Sensor Plot Flight Path Analysis

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flight_path_analysis … end_flight_path_analysis

flight_path_analysis

   Stub Definition Commands

   # Sensor Control

   reverse_evaluations ...
   sensor_platform_yaw ...
   sensor_platform_pitch ...
   sensor_platform_roll ...
   mode_name ...
   exclude ...
   no_exclude ...
   automatic_target_cueing ...

   # Jammer Control

   jamming_platform_name ...
   jammer_to_signal_reference ...

   # Target Platform Selection

   target_platform_name ...

   # Sample Point Specification

   path ...
   alarm_fpa_file ...
   tspi_file ...
   sample_interval ...

   # Output Selection

   variable ...
   script_variable ...
   detection_reference ...

   gnuplot_file ...
   header_line_1 ...
   header_line_2 ...
   header_line_3 ...

end_flight_path_analysis

Overview

The flight_path_analysis function will create a file that contains the values of user-requested variables at sample points that have been provided by:

• A list within the command.

• A standard TSPI file.

• An ALARM Flight Path Analysis (FPA) file.

• A platform with a route, and a specified sample interval.

To create a file for active detection systems (e.g.: radar) detecting a target following a specified path, the following process should be followed:

• Define the target platform with the desired characteristics with the desired radar, infrared, :command`optical <optical_signature>` or acoustic signature depending on the type(s) of sensors being tested. The name of the target platform must have the name defined by the target_platform_name command (default: TARGET).

• Define one or more platform instances that contain the sensors that will attempt to detect the target.

• Define zero or more platform instances that contain jammers that will attempt to jam the sensors.

• Define the sensor_plot_flight_path_analysis input block with:

  • Commands to select the sensors to be included, and other sensor behavior.

  • Commands to define the sample points.

  • Output selection commands.

For analysis of sensors contained on the ‘target’ platform, see the reverse_evaluations command.

Note

This function maintains the concept of simulation time. The first detection chance will occur at 1 second and subsequent chances will occur at the interval specified by sample_interval. Any ‘execute at_time’ blocks used to cue jammers or sensors should specify a time before 1 second. If a route and sample_interval are used to generate the sample points, it may be desirable to specify ‘start_time 1 sec’ on the route of the target platform so the first detection chance occurs exactly at the first point of the route.

Sensor Control

reverse_evaluations <boolean-value>

Normally the flight_path_analysis function creates the output file using the results of detection attempts against the platform defined by target_platform_name performed by all the sensors on the other defined platforms (subject to the exclude and no_exclude commands). If the value of this command is ‘true’, the output file is created using the results of the sensors on target_platform_name against all other platforms in the scenario. This is primarily used for evaluating passive systems (e.g.: ESM, EO, IR)

Several items of interest need to be noted:

• The sensor selection, mode selection and sensor orientation defined in this section (i.e.: Sensor Control are ignored. The sensor definition(s) on the platform defined by target_platform_name represent the sensors to be evaluated.

• ALL other platforms and the sensors contained on them will be the object of the detection attempts. There are no exclusions.

• This function has not been tested where the object of a detection attempt is a tracking sensor or a comm system. These systems should probably be replaced by a simple non-tracking radar system with the same RF parameters.

Default false

sensor_platform_yaw <angle-value>

sensor_platform_pitch <angle-value>

sensor_platform_roll <angle-value>

Specify the orientation of the sensing platform with respect to the direction of flight. The yaw angle is added to the heading and the pitch and roll angles are used directly as specified. This is useful for examining sensor coverage when the platform is flying in some other condition other than straight-and-level. Default 0 degrees for all angles

mode_name <mode_name>

Specifies the name of the mode to be used if the sensor is a multi-mode sensor.

Default The default mode of the sensor. This will be the value of the initial_mode command of the sensor (if defined) or the first mode (if initial_mode was not defined).

Note

This is valid only for single-sensor executions. For multiple-sensor executions, the default mode as defined above will be used.

exclude [ sensor_type | sensor_category | platform_type | platform_category ] <type-or-category>

no_exclude [ sensor_type | sensor_category | platform_type | platform_category ] <type-or-category>

These commands provide the mechanism to choose which sensors in a multiple-sensor scenario are to be included in the plotting process. This is useful when a existing scenario is being used but only a subset of sensors are to be used for the plot.

By default, all sensors in the scenario are included in the plot. A sensor will be excluded if specified in an exclude command and not specified in a no_exclude command. The no_exclude command is typically used to prevent the exclusion of a smaller group of sensors from a larger list that have been excluded.

automatic_target_cueing <boolean-value>

If ‘true’, the sensor will be cued to point at the target when performing a detection chance. If ‘false’, the sensor will be remain in its initial condition.

Default true (The sensor will always be cued to point at the target)

Jammer Control

jamming_platform_name <platform-name>

Specifies the platform that will be used to calculate the required jamming power. This input is to be used when plotting the ‘required_jamming_power’ variable for the location of the jammer system.

