Satellite WorldView-4 : imaging and data – highest-resolution 30 cm

0
2452

Lockheed Martin has successfully launched today the WorldView-4 commercial remote sensing spacecraft for DigitalGlobe, Inc. An Atlas V 401 blasted off at 10:30 a.m. Pacific Standard Time from Space Launch Complex 3 East, placing the satellite in orbit for customer DigitalGlobe and marking the 137th consecutive successful Atlas launch to date.

The WorldView-4 satellite is the latest in a series of imaging and data satellites for customers around the world.

The satellite will capture images so clear that they can distinguish between a sedan, van, and truck from nearly 400 miles in space. DigitalGlobe currently has five satellites in orbit – four Worldview series spacecraft and a single GeoEye satellite.

By leveraging DigitalGlobe’s advanced constellation scheduling system to operate in concert with WorldView-3 , WorldView-4 will more than double DigitalGlobe’s coverage of the world’s highest-resolution 30 cm commercial satellite imagery and increase the rate at which it grows its 16-year library of time-lapse high-resolution imagery.

WorldView-4 orbits Earth every 90 minutes, traveling 17,000 miles per hour and capturing as much as 680,000 square kilometers of the Earth’s surface daily (18 terabytes).

DigitalGlobe, Inc., provides satellite imagery services to the US government and defense services as well as foreign government and commercial customers.

The company’s largest customer is the U.S. National Geospatial-Intelligence Agency (NGA) which has recently renewed the Global Enhanced GEOINT Delivery (Global EGD) program under the EnhancedView contract through 2022.

Under this contract DigitalGlobe provides on-demand access to global high-resolution commercial satellite imagery. Users can access mission-ready satellite imagery in multiple classification levels via web browser or mobile device, typically within two to four hours after downlink.

Hundreds of thousands of U.S. Government users leverage Global EGD imagery, whether directly or through U.S. Government mobile devices and web portals.

The imagery service provides essential mission planning data to warfighters, the intelligence community, and other U.S. Government users.

New capabilities to be added to the service include the addition of shortwave infrared imagery (SWIR) and 8-band multi-spectral imagery, e-mail alerts of new collections over a user’s area of interest, and improved archive ordering.

Other products designed for the civilian market include the Basemap Suite that features 1.5 billion square kilometers of high-accuracy, high-resolution imagery – 10 times the land surface area of the Earth.

In particular, Basemap +Metro covers over 500 population centers in at 30 cm resolution and 1,700 cities available at 50 cm or better resolution.

The company also offers a free imagery servcie online, under the SpaceNet program, an online repository of satellite imagery and labeled training data that will advance the development of machine learning and deep learning algorithms that leverage remote sensing data. SpaceNet is a collaboration between DigitalGlobe, CosmiQ Works, and NVIDIA, and the imagery is now freely available as a public data set on Amazon Web Services, Inc. Spacenet aims to automatically detect and extract features in satellite imagery, fueled by the massive amount of information about our changing planet that DigitalGlobe collects every day, and that of emerging commercial satellite imagery providers.

The WorldView constellation enabled the company to expand its services abroad and the expectation from the WorldView-4 are high.

In April and July DigitalGlobe received requests from several foreign governments for satellite capacity commitments from international defense and intelligence customers, seeking high-resolution imagery products from WorldView-4.

The company already serves 12 such customers with Direct Access Program customers.

Today’s mission was launched by the United Launch Alliance (ULA) aboard an Atlas V 401 configuration vehicle, which includes a 4-meter-diameter large payload fairing.

The Atlas booster for this mission was powered by the RD AMROSS RD-180 engine and the Centaur upper stage was powered by the Aerojet Rocketdyne RL10C engine.

Built by Lockheed Martin, DigitalGlobe’s WorldView-4 satellite is enclosed in the four-meter fairing that will then be placed atop an Atlas V 401 rocket. Photo courtesy of Lockheed Martin and United Launch Alliance. Photo: Lockheed Martin
Built by Lockheed Martin, DigitalGlobe’s WorldView-4 satellite is enclosed in the four-meter fairing that will then be placed atop an Atlas V 401 rocket. Photo courtesy of Lockheed Martin and United Launch Alliance. Photo: Lockheed Martin
 – – – – – – –

WorldView-4 will offer exceptional geolocation accuracy, which means that customers will be able to map natural and man-made features to better than <4 meter CE90 of their actual location on the Earth’s surface without ground control points.

WorldView-4 will be flying at an altitude of 617 km (383 miles) and will be able to “revisit” any point on the globe every 4.5 days or sooner, depending upon the required look angle.

The altitude could be revised before launch to utilize the recently obtained permission to acquire and deliver 0.25m resolution Imagary.

WorldView-4 customers will have a choice of ordering BASIC (satellite projection), Geo (geometrically corrected), GeoProfessional (terrain corrected or ortho-rectified), or GeoStereo (stereo pair) products, as well as imagery-derived products, including Digital Elevation Models (DEMs), Digital Surface Models (DSMs), large-area mosaics and feature maps.

Resolution restrictions have been relaxed

During June 2014 DigitalGlobe received permission from the US Department of Commerce to collect and sell imagery at the best available resolutions.

Additionally, six months after WorldView-3 is operational DigitalGlobe will be permitted to sell imagery at up to 25 cm panchromatic and 1.0 m multispectral GSD.

We applaud the US Government’s relaxation of satellite resolution restrictions, as it benefits our customers, and the industry in general.

WorldView-4 Satellite Sensor Specifications

Orbit Altitude: 617 km
Type: SunSync, 10:30 am descending Node
Period: 97 min.
Life Estimated Service Life: 10 to 12 years
Spacecraft Size
and Aperture
Size: 5.3 m (17.7 ft) tall x 2.5 m (8 ft) across
7.9 m (26 ft) across deployed solar arrays
Aperture: 1.1m
Sensor Bands Panchromatic: 450 – 800 nm
4 Multispectral:
Red:655 – 690 nm
Green:510 – 580 nm
Blue:450 – 510 nm
Near-IR:780 – 920 nm
Sensor Resolution
(GSD, Ground Sample
Distance, geometric mean)
Panchromatic Nadir:0.31 m
20° Off-Nadir:0.34 m
56° Off-Nadir:1.00 m
65° (earth limb):3.51 m
Multispectral Nadir:1.24 m
20° Off-Nadir:1.38 m
56° Off-Nadir:4.00 m
65° (earth limb):14.00 m
Dynamic Range 11-bits per pixel
Swath Width At nadir: 13.1 km
Attitude Determination
and Control
Type: 3-axis Stabilized
Actuators: Control Moment Gyros (CMGs)
Sensors: Star trackers, precision IRU, GPS
Retargeting Agility Time to Slew 200 km: 10.6 sec
Onboard Storage 3200 Gb solid state with EDAC
Communications Image & Ancillary Data: 800 Mbps X-band
Housekeeping: 120 kbps real time, X-band
Command: 64 kbps S-band
Max Contiguous Area
Collected in a Single Pass
(30° off-nadir angle)
Mono: 66.5 km x 112 km (5 strips)
Stereo: 26.6 km x 112 km (2 pairs)
Revisit Frequency
(at 40°N Latitude)
1 m GSD: < 1.0 day
Total constellation >4.5 accesses/day
Geolocation Accuracy (CE90) Predicted <4 m CE90 without ground control
Capacity 680,000 km² per day

LEAVE A REPLY

Please enter your comment!
Please enter your name here

Questo sito usa Akismet per ridurre lo spam. Scopri come i tuoi dati vengono elaborati.