WSF_PASSIVE_SENSOR¶
- sensor WSF_PASSIVE_SENSOR¶
Script Classes: WsfPassiveSensor
sensor <name> WSF_PASSIVE_SENSOR ... Platform Part Commands ... ... Common sensor Commands ... reported_target_type .. end_reported_target_type reported_emitter_type .. end_reported_emitter_type unframed_detection_optimization ... unframed_detection_coast_time ... mode <name> ... Common Mode Commands ... ... Detection Scheduling Commands ... ... Track Formation Commands ... ... Track Information Reporting Commands ... ... Antenna Commands ... ... receiver ... end_receiver frequency_band ... dwell_time ... revisit_time ... detection_sensitivity ... continuous_detection_sensitivity ... pulsed_detection_sensitivity ... detection_sensitivities ... end_detection_sensitivities detection_threshold ... continuous_detection_threshold ... pulsed_detection_threshold ... detection_thresholds ... end_detection_thresholds detection_probability ... end_detection_probability scan_on_scan_model ... azimuth_error_sigma_table ... end_azimuth_error_sigma_table elevation_error_sigma_table ... end_elevation_error_sigma_table range_error_sigma_table ... end_range_error_sigma_table ranging_time ... ranging_time_track_quality ... end_mode end_sensor
Overview¶
WSF_PASSIVE_SENSOR implements a basic passive RF detection sensor. This can be used to model things like RWR, SIGINT and ELINT sensors.
The sensor uses two different detection methods to gather data for reporting:
Framed or sampling: The sensor looks at all transmitters within its frequency band whose emission patterns are regular. This is how the sensor detects search radars. The sample interval for the sensor is specified by the frame_time mode command.
Unframed: The sensor uses this method to detect transmitters within its frequency band whose emission patterns are irregular. This would include tracking radars that employ electronic beam steering to track multiple targets, and communications devices that transmit only when a message is being sent.
The sensor combines the results from both detection methods to produce detection reports (WsfTrack) for each target it detects. The detection reports for a given target are produced at intervals defined by the frame_time. Unframed detections that occur in between frame samples are reported at the next frame sample.
Unframed detections of transient communication signals are reported for each frame sample in which the signal was present. That is, the transmission of a long message will be detected for the duration of the transmission. Note, however, that the detection results from the first sample are reported for subsequent samples of the same transmission (the assumption is being made that very little will change during the duration of transmission).
Commands¶
- reported_target_type … end_reported_target_type¶
Defines how the passive sensor reports target type information in tracks.
reported_target_type default_time_to_declare ... default_time_to_reevaluate ... type <target_type> ... type sub-commands ... type <target_type> ... type sub-commands ... ... default_type ... type sub-commands ... end_reported_target_type
Subcommands
- default_time_to_declare <time-value>¶
Defines the duration of time after the initial detection that is required to make a determination of the target type.
Default: 0 sec
- default_time_to_reevaluate <time-value>¶
Defines the time interval used for reevaluating the identification of the target. A value of 0 seconds indicates no reevaluation will take place.
Default: 0 sec
- type <target_type>¶
Specifies the truth type to which the following subcommands apply.
- default_type¶
Specifies that the following type subcommands apply for any type not defined with the type command.
Type SubCommands
- time_to_declare <time-value>¶
Defines the duration of time after the initial detection that is required to make a determination of the target type.
Default: set by the default_time_to_declare command
- time_to_reevaluate <time-value>¶
Defines the time interval used for reevaluating the identification of the target.
Default: set using the default_time_to_reevaluate command
- report_type <type-name> emitter <emitter-name>¶
report_type <type-name1> emitter <emitter-type-1> emitter <emitter-type-2> ... emitter <emitter-name-N> report_type <type-type-2 ...
Defines the reporting type-name as the target type based on the listed emitter-type(s) being reported in the emitter list. Currently exact matches between the emitter’s defined for the report_type and a track’s emitter list must happen for the given report_type to be reported. If there are differences another report_type or the default_type will be reported.
- report_type <type-name> <probability>¶
Defines the probability of reporting type-name as the target type. The probability parameter is a value between 0.0 and 1.0. Any number of report_type commands may be specified as long as the probability parameters add up to 1.0. For greater ease of use, the value remainder may be used as the probability parameter to specify whatever value is required to add up to 1.0.
- report_truth¶
Specifies that the sensor will report the truth type. This is only valid under the default_type command.