Default TARGET_PLATFORM_TYPE

jammer_to_signal_reference <db-ratio-value>

Specifies the jammer-to-signal (J/S) reference to be used when plotting the ‘required_jamming_power’ variable.

Default 0.0 db

Target Platform Selection

target_platform_name <platform-name>

Specify the name of the target platform.

Default TARGET

Sample Point Specification

The sample points can be selected by any of the following methods or by specifying a route in the target platform and specifying the ‘sample_interval’ command. If any of the commands that define points explicitly are used, the route in the target platform is ignored.

path <path-points> end_path

Define the sample points in standard waypoint format. The points are defined using the following commands

• position <latitude-value> <longitude-value>

• altitude <length-value> [ msl | agl ]

• speed <speed-value>

• heading <angle-value>

• pitch <angle-value>

• roll <angle-value>

A new point is started with each position command. Commands up to the next position command (or the end of the block) apply to the current position. Unspecified values default to the values from the previous point.

alarm_fpa_file <file-name>

Specify the name of an ALARM flight path analysis file that contains target sample points.

tspi_file <file-name>

Specify the name of a time-space-position-information (TSPI) file that contains the target sample points.

Note

You may require the use of commands to specify the format of the data contained in the TSPI file. These commands are documented in the WSF_TSPI_MOVER section of WSF_TSPI_MOVER

sample_interval <time-value>

The time interval to be used for generating sample points when using a route on the target platform.

Output Selection

variable <variable-name>

<variable-name>	Description	Notes
pd	The probability of detection.	If multiple sensors are provided, the result will be the maximum probability of detection by any sensor.
detection_threshold	The detection threshold in dB.	If multiple sensors are provided, the result will be the minimum detection threshold by any sensor. For WSF_ESM_SENSOR types the detection threshold is only valid when a successful interaction happens between the transmitter and receiver.
required_rcs**or **rcs_required	The radar cross section required for the sensor to detect the target in dBsm.	If multiple sensors are provided the result will be the minimum value determined for any sensor. Selecting this may also require the specification of detection_reference
required_jamming_power or jamming_power_required or required_jammer_power or jammer_power_required	The jamming power required to overcome the target signal by in dBsm.	If multiple sensors are provided the result will be the maximum value determined for any sensor. Selecting this may also require the specification of jammer_to_signal_reference.
radar_signature	The radar signature of the target presented to the sensor in dBsm.	If multiple sensors are provided, the result will be the maximum value presented to any sensor.
optical_signature	The optical signature of the target presented to the sensor in dB.	If multiple sensors are provided, the result will be the maximum value presented to any sensor.
infrared_signature	The infrared signal of the target presented to the sensor in w/sr.	If multiple sensors are provided, the result will be the maximum value presented to any sensor.
signal_power	The received signal power in dBW.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
clutter_power	The received clutter power in dBW.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
noise_power	The receiver noise power in dBW.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
jammer_power	The received jammer power, to include noise and pulsed-noise, in dBW.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
noise_jammer_power	The received noise only jammer power in dBW.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
pulse_jammer_power	The received non-coherent pulse (pulsed noise) jammer power in dBW.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
coherent_jammer_power	The received coherent (coherent pulse and false-target) jammer power in dBW.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
jammer_to_mds	The jammer (noise and pulsed noise) to minimum detectable signal (detection_threshold + noise_power) in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
jammer_to_signal	The jammer (noise and pulsed noise) to signal ratio in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
noise_jammer_to_signal	The jammer (noise power only) to signal ratio in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
pulse_jammer_to_signal	The jammer (pulsed noise power only) to signal ratio in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
coherent_jammer_to_signal	The jammer (coherent jammer power only) to signal ratio in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
coherent_jammer_to_noise	The jammer (coherent jammer power only) to receiver noise power in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
signal_to_noise	The signal to noise ratio in dB. Only the receiver thermal noise is accounted for.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
signal_to_interference	The signal to interference ratio in dB.	Includes the interference power due to receiver thermal noise, clutter, and jamming (if present). If multiple sensors are provided, the result will be the maximum value seen to any sensor.
signal_at_target	The signal power density present at the target in dBW/m^2.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
background_radiant_intensity	The background radiant intensity as seen by the sensor.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
contrast_radiant_intensity	The contrast radiant intensity as seen by the sensor.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
attenuation_factor	The atmospheric attenuation factor of the signal as seen by the sensor in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
propagation_factor	The propagation factor of the signal as seen by the sensor in dB.	If multiple sensors are provided, the result will be the maximum value seen to any sensor.
transmit_antenna_gain	The transmit antenna gain in dB.	If multiple sensors are provided, the result will be the maximum value for any sensor.
receive_antenna_gain	The receive antenna gain in dB.	If multiple sensors are provided, the result will be the maximum value for any sensor.
transmit_gain_propagation_factor	The transmit antenna gain multiplied by the one-way propagation factor, in dB.	If multiple sensors are provided, the result will be the maximum value for any sensor. This variable is only valid for monostatic radars.
receive_gain_propagation_factor	The receive antenna gain multiplied by the one-way propagation factor, in dB.	If multiple sensors are provided, the result will be the maximum value for any sensor. This variable is only valid for monostatic radars.
slant_range	The slant range from the sensor to the target in meters.	If multiple sensors are provided, the result will be maximum the value seen to any sensor.
ground_range	The ground range from the sensor to the target in meters.	If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
azimuth_angle	The azimuth angle from the sensor to the target in degrees.	If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
elevation_angle	The elevation angle from the sensor to the target in degrees.	If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
angle	The angle between the sensor boresight and the beam center.	This is typically used to deterimine the beam steering angle for electronically scanned sensor. If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
grazing_angle	The angle between the sensor antenna location (NOT boresight) to the target in degrees.	If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
target_to_sensor_slant_range	The slant range from the target to the sensor in meters.	If multiple sensors are provided, the result will be maximum the value seen to any sensor.
target_to_sensor_ground_range	The ground range from the target to the sensor in meters.	If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
target_to_sensor_azimuth_angle	The azimuth angle from the target to the sensor in degrees.	If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
target_to_sensor_elevation_angle	The elevation angle from the target to the sensor in degrees.	If multiple sensors are provided, the result will be the value seen by the last sensor processed, since this variable is only applicable to single-sensor plots.
sensor_latitude	The latitude of the sensor platform in decimal degrees.
sensor_longitude	The longitude of the sensor platform in decimal degrees.
sensor_altitude	The altitude of the sensor platform in meters.
sensor_speed	The speed of the sensor platform in meters/second.
sensor_heading	The heading of the sensor platform measured clockwise from north.
sensor_pitch	The pitch angle of the sensor platform in degrees.
sensor_roll	The roll angle of the sensor platform in degrees.
target_latitude	The latitude of the target in platform decimal degrees.
target_longitude	The longitude of the target in platform decimal degrees.
target_altitude	The altitude of the target platform in meters.
target_speed	The speed of the target platform in meters/second.
target_heading	The heading of the target platform measured clockwise from north.
target_pitch	The pitch angle of the platform target in degrees.
target_roll	The roll angle of the platform target in degrees.
sar_dwell_time	The dwell time (in seconds) needed to produce an image of the desired resolution specified in the sensor definition.	The sensor being tested must be of type WSF_SAR_SENSOR.
sar_resolution	The resolution (in meters) of an image that can be produced with the dwell time specified in the sensor definition.	The sensor being tested must be of type WSF_SAR_SENSOR.
sar_clutter_to_noise	The SAR clutter-to-noise ratio (in dB).	The sensor being tested must be of type WSF_SAR_SENSOR.
sar_doppler_foldover	The difference between the PRF and the minimum PRF that could be used without causing ‘doppler foldover’.	The sensor being tested must be of type WSF_SAR_SENSOR.
pixel_count	The number of pixels the target occupies in the image.	Available for WSF_EOIR_SENSOR and WSF_SAR_SENSOR.
masking_status	The masking status at the point.	The value will be 0 if the target is not masked, 1 if masked by the horizon and 2 if masked by the terrain.
terrain_elevation	The terrain elevation in meters.	Use with horizontal_map.

