aircraft_signature_parameters

Overview

aircraft_signature_parameters … aircraft_signature_parameters
aircraft_signature_parameters
   // Required Commands
   side ...
   // Optional Commands
   fuselage_frontal_area ...
   wing_area ...
   tail_area ...
   engine_inlet_area ...
   engine_exit_area ...
   sweep_angle ...
   signature_reduction_factor_overall ...
   signature_reduction_factor_nose ...
   nose_signature_reduction_angle ...
end_aircraft_signature_parameters

Required Commands

side [red ; blue]

Specifies the side for which the aircraft signature parameters apply. The available options are ‘red’ and ‘blue’.

The side command determines the default signature parameters. These can be overwritten with the Optional Commands.

For example:

# An aircraft of side blue will have the default signature parameters, except for the sweep angle.
aircraft_signature_parameters
   side          blue
   sweep_angle   40 degrees
aircraft_signature_parameters

Optional Commands

The commands in this section are used to determine the expected detection range of the target aircraft (R_d). An effective cross sectional area is computed (A_{eff}), which is used in an empirically-determined equation to obtain the detection range. The equation used is fairly simplistic and is used in the absence of more accurate aircraft signatures. Future releases will include more sophisticated mechanisms to accurately define radar signatures. Each command corresponds to a variable in the equations below. The following table defines the mapping between equation variable names and command names (or a description if no command exists):

command/description

variable

fuselage_frontal_area

A_f

wing_area

A_w

tail_area

A_t

engine_inlet_area

A_i

engine_exit_area

A_e

sweep_angle

\omega

signature_reduction_factor_overall

f_o

signature_reduction_factor_nose

f_n

azimuth angle

\phi

elevation angle

\theta

range constant

k

effective cross sectional area

A_{eff}

expected detection range

R_d

The expected detection range is computed using Equation (1). The range constant k is determined such that a 10 m^2 target produces a detection range of 200 km. This results in a k value of 1.6e20 m^2.

(1)R_d = (k \cdot A_{eff})^{1/4}

The effective radar cross section A_{eff} is defined by the following equation:

(2)A_{eff} = f_o \cdot f_n \cdot [A_f + A_w \sin{\theta} + A_t \sin{\theta} \sin{\phi} + A_i \cos({\max({\theta,\phi})}) + A_e \cos({\max({\theta,\pi - \phi})}) + A_w \cos{\theta} \cos^4({\phi - \omega}) ]

Physical Attributes

fuselage_frontal_area <area-value>

The frontal area of the aircraft fuselage (projection on the y-z plane) to be used when determining the radar cross section. See Equation (2).

Default: 3.0 m^2

wing_area <area-value>

The wing area of the aircraft to be used when determining the radar cross section. See Equation (2).

Default: 30.0 m^2

tail_area <area-value>

The area of the aircraft’s vertical tail to be used when determining the radar cross section. See Equation (2).

Default: 4.0 m^2

engine_inlet_area <area-value>

The inlet area of the aircraft’s engine to be used when determining the radar cross section. See Equation (2).

Default: 2.0 m^2

engine_exit_area <area-value>

The exit area of the aircraft’s engine to be used when determining the radar cross section. See Equation (2).

Default: 2.0 m^2

sweep_angle <angle-value>

The sweep angle of the aircraft’s wing to be used when determining the radar cross section. See Equation (2).

Default: 45 degrees

Signature Reduction Factors

signature_reduction_factor_overall <real>

The overall reduction factor of the signature. See Equation (2).

Default: 1.0

signature_reduction_factor_nose <real>

The reduction factor of the signature due to the aircraft’s nose shape. This factor is only used if nose_signature_reduction_angle is more than the azimuth and more than the elevation. See Equation (2).

Default: 1.0

nose_signature_reduction_angle <angle-value>

The nose angle used to determine signature_reduction_factor_nose. If nose_signature_reduction_angle is more than the azimuth and more than the elevation, then the effective radar cross section will be multiplied by signature_reduction_factor_nose.

Default: 45 degrees