- reported_emitter_type … end_reported_emitter_type¶
Defines how the passive sensor reports emitter type information in tracks.
reported_emitter_type default_time_to_declare ... default_time_to_reevaluate ... type <emitter_type> ... type sub-commands ... type <emitter_type> ... type sub-commands ... ... default_type ... type sub-commands ... end_reported_emitter_type
Subcommands
- default_time_to_declare <time-value>¶
Defines the duration of time after the initial detection that is required to make a determination of the emitter type.
Default: 0 sec
- default_time_to_reevaluate <time-value>¶
Defines the time interval used for reevaluating the identification of the emitter. A value of 0 seconds indicates no reevaluation will take place.
Default: 0 sec
- type <emitter_type>¶
Specifies the truth emitter type to which the following subcommands apply.
- default_type¶
Specifies that the following type subcommands apply for any type not defined with the type command.
Type SubCommands
- time_to_declare <time-value>¶
Defines the duration of time after the initial detection that is required to make a determination of the emitter type.
Default: set by the default_time_to_declare command
- time_to_reevaluate <time-value>¶
Defines the time interval used for reevaluating the identification of the emitter.
Default: set using the default_time_to_reevaluate command
- report_type <type-name> <probability>¶
Defines the probability of reporting type-name as the emitter type. The probability parameter is a value between 0.0 and 1.0. Any number of report_type commands may be specified as long as the probability parameters add up to 1.0. For greater ease of use, the value remainder may be used as the probability parameter to specify whatever value is required to add up to 1.0.
- report_truth¶
Specifies that the sensor will report the truth type. This is only valid under the default_type command.
- unframed_detection_optimization <boolean-value>¶
This command indicates if unframed detection optimization will be used. If enabled, once the sensor successfully detects a given transmitter within a frame, subsequent attempts to detect the same transmitter in the same frame will be suppressed. For instance, if multiple messages are sent from a single transmitter during the passive frame, the passive sensor will only report on the first message that it can detect (if any). If the first message cannot be detected because of transmitter antenna pointing, it will report the second message if it can be detected, an so on.
Default: true
Note
Use this if it is desired to have one ATTEMPT_TO_DETECT event_output message for every SENSOR_DETECTION_ATTEMPT or MESSAGE_DELIVERY_ATTEMPT message, or if it desired to report the absolute best detection within the frame.
- unframed_detection_coast_time <time-value>¶
If the passive sensor is running at a faster frame time than the sensors it is trying to detect, it may detect the transmitter one frame and not the next. This can cause a lot of track creation and deletion. This value indicates how long a successful detection from a transmitter will be reported.
Default: 2 seconds
Passive-Specific Mode Commands¶
- frequency_band <lower-frequency> <upper-frequency>¶
Defines a band of frequencies this sensor can detect. This command may be specified more than once if the sensor can detect multiple bands.
- dwell_time <time-value>¶
- revisit_time <time-value>¶
These two commands pertain to the immediately preceding frequency_band and define how long the sensor dwells in the band and the interval between dwells. These commands are effectively only when the scan_on_scan_model is enabled and are used to determine the temporal probability that the sensor would be looking at the frequency of the target emitter when a detection chance occurs.
If these commands are defined for any band in the sensor then they must be defined for all bands in the sensor.
- continuous_detection_sensitivity <db-power>¶
- pulsed_detection_sensitivity <db-power>¶
- detection_sensitivity <db-power>¶
Defines the minimum signal strength that can be ‘reliably’ detected. If detection_probability is defined then this is the signal strength that would result in a Pd of 0.5. If detection_probability is not defined then this defines the signal strength for which a successful detection will be declared.
The first two forms set the detection sensitivity for continuous wave and pulsed signals, respectively. The last form sets both sensitivities to the same value. If continuous_detection_sensitivity is used then pulsed_detection_sensitivity must also be specified, and vice-versa. If no values for the detection thresholds or sensitivities are specified then the detection_threshold criteria will be used to set the default value.
Default: See detection_threshold.
- detection_sensitivities … end_detection_sensitivities¶
This command allows the definition of frequency-dependent or signal-type- and frequency-dependent detection sensitivities.
