14 November 2003
An improved relative radiometric calibration procedure is available for ACRES Landsat 5 TM products.
The improved method implements radiometric calibration of TM reflective band image data through a time-dependant calibration Look-Up Table (LUT). This method is different from the only technique previously available for ACRES products that used data from Internal Calibration (IC) lamps on a scene-by-scene basis for radiometric calibration. The LUT method models the detector gain as a time-dependant function to account for inconsistencies in the IC lamps over time.
14 November 2003
The price for MODIS Archive products has recently been reviewed. MODIS Archive data is now available at the reduced price of $150 per pass.
The price reduction is the result of processing efficiencies from recently implemented improvements to ACRES MODIS products and services. Archive products are now similar to MODIS Online products, which are processed using post-pass ephemeris information to improve geolocation accuracy.
ACRES has recently upgraded its MODIS processing software. IMAPP v1.5 has a number of enhancements including updated calibration look-up tables and improvements to geolocation. From 10 November 2003, all ACRES MODIS data will be processed with the new version of IMAPP software.
14 November 2003
Landsat 5 TM products are now available through the STAR (Speedy Transmission after Reception) Service. ACRES reintroduced acquisition of Landsat 5 data in July this year.
The STAR Service was introduced in early 2001 to provide fully processed satellite data within 12 hours of the satellite overpass.
STAR Service is now available for RADARSAT, ERS and Landsat 5 imagery.
14 November 2003
NASA reports that it will not be proceeding with the Request for Proposal (RFP) for the Landsat Data Continuity Mission (LDCM) Implementation phase.
"Consistent with guidance contained in the "Remote Sensing Policy Act of 1992", NASA is considering other options for ensuring the continuity of valuable Landsat data".
THE LDCM Implementation phase involved the assessment of various system development and management options for a satellite system to succeed Landsat 7. A preference was expressed for private sector investment even though six of the previous seven Landsat satellites had been government owned and developed.
One of the key objectives of LDCM is to make all Landsat equivalent data collected available at affordable cost. This will enable the many different sectors of the population to continue to utilise this data for high quality research and applications.
14 November 2003
Wenjun Wu (Project Development Engineer) and Qian Xu (Software Developer) have been recognised for their innovative development of the ACRES Automatic Cloud Cover Assessment algorithm for Landsat 7 ETM+ data.
Wenjun and Qian developed this extremely accurate and efficient software after analysing more than 10,000 Landsat 7 scenes covering Australia during all seasons and including such diverse features as snow fields, sand dunes, salt lakes, breaking surf and agriculture. Whilst other automatic cloud cover software has been previously developed, it required multiple processing passes to achieve results that were often less than accurate.
Wenjun and Qian's excellent efforts have been recognised with two awards. Chief Executive Officer, Dr Neil Williams, presented each of them with Geoscience Australia's "Distinguished Lecturer's Award" and BAE SYSTEMS presented them with a Bronze Award under the "International Chairman's Awards for Innovation Scheme".
ACRES is currently making the most of Wenjun's and Qian's expertise to work on an automatic cloud cover algorithm for Landsat 5 TM data.
28 November 2003
ACRES principal antenna at Alice Springs has gone through several major modifications in the last twelve months as part of the 9-metre antenna upgrade project.
The first major task performed during October last year was the replacement of the antenna mechanical bearings. The disassembly of the antenna also provided the opportunity to perform other minor structural repairs and maintenance.
The replacement of the low noise amplifier (LNA) in June 2003 with one of significantly lower noise has given the antenna an improvement of more than 2 dB in signal to noise ratio. This will enable reliable reception in what were previously marginal conditions.
The installation of new signal processing equipment (the downconverter) that is located inside the antenna was completed in November. The advantages of this upgrade are improvements to data reliability and data quality.
Preparation for the installation and testing of the new antenna positioning systems and associated electronics that drive and control the antenna began in late October. The preparation progressed according to plan and the new servo-mechanical system was successfully installed over the period of one week in November.
The last phase of the 9-metre antenna refurbishment will be the replacement of the computer that controls antenna movement, the Antenna Control Unit (ACU). This unit determines where to point and track the antenna from a list of available satellites. Work has commenced on development and implementation of the ACU and is likely to continue through to January 2004.
At the conclusion of the upgrade project the main ACRES antenna at Alice Springs will have completely new electronics of current technology. This will allow efficient and reliable tracking of satellites for many years to come.
10 December 2003
ACRES has recently released a new remote sensing product on DVD. ACRES Landsat 7 Mosaic of Australia is an inexpensive satellite image of Australia using recent imagery (1999-2000). It displays ground features in photographic-like perspective.
Now schools and individuals have access to imagery previously used only by spatial data specialists. ACRES Landsat 7 Mosaic of Australia is derived from ACRES Landsat 7 Y2K Mosaic data that was produced by the Australian Greenhouse Office in 2000 as part of the National Carbon Accounting System.
Before this product was available, it cost several thousand dollars to order this mosaic map as a custom product. Now anyone can access it at a fraction of the cost - only $99 from ACRES distributors or Geoscience Australia's Sales Centre.