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Orientation-average scattering from a stored TMM object

Source: R/tmm-orientation.R
tmm_average_orientation.Rd

Reuses the stored TMM blocks to average the differential scattering cross section over a user-supplied set of incident orientations. By default the receive direction is taken to be the exact monostatic direction for each supplied orientation.

Usage

tmm_average_orientation(
  object,
  theta_body = NULL,
  weights = NULL,
  phi_body = pi,
  theta_scatter = NULL,
  phi_scatter = NULL,
  distribution = NULL
)

Arguments

object

Scatterer-object previously evaluated with target_strength(..., model = "TMM", store_t_matrix = TRUE).

theta_body

Numeric vector of incident polar angles (radians).

weights

Optional numeric vector of averaging weights. When omitted, equal weights are used.

phi_body

Incident azimuth angle(s) (radians). Either scalar or the same length as theta_body. Defaults to pi.

theta_scatter

Receive polar angle(s) (radians). Either scalar or the same length as theta_body. Defaults to the monostatic direction.

phi_scatter

Receive azimuth angle(s) (radians). Either scalar or the same length as theta_body. Defaults to the monostatic direction.

distribution

Optional orientation distribution created by tmm_orientation_distribution. When supplied, it overrides the direct theta_body, weights, and phi_body inputs.

Value

A data frame containing the frequency, the orientation-averaged differential backscattering cross section and the corresponding orientation-averaged target strength.

See also

tmm_scattering

Examples

target <- fls_generate(
  shape = sphere(radius_body = 0.005, n_segments = 20),
  g_body = 1,
  h_body = 1
)
stored <- target_strength(
  target,
  frequency = 12e3,
  model = "tmm",
  boundary = "pressure_release",
  store_t_matrix = TRUE
)
distribution <- tmm_orientation_distribution(n_theta = 5)
tmm_average_orientation(stored, distribution = distribution)
#>   frequency     sigma_bs        TS
#> 1     12000 2.157667e-05 -46.66015