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
HH, VV, VH, HV
Polarization isolation
> 30 dB
Noise equivalent σ°
-41 dB &
Total number of active channels
32
Interferometric baseline
25m
Pulse length
1 μsec - 50 μsec
Array peak power
40 Watts
PRF
100 Hz - 10 KHz
Finest range resolution
0.75 m
Single look azimuth resolution
0.5 m
Vertical accuracy
~ 1m
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.
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
Type
Stacked Patch
Center Frequency
435 MHz
Max Bandwidth
Gain
19 dB
Area
3m2
Dual, linear
Cross Polarization Isolation
Number of Sub Arrays
10
Total Number of Elements
20
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.
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.