To define a table that is only frequency-dependent (for both “continuous” and ‘pulsed” signal-types):
detection_sensitivities frequency <frequency-value-1> <db-power-1> frequency <frequency-value-2> <db-power-2> frequency <frequency-value-n> <db-power-n> end_detection_sensitivities
To define a table that is signal-type- and frequency-dependent:
detection_sensitivities signal_type <signal-type-1> frequency <frequency-value-1> <db-power-1> frequency <frequency-value-2> <db-power-2> frequency <frequency-value-n> <db-power-n> signal_type <signal-type-2> frequency <frequency-value-1> <db-power-1> frequency <frequency-value-2> <db-power-2> frequency <frequency-value-n> <db-power-n> end_detection_sensitivities
- <signal-type>
A string input of the signal-type the table is for, valid values are [“continuous” | “pulsed” | “both”].
- <frequency>
A frequency value.
- <db-power>
The received signal strength required for detection at the indicated frequency.
When defining a signal-type- and frequency-dependent table, the following rule(s) must be noted:
Any ‘frequency’ entry that occurs before the first ‘signal_type’ entry is assumed to apply to the “both” (i.e., continuous and pulsed) signal-types. If a ‘signal_type’ is then entered the corresponding data entered before for that signal-type will be cleared and the new data entered.
The process for determining sensitivity uses the following algorithm:
If a signal-type-dependent table is being used, the signal-type of the received signal is used to locate the appropriate signal-type-specific set of frequency entries.
Frequencies greater than or equal frequency-value-m and less than frequency-value-m+1 will use db-power-m
Frequencies less than frequency-value-1 will use db-ratio-1.
Frequencies greater than or equal to frequency-value-n will use db-power-n.
Note
Entries will be sorted into increasing order of frequency.
Note
If detection_threshold and/or continuous_detection_threshold and/or pulsed_detection_threshold and/or detection_thresholds and/or sensitivity_threshold and/or continuous_sensitivities and/or pulsed_sensitivity_threshold and/or detection_sensitivities are specified, the last one is used.
Note
If neither detection_threshold and/or continuous_detection_threshold and/or pulsed_detection_threshold and/or detection_thresholds and/or detection_sensitivity and/or continuous_detection_sensitivity and/or pulsed_detection_sensitivity and/or detection_sensitivities are specified, the detection_threshold will assumed to be 3.0 dB for pulsed and continuous signal-types
- continuous_detection_threshold <db-ratio>¶
- pulsed_detection_threshold <db-ratio>¶
- detection_threshold <db-ratio>¶
This is an alternative to detection_sensitivity. It defines the minimum signal-to-noise ratio that can be ‘reliably’ detected. If detection_probability is defined then this is the signal-to-noise ratio that would result in a Pd of 0.5. If detection_probability is not defined then this defines the signal-to-noise ratio for which a successful detection will be declared.
The first two forms set the detection threshold for continuous wave and pulsed signals, respectively. The last form sets both thresholds to the same value. If continuous_detection_threshold is used then pulsed_detection_threshold must also be specified, and vice-versa. If no values for the detection thresholds or sensitivities are specified then both thresholds will be set to 3.0 db to be consistent with old input files.
Default: 3.0 dB (if both detection_threshold(s) and detection_sensitivity(s) are not defined)
- detection_thresholds … end_detection_thresholds¶
This command allows the definition of frequency-dependent or signal-type- and frequency-dependent detection thresholds.
To define a table that is only frequency-dependent (for both ‘continuous’ and ‘pulsed’ signal-types):
detection_thresholds frequency <frequency-value-1> <db-ratio-1> frequency <frequency-value-2> <db-ratio-2> frequency <frequency-value-n> <db-ratio-n> end_detection_thresholds
To define a table that is signal-type- and frequency-dependent:
detection_thresholds signal_type <signal-type-1> frequency <frequency-value-1> <db-ratio-1> frequency <frequency-value-2> <db-ratio-2> frequency <frequency-value-n> <db-ratio-n> signal_type <signal-type-2> frequency <frequency-value-1> <db-ratio-1> frequency <frequency-value-2> <db-ratio-2> frequency <frequency-value-n> <db-ratio-n> end_detection_thresholds
- <signal-type>
A string input of the signal-type the table is for, valid values are [“continuous” | “pulsed” | “both”].
- <frequency>
A frequency value.
- <db-ration>
The signal-to-noise ratio required for detection at the indicated frequency.
When defining a signal-type- and frequency-dependent table, the following rule(s) must be noted:
Any ‘frequency’ entry that occurs before the first ‘signal_type’ entry is assumed to apply to the “both” (i.e., continuous and pulsed) signal-types. If a signal_type is then entered the corresponding data entered before for that signal-type will be cleared and the new data entered.
