Joel Barnes

Experimental results of Locata: A high accuracy indoor positioning system

Accurate indoor positioning is required for a variety of commercial applications, including warehouse automation, asset tracking, emergency first-responders, and others. In fact, the general expectation of users today is for ℌGPS-likeℍ positioning performance anywhere they go. The inherent limitations of GPS signal availability indoors and in satellite-occluded environments, however, has forced researchers to investigate alternative technologies which may be able to replicate GPS/GNSS performance indoors. A new terrestrial RF-based distance measurement technology, trademarked ℌLocataℍ, has overcome the technical challenges required to create ℌa localised autonomous terrestrial replica of GNSSℍ. Signals from the Locata network are seen by receiver devices as equivalent to (but totally independent from) the GNSS satellite constellation(s). This technical paper describes indoor positioning results with the latest generation of Locata positioning devices. The results demonstrate that Locatas technology enables cm-level positioning in severe multipath environments where conventional high-accuracy radiopositioning has previously been impossible.

The Integration of GPS and Pseudolites for Bridge Monitoring

One application in structural engineering is measuring the movement of suspension bridges. Under unfavourable wind conditions or heavy traffic loads cable suspension bridges may move up to a few metres. Therefore, a positioning system used to monitor bridge movements can provide extremely valuable information. For such monitoring applications it is desirable for the positioning system to deliver equal precision in all position components, all the time.

Experimental Analysis of GPS/Pseudolite/INS Integration for Aircraft Precision Approach and Landing

This paper analyses flight trial results to study the overall performance and limitations of a GPS/Pseudolite/INS integration approach for aircraft precision approach and landing applications. For this purpose, the series of approaches were flown at Wedderburn Airfield, Australia. The analysed results show that pseudolite signals strengthen the ranging signal availability and the satellite geometry. Most of the geometry enhancement is found in the vertical position component, improving the accuracy of the aircrafts altitude. Furthermore, the results reveal that the inclusion of a pseudolite enhances both internal and external reliabilities. A dramatic improvement of the external reliability in the vertical component is observed.

Flight Evaluation of a Locata-augmented Multisensor Navigation System

Abstract The Global Navigation Satellite System (GNSS) is a widely used technology for high accuracy positioning in support of many applications, including airborne mapping and sensor georeferencing. The integration of GNSS and an Inertial Navigation System (INS) is a critical navigation component in an airborne mapping system, because it can provide high update rate of solutions, platform attitude information and improved performance (e.g. accuracy, availability). However, GNSS signals can be easily blocked or interfered with, and sometimes the satellite geometry may not be good enough for high accuracy and high reliability applications. Therefore the development of alternative, non-GNSS-based navigation solutions has attracted increased interest in situations where GNSS system availability cannot be guaranteed. Locata is a groundbased navigation system which can transmit ranging signals at several frequencies in the 2.4 GHz Industrial, Scientific and Medical radio bands. Tracking of Locata signals allows additional range-like measurements to be made, which can be processed in a manner not unlike GNSS measurements. Hence the integration of GNSS, INS and Locata can address requirements for seamless precise positioning in many situations. This paper describes a flight test of a GPS+INS+Locata triple-integrated system. The test was conducted in October 2011, during a flight from Bankstown Airport, Sydney, to Cooma Snowy Mountains Airport. The Locata pseudorange measurements were collected and postprocessed to evaluate overall navigation performance and to investigate the limitations of such an integrated system.

Precise Maritime Navigation with a Locata-Augmented Multi-Sensor System

This paper investigates use of Locata—a ground signal-based navigation system—to augment a standard GNSS/INS integrated system for use in the marine environment. A loosely-coupled decentralized integration architecture based on a Kalman filter was implemented. The multi-sensor experiment was conducted on Sydney Harbour, Australia. The GNSS, INS and Locata measurements were collected and post-processed to evaluate the overall positioning performance of the integrated system. The test results indicate that the addition of the Locata measurements significantly improves the overall system performance. Moreover, accurate seamless navigation is achievable even when GNSS signals are unavailable.