Developing an asset tracking system with such a comprehensive development kit can save a lot of trouble!

Article Overview

This article discusses the GNSS , sensors, connectivity, and other factors to consider when developing asset tracking and condition monitoring systems . It then introduces a comprehensive development kit from STMicroelectronics , which includes multiple printed circuit boards for various sensors, GNSS positioning, and communication functions. The kit also includes batteries and advanced power management (to maximize battery life), software and firmware libraries, and application development tools.

Real-time asset tracking and status monitoring are essential for agricultural operations such as livestock management, cold chain storage for food and pharmaceuticals, fleet management, and flexible production operations in Industry 4.0 . This is a complex process involving the use of multiple sensors to monitor environmental conditions. This process emphasizes that, to ensure accurate location information, assets must support multi-star Global Navigation Satellite System (GNSS) capabilities, including GPS , Galileo , Glonass , BeiDou, and QZSS . Furthermore, multi-connectivity solutions must be able to report the location and status of assets in real time, regardless of the surrounding environment, including connections to the cloud for centralized monitoring. Simultaneously, energy efficiency is required to minimize battery power demands, and the system must be secure and reliable, resistant to hacking.

Designing an asset tracking and condition monitoring system is a complex, multidisciplinary activity that requires significant resources and time. In addition to the considerable complexity of the hardware design, the data also needs to be securely connected to the cloud and mobile devices to provide the rich information generated in an operational format.

When designing asset tracking systems, designers can use development kits and reference designs to simplify the prototyping, testing, and evaluation of advanced asset tracking applications, rather than starting from scratch.

Where exactly are the assets?

The first step in asset tracking is to collect current location information using the National Marine Electronics Association (NMEA) data format. To ensure interoperability, all GPS manufacturers use the NMEA standard. The standard NMEA message format is called a statement. NMEA defines several statements to provide different types of information, including:

• GGA – Global Positioning System Fixed Data, including 3D coordinates, status, number of satellites used, and other data.

• GSA – Precision Attenuation Factor (DOP) and Active Satellites

• GST – Location Error Statistics

• GSV – Number of visible satellites and pseudo-random noise (PRN) code, elevation angle, azimuth angle, and signal-to-noise ratio for each satellite.

• RMC – Position, Velocity, and Time

• ZDA – UTC day, month, year, and local timezone offset

Because different types of GPS receivers can use the same interface and can easily access specific datasets using corresponding statements, the development of positioning software can be simplified by using NMEA .

How to improve accuracy?

Raw GNSS data provides only limited positioning accuracy. Several tools can improve positioning estimates, including the Differential Global Positioning System (DGPS) service, which provides correction signals to shipboard GPS navigation equipment. DGPS uses the Maritime Radio Technical Committee (RTCM) protocol to provide enhanced positioning data. Additionally, satellite-based augmentation systems (SBAS) can be used to improve the accuracy of position information; these include the U.S. Wide Area Augmentation System (WAAS) , the European Geostationary Orbit Navigation Overlap System (EGNOS) , the Asian Multifunctional Satellite Augmentation System (MSAS) , and India's regional SBAS , GPS -Assisted Geostationary Orbit Augmentation Navigation (GAGAN) (Figure 1 ).

Figure 1 : The TESEO LIV3F multi-planet GNSS receiver includes a suite of tools such as DGPS , SBAS , and RTCM (bottom left) to achieve a high-precision positioning solution. (Image credit: STMicroelectronics )

What is the status of their assets?

In many cases, knowing the location of an asset is only one challenge. Gathering information about the asset's condition can also be important, including its physical state and whether it is moving or stationary. Various sensors can be deployed as needed, including:

• Temperature sensor - operating temperature range -40 ° C to +125 ° C , high accuracy, traceably calibrated by the National Institute of Standards and Technology (NIST) , and verified according to IATF 16949:2016 .

• Pressure Sensor - Compact and rugged microelectromechanical systems (MEMS) piezoresistive absolute sensors can be used as digital output barometers with an absolute pressure range of 260 to 1260 hPa (also known as millibars). This sensor must be highly accurate and include temperature compensation.

• The humidity sensor operates in a temperature range of -40 ° C to +120 ° C and measures humidity from 0 to 100% relative humidity (rH) . Temperature compensation should be applied to achieve an accuracy of ± 3.5% rH within the range of 20% to 80% rH .

• Inertial measurement unit (IMU) - which includes MEMS - based 3D accelerometers and 3D gyroscopes, is used to determine whether an asset is moving or stationary.

• Accelerometers – such as MEMS - based triaxial linear accelerometers – are used to measure shocks and vibrations experienced by assets.

Figure 2 : The mainboard of the STEVAL-ASTRA1B asset tracking platform includes the STM32WB5MMG for short-distance connections , the STM32WL55JC for long-distance connections , and the STSAFE-A110 for secure operation . (Image source: STMicroelectronics )

Asset tracking development environment

Developers of asset tracking applications may consider using STMicroelectronics ' STEVAL-ASTRA1B hardware and software development kit and reference design, which facilitates the prototyping, testing, and evaluation of advanced asset tracking systems (Figure 3 ). The STEVAL-ASTRA1B is built upon the STM32WB5MMG module and the STM32WL55JC SoC , which combine to provide short-range and long-range connectivity ( BLE , LoRa , and proprietary 2.4 GHz and sub-1 GHz protocols). For NFC connectivity, the ST25DV64K can be used . The STSAFE-A110 supports secure operation, while the Teseo-LIV3F GNSS module provides outdoor positioning.

