RCS simulation of the Predator UAV with efield® MLFMM

Dimensions are:

  • Length: 8.45 m
  • Wing span: 15 m
  • Height: 2.1 m
Aircraft model;
Aircraft model


Simulation

RCS results were computed for both monostatic and bistatic RCS.

Bistatic RCS:

  • For frequency f1=1 GHz and f2=3 GHz
  • Plane wave excitation at the front for θ = 90 degrees and φ = 270 degrees
    • Bistatic RCS in the x-y plane for θ = 90 degrees and φ = 180 to 270 degrees
  • Polarizations: VV (θθ) VH (θφ), HH(φφ) and HV(φθ)

Monostatic RCS:

  • For frequency f2=3 GHz
  • Monostatic RCS in the x-y plane for θ = 90 degrees and φ = 270 to 330 degrees with one degree step
  • Polarizations: VV (θθ) VH (θφ), HH(φφ) and HV(φθ)

The problem was solved using the Efield OpenMP parallelized Multi Level Fast Multipole Method (MLFMM) solver. A Combined Field Integral Equation (CFIE) was used to speed up the convergence. The CFIE is given as a linear combination of the EFIE and the MFIE according to

    CFIE = α EFIE + (1- α) MFIE

The simulation was run on 4 processor on an AMD Dual Core Opteron 285 2.6 GHz with 16 Gb memory. In Table 1 and Table 2 model and simulation data is given for the bistatic and monostatic RCS computations using Efield MLFMM solver. In Table 3 for the monostatic RCS computation using Efield PO solver.

In Figure 1 to Figure 4 bistatic RCS results at 1 and 3 GHz obtained with Efield MLFMM are shown. In Figure 5 and Figure 6 monostatic RCS results at 3 GHz obtained with Efield MLFMM and Efield PO are shown.

Table  1:  Model and simulation data for the bistatic RCS computations with efield MLFMM.
Frequency Number of unknowns Number of elements CFIE alpha Number of iterations Memory CPU-time init (hours) CPU-time solve (hours) CPU-time total (hours)
1GHz 321259 214198 0.8 39/42 4.0Gb 0.34 0.08 0.42
1GHz 321259 214198 0.2 17/20 4.0Gb 0.34 0.04 0.38
3GHz 1309379 872970 0.8 175/148 10.0Gb 0.69 2.67 3.36
3GHz 1309379 872970 0.2 22/22 10.0Gb 0.72 0.39 1.11


Table  2:  Model and simulation data for the monostatic RCS computations with efield MLFMM.
Frequency Number of unknowns Number of elements CFIE alpha CPU-time init (hours) CPU-time solve (hours) CPU-time solve per RHS(hours) CPU-time total (hours)
3GHz 1309379 872970 0.2 0.94 34.32 0.28 35.26


Table  3:  Model and simulation data for the monostatic RCS computations with efield PO.
Frequency Number of unknowns Number of elements CPU-time total (hours)
3GHz 1309379 872970 0.3


Bistatic RCS at 1GHz. Polarization φφ
Figure 1: Bistatic RCS at 1GHz. Polarization φφ


Bistatic RCS at 1GHz. Polarization θθ
Figure 2: Bistatic RCS at 1GHz. Polarization θθ


Bistatic RCS at 3GHz. Polarization φφ
Figure 3: Bistatic RCS at 3GHz. Polarization φφ


Bistatic RCS at 3GHz. Polarization θθ
Figure 4: Bistatic RCS at 3GHz. Polarization θθ


Monostatic RCS at 3GHz. Polarization HH
Figure 5: Monostatic RCS at 3GHz. Polarization HH. Comparison of Efield MLFMM, and the Efield PO.


Monostatic RCS at 3GHz. Polarization VV
Figure 6: Monostatic RCS at 3GHz. Polarization VV. Comparison of Efield MLFMM, and the Efield PO.


Surface currents for plane wave excitation with horizontal polarization at 3 GHz
Figure 7:  Surface currents for plane wave excitation with horizontal polarization at 3 GHz.