7 Dec 2007 09:00:00 +1000
On 6 October 2007, Landsat 5 experienced an issue with its on-board battery #2 leading to a temporary suspension of imaging.
Since then, the satellite has continued to operate on battery #3 which provides enough power to maintain health and safety standards only. During this time, significant work has been done and battery #2 was brought back online on 19 November.
At this stage the battery's performance is exceeding expectations; however further testing is still necessary and the United States Geological Survey (USGS) are hopeful of a return to imaging in the coming weeks.
Tue, 2 NOV 2007 09:00:00 +1000
ACRES have successfully installed software upgrades for the ALOS processing system for PRISM and AVNIR-2 data. The direct benefit for customers is improved positional accuracy and better de-striping for PRISM data. The upgrade for PALSAR is expected to be installed soon. We have updated the ACRES web page on ALOS Geometric and Radiometric Specifications to reflect the change and have included the results of our own positional accuracy testing.
Tue, 2 Nov 2007 09:00:00 +1000
The 17th International Seaspace Remote Sensing Conference and the Land & Vegetation Direct Readout Workshop were held in Mexico City on the 8-11 October. Craig Smith represented Geoscience Australia at the Meeting which was hosted by Conabio (The Mexican National Commission for the Knowledge and Use of Biodiversity). The meetings are a major forum for those involved in the acquisition, processing, and application of imagery from earth observation satellites commonly described as the Direct Readout (DR) or Direct Broadcast (DB) Missions.
The main focus of the meeting was presentations and discussions on the acquisition, processing, and applications of imagery from NOAA Polar Operational Environmental Satellite (POES), the National Polar-orbiting Operational Environmental Satellite System (NPOESS), and METOP missions. The satellite imagery acquired by these missions of most interest to the Australian community is AVHRR, MODIS, and the VIIRS instrument on the NPOESS Preparatory Program (NPP) & NPOESS Missions.
Presentations were made at the meeting by representatives of satellite data acquisition systems, remote sensing scientists and practitioners working in government and academia, the Direct Readout Laboratory (DRL), and the Integrated Program Office (IPO)
The DRL represents the interests of the DB community at NASA. Services provided by the DRL include the provision of standardised image processing and application algorithms to the DB community and advocating the interests and requirements of the DB community in current and future NASA missions. More information about the activities and software support available from the DRL is available at the NASA website.
The IPO was established to develop, acquire, manage, and operate the next generation of polar-orbiting operational environmental satellites. As part of this effort, the United States has also partnered with the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the Japan Aerospace Exploration Agency (JAXA) to provide long-term continuity of observations from polar orbit that will continue and improve the operational meteorological and environmental forecasting and global climate monitoring services. More information about the IPO NPP & NPOESS is available at the IPO website.
The key outcomes of the meeting were:-
The operational status of the TERRA & AQUA Mission is good, with support for these missions continuing at least until the launch of the NPP planned for October 2009.
Software and algorithms required to receive data and process basic image products from the NPP is planned to be available to the direct broadcast community about 6 months before the launch of NPP.
A major application at Near Real Time DB facilities is fire hotspots and fire affected mapping. These applications are leading to increased activity in the remote sensing of fire intensity and fuel loads.
Additional information about the land and vegetation applications from DB imagery can be found at:
Tue, 2 Oct 2007 09:00:00 +1000
Geoscience Australia was represented at the Landsat Ground Station Operators Working Group (LGSOWG-36) meeting, recently hosted by the South African Satellite Application Centre (SAC).
Status of Landsat 5 and 7 satellites
Landsat 5's second battery became inoperable on the 6th October 2007 (first battery failed in May 2004). The satellite is now switched to battery 3 which can only support minimum survival activities, with no imaging capability. The United States Geological Survey (USGS) has been working on a recovery plan to revive battery 2 and improve the performance of battery 3. According to the information provided at the meeting, image acquisition may resume by the end of November or early December 2007. However, the duty cycle may be reduced to some extent during the post-recovery phase. Landsat 5 has managed to survive several major failures due to aging components but has enough fuel to keep the operations going until 2012. Landsat 7 continues to perform well in SLC-off mode.
