Recent developments in Synthetic Aperture Radar (SAR) technologies have shown their potential for assessing and quantifying above-ground biomass (AGB) at landscape levels in different biomes. This paper examines the application of full polarimetric data to retrieve information related to potential woody biomass in sparse communal savanna woodlands in southern Africa using the Advanced Land Obse...

The WAAS MOPS describes the method by which a Wide Area Augmentation System (WAAS) transmits its differential GPS corrections and integrity information to users in 250 bit messages. These messages must be decoded and interpreted every second. The corrections even for a single satellite are distributed across several individual messages. The corrections for individual satellites must be combined...

Collecting information about the roadway infrastructure is a task that DOTs at all governmental levels need to accomplish. One way to increase the operational efficiency of these efforts is to use a relatively inexpensive mobile data collection platform that acquires information that is general enough to serve multiple purposes. The design and evaluation of one such platform that costs roughly ...

A differential global positioning system (DGPS) is one of the most widely used augmentation systems for a low-cost L1 (1575.42 MHz) single-frequency GPS receiver. The positioning accuracy of a low-cost GPS receiver decreases because of the spatial decorrelation between the reference station (RS) of the DGPS and the users. Hence, a network real-time kinematic (RTK) solution is used to reduce the...

Geometric calibration of the European Remote Sensing (ERS) Satellite synthetic aperture radar (SAR) slant range images is important in relation to mapping areas without ground reference points and also in relation to automated processing. The relevant SAR system parameters are discussed and calibrated by using the European Space Agency (ESA) transponders at Flevoland. The resulting accuracy of ...

We have evaluated the accuracy of digital elevation models (DEMs) generated by the JPL/NASA TOPSAR synthetic aperture radar interferometer instrument by acquiring topographic data in the summer of 1992 over the National Training Center, Ft. Irwin, California, a desert area with significant relief and varied terrain, and comparing the measurements to a very accurate digital elevation model deriv...

An onboard vehicle-to-vehicle multi-hop wireless networking system has been developed to test the realworld performance of telematics applications. The system targets emergency and safety messaging, traffic updates, audio/video streaming and commercial announcements. The test-bed includes a Differential GPS receiver, an IEEE 802.11a radio card modified to emulate the DSRC standard, a 1xRTT cell...

Direct sensor orientation, i.e. the determination of exterior orientation based on GPS and inertial measurements without the need for photogrammetric tie points, has gained considerable popularity over the last years. One pre-condition for direct sensor orientation is a correct sensor and system calibration. The calibration can only be carried out by a combination of a photogrammetric solution ...

There is a widespread misconception within the spatial science community that the three geocentric datums widely used in Australia, GDA94, ITRF and WGS84 are identical “for all practical purposes”. This is a fair assumption for navigation and many mapping purposes, however users of wide area differential GPS and precise positioning services with a precision of less than a metre are beginning to...