Articles in the Positioning Category

Mar 2011 | One Comment

The year 1978 saw the launch of the first Global Positioning System (GPS) satellite. Today, GPS, as the first and currently only operational global navigation satellite system (GNSS), is widely used and is a vital technology for many of society’s economic, scientific and social activities. Applications can be found everywhere, such as spacecraft navigation, geodesy, surveying and mapping, precision navigation, machine guidance, vehicle fleet management and “intelligent transport systems” (ITS), emergency services and “location based services” (LBS). Clearly the development of GPS has revolutionised what are now termed “positioning, navigation and timing” (PNT) activities.

Feb 2011 | No Comment

Around the transit area between the indoor and outdoor environments of buildings, it is anticipated that the number of available measurements may not be sufficient for localization and the undesirable non-line-of-sight (NLOS) and multipath errors would severely deteriorate the localization accuracy. To estimate user location reliably where measurements from global positioning system (GPS) receivers are corrupted or not available, network-based methods have been actively investigated.

Feb 2011 | No Comment

Nowadays, a growing number of GNSS users demand highly-accurate positioning with minimal latency. PPP is a new positioning technique providing centimeter-level error. Precise Point Positioning (PPP) processes measurements from a single user receiver, using detailed physical models and corrections, and precise GNSS orbit and clock products computed beforehand.

Jan 2011 | No Comment

GPS receivers are able to be employed in the survey field as low cost sensors or for applications where it is necessary to have a good ratio between cost and benefits. Nowadays, there are several low cost GPS receivers able to provide both pseudorange and carrier phase measurements in the L1band, that allow to have good real-time performances in outdoor condition. The present paper describes a set of dedicated tests in order to evaluate the positioning accuracy in static conditions.

Jan 2011 | No Comment

A very interesting feature of the transmitter approach is the possibility to locate transmitters underneath the receiver. The transmitter-based approach is an indoor positioning method, based on the use of a local infrastructure, aiming to provide accuracies of 1 to 2 meters. The GNSS signals are received by an outdoor antenna located in a place with an unobstructed view of the satellites. Note that another possibility is to use a GNSS signal generator (generating one or 4 satellites) instead of the outdoor antenna.

Oct 2010 | No Comment

The Arctic ice is receding at a faster pace than expected a few years ago, and is quickly opening for increased human activities beyond the Arctic Circle (66.56° N). This drives a growing demand for navigation in the Arctic area, which is mainly composed of marine expanses and the land masses of Norway, Iceland, Greenland (Denmark), Northern Canada, Alaska (USA), and the Northern parts of Russia…

Dec 2009 | No Comment

Phase multipath is one of the most crucial error sources in centimetre or millimetre level GNSS high precision positioning. Short-delay multipath is still especially difficult to detect or mitigate by the state-of-the-art hardwarebased techniques. Therefore, processing algorithm-based multipath mitigation methods are crucial for the further improvement of positioning accuracy, either integrated with other techniques or in a stand-alone mode…

May 2009 | Comments Off on Flight evaluation of a ‘GADA’

For the final evaluation of a GPS attitude determination algorithm (GADA), it was determined its true performance in terms of its accuracy, reliability and dynamic response. To accomplish that, a flight test campaign was carried out at the Brazilian Flight Test Division (GEEV) to validate the attitude determination algorithm. In this phase, the measured aircraft attitude was compared to a reference attitude, to allow the determination of the errors…

Feb 2009 | One Comment

Satellite positioning is the term used to describe the determination of the absolute and relative coordinates of points on (or above) the Earth’s land or sea surface by processing measurements to, and/or form, artifi cial Earth Satellites. In this context, absolute coordinates refer to the position of a point in a specified coordinate system, whereas relative coordinates refer to the position of one point with respect to another…

Feb 2009 | No Comment

GNSS positioning/navigation devices are rapidly merging into and changing our modern lives, just like the personal computer in the 1980’s and the cellular phone in the 1990’s. It is predicted that by 2012, the annual shipment of navigation devices will increase to over 65 million units, which is more than three times the 19.8 million shipped in 2006 [1]. Also in a situation personal computer and cellular phone ever faced, a higher standard service…