GNSS Raw Measurement on the Latest MediaTek Platform

Abstract

In this article, we are going to illustrate the GNSS raw measurement on the latest MediaTek platform in 2017 with Android-N or the later version of Android releases. With the opening of the raw measurement in the location framework of Android-N in 2016, the GNSS raw measurement and navigation message are much easier to be obtained on the mobile devices. The new interfaces on mobile device provide the possibility to develop some advanced applications on single device or between multiple devices. The kinds of application almost could not be done on the mobile devices in the past. The raw measurement also could be used for improving positioning accuracy with combining the cloud based services or small cluster of devices. Sub-meter level accuracy on mobile devices is also becoming possible. Since 2016, Google announced the first version of GNSS raw measurements API along with the ‘N’ release (Android-N). This allows the end users of Android-platform and APP developers finally have the opportunity to directly access the un-processed/un-filtered GNSS raw measurement. This information was used to be obtained in single-chip GNSS solution or geodetic purpose receiver. With the new API of GNSS raw measurement, the traditional tricks on signal-chip solution become possible on the mobile phone as well. The further applications and integration in the application level is also expected through combining the raw measurement with multiple sensor sources on mobile devices. With the MediaTek new designed chipset, the GNSS raw measurements from four GNSS constellations can be provided simultaneously, including GPS, GLONASS, BeiDou and Galileo. The more GNSS constellations mean more satellite visibility. In point of raw measurement, the device will have more chance to get the well-locked raw measurement, including code-phase and carrier-phase. The most straightforward possible improvement is on speeding up the convergence of RTK (Real-Time-Kinematic) application with more well-locked raw measurements from different constellations. The sub-meter level positioning accuracy is also becoming possible on mobile devices with the proper aiding information or algorithm. As a mobile chipset vendor, the raw measurement API is not only for the positioning or application purpose. Furthermore, it provides a unified interface to collect data for examining the quality of hardware design on mobile devices. Especially, there are multiple radio devices coexisting with GNSS RF devices. Any improper hardware design might harm the measurement quality of GNSS signal. Before Android-N, the manufactory of mobile devices only can qualify the GNSS performance for the final positioning result in cheap way. After Android-N, this new API provides a new way to allow the manufactory has the chance to aware the hardware design quality in really early stage and have the chance to improve it if necessary. We are going to share what kind of benefits can be obtained. In summary, we will illustrate some of possible applications by using the new API on single mobile or between multiple devices on the MediaTek latest platform. The corresponding concepts and results will be shared. The possible ways to validate the design of hardware will also be discussed.