script_variable <variable/script-name>

Specify the name of the ‘global’ script variable to use to derive and manipulate a variable from the sensor detection attempt interaction result.

Note

The script must have a ‘double’ as the return type and have inputs in the format and order of ‘WsfPlatform , WsfSensor , WsfPlatform , WsfSensorInteraction’.

Note

The script must be defined globally, i.e. outside any platforms or the sensor_plot mapping blocks.

Note

If multiple sensors are provided, the result will be the maximum value presented to any sensor.

Example script that writes out the Jammer/MDS, need to include script_variable jammer_to_mds also to run the script:

script double jammer_to_mds(WsfPlatform aPlatform, WsfSensor aSensor, WsfPlatform aTarget, WsfSensorInteraction aResult)
   if ((aResult.DetectionThreshold() > -300.0) &&
       (aResult.RcvrNoise() > -300.0) &&
       (aResult.NoiseJammerPower() > -300.0) &&
       (aResult.NoiseJammerPower() != 0.0))
   {
      double MDS =  aResult.DetectionThreshold() + aResult.RcvrNoise();
      return aResult.NoiseJammerPower() - MDS;
   }
   return -300.0;  // default value in dB
end_script

detection_reference <db-ratio>

The reference signal-to-noise ratio used to determine the required_rcs or rcs_required variable.

Default 12.8 dB

gnuplot_file <file-name>

Specifies the name of the file to which ‘gnuplot’ output will be written.

Default None - must be specified.

header_line_1 <text>

header_line_2 <text>

header_line_3 <text>

Specifies the text to be contained in the first three lines of the output file.

Default all header lines are blank.