Status of Landsat Data Continuity Mission (aka Landsat 8)
Preparations for the proposed data continuity mission are now in full swing. The target date for Landsat Data Continuity Mission (LDCM) launch is July 2011. Ball Aerospace Technologies won the contract in July 2007 to build the Operational Land Imager (OLI) sensor, while tenders for spacecraft will be issued in November 2007. OLI sensor on Landsat 8 will acquire data in 9 spectral bands at 30 m spatial resolution plus an improved 15 m panchromatic band. With a dynamic range of 12 bits there is no need for instrument gain settings. OLI offers one new band in the blue region for improved coastal water applications and two new bands in Infra Red (IR) region to detect cirrus clouds. The satellite is being designed for 5 a year mission life with enough fuel to last for 10 years.
National Land Imaging Program (NLIP)
Dr Tom Loveland, remote sensing scientist from USGS, presented outcomes from the Future of Land Imaging Interagency Working Group's (FLIWG) final report. The key recommendations of this group were to establish and maintain core operational capability to collect moderate resolution land imagery; and set up a National Land Imaging Program (NLIP) office within the Department of Interior by early 2009. Continuity of Landsat program beyond LDCM will be addressed through this program. The anticipated data policy, through NLIP, is to continue unrestricted free of cost access to and use of data acquired by US govt-owned moderate resolution systems, and to increase electronic data distribution via Internet.
Tue, 2 NOV 2007 09:00:00 +1000
The Tasmanian Earth Resources Satellite Station (TERSS) has now returned to operations after a prolonged outage due to a failure in the servo control system.
A power transistor in the servo amplifier failed, rendering this board unrepairable. This system is no longer supported by the manufacturer. Significant effort was expended both by ACRES staff and the manufacturer to identify a suitable replacement.
Whilst a replacement was identified, there were substantial differences in the status and control signals passed between the servo system and the computer controlling it. As many of these signals are used in the software and are integral to the operation of the system major changes needed to be effected to restore control.
We are pleased to announce that these changes have been installed and tested and the station is tracking again. There has been a slight degradation in performance, particularly for very low elevation passes, but additional tuning work will continue to improve the station's capability.
Tue, 2 Oct 2007 09:00:00 +1000
As part of a strategic review of ACRES Online MODIS product delivery we are considering providing our map products with a latitude/longitude projection. This will mean a discontinuation of our current ACRES Lambert Conformal Conic projection product - a move which may disadvantage some users of our data. The MODIS Composite Information products, due for release early next year, will also use the new projection parameters.
Additionally, as part of our focus on near real time delivery we would like to make our MODIS pre-processed products available sooner by removing the requirement to have definitive positioning and ancillary atmospheric observations before processing (typically this can take up to 48 hours). Our intention is to provide the MODIS pre-processed products with predicted and forecast ancillary input and the Archive MODIS data (available through the ACRES Catalogue) with definitive and observation ancillary data.
We would like to implement these changes prior to Christmas. If you feel that this change will cause significant inconvenience to your processes we would like to hear from you as soon as possible. Please contact earth.observation@ga.gov.au with your comments.
Tue, 2 Oct 2007 09:00:00 +1000
Wenjun Wu and Lan-Wei Wang represented ACRES at the 12th ALOS data node meeting on 18 - 20 September 2007, Frascati, Italy. Overall, the ALOS satellite bus subsystems and the three sensors are in good health. ALOS has completed its first 1 1/2 years on orbit with successful operations. Around 603,000 PRISM scenes, 269,000 AVNIR-2 scenes and 422,000 PALSAR scenes have been acquired between 16 May 2006 and 22 July 2007. This resulted in a near complete PRISM/AVNIR-2 coverage (cloud < 2%, based on JAXA's cloud assessment algorithm) and a complete PALSAR coverage over Australia.
There were a few product quality issues raised during the meeting. Through bilateral discussion, JAXA has agreed to generate sample reference products over Australia for validation following ALOS Core software updates. This will help to ensure ALOS product consistency between Geoscience Australia and JAXA.
To improve coordination for ALOS disaster monitoring, JAXA has proposed new ALOS emergency request procedures and is currently coordinating with relevant agencies and users in Japan. From October 2007, emergency request for ALOS observation and acquisition can be submitted directly by ACRES to JAXA rather than go through Sentinel-Asia. This change is expected to produce more effective communication, resulting in shorter confirmation time during emergency circumstances.