Sony�s CXD5603GF - The Lowest Power Consumption GNSS Chip in the IoT Tracker Market

Abstract

The scale and scope of the IoT (Internet-of-Things) market have the potential to challenge GNSS (Global Navigation Satellite System) system architects and designers. The vast majority of IoT sensing devices demand location-awareness to provide a reliable data. GNSS technologies are expected to play an integral part in many location-aware IoT devices. Power consumption is one of the most important design aspects of many IoT applications. Lower power consumption climbed up to be the primary GNSS customers’ requirement followed by higher sensitivity, TTFF (Time-To-First-Fix), and positioning accuracy. IoT device manufacturers and module makers look at GNSS chip as a threat to the power budget and wish to replace the need for an onboard GNSS chip with other competing positioning technology. GNSS power consumption remains in the eye of many IoT device manufacturers a significant challenge to extend device’s battery lifetime. Sony designed the world’s lowest power consumption GNSS chip, CXD5603, in the IoT market. We achieved a total power consumption of around 6 mW in a continuous track operational mode. This accomplishment has been made possible by re-designing a new generation of Sony’s GNSS chip aiming toward IoT market demands. We started by looking into chip fabrication technology, receiver architecture, acquisition/tracking strategies, and navigation engine. CXD5603 has been in mass production since 2015 and successfully adopted by strategic partners who are dominating the wearable market. This paper provides an overview of Sony’s CXD5603 GNSS hardware capabilities, insights about its system architecture, and touch on critical algorithms developed to maintain superior performance at the lowest power consumption budget. In addition to this, we specify the use case of IoT tracker, optimize the system configuration for that, and measure the power consumption. Asset tracking, smart meter, pet tracker, kids tracker, personal emergency responders are a few of many IoT tracker’s currently penetrating the market. Power consumption is crucial to the success of many IoT tracker devices. Typically, power consumption depends on the tracker’s potential use case scenarios, which can be illustrated by considering two components: the frequency of a position fix and the utilized data communication technology. In this paper, we categorize IoT tracker’s applications into two categories, “Consumer” tracker, C-tracker, and “Industrial” tracker, I-tracker. The C-tracker mainly consists of a GNSS module for positioning, and a connectivity module to report back positioning information. The I-tracker consists of a connectivity module as well, however, adds a 6-DoF, Degrees-of-Freedom, Inertial Measurement Unit (IMU) (3-axis accelerometer + 3-axis gyroscopes) to the positioning module. C-tracker targets application like pet tracker, kid tracker, personal emergency responder, and smart meters, while I-tracker targets application like fleet management and vehicle tracker. The paper provides actual power consumption measurements for real IoT tracker market. We explore the following use cases: 1) C-tracker with one position update per day, 2) C-tracker with three position updates per day, 3) I-tracker with continuous monitoring, and 4) I-tracker with continuous monitoring, while the I-tracker utilizes an adaptive power saving mode. We demonstrate the positioning performance and power consumption of Sony’s CXD5603 GNSS technology. The power consumption of an LTE(Cat. M1, Cat. NB1) modem, Wi-Fi access point, Low Power Wide Area (LPWA), and Bluetooth Low Energy (BLE) are measured as potential data communication technologies.