Solving the Challenges of eMobility with Quectel's Dual-Band, Multi-Constellation GNSS Modules
July 10, 2020
GNSS has been widely adopted as a method to track and trace large items such as ships, trucks, heavy equipment, cars and high-value freight.
GNSS has been widely adopted as a method to track and trace large items such as ships, trucks, heavy equipment, cars and high-value freight. However, when it comes to smaller or lower value things, deployment has been constrained by the power demands of GNSS, the necessary form factor and the ability to site antennas on smaller items in ways that can enable them to track satellites effectively.
These limitations are starting to be addressed by the latest range of GNSS modules that combine small form factor and low power consumption at a pricepoint that makes them viable for integration into lower value devices. We’re not at the commodity level of tracking low value items such as small parcels but we have reached a level where small vehicles such as eScooters or eBikes can access the capabilities of GNSS.
GNSS offers the best global positioning technology solution for moving objects and that’s why car makers, for example have adopted the technology so widely. A car, though, is very different to an eScooter. Cars are expensive items so adding GNSS technology is a small incremental addition to the overall cost of a vehicle. In addition cars have unconstrained access to power from the vehicle’s systems and space requirements are not an issue. Finally, a GNSS antenna can be easily mounted on the exterior of a car or truck.
For small vehicles, like eScooters or last mile delivery robots, the opposite is true. eScooters can cost less than US$400 so additional cost has more of an impact on affordability, the vehicle’s batteries are less powerful so power demand is a consideration, and the motors and batteries leave little room for additional equipment to be integrated. In addition, the rider can present a barrier between the antenna and the satellite, obscuring the ability to connect to a constellation.
As eMobility vehicles become more popular, suppliers have innovated to develop GNSS modules that address the limitations of deployments into smaller, lower value vehicles. However, whilst the positioning performance of GNSS can meet the eMobility industry’s needs, the deployment scenarios pose further challenges. Vibration, operation in deep urban canyons, the extremely high accuracy demanded for users to locate hire fleet vehicles and emerging regulation to geofence vehicles all place further demands on positioning capability.
For these reasons, GNSS alone can’t guarantee to provide the accuracy the eMobility industry demands. The perfect scenario, in which GNSS is an ideal positioning technology, of clear skies and no obstructions such as bridges or being left in underground parking garages doesn’t exist at all times. This means GNSS needs to be augmented by supporting technologies to achieve accurate positioning when satellites can’t be found in deep urban canyons.
There are two dimensions to achieving maximized positioning accuracy in these challenging deployments. First, maximize the possible number of satellites available to connect to by selecting a module that includes an L1 and L5 dual band, multi-constellation GNSS receiver that can connect to a large number of satellite constellations. Second, adopt an additional technology that can provide location data from other information which can be correlated with GNSS data.
A well-established method for providing this additional information is dead reckoning. Dead reckoning combines wheel speed and inertial measurement (IMU) data with GNSS. IMU data is often composed of accelerometer and gyroscopic information which enables the location of the vehicle to be tracked. However, dead reckoning doesn’t have all the answers. Position accuracy can be affected by issues such as changes in tyre pressure which affect its circumference, road vibration and atmospheric differences.
The limitations that affect dead reckoning mean a combination of it and GNSS data provides the most accurate and comprehensive solution for eMobility applications so precise location can be achieved more of the time.
A critical ingredient of the combined dead reckoning and GNSS solution is the GNSS receiver itself and Quectel has developed its LC79D module with receiver capability in mind to enable multiple constellations to be accessible. The GNSS receiver has an ultra-low form factor with dimensions of 10.1mm × 9.7mm ×2.4mm which suits space-constrained designs such as eMobility vehicles.
The LC79D can track L1 and L5 bands for satellite systems including GPS, Galileo and QZSS. On the L1 band, the LC79D can track the GLONASS and Beidou satellite systems and the module tracks the IRNSS system in the L5 band. Providing both L1 and L5 capability offers huge diversity and connection choice and this coupled with dead reckoning data means eMobility companies can ensure their users and their workers can easily find their vehicles in even the most unfriendly locations.
To learn more about how Quectel’s LC79D enables precise positioning for eMobility vehicles, download your free Quectel whitepaper, “Why GNSS for eMobility must balance precision, price, power and packaging” today.