Techniques for the Application of Radar in Off- Road Robotics

Transcription

1 Techniques for the Application of Radar in Off- Road Robotics M. Sc. Paul Fritsche Page 1

2 Motivation Why we want to use RADAR in Field Robotics? + - Immune against rain, snow, dust, smog, sunlight Ability to penetrate certain material High range Wide beams, bad angle resolution Bad distance resolution Slow scan speed Optical effects Almost impossible to determine target shape Page 2

3 Motivation Why we want to use RADAR in Field Robotics? Page 3

4 Motivation What can we do with radar? - Detect objects - Object tracking - Mapping - Sensorintegration Page 4

5 1. Range and velocity estimation Page 5

6 1. Range and velocity estimation Ramp-Generator Page 6

7 1. Range and velocity estimation Voltage-Controlled Oscillator (VCO) Page 7

8 1. Range and velocity estimation Amplifier Page 8

9 1. Range and velocity estimation Sending and Receiver Antenna Page 9

10 1. Range and velocity estimation Object RCS (σ) in m 2 Car 10 Garage door 100 Ship 1000 Human 1 Corner reflector 15cm 13 Page 10

11 1. Range and velocity estimation Distance estimation f Page 11 t

12 1. Range and velocity estimation v f Distance and velocity estimation Page 12 t

13 1. Range and velocity estimation Distinguish accuracy and resolution! Θ ΔR= Θ Points inside a resolution cell merge to one object Page 13

14 2. Imaging methods Imaging Methods - Beam focusing and mechanical pivoting - Parabolic reflectors - Group antennas - Luneburg lens - Lenses Quelle: les/2013/05/modern-solution-multiaperture-and-phased-arrayantenna-characterization Quelle: burg-linse Quelle: ml

15 2. Imaging methods - Lateration Distance equations for m sensors and n objects: Page 15

16 2. Materials and Methods - Lateration - Scanner Data association and convert the distance equations to a linear system of equation for every object i: System gets overdetermined if number of sensors m+1 is higher then the dimension of the operating space. 8/7/2015 ICINCO 2015 RTS UNI HANNOVER Page 16

17 2. Materials and Methods - Lateration - Scanner Wrong data association can result in ghost targets. Condition for the appearance: R < d Ant 2 Ghost targets can be resolved by discretizing the observation space into a finite set of possible object positions and calculating a mean square error E for them. j m j 8/7/2015 ICINCO 2015 RTS UNI HANNOVER Page 17

18 2. Materials and Methods - Lateration - Scanner Wrong data association can result in ghost targets. Condition for the appearance: R < d Ant 2 Ghost targets can be resolved by discretizing the observation space into a finite set of possible object positions and calculating a mean square error E for them. j m j 8/7/2015 ICINCO 2015 RTS UNI HANNOVER Page 18

19 Power at receiver Antenna Institute of Systems Engineering - Real Time Systems Group 2. Imaging methods φ ß φ Angle ß Angle ß Sensors are placed close as possible to each other, but facing slightly to different directions with φ. Page 19

20 2. Imaging methods Quelle: A Target Shape Estimation Algorithm for Pulse Radar System Based on Boundary Scattering Transform, Sakamoto, T. and Sato, T.

21 2. Imaging methods IBST: x = X Y dy dx y = Y 1 ( dy dx )2 Quelle: A Target Shape Estimation Algorithm for Pulse Radar System Based on Boundary Scattering Transform, Sakamoto, T. and Sato, T.

22 3. Summary Beam focusing (Applied in scanner setups, suitable for mapping, sensor integration with Laser) Lateration (Suitable for object tracking, sensor integration with camera) ASR (Suitable for tracking and further beam sharpening) IBST (Mapping?) Page 22

23 Thank you for your attention! Page 23