NIGHT CREW LABS
May 2011 – A weather balloon launched from Gilroy, California tested high-altitude smartphone GPS receiver performance. Based on the successful mission results, billions of smartphones (and counting) are now enabled with high-altitude GNSS location services.
Mission
This mission tested the ability of a smartphone to compute GPS positions at high altitudes (over 60,000 feet). US export control law requires commercial GPS units to cease functioning if above 60,000 feet AND traveling faster than 1000 knots. Since phone manufactures didn’t think people would be making phone calls above 60,000 feet, this was the only condition in place to cut off GPS. We worked with Dr. Frank van Diggelen, V.P. of GPS Technology at Broadcom as well as a Consulting Professor at Stanford University, who built a test unit smartphone to work at the high altitudes we achieved, in this case 102,300 feet (31.2 km). Our work led to Broadcom making it standard for their GNSS chips to work above 60,000 ft (provided the GPS speed limit of 1000 knots is maintained), enabling smartphones the ability to track high-altitude flights out of the box.
During the mission, the payload landed in New Hogan Lake, CA. While the team went to frantically procure an inflatable raft before the payload sank, unbeknownst to us a fisherman on the lake picked up the payload and drove off with it, resulting in a wild goose chase for several hours before a successful recovery at the fisherman’s house.
Equipment
-Google Nexus S Smartphone (Samsung)
-Canon A480 Digital Camera with CHDK firmware
Results
Results were presented at the Institute of Navigation’s (ION) Global Navigation Satellite Systems (GNSS) conference in September of 2011 in Portland, Oregon and the academic paper can be found here. This project won “Best Presentation Award” for its session.