university of brasília laboratory of array signal processing 1 improved landing radio altimeter for...
TRANSCRIPT
University of BrasíliaLaboratory of Array Signal Processing
1
Improved Landing Radio Altimeter for Unmanned Aerial Vehicles based on an Antenna Array
Ronaldo S. Ferreira Júnior, Marco A. M. Marinho, Kefei Liu, João Paulo C. Lustosa da Costa, Arthur V. Amaral , and Hing Cheung So
University of Brasília (UnB)Department of Electrical Engineering (ENE)Laboratory of Array Signal Processing
PO Box 4386Zip Code 70.919-970, Brasília - DF
University of BrasíliaLaboratory of Array Signal Processing
2
Outline
Motivation
Traditional radio altimeter
Antenna array based radio altimeter
Simulation results
Conclusions
University of BrasíliaLaboratory of Array Signal Processing
3
Outline
Motivation
Traditional radio altimeter
Antenna array based radio altimeter
Simulation results
Conclusions
University of BrasíliaLaboratory of Array Signal Processing
4
Motivation (1)
ApplicationsÞ Landing and approaching of Unmanned Aerial VehiclesÞ Detect dangerous obstaclesÞ Manned operations where life can be put in risk
DrawbackÞ Only the main power component reflected component
• Multipath components are not taken into account Antenna array based Radio Altimeter
Þ The multipath components are estimated.Þ The ground can be mapped.
University of BrasíliaLaboratory of Array Signal Processing
5
Motivation (2)
Example with 3 MPCs
Which one is detected?
University of BrasíliaLaboratory of Array Signal Processing
6
Motivation (3)
By detecting only the red component:Þ A crash is prevented.
How to detect all multipath components?Þ By detecting the Direction of Arrival (DoA) and the Time
Delay of Arrival (TDoA) of the MPCs
University of BrasíliaLaboratory of Array Signal Processing
7
Motivation (4)
Solution for Direction of Arrival (DOA) estimation Another candidate solution: Rotating antenna
Þ Advantage• DOA detection according to the antenna position
Þ Drawback:• Heavy weighted, large sized and slow scanning
Proposed solution: Antenna arraysÞ Advantages:
• Compact, power saving and light weightedÞ Drawback:
• Complex software and complex hardware
University of BrasíliaLaboratory of Array Signal Processing
8
Outline
Motivation
Traditional radio altimeter
Antenna array based radio altimeter
Simulation results
Conclusions
University of BrasíliaLaboratory of Array Signal Processing
9
Traditional Radio Altimeter (1)
General informationÞ Frequency Modulated–Continuous Wave (FM-CW) radio
altimeterÞ Uses saw-tooth or triangle wave as the modulating signalÞ Altitude-to-frequency conversion
• the time-delayed wave mixed with the transmitted wave
Þ Not possible to distinguish the MPCs
University of BrasíliaLaboratory of Array Signal Processing
10
Simplified block diagram of a traditional radio altimeter for UAVs
Traditional Radio Altimeter (2)
University of BrasíliaLaboratory of Array Signal Processing
11
Outline
Motivation
Traditional radio altimeter
Antenna array based radio altimeter
Simulation results
Conclusions
University of BrasíliaLaboratory of Array Signal Processing
12
Simplified block diagram of an antenna array based radio altimeter
Antenna Array based Radio Altimeter (1)
University of BrasíliaLaboratory of Array Signal Processing
13
Antenna Array based Radio Altimeter (2)
Candidate solutions for the signal processing block
Þ MUSIC• High-resolution • More computational effort
Þ ESPRIT• Closed-form solution • Worse resolution than MUSIC • Array with shift invariance structure
University of BrasíliaLaboratory of Array Signal Processing
14
Antenna Array based Radio Altimeter (3)
[1]: J. P. C. L. da Costa, A. Thakre, F. Roemer, and M. Haardt, “Comparison of model order selection techniques for high-resolution parameter estimation algorithms”, in. Proc. 54 th International Scientific Colloquium (IWK), Ilmenau, Germany, Sept. 2009.
The model order d can be estimated based on [1].
We consider it as known.
Matrix data model
University of BrasíliaLaboratory of Array Signal Processing
15
Antenna Array based Radio Altimeter (4)
Selection matrices and Þ To estimate the spatial frequencies (ESPRIT)
University of BrasíliaLaboratory of Array Signal Processing
Estimation of Signal Parameters via Rotation Invariance Techniques
ESPRIT
16
The steering matrix A and the first d eigenvectors U of the covariance matrix generate the same subspace
Note that Us is related to the low-rank approximation.
Spatial frequencies
Antenna Array based Radio Altimeter (5)
University of BrasíliaLaboratory of Array Signal Processing
17
Outline
Motivation
Traditional radio altimeter
Antenna array based radio altimeter
Simulation results
Conclusions
University of BrasíliaLaboratory of Array Signal Processing
18
Simulation Results (1)
University of BrasíliaLaboratory of Array Signal Processing
19
Simulation Results (2)
University of BrasíliaLaboratory of Array Signal Processing
20
Simulation Results (3)
University of BrasíliaLaboratory of Array Signal Processing
21
Outline
Motivation
Traditional radio altimeter
Antenna array based radio altimeter
Simulation results
Conclusions
University of BrasíliaLaboratory of Array Signal Processing
22
Conclusions
The antenna array based radio altimeterÞ Ground mapping and imagingÞ Ground inclination and obstacle detectionÞ Electronic receiving lobe sweep Þ Light weight and small sized compared to a mechanical
scanning radar
University of BrasíliaLaboratory of Array Signal Processing
23
Thank you for your attention!
Prof. Dr.-Ing. João Paulo C. Lustosa da Costa
University of Brasília (UnB)Department of Electrical Engineering (ENE)Laboratory of Array Signal Processing
PO Box 4386Zip Code 70.919-970, Brasília – DF
E-mail: [email protected]