Remote Sensing Lab

Image acquired by the VENµS satellite, 2018, over the Zin Valley, Negev Desert, Israel

Scientific Mission

The Scientific Mission of the VENμS Program

Prof. Arnon Karnieli

Agreement Sign

Vegetation and Environmental New Micro Spacecraft (VENμS)

12 April 2005

Venµs System Components

  • Satellite
    • Bus -based on IAI/MBT-SPACE platform
    • Supper-spectral camera –El-Op (CNES responsibility)
    • Hall Effect Thrusters (IHET) -RAFAEL
  • S-Band Station –MBT-SPACE
  • Technological Mission Center -RAFAEL
  • Launch Vehicle -CNES.
  • Ground Receiving Station at KIRUNA -CNES.
  • International Scientific Center -CNES
  • Israeli Scientific Center -BGU

Mission Characteristics

  • Orbit: near polar, sun-synchronic (constant view angle)
  • Altitude: 720 km
  • Inclination: 98.27°
  • Revisit time: two days  
  • Swath: 27.56 km  
  • Spatial resolution: 5.3m  
  • Number of spectral bands: 12 (VIS-NIR)  
  • Tilting capability: +/-30° across and along track  
  • Radiometric resolution: 10 bits
  • Equator crossing time: 10:30 AM, descending mode
  • Mission start/duration: 2018, ³ 4.25 years  

1 Aug. 2017

Objectives of Missions

The VENµS program consists of two missions:

  1. Scientific mission;
  2. Technological mission

The overall aim of the scientific mission is to acquire frequent, high spatial resolution, multi-spectral images of 110 sites all around the world.

  • 12 spectral bands in the visible and near infrared region;
  • 2-days revisit time in a constant view angle;
  • 5.3 m spatial resolution;

Payload

The payload includes:
 
  • a scientific component:
the superspectral camera.
  • a technological component:
                 the Israel Hall Effect truster (IHET).

Band Setting

Band Location

Band Location

Main Applications

Scientific Applications

Land Applications

Land Applications

Main Application - Vegetation Indices

NDVI

Advanced Vegetation Indices

Atmospheric Resistant

Vegetation Index (ARVI):

Enhanced Vegetation Index

(EVI):

Forest Variables

Red Edge and Chlorophyll

Red Edge line shifts to longer wavelengths during plant growth and to shorter wavelengths when the plant is under stress and during senescence;

Red-Edge Bands Setting

Red Edge Position

After Guyot and Baret, 1988

REIP for LAI Assessment

Nitrogen in Wheat and Maize

Chlorophyll Index

Soil Indices

(Karnieli, 1997)

(Ben-Dor et al., 2006)

Water Applications

Water Applications

Coastal and Inland Water Applications

Monitoring chlorophyll that indicates pollution or sediments transport.

Water Spectra

Atmospheric Applications

Water Vapor Bands

Aerosol Optical Thickness (AOT)

Aerosol Optical Depth @550 nm

Monitoring aerosols such as dust, biomass burning smoke, volcanic ash, or anthropogenic air pollution.

Digital Elevation Model (DEM)

Digital Elevation Model

VENµS Camera

Venus DEM

Duplication of 638 nm band, with such an arrangement in the focal plane that the line of sight of the two 638 nm bands differs by an angle of 1.45 degree (Δt = 2.7 sec).

DEM Application

From this small stereoscopic effect it will be possible:

  • to generate elevation, slope, aspect, drainage basin, etc.;
  • to detect clouds by their altitudes.

Revisit Time Advantages

GSD Vs. Off-Nadir Angle

Dynamic Land Cover / VI Monitoring

Land-use & land-cover Classification

Classes are separated by using their spectral and temporal profiles.

Time series of images increases the classification accuracy.

Pollution Dispersion –11 –25, June 2001

Cloud Mask

VenµS combines 2 methods for clouds detection

Multi-temporal analysis of the surface reflectances

Clouds altitude detection by stereoscopy, computation of the location of clouds shadows

Product Levels

Location of International Sites

Strips over Israel

VENµS Strips and Agriculture Areas

Parks, National Reserves, and Forests

LTER Sites

Water Reservoirs

Imaging over Israel

West Strip
Start: 10:30 AM
12 tiles, 36 sec
Forward view
 
Camera standby 35 sec
Satellite maneuvering
 
East Strip
5 tiles, 20 sec
Backward view
 
Camera standby 40 sec
Satellite maneuvering
 
South Strip
10 tiles, 30 sec
Backward view
 
Total: 27 tiles, 161 sec

Summary

Uniqueness of the VENµS system:

  1. Combination of high spatial, spectral, and temporal resolutions;
  2. Technological payload.
  3. High spatial resolution for monitoring individual fields and provide information for precision farming.
  4. Several bands, including along the red edge for assessing the state of vegetation;
  5. Several bands for assessing water quality.
  6. High revisit time to acquire rapid changes of vegetation and water quality, as well as for cloud mask.
  7. Duplication of the red band to produce DEM;

update: 22 May 06