furthermore, several popular I/O interfaces (UART, USB, SPI, I2C, GPIO, PWM, etc.) and controller area network (CAN) bus are supported, which can be widely used in vehicle management and car navigation. To support attitude determination function concurrently, two GNSS SoC are integrated into a 16.0 mm by 18.0 mm module. This module also has a capacity of integrating microelectromechanical systems (MEMS) sensors to assist RTK and attitude determination engines to bridge obstruction.