What can we look forward to from WorldView-3

DigitalGlobe is a big player in the provision of satellite imagery, so it’s no surprise that the earth observation community is looking forward to the launch of their new satellite, WorldView-3. The company already operates a constellation of satellites that are widely used in commercial image analysis (QuickBird, WorldView-1 and WorldView-2, http://www.digitalglobe.com/about-us/content-collection#overview). But besides the obvious benefits of more satellites giving greater coverage of the Earth’s surface, what other benefits will WorldView-3 be bringing to the party?

Well first, a bit of background. Like its sister satellites QuickBird and WorldView-2, WorldView-3 (WV-3) is multispectral. This means that it is observing light reflected from the Earth at a number of different frequency bands across the electromagnetic spectrum (unlike WV-1 which only observes one bands of frequencies, i.e. panchromatic). Typically these bands are sited within the red, green and blue portions of the spectrum, with a fourth band within the Near Infra-Red (NIR). The three RGB bands allow us to produce images as the human eye would see, whilst the NIR band is useful for delineating features such as land/sea boundaries or identifying clouds -- basically any feature where we’d expect a sudden change in temperature. This is the approach of QuickBird and many other commercial satellites. 

 

 WorldView-2 takes this approach a little further, by utilising 8 bands in the Visible and NearInfra-Red spectra (VNIR). I’ve listed the bands used by all of these satellites in the accompanying table. We can see that as well as the standard RGBand NIR, WV-2 has some additional bands -- Coastal Blue, Yellow, Red Edge and a second NIR band. Each of these bands is chosen to be sensitive to a particular feature on the surface. For example, the Coastal Blue band is more sensitive to moisture within an image than the traditional Blue band, so it can be used to improve on water depth measurements around harbours. These additional bands really help with image analysis because the additional information allows for more accurate image classification and segmentation which would be carried out with analysis software such as ENVI. 

WorldView-3 takes the advances made with WorldView-2 the next step forward and includes 8 more bands within the Short-Wave Infra-Red (SWIR) region of the spectrum (http://www.satimagingcorp.com/satellite-sensors/WorldView3-DS-WV3-Web.pdf), in addition to the VNIR channels of WorldView-2 (also listed in the table).  This allows WV-3 to observe a much wider range of the electromagnetic spectra than most other commercial satellites, and will allow us to start looking for the individual spectral signatures of materials. The accompanying plot shows the spectral signatures of three minerals. The light blue regions on the plot denote the VNIR bands covered by WV-2and WV-3. The light red regions denote the SWIR bands covered by the 8 new WV-3 bands. This shows just how much further the new bands penetrate into the electromagnetic spectrum. The spectral profiles of each pixel in an image can be compared to a spectral library (such as the reflectance spectras shown) to classify what material is contained within that pixel.

 

This type of automated spectral classification is commonly carried out in ENVI with hyperspectral data (from satellites containing hundreds of spectral bands) which can sometimes be costly to acquire. However, the ability to remotely monitor materials is invaluable to a great number of industries for example in forestry applications where we see users wanting to monitor tree health and pest infestation in remote regions. WorldView-3 brings a limited version of this capability to users at a reduced price, so we still won’t expect the accuracy of a hyperspectral satellite, but it really is a step beyond the features we could extract from multispectral data. So, I’ll stick with Digital Globe’s marketing and refer to it as ‘super-spectral’.

WorldView-3 will be launching in the next few months, so the first data is likely to be available at the beginning of 2015. As a partner of Digital Globe, we’ve been preparing for this. In fact, our parent company developed the SWIR sensor aboardhttp://www.exelisinc.com/news/pressreleases/Pages/Exelis-delivers-first-of-its-kind-commercial-payload-to-DigitalGlobe-for-WorldView-3-satellite.aspx). The data will be able to be loaded into ENVI as soon as it’s available, so I advise you to keep an eye out for further updates because this instrument looks like it will be a great addition.

Author: James Slater / Wednesday, April 02, 2014

Vegetation Analysis Via SkySat-1 Near Infrared Imagery

By Ty Kennedy-Bowdoin, Processing Platform Product Manager


SkySat-1 collects imagery using 5 channels: blue, green, red, near infrared (NIR), and panchromatic. Everyone is familiar with the first three channels because the human eye is sensitive to this range of the electromagnetic spectrum and our brains have evolved to interpret this information intuitively. For this reason, cameras and satellite data are typical viewed in this “true-color” scheme that we see in platforms like Google Maps.

