SPACEBORNE SAR: A HISTORY

HISTORY OVERVIEW• SAR was invented in 1951/1952 by Carl A. Wiley.

• Classified research of SAR occurred during the 1950’s and early 1960’s. The first unclassified papers of SAR were published in 1961.

• This first civilian spaceborne SAR was launched in 1978.

SEASAT• Launched June 27, 1978 by NASA and JPL

• Objective: To collect and provide oceanographic data. To provide data for an operational ocean remote sensing system.

• 42 hours of real time data collected.

• Seasat did not have any way to record data on the satellite, so data was transmitted in real time to five ground stations.

• Alaska Satellite Facility has processed the data fully into digital images. Only about 10 percent of the data had been processed digitally.

• Seasat lasted 106 days at which point the satellite was lost due to a power failure.

SEASAT TECHNICAL SPECIFICATIONS

JERS-1/FUYO-1• Japanese (JAXA) satellite launched February 11, 1992.

• Objectives: Generated data sets with SAR and OPS to survey global resources, establishing an integrated Earth observation system, verifying system performances.

• The applications can be used to survey geological phenomena and various topographical monitoring of the Earth.

• JERS-1 has a recording time of up to 20 minutes, the capacity is 72 Gbit, then uses QPSK modulation to transmit at a rate of 60 Mbit/s.

• A malfunction on Oct. 11, 1998 ended the satellites operations. It had stopped being able to record data in August 1997 anyway. The planned lifetime had been 2 years, but it lasted over 6 years.

JERS-1/FUYO-1 TECHNICAL SPECIFICATIONS

ENVISAT/ASAR• Launched March 1, 2002 by the European Space Agency

• Objectives: Studying the Earth. Applicable disciplines are: meteorology, climatology, environment, atmospheric chemistry, ocean and ice process, and more.

• Envisat has one tape recorder of 30 Gbit and two SSR of 60 Gbit. The data rate for most of the modes is up to 100 Mbit/s.

• Loss of contact on April 8, 2012. The mission lasted for 10 years even though only 5 were planned.

ENVISAT/ASAR TECHNICAL SPECIFICATIONS

RADAR ANALYSIS

Satellite Data rate Onboard recording cap.

Seasat Analog None

JERS-1 60 Mbit/s 72 Gbit

Envisat 100 Mbit/s Total: 150 Gbit