Intel GNSS Assistance Server Solution
Murugan Natesan, Geraint Ffoulkes-Jones, Siddhant Sadanah, Intel, India
Alternate Number 4
In consumer products such as mobile handsets, wearables, etc. GNSS receivers require longer duration in order to demodulate all the required Navigation Message data from satellites required to compute the location of the device. There are various means currently existing to supply the GNSS Assistance data to the connected GNSS devices to speed up the time required to compute the location, especially in cold & warm start conditions. These various mechanisms include, providing the GNSS assistance from the mobile operators network, GNSS Assistance servers such as SUPL server, Proprietary mechanisms, etc.
This paper describes one proprietary way to provide the required GNSS assistance data to consumer GNSS devices targeting to improve the time to fix, to aid mitigation against GNSS Spoofing and to improve location aware applications user experience. A system that is capable of the providing various GNSS Assistance data such as broadcast ephemeris, almanac, time models, and predicted ephemeris for up to 7 days into the future for GPS, GLONASS, QZSS, Galileo and Beidou is described in detail.
The paper also describes in detail, the level of server side validation checks that are performed in order to qualify the GNSS Assistance data prior to it being provided to GNSS devices in the field. As part of this validation, the candidate GNSS assistance data are fed into a range of test GNSS devices that are deployed across the globe. The performance of these devices are monitored and metrics are collected to ensure the quality of the generated assistance data. After confirming that the generated GNSS assistance data is indeed performing as expected, it becomes qualified for deployment.
These qualified assistance data are then uploaded to the dedicated assistance servers which can be accessed by the millions of consumer GNSS devices on the field, via secure HTTP link. This process of collection of the GNSS data, generation of the predicted ephemeris for up to 7 days into the future, validation of these GNSS assistance data and deployment are repeated at regular interval ensuring the latest validated GNSS assistance are made available to the GNSS devices consumption. Even after the GNSS assistance data has been provided to the GNSS devices on the field, the solution continues to perform the validation on the already generated data for its entire 7 days validity period in to the future. This helps to catch issues first hand within the solution, or sudden changes to the GNSS constellation status, and allows for a rapid provision of a mitigation mechanism to the GNSS Devices on the field, without having to rely on the user devices finding and reporting the problem.
It is these validation mechanisms that greatly distinguish this solution from any of the existing solutions that provide GNSS Assistance data to the devices on the field. In this paper, metrics are also provided that illustrate the expected validation coverage, with examples of the types of issues that can be identified before they get to the end user.