implementation of radar algorithms on an acoustic array
DESCRIPTION
Implementation of Radar Algorithms on an Acoustic Array. Sarah Middleton Supervised by: Anton van Wyk , Jacques Cilliers , Pascale Jardin and Florence Nadal. 3 December 2010. Overview. Introduction to Phased Array Radar versus MIMO Radar. Project Objectives. - PowerPoint PPT PresentationTRANSCRIPT
IMPLEMENTATION OF RADAR
ALGORITHMS ON AN ACOUSTIC
ARRAYSarah Middleton
Supervised by: Anton van Wyk, Jacques Cilliers, Pascale Jardin and Florence Nadal
3 December 2010
OVERVIEW1. Introduction to Phased Array Radar
versus MIMO Radar.2. Project Objectives.3. The Acoustic Array Hardware System.4. Testing Procedures.5. Beampattern Measurements.6. Target Parameter Estimation Results.7. Conclusion.
PHASED ARRAY AND MIMO Phased array
The ith element transmits a base signal multiplied by a complex weight wi.
The signals sum constructively and destructively to form a high powered beam in a desired direction.
MIMO Each element transmits a signal which
is orthogonal to all of the other signals.
This allows an omnidirectional pattern to be transmitted, and increases the degrees of freedom.
0
1
2
L-2
L-1
wavefront
ΔτL-1
ΔτL-2
Δτ2
Δτ1
TRANSMITTER BEAMFORMING ON RECEPTION If a set of orthogonal signals is transmitted, a matched filter bank can be
used to extract the signals from the received signal. Transmitter beamforming can then be applied to the signals, after they
have been received. This also has the effect of increasing the effective array aperture. Also, the radar field of view can be scanned for targets after the
transmission of a single burst.
INCREASED ARRAY APERTURE
PROJECT OBJECTIVES
• Design and build a transmitter array which can be used to demonstrate radar array techniques.
Transmitter Array
• Compare the patterns that can be formed with phased array and MIMO techniques.
Beampattern Design
• Compare the accuracy and resolution of phased array and MIMO target range and angle estimation techniques.
Parameter Estimation
Literature Review -> Simulation -> Hardware Design -> Testing -> Results Analysis
Approach
THE HARDWARE SYSTEM
Receiver ArrayTransmitter Array
Master Control Unit (MCU)Implemented on an FPGA.
PCC application receives Ethernet packets from MCU.
Matlab applications perform signal processing.
TRANSMITTER ARRAY
16 small speakers make up the transmitter array.
The transmitter analogue board consists of: A digital to analogue converter. A low-pass reconstruction filter. A Class AB audio amplifier.
RECEIVER ARRAY
16 small microphones are configured as a ULA.
The receiver analogue electronics consists of: An amplifier board. An second amplifier stage. A low-pass anti-aliasing filter. An analogue to digital converter.
MASTER CONTROL UNIT (MCU)
Finish
Transmit 400 samples on 16 channels.
Receive 800 samples on 16 channels.
Send received signal over Ethernet.
Start
Xilinx Virtex 5 on an ML505 development board.
PC
The PC is responsible for Designing the set of 16 signals which combine to give a
desired pattern. Receiving Ethernet packets from the MCU. Converting the data in the Ethernet Packet into the
voltages that it represents. Calibrate the received signal. Band-pass filtering, demodulating and low-pass
filtering the signals. Applying parameter estimation algorithms to
determine the target locations.
TESTING Testing was performed in an anechoic chamber. The sampling frequency was 40 kHz. The chirp bandwidth or MIMO signal symbol
frequency was 4 kHz. The carrier frequency was 10 kHz. Transmitted signal duration was 10 ms.
PATTERNS WITH ONE MAIN LOBE
The phased array andMIMO patterns are verysimilar, but the power ofthe phased array pattern isapproximately 7 dB higher.
PATTERNS WITH THREE MAIN LOBES
The side lobe levels of the measured signals are higher than the simulated signals.
OMNIDIRECTIONAL PATTERN
Between -60° and 60°, the measured pattern has about 3.5 dB variation making it significantly more omnidirectional than the other patterns.
PARAMETER ESTIMATION WITH ONE TARGET
Phased Array
MIMO
ALGORITHM COMPARISONPhased Array Rank MIMO RankConventional Beamformer + Capon Beamformer +
Capon Beamformer + Amplitude and phase estimation (APES)
-
Music Algorithm + Generalised Likelihood Ratio Test (GLRT)
+
Deterministic Maximum Likelihood (DML)
- Approximate Maximum Likelihood (AML)
?
Transmitter Beamforming on Reception
++
MIMO Transmitter Beampattern Design RankOmnidirectional Pattern -
Maximum Power Design --Pascales Design +Beampattern Matching Design +
PARAMETER ESTIMATIONWITH THREE TARGETS
Phased Array
MIMO
CONCLUSION An acoustic array hardware system has been
successfully built and tested. Beampatterns which transmit power
omnidirectionally, in one direction and in three directions have been generated.
Target parameter estimation shows: A corner reflector target can be detected. MIMO techniques can provide higher angular
resolution estimates.
THANK YOU!
ANY QUESTIONS?