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Univ. of Electro. Sci. & Tech. of China

Junjie Wu, Jianyu Yang, et.al.

First Result of Bistatic Forward-looking SAR

with Stationary Transmitter

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ContentsContents

1.Introduction

2.System Setup

3.Experimental result of stationary transmitter BFSAR

4.Current work

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May, 12th, SichuanMay, 12th, Sichuan

Mar, 11th, Tohuku

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Side-looking

Squint-looking

Squint-looking

Backward-looking

Forward-looking1.Introduction

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• Obstruction warning

• Scene matching guidance

• Self-landing

• Self-navigation

• Materials and/or troop dropping

1.Introduction

Forward-looking radar imaging ：

Forward Squint SAR

Forward Squint SAR

Boresight SAR

Boresight SAR

Forward looking radar

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Why can not SAR work in forward-looking mode?

1.Introduction

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SAR imaging conditions ：

• there is enough separation angle----2D resolution• sole intersection----No ambiguity

Iso-range and Iso-Doppler lines —

Monostatic SAR Iso-range and Iso-Doppler lines

Monostatic SAR imaging area ：• Iso-range and Iso-Doppler lines are orthogonal

• Sole intersection

1.Introduction

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Monostatic SAR Iso-range and Iso-Doppler lines

Monostatic SAR forward-looking area ：• Iso-range and Iso-Doppler lines are parallel

• Double intersections

ar

Monostatic SAR ： can not image the forward-looking area

1.Introduction

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What can we do?

Separate the transmitter and receiver

Bistatic

1.Introduction

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Bistatic SAR ：can image the forward-looking area of the receive station

Bistatic SAR Iso-range and Iso-Doppler lines

Bistatic SAR forward-looking area ：• Iso-range and Iso-Doppler lines are not parallel

• Sole intersections

1.Introduction

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• Transmitter Side-looking or Squint

• Receiver forward-looking

BFSAR with two moving platforms

• Spaceborne transmitter——Airborne receiver

• Airborne transmitter——Airborne receiver

• Reconnaissance

• Self-navigation

• Air-drop

TransmitterSide-looking

ReceiverForward-looking

1.Introduction

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FGAN-Germany

Spaceborne transmitter side-looking

Airborne receiver backward-looking

• Spaceborne/airborne bistatic backward-looking experiment (2009.12)

BFSAR1.Introduction

Resolution ： 1-3m Area: 3×5km

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Forward-looking Receiver

Stationary transmitter

1.Introduction Stationary Transmitter (ST) BFSAR

• Transmitter----high tower, mountain, geostationary satellite, stratosphere low speed airship…• Receiver----airborne

• Reconnaissance

• Self-navigation

• Air-drop

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(a) monostatic FSAR (b) ST-BFSAR

1.Introduction Imaging principle of ST-BFSAR

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2.System Setup

Vector Signal Generator

Agilent 8267D

Stationary Transmitter

Wideband signal receiver

target

Vehicle-borne Moving Receiver

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2.System Setup

Bandwidth: 80MHz

PRF: 500Hz

Pulse Width: 20us

Receiver velocity: 7m/s

Carrier Frequency: 9.6GHz

System parameters

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2.System Setup

Downward-looking angle is too small

Target

Upward forward-looking Downward forward-lookingEquivalent

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2.System Setup

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方 位 向 采 样 点0 1000 2000 3000 4000 5000 6000 7000 8000 9000

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方 位 向 频 率 ， 采 样 点

3. Experimental results

Slow time domain Doppler domain

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Imaging result of ST-BFSAR

3. Experimental results

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4.Current Work

A

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B

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2D spatial variance

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4.Current Work

Keystone-based azimuth nonlinear Chirp Scaling imaging algorithm

Keystone transform:

Correct the linear range walk of all targets

----remove the variance of range migration

NLCS:

Equalize the FM rates of all targets

---- remove the variance of azimuth FM rate

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Thank you