The NIR channel (740 - 900 nm) is designed to capture light in a range just beyond the visible spectrum (390 - 700 nm).  To visualize a “color infrared” image we typically map the NIR channel to red, while assigning the red to the green and the green to the blue channels. This allows us to visualize the near infrared channel as red, so materials that reflect well in this wavelength range appear very red. 

One of the more interesting characteristics of the NIR channel is that lush vegetation reflects very strongly relative to other materials or woody vegetation. Healthy vegetation generates more chlorophyll in the leaves, which reflects well in the NIR, while less healthy leaves are much less reflective. Many interesting metrics depict vegetation health based on ratios of the red to NIR channel. 

One of the most common vegetation health metrics is the Normalized Difference Vegetation Index (NDVI) which works well in consistently vegetated areas. The Modified Soil Adjusted Vegetation Index (MSAVI) takes this metric one step further by correcting for the amount of exposed soil in each pixel in agricultural areas where vegetation is surrounded by exposed soil. 

The example in Figure 1 illustrates a color infrared rendering of some center pivot irrigated fields in Saudi Arabia. Figure 2 illustrates the MSAVI results from this same dataset. I have rendered the colors to depict healthy vegetation with hot colors and less healthy vegetation in cool colors. While we could qualitatively determine that one of the center pivot irrigated fields was well watered and the others appear to be fallow in the color infrared image, we now can quantify this with metrics that can be compared throughout the seasons or years and correlated with the factors measured on the ground like water usage, fertilization, seed varieties, crop yield, etc. 

Mineral deposits rich in Iron Oxide are another common source of reflective NIR values in satellite images. This can be very interesting to geologists searching for assemblages of minerals indicative of higher concentrations of valuable metals.

This is only the beginning of what we can do multispectral imagery! Interested in learning more? Feel free to reach out to me at ty@skybox.com

Figure: MSAVI Results of a Center Pivot Irrigated Field in Saudi Arabia. Captured by SkySat-1 on 12/26/13.

Ball Aerospace satellite readied for launch by DigitalGlobe

WorldView-3 spacecraft to enhance Longmont firm's high-resolution imagery capabilities

By Charlie Brennan, Camera Staff Writer

 

Ball Aerospace & Technologies Corp. has completed assembly of its WorldView-3, the fourth remote-sensing satellite it has built for DigitalGlobe, scheduled to launch this summer from California's Vandenberg Air Force Base.
The WorldView-3 spacecraft is billed by Ball Aerospace as the first multi-payload, super-spectral high resolution commercial satellite for Earth observations and "advanced geospatial solutions."
Ball, in addition to the satellite bus, will provide an atmospheric instrument that it calls CAVIS -— Cloud, Aerosol, Water Vapor, Ice, Snow.
CAVIS, integrated with the spacecraft, will monitor the atmosphere and provide correction data to enhance WorldView-3's imagery when it documents Earth features through dust, haze or other things that might impair visibility.
DigitalGlobe, based in Longmont but moving to Westminster next year, claims to own and operate one of the most agile and sophisticated collections of high-resolution commercial Earth imaging satellites in the world, capable of collecting more than 1 billion square kilometers of high-quality imagery every year.
WorldView-3 is described by Ball Aerospace as building on WorldView-2 and WorldView-1 technology by enhancing the satellite's control moment gyroscopes, which reorient a satellite over a targeted area in 4-to-5 seconds, compared to the 30-to-45 seconds required for traditional reaction wheels.
WorldView-3 utilizes the Ball Configurable Platform BCP 5000 spacecraft, which is designed to handle the next-generation optical and synthetic aperture radar remote sensing payloads, and is currently meeting or exceeding all its performance specifications on the WorldView-2 satellite.
Companies 'have grown up together'
For Jeff Dierks, Ball Aerospace program manager for WorldView-3 and its predecessor, WorldView-2, the next step in its partnership with DigitalGlobe only further cements what has been a rich relationship since the early 1990s.
"We have grown up together with them," said Dierks, noting that there has been cross-pollination in staff between the two companies since not long after DigitalGlobe was founded in 1992 as the WorldView Imaging Corporation.
In 1995, WorldView became EarthWatch Incorporated, merging with the BallAerospace commercial remote sensing operations, becoming DigitalGlobe in 2001.
"What's exciting is watching the business grow over the years," Dierks said. "DigitalGlobe has become quite a successful company, and is a remarkably different company than when they first started both in size and success."
And it has been fruitful as well for Ball Aerospace, which Dierks said was paid "a little over $200 million" for its design and build of the WorldView-3 spacecraft and CAVIS instrumentation.
Kumar Navulur, director of research and development for DigitalGlobe, expressed excitement about the advanced imaging capabilities that WorldView-3 will facilitate.
"There are several advantages with the WorldView-3, compared to our previous satellites," Navulur said. "The first one is the satellite will capture pictures at 1 foot, or 30 centimeters resolution," as opposed to the 50-centimeter resolution afforded by its precursors.
"The only caveat is that today, DigitalGlobe can only sell 50-centimeter to commercial customers. We have asked for a relaxation from the government, but at this point we don't know when we will be able to get it. In the worldwide market, 1-foot images are the sweet spot."
Navulur said WorldView-3 moves DigitalGlobe from multi-spectral imaging (utilizing up to 10 spectral bands) to super-spectral imaging (using 10-20 bands).
And, in addition to recording data in the visible and near-infrared parts of the solar spectrum, Navulur said, WorldView-3 also will be looking into the shortwave infrared spectrum, "where there is a lot more information."
Many uses of imaging data
Navulur cited examples of the data that such imaging will yield, and its applications. For agricultural clients, it will now be possible to look at things such as crop inventory and the moisture content of soil.
Forestry clients will be able to conduct inventories that differentiate not only between coniferous and deciduous trees, but between trees species.
Wildfire managers will be able to detect hotspots, which could have life-saving implications if firefighters can be steered away from lethal pockets.
And miners and geologists will be afforded a much better picture of the presence of mineral deposits, while those in the oil and gas industry will realize a similar benefit, Navulur said.
WordView-3 will be moved to its California launch site about two months before its summer liftoff, and integrated with its Atlas V rocket —- manufactured by United Launch Alliance, another Colorado company — and readied for delivery into its orbit altitude of 617 kilometers.
It should start collecting data about 45 to 90 days after launch, Navulur said.
Contact Camera Staff Writer Charlie Brennan at 303-473-1327, brennanc@dailycamera.com at twitter.com/chasbrennan. 

