GPS is the first and most well known Global Navigation Satellite Systems (GNSS). It actually came out of the space race as it's forerunner was created to meet a need to track the first satellites launched. Today, GNSS is no longer just reserved for a few exclusive high-tech, high-cost applications, we all use this space-based geodetic tool when using our smart phones. Finding the best or the closest restaurant when visiting a new city or get direction driving from your hotel to your meeting location be it in a city you know or in a place you never visited before, our smart phone location and map applications are all based on GNSS.
Going indoors and diving subsea
I just came off a webinar hosted by the InGNSS, a magazine dedicated to the global community developing and using the current GNSS: GPS (US), Galileo (Europe), GLONASS (Russia), BeiDou (China) as well as regional/augmentation systems.
GNSS/Inertial integration - applying the technologies
GNSS is a satellite based system providing signals that enable us to compute position, time and velocity. As long as your antennae can 'see' a sufficient number of satellites GNSS gives us high accuracy. However, in places like narrow canyons, indoors or othre places where trees or buildings block the line of signals from the satellites to the antennae, navigation with GNSS becomes unreliable and even impossible. This can be compensated by building an Inertial Navigation System (INS) that use rotation and acceleration information from an Intertial Measurement Unit (IMU) to compute accurate position over time. An INS can also provide information about the attitude, in this case not a bad attitude kind of attitude but rather roll, pitch and heading of a moving vehicle for instance. INS is not reliant on external measurement to compute a solution ie, information about position etc. In the absence of an external reference, the INS solutions will drift over time due to it adding up the errors in the IMU data. When combined, the two techniques GNSS and INS will provide a poignant navigation solution with many exciting application possibilities.
These applications where discussed and explained in rather detailed manners in the webinar hosted by InGNSS I mentioned earlier: GNSS/Inertial integration - applying the technologies
Underwater. Underground. Under tree canopies. In urban canyons.
The absence or unreliability of GNSS signals is probably the leading motivation for incorporating inertial technology into an integrated navigation system.
Learn how GNSS/inertial integration can help you deal with GNSS-challenged environments by joining Inside GNSS and three experts in the field on
European industry Galileo http://www.insidegnss.com/node/3605