The process for determining threshold uses the following algorithm:
If a signal-type-dependent table is being used, the signal-type of the received signal is used to locate the appropriate signal-type-specific set of frequency entries.
Frequencies greater than or equal frequency-value-m and less than frequency-value-m+1 will use db-ratio-m
Frequencies less than frequency-value-1 will use db-ratio-1.
Frequencies greater than or equal to frequency-value-n will use db-ratio-n.
Note
Entries will be sorted into increasing order of frequency.
Note
If detection_threshold and/or continuous_detection_threshold and/or pulsed_detection_threshold and/or detection_thresholds and/or sensitivity_threshold and/or continuous_sensitivity_threshold and/or pulsed_sensitivity_threshold and/or detection_sensitivities are specified, the last one is used.
Note
If neither detection_threshold and/or continuous_detection_threshold and/or pulsed_detection_threshold and/or detection_thresholds and/or sensitivity_threshold and/or continuous_sensitivity_threshold and/or pulsed_sensitivity_threshold and/or detection_sensitivities are specified, the detection_threshold will assumed to be 3.0 dB for pulsed and continuous signal-types
- detection_probability¶
Defines a function of probability of detection (Pd) versus received signal strength (expressed as a ratio of the received power to the detection sensitivity). The table is defined as follows:
detection_probability signal <db-ratio-1> pd <pd-value-1> signal <db-ratio-2> pd <pd-value-2> ... signal <db-ratio-n> pd <pd-value-n> end_detection_probability
- <db-ratio-n>
The ratio of the received signal power to the detection sensitivity.
- <pd-value-n>
The probability of detection associated with the ratio.
Signals that exceed the limits of the table will be clamped to the appropriate endpoint. Intermediate values will be determined using linear interpolation.
If this function is not defined then a binary detector is used. The Pd will be 1.0 if the signal level is equal to or exceeds the detection sensitivity.
Default: Function is not defined - the binary detector is used.
Note
If detection_threshold or detection_thresholds is used, the detection sensitivity will be computed as the detection threshold times the noise power.
- scan_on_scan_model <boolean-value>¶
Specifies if the Probabilistic Scan-On-Scan (PSOS) model should be employed. This model attempts to probabilistically capture the temporal effects in which the passive sensor is scanning in frequency and the emitter may be scanning in angle.
If the model is off, detection attempts will assume the target emitter is pointed (as closely as possible) directly at the passive sensor and that the passive sensor is currently attempting to detect the frequency at which the target emitter is emitting. This often results in an overly optimistic detection results.
If the model is on, the detection attempts will probabilistically consider the fact that the target emitter may be rotating and that the passive sensor may be scanning in frequency. The probabilistic frequency effects will be employed only if dwell_time and revisit_time are specified for every frequency_band.
Default: off
- azimuth_error_sigma_table¶
- elevation_error_sigma_table¶
- range_error_sigma_table¶
These commands provide the ability to define error sigmas that are a function of the frequency of the received signal instead of the fixed sigmas that are provided by the single-valued azimuth_error_sigma, elevation_error_sigma and range_error_sigma commands. The points define a curve on a plot whose x-axis is the log_10 of the frequency and the y-axis is the error sigma. Linear interpolation is used to derive the values for intermediate frequencies. Signals whose frequencies are outside the range of the table use the value from the appropriate endpoint (i.e., extrapolation is not performed).
The format of the command follows
type_error_sigma_table frequency <frequency-1> <error-sigma-1> frequency <frequency-2> <error-sigma-2> ... frequency <frequency-n> <error-sigma-n> end_type_error_sigma_table
type is azimuth, elevation or range and <error-sigma> is a sigma using the same format as the values in azimuth_error_sigma, elevation_error_sigma and range_error_sigma commands. Independent tables may be provided for each type.
Note
The entries must in order of monotonically increasing frequency.
Note
Providing a table will override any specification of its single-valued counterpart.
- ranging_time <time-value>¶
Adds range information to any track generated by this sensor after the specified time has elapsed. This basically simulates that the system could triangulate and get the range after a sufficient period of time.
- ranging_time_track_quality <quality-value>¶
If the ranging time is used to generate a track with range information, this parameter controls the track quality once range is valid. The quality-value must be non-negative.
