WorldView-1 Overview - Remote Sensing Satellite Image Tutorial
WorldView-1 Overview

WorldView-1, launched September 2007, is the first of our next-generation satellites—the most agile satellites ever flown commercially. The high-capacity, panchromatic imaging system features half-meter resolution imagery. Operating at an altitude of 496 kilometers, WorldView-1 has an average revisit time of 1.7 days and is capable of collecting over one million square kilometers per day of half-meter imagery. The satellite is also equipped with state-of-the-art geolocation accuracy capabilities and exhibits stunning agility with rapid targeting and efficient in-track stereo collection.

 

Features

Benefits

Very high resolution

  • 50 cm panchromatic at nadir
  • 55 cm GSD at 20° off-nadir

Provides highly detailed imagery for precise map creation, change detection and in-depth image analysis

Industry-leading geolocation accuracy

  • Ultra-stable platform, high-precision attitude sensors and GPS

Allows the creation of accurate maps in remote areas, maximizing the utility of whatever resources are available:

  • Geolocation accuracy specification of 6.5 m CE90 at nadir, with actual accuracy in the range of 4.0 - 5.5 m CE90 at nadir, excluding terrain and off-nadir effects

Highest capacity over a broad range of collection types

  • 17.7 km width imaging swath (wider than any competitor)
  • Bi-directional scanning
  • Rapid retargeting using Control Moment Gyros (>2x faster than any competitor)
  • 2199 gigabits on-board storage
  • 800 Mbps X-band data downlink

Collects, stores and downlinks a greater supply of frequently updated global imagery products than competitive systems

  • DigitalGlobe ImageLibrary filled with unrivaled speed
  • Broadest range of collection sizes, without sacrificing capacity from small points to long strips and large areas
  • Stereoscopic areas on a single pass, ensuring image continuity and consistency of quality

Direct downlink to customer sites available using same high-speed 800 Mbps X-band downlink

Expedites image processing and delivery to customers where speed is a driving factor

World-class telescope

  • High contrast (MTF) and signal to noise ratio
  • Selectable Time Delay Integration (TDI) levels
  • 11-bit dynamic range

Extends the range of suitable imaging collection targets and enhances image interpretability, because images can be acquired at even the lowest light levels

Frequent revisits at high resolution

  • 1.7 days at 1 meter GSD or less
  • 5.4 days at 20° off-nadir or less (55 cm GSD)

Frequent revisits increase image collection opportunities, enhance change detection applications and enable accurate map updates

 

Design and Specifications

Launch Information

Date: September 18, 2007
Launch Vehicle: Delta 7920 (9 strap-ons)
Launch Site: Vandenberg Air Force Base, California

Orbit

Altitude: 496 kilometers
Type: Sun synchronous, 10:30 am descending node
Period: 95 minutes

Mission Life

7.25 years, including all consumables and degradables
(e.g. propellant)

Spacecraft Size, Mass and Power

3.6 meters (12 feet) tall x 2.5 meters (8 feet) across,
7.1 meters (23 feet) across the deployed solar arrays
2500 kilograms (5500 pounds)
3.2 kW solar array, 100 Ahr battery

Sensor Bands

Panchromatic: 400 - 900 nm

Sensor Resolution (GSD = Ground Sample Distance)

50 cm GSD at nadir
55 cm GSD at 20° off-nadir

Dynamic Range

11-bits per pixel

Time Delay Integration (TDI)

6 selectable levels from 8 to 64

Swath Width

17.7 kilometers at nadir

Attitude Determination and Control

3-axis stabilized
Actuators: Control Moment Gyros (CMGs)
Sensors: Star trackers, solid state IRU, GPS

Pointing Accuracy and Knowledge

Accuracy: < 500 meters at image start and stop
Knowledge: Supports geolocation accuracy below

Retargeting Agility

Acceleration: 2.29 deg/s/s
Rate: 4.45 deg/s
Time to Slew: 200 kilometers: 10 seconds

Onboard Storage

2199 gigabits solid state with EDAC

Communications

Image and Ancillary Data: 800 Mbps X-band
Housekeeping: 4, 16 or 32 kbps real-time, 524 kbps stored, X-band
Command: 2 or 64 kbps S-band

Max Viewing Angle / Accessible Ground Swath

Nominally +/-45° off-nadir = 1,035 km wide swath
Higher angles selectively available

Max Contiguous Area
Collected in a Single Pass
(30° off-nadir angle)

Mono: 111 x 112 km (6 strips)
Stereo: 51 x 112 km (3 pairs)

Revisit Frequency
(at 40°N Latitude)

1.7 days at 1 meter GSD or less
5.4 days at 20° off-nadir or less (0.55 meter GSD)

Geolocation Accuracy (CE90)

Specification of 6.5 m CE90 at nadir, with actual accuracy in the range of 4.0 - 5.5 m CE90 at nadir, excluding terrain and off-nadir effects

With registration to GCPs in image : 2.0 meters (6.6 feet)

Source: http://www.digitalglobe.com