Figure 3 : The STEVAL-ASTRA1B platform includes all the hardware, firmware, and software tools required for advanced tracking system development. (Image source: DigiKey )

This GNSS positioning receiver is compatible with six systems: GPS , Galileo , GLONASS , BeiDou, QZSS , and Nav IC (also known as IRNSS ). The system also includes support for WAAS , EGNOS , MSAS , WAAS , and GAGAN SBAS . A notch filter is included in the system for interference suppression.

It also includes a series of sensors for condition monitoring (Figure 4 ):

• The STTS22HTR is a digital temperature sensor operating from -40 ° C to +125 ° C , with a maximum accuracy of ± 0.5 ° C within the -10 ° C to +60 ° C range. It provides 16 -bit temperature data output. Calibration is NIST traceable, and the device is 100% tested and verified. The equipment used for testing and verification is calibrated according to IATF 16949:2016 .

• LPS22HHTR – MEMS piezoresistive absolute pressure sensor , used as…

• This digital output barometer measures absolute pressure from 260 to 1260 hPa . It boasts an absolute pressure accuracy of 0.5 hPa , a pressure sensor noise as low as 0.65 Pa , and provides 24 -bit pressure data output.

• HTS221TR – Relative Humidity and Temperature Sensor. It can measure 0 to 100% rH with a sensitivity of 0.004% rH/ LSB , humidity accuracy of ±3.5% rH in the range of 20 % to + 80% rH , and temperature accuracy of ± 0.5 ° C in the range of +15 ° C to +40 ° C .

• The LIS2DTW12TR – a MEMS triaxial linear accelerometer and temperature sensor – offers user-selectable full-scale ranges of ± 2g/ ± 4g/ ± 8g/ ± 16g , measures acceleration, and outputs data rates from 1.6 Hz to 1600 Hz .

• The LSM6DSO32XTR – IMU module contains an always-on 32g 3D digital accelerometer and a 3D digital gyroscope with a full-scale range of ± 4/ ± 8/ ± 16/ ± 32g and an angular range of ± 125/ ± 250/ ± 500/ ± 1000/ ± 2000 degrees / second (dps) full scale.

Figure 4 : The STEVAL-ASTRA1B motherboard includes a complete set of sensors (left), a system board (yellow box), and GNSS connectivity components ( TESEO LIV3F and antenna in the lower right corner). (Image source: STMicroelectronics )

Power management is crucial for wireless tracking devices. To ensure long battery life, the STEVAL-ASTRA1B incorporates numerous power management components, such as:

• The ST1PS02D1QTR is a 400 mA synchronous buck converter with an input voltage range of 1.8 V to 5.5 V , an input quiescent current of 500 nA at an input voltage of 3.6 V , and a typical efficiency of 92% .

• The STBC03JR battery power management and charger IC includes: a linear battery charger section for a single-cell lithium-ion (Li-ion) battery using a constant current / constant voltage (CC/CV) charging algorithm; a 150 mA low dropout regulator (LDO) ; two single-pole double-throw (SPDT) load switches ; and circuitry to protect the battery in case of a fault.

• The TCPP01-M12 USB Type-C® port protection IC includes: VBUS overvoltage protection, adjustable from 5 V to 22 V (via an external N- channel MOSFET ); 6.0 V overvoltage protection (OVP) on the CC line to prevent VBUS short circuits system-level electrostatic discharge (ESD) protection for connector pins CC1 and CC2 , compliant with IEC 61000-4-2 Class 4 standards.

Software and firmware libraries

The STEVAL-ASTRA1B contains or can provide a variety of software and firmware for developing asset tracking applications. Examples include:

• The FP-ATR-ASTRA1 feature package, included in the STEVAL-ASTRA1B , enables complete asset tracking applications . This package acquires positioning data from a GNSS receiver, reads data from environmental and motion sensors, and transmits the data to the cloud using BLE and LoRaWAN connections. Customizable use cases are included in the package, such as fleet management, livestock monitoring, cargo monitoring, and logistics.

• The STAssetTracking application allows for remote configuration of asset tracking devices that support BLE , Sigfox , or NFC . It can be used to enable data logging for specific sensors and set trigger thresholds to start and stop logging.

• The DSH-ASSETRACKING dashboard is a cloud application powered by Amazon Web Services (AWS) that provides an intuitive interface optimized for collecting, visualizing, and analyzing data from GNSS positioning services and motion and environmental sensors. The dashboard can plot real-time or historical location data and sensor values, and monitor environmental conditions and events (Figure 5 ).

Figure 5 : The DSH-ASSETRACKING dashboard is an AWS- supported cloud application for asset tracking. (Image source: STMicroelectronics )

Summarize

Asset tracking is a critical and complex function required for applications such as livestock monitoring, fleet management, and logistics. As described in this article, STMicroelectronics ' STEVAL-ASTRA1B hardware and software development kit and reference design include GNSS positioning services, a full suite of environmental and motion sensors, power management components, and a complete software and firmware suite to accelerate the design of high-performance asset tracking devices. Feel free to leave a comment and share your thoughts with the DigiKey community!