GNSS

FAA researching advanced RAIM for GPS approaches

An official evaluation of Advanced RAIM (ARAIM), a GPS technique used in aviation receivers for safer landings and take-offs, is being conducted by the William J. Hughes Technical Center (WJHTC) of the U.S. Federal Aviation Administration (FAA).

The WAAS Test Team at the technical center has begun to monitor the Integrity Support Data (ISD) parameters of ARAIM using evaluation tools and methods developed by both the center and Stanford University. Results of this monitoring will be published in a quarterly report on the WAAS Test Team website.

ARAIM addresses various weaknesses of Receiver Autonomous Integrity Monitoring (RAIM). To assure the integrity of GPS, aviation receivers implement RAIM, which detects any GPS satellite fault, and can then isolate and remove it from the navigation solution.

However, RAIM provides integrity only for horizontal operations, such as enroute and non-precision approach. Additional integrity is needed to allow advanced capabilities, such as vertically guided approaches. Other integrity systems, including the Wide Area Augmentation System (WAAS), provide the integrity needed to permit these additional operations.

Since RAIM’s debut, GPS and other GNSS have evolved to improve their performance and upgraded to add an additional civilian signal, making possible ARAIM architecture.

ARAIM increases the geometric diversity and integrity availability by using two core GNSS constellations (such as GPS and Galileo). ARAIM takes advantage of the second civilian signal by specifying dual-frequency processing so that the ionospheric error from GNSS signals is directly measured by the user equipment. www.faa.gov

Galileo High Accuracy Service goes live!

Galileo, European Union GNSS, begins the delivery of its High Accuracy Service (HAS) as officially announced by Thierry Breton, European Commissioner for Internal Market, “feeding a prosperous market for innovative applications – from farming to drone navigation and autonomous driving.”

The precise corrections provided by the Galileo HAS will allow users to improve the accuracy associated with the orbit, clocks and biases provided through the Galileo Open Service broadcast navigation messages and the GPS Standard Positioning Service navigation data. These corrections enable the computation of a high accuracy positioning solution in realtime when processed by an appropriate algorithm in the users’ receivers tracking the Galileo E6-B signal.

The typical accuracy below a few decimetres (<25cm horizontal) in nominal conditions of use is a revolution where Europe provides this as an integrated service for free, thus allowing the massive development of applications worldwide. www.gsc-europa.eu

Inertial Labs launches updated GPS-Aided Navigation System

Inertial Labs released an upgraded version of the “INS-U” GPS-Aided Inertial Navigation System, an extended version of Differential Pressure Sensor and Embedded Air Data Computer, allowing the unit to measure airspeed with up to 600 KNOTS to enhance high dynamic applications. It can output fused (GNSS + IMU) NMEA data to Pixhawk Autopilot, which allows Pixhawk Autopilot to navigate UAV in a long-term GNSS-denied environment (more than 1 hour). Intertial Labs is a developer of GPS-Aided Inertial Navigation and Measurement Units. https://inertiallabs.com