GRSG Meeting, 9-11 December 2013, Berlin 'Status and developments in geological remote sensing' - First Call for Papers

Dear Members

The Geological Remote Sensing Group (GRSG) are pleased to announce that the 24^th annual meeting of the GRSG will be held in Berlin between 9-11 December 2013.

For further information or visit www.grsg.org.uk

The GRSG is an association of enthusiasts keen on the geological aspects of remote sensing. The current membership includes geologists and remote sensing experts employed within industry, academia and government agencies, as well as graduate students. The GRSG (est.1989) is a Joint Specialist Group of the Remote Sensing and Photogrammetry Society and the Geological Society of London. Although the parent bodies are both based in the UK the GRSG is an international organization with members around the globe. New members are always welcome.

The organising committee for GRSG Berlin 2013 include the UK-GRSG committee and also GRSG members in Germany: Cornelia Glaesser (Martin Luther University Halle-Wittenberg, MLU), Friedrich Kuehn (BGR) and Christian Fischer (DLR).

We look forward to seeing you in Berlin

Best Wishes, the Organising Committee

********************************************
The Remote Sensing and Photogrammetry Society
c/o School of Geography
University of Nottingham
University Park
Nottingham  NG7 2RD
UK

Landsat 8 (LDCM)

Σε αναμονή

Σε αναμονή της έναρξης επιχειρησιακής λειτουργία του συστήματος LDCM ή Landsat8 που αναμένεται τον ερχόμενο Απρίλιο, παραθέτουμε τα βασικά χαρακτηριστικά του νέου μέλους του μακροβιότερου διαστημικού προγράμματος. Από την ημέρα εκτόξευσης (11 Φεβρουαρίου 2013) γίνονται καθημερινά δοκιμές, ρυθμίσεις και προσαρμογές χωρίς να έχει αναφερθεί κάποιο πρόβλημα. Οι πρώτες εικόνες εκτιμάται πως θα είναι διαθέσιμες για το ευρύ κοινό στα μέσα του Μαϊου.

Δορυφόρος 

Το διαστημικό όχημα έχει βάρος 2,071 τόνους, μήκος 3 μέτρα και διάμετρο 2,4μ. Μια πλήρης τροχιά απαιτεί χρόνο 98,9 λεπτών και ολόκληρη η γη καλύπτεται σε 16 ημέρες από ύψος 705 χιλιομέτρων. Αναμένεται να συλλέξει δεδομένα όγκου 400 Terrabytes σε διάστημα 5 ετών.

Καταγραφείς 

Ο φορέας είναι εξοπλισμένος με δύο όργανα το Operational Land Imager (OLI) που καταγράφει την αντανάκλαση του ορατού και εγγύς υπέρυθρου (επιπλέον θα υπάρχει και παγχρωματική καταγραφή στα 500-680nm) και το Thermal Infrared Sensor (TIRS) που θα ανιχνεύει τη θερμική ακτινοβολία σε μήκη κύματος 10300-12500nm. 

