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EcoSAR Instrument Technology and Specifications

EcoSAR instrument mounted on the wings of a P3 plane.

System Description

Two polarimetric antenna arrays support single pass InSAR and Pol-InSAR. Beamforming architecture enables one-dimensional (across-track ) scanning.

Digital Arbitrary Waveform Generators determine beam steer and beam shape on transmit over a range of +/- 45 degrees. Digital Beamforming synthesizes customized beams on receipt.



Main Characteristics

Center frequency

435 MHz (69 cm wavelength)

Maximum bandwidth

200 MHz

Operational band

335-535 MHz



Polarization isolation

> 30 dB

Noise equivalent σ°

-41 dB &

Total number of active channels


Interferometric baseline


Pulse length

1 μsec - 50 μsec

Array peak power

40 Watts


100 Hz - 10 KHz

Finest range resolution

0.75 m

Single look azimuth resolution

0.5 m

Vertical accuracy

~ 1m


EcoSAR Architecture 


The Radar Digital Unit (RDU) generates multiple independent waveforms with programmable phase and amplitude. RDU acquires and processes radar returns.

Digital Beamforming is performed on board or off line. Multiple radar channels enable full polarimetry, standard and ping pong InSAR modes, and cross-track scanning over a wide range of angles.


3 IMU systems measure acceleration, angular velocity, and position at the wings and fuselage.
Two wing-mounted antenna arrays form a 25 m Interferometric baseline.


A custom stacked patch design permits polarimetric radar operation with bandwidths up to 200 MHz. Each antenna consists of 10 subarrays enclosed in an aerodynamic fairing.

Antennae are installed under the wings of the P3 aircraft using aircraft pylons.

Antenna Parameters


Stacked Patch

Center Frequency

435 MHz

Max Bandwidth

200 MHz


19 dB




Dual, linear

Cross Polarization Isolation

> 30 dB

Number of Sub Arrays


Total Number of Elements



Radar Electronics Unit (REU)

The Radar Electronics Unit (REU) consists of 32 polarimetric (dual) transmit/receive (T/R) modules which reside inside the aircraft fuselage.

The T/R modules are equipped with 20-Watt solid state power amplifiers (SSPA), low noise amplifiers (LNA), circulators, couplers, filters, and control switches.

Simplified transceiver block diagram.

Radar Digital Unit (RDU) 

The RDU is a multi-channel waveform synthesizer/acquisition and processor system designed around the Xilinx Virtex 6 FPGA. 32 waveform generators directly synthesize P-band signals with up to 200 MHz bandwidth. 32 acquisition channels sample the radar returns directly.

The processor implements onboard digital I&Q demodulation, decimation, filtering. Data is transferred to host computer/raid system via 10 G-bit Ethernet. The RDU is fully programmable through a graphical interface unit on a host computer.

Radar Digital Unit (8 channels shown)


Graphical Interface Unit