干旱区生态环境知识资源中心

"Kila Mahali" means "everywhere" in the Swahili language. Here, it is used to describe the potential of the new Mahali Space Weather Monitoring project funded by the U. S. National Science Foundation. The Mahali Project is based on a revolutionary architecture that utilizes mobile devices, such as phones and tablets, to form a global space weather monitoring network. The goal of Mahali is to exploit the existing GNSS infrastructure - more specifically, delays in multi-frequency GNSS signals - to acquire a vast set of global total electron content (TEC) estimates. With connectivity available worldwide, mobile devices are excellent candidates to establish crowd sourced global relays that feed multi-frequency GNSS sensor data into a cloud processing environment. Once the GNSS data are in the cloud, a picture of the space environment, and its dynamic changes, can be reconstructed and broadcast globally.

The Mahali vision is made possible by advances in multicore technology that have transformed mobile devices into parallel computers with several processors on a chip. In our example, local GNSS data can be preprocessed, validated with other sensors nearby, and aggregated when transmission is temporarily unavailable. Intelligent devices can also autonomously decide the most practical way of transmitting data with in any given context, e.g., over cell networks or Wifi, depending on availability, bandwidth, cost, energy usage, and other constraints. By exploiting GNSS time-tagged local storage and deferred uploads, Mahali will also lead to improved data collection over oceans, deserts, and other remote locations [Pankratius, 2014].

The Mahali project enables GNSS ionospheric science in three ways. The first relates to the ease of redeployment. In the field, a scientist can easily configure and reconfigure a dense array of GNSS receivers/cell-phones to enable the collection and processing of data in near real-time, all with the goal of investigating different scale ionospheric structures. We will test this capability during the initial demonstration of Mahali at the Poker Flat incoherent scatter radar site outside of Fairbanks, Alaska. The second way the Mahali project will enable science is that it will allow for space weather data collection in places where data coverage is now scarce. Africa is a prime example, where even in the remotest locations, cell-phone technology is flourishing. Finally, the crowd sourcing potential of Mahali project for scientific purposes is immensely intriguing and could be transformational in our efforts to monitor geophysical events from earthquakes to tsunamis.