Φασματικά Χαρακτηριστικά OLI 

Φασματικά Χαρακτηριστικά TIRS

Συνολικά ο Landsat8 θα συλλέγει πληροφορία σε 11 κανάλια:

Κανάλι	Μήκος Κύματος (micrometers)	Ανάλυση (meters)
Band 1 - Coastal aerosol	0.43 - 0.45	30
Band 2 - Blue	0.45 - 0.51	30
Band 3 - Green	0.53 - 0.59	30
Band 4 - Red	0.64 - 0.67	30
Band 5 - Near Infrared (NIR)	0.85 - 0.88	30
Band 6 - SWIR 1	1.57 - 1.65	30
Band 7 - SWIR 2	2.11 - 2.29	30
Band 8 - Panchromatic	0.50 - 0.68	15
Band 9 - Cirrus	1.36 - 1.38	30
Band 10 - Thermal Infrared (TIRS) 1	10.60 - 11.19	100
Band 11 - Thermal Infrared (TIRS) 2	11.50 - 12.51	100

Συλλογή - Μετάδοση – Διανομή Δεδομένων

Κάθε σκηνή  θα καλύπτει μια επιφάνεια  170 Χ 185 χιλιομέτρων με ανάλυση 30 μέτρων για το όργανο OLI (το παγρωματικό στα 15μ) και 100 μέτρων για τα δύο θερμικά κανάλια του TIRS. Η μετάδοση των δεδομένων θα γίνεται μέσω των επίγειων σταθμών λήψης GNE προς σταθμούς DPAS όπου οι εικόνες θα ελέγχονται για θόρυβο και κορεσμό, θα συμπληρώνονται τα απορριπτέα δεδομένα και θα αποκτούν τα αναγκαία μεταδεδομένα προτού αρχειοθετηθούν. 

Σε αυτή τη φάση θα διατηρούνται σε μορφή HDF5 (ένα αρχείο για κάθε όργανο) με το διακριτικό Level 0 ( L0 ή L0Ra) και σε ραδιομετρική ανάλυση 12bit.

Στη συνέχεια τα δεδομένα θα αναφέρονται στο σύστημα διανομής σκηνών WRS-2 χωρίς επιπλέον επεξεργασία. Θα ακολουθεί η επεξεργασία από το σύστημα LPGS όπου θα γίνεται η ραδιομετρική και η γεωμετρική διόρθωση. Η ραδιομετρική διόρθωση των δεδομένων θα μετασχηματίζει πηγαία δεδομένα σε καθαρούς αριθμούς (digital counts) ενώ η γεωμετρική διόρθωση θα γίνεται με τη χρήση ψηφιακού υψομετρικού μοντέλου και επίγειων σημείων ελέγχου ώστε να προκύψουν ορθοδιορθωμένες εικόνες που θα αναφέρονται στο σύστημα UTM. Τα δεδομένα θα διακρίνονται γενικά ως LDCM Level 1 και ειδικότερα:

• Level 1 Radiometric (L1R): Ραδιομετρικά διορθωμένα δεδομένα L0
• Level 1 Systematic (L1G): Δεδομένα L1R με συστηματική γεωμετρική διόρθωση
• Level 1Gt (L1Gt): Δεδομένα L1R ορθοδιορθωμένα με συνυπολογισμό του   ανάγλυφου  και χρήση επίγειων σημείων ελέγχου (διόρθωση παράλλαξης).
• Level 1 Terrain (L1T): Δεδομένα L1R

Οι εικόνες θα διανέμονται στους τελικούς χρήστες με ανάλυση 16bit σε μορφή GeoTIIFF (ένα αρχείο για κάθε κανάλι). Η διάθεση των εικόνων θα είναι ελεύθερη μέσω του Earth Explorer, του GLOVIS και άλλων διαδικτυακών τόπων. Περισσότερες πληροφορίες για τη μορφή των εικόνων Level 1 μπορείτε να δείτε στο εγχειρίδιο LEVEL 1 DATA FORMAT CONTROL BOOK.

Διάρκεια Ζωής 

Το σύστημα έχει σχεδιασθεί για να λειτουργήσει τουλάχιστο 5 χρόνια, ενώ ήδη από τη διαδικασία εκτόξευσης εξοικονομήθηκαν καύσιμα που θεωρητικά επεκτείνουν το ελάχιστο χρόνο λειτουργίας του δορυφόρου κατά δύο επιπλέον χρόνια.

Landsat 8 - LDCM

Landsat Data Continuity Mission (LDCM) – Landsat 8

Projected Launch: February 11, 2013

The Landsat era that began in 1972 will continue with the successful launch of the Landsat Data Continuity Mission (LDCM) in February 2013. Global, synoptic, and repetitive coverage of the Earth’s land surfaces will continue at a scale where natural and human-induced changes can be detected, differentiated, characterized and monitored over time.

Details about the spacecraft, launch vehicle and logistics, sensors on board, ground system specifics, and orbit details are listed onhttp://landsat.usgs.gov/about_ldcm.php and http://ldcm.nasa.gov/spacecraft_instruments.html.

Additional pictures, updates and media resources about the LDCM can be found at http://www.nasa.gov/mission_pages/landsat/main/index.html.

Timeframe from Launch to Data Availability

After a successful launch, a commissioning time of approximately 90 days will allow the spacecraft to perform orbit maneuvers, systems initialization and calibration to occur, and move into the WRS-2 collection grid. After final observatory checkout, nominal data products will become available to all users.

 

Landsat 8 Sensors and Data Products

LDCM will carry two push broom sensors: Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS). The band names, wavelengths and resolution for each sensor are listed on http://landsat.usgs.gov/band_designations_landsat_satellites.php.

The data products available from the Landsat 8 mission will be consistent with the already-processed and archived Landsat 1 through 7 data products:http://landsat.usgs.gov/LDCM_DataProduct.php. The additional bands will create a larger data file size, at approximately 1 GB with compression. Sample data products are also available on this page.

All upcoming news will be posted to the Landsat Mission Headlines on the Landsat webpage.

Goodbye Envisat ... and thank you

Just weeks after celebrating its tenth year in orbit, communication with the
Envisat satellite was suddenly lost on 8 April.  A team of engineers has spent
the last month attempting to regain control of Envisat, investigating possible
reasons for the problem. Despite continuous commands sent from a widespread
network of ground stations, there has been no reaction yet from the satellite.

The team has been collecting other information to help understand the
satellite's condition. These include images from ground radar and the
French Pleiades satellite. With this information, the team has gradually
elaborated possible failure scenarios. One is the loss of the power regulator,
blocking irreversibly telemetry and telecommands. Another scenario is a short
circuit, triggering a 'safe mode' - a special mode ensuring
Envisat's survival. A subsequent anomaly may have occurred during the
transition to safe mode, leaving the satellite in an intermediate and unknown
condition. The investigation team's assessment is that the chances of
recovering Envisat are extremely low.

Therefore the end of the Envisat satellite operations is being declared. The
investigation team will nevertheless continue attempts to re-establish contact
while considering failure scenarios for the next two months.

The outstanding performance of Envisat over the last decade led many to
believe that it would be active for years to come, at least until the launch
of the follow-on Sentinel missions. However, Envisat had already operated for
double its planned lifetime, making it well overdue for retirement. 

With ten sophisticated sensors, Envisat has observed and monitored Earth's
land, atmosphere, oceans and ice caps during its ten-year lifetime, delivering
over a thousand terabytes of data. An estimated 2500 scientific publications
so far have been based on this information, furthering our knowledge of the
planet. Envisat provided crucial Earth observation data not only to
scientists, but also to many environmental services, such as monitoring floods
and oil spills.

Now with the end of Envisat's mission, the launch of the upcoming GMES
Sentinel satellites has become even more urgent to ensure the continuity of
data to users, improve the management of the environment, understand and
mitigate the effects of climate change and ensure civil security.

See also Press Release on the ESA Portal at
http://www.esa.int/esaCP/SEM1SXSWT1H_index_0.html
 

OrbView3, free high resolution satellite images

OrbView3
U.S. Geological Survey (USGS) distributes for free long a very large volume of earth observation data through Earth Explorer, including multispectral and hyperspectral images of medium resolution (10-30m) such as Landasat, Hyperion, Ali and DTMs for the entire the world and for a period covering the last 40 years! Many of these images are available in raw data format and are suitable for complete reomte sensing processing and analysis.


Recently earthexplorer  enriched its content with high spatial  resolution images captured from OrbView3 sensor. The system was set in orbit in 2003 from  ORBIMAGE (now GeoEye) and was able to record multispectral (visible and near infrared) and panchromatic images with spatial resolution of 1m and 4 respectively. In April 2007 GeoEye announced the end of the  system, retaining vehicle’s control until March 2011 when the satellite crashed in the Pacific Ocean in a controlled manner.

Panchromatic image

Data where accessed with ENVI Software. A brief description follows:
Band : Panchromatic
Spatial resolution: 1m
Projection: Geographic
Metadata: RPCs


Users should read license file.