target_assignment: Target assignment

In battleVerse/nautilus: Automated track-to-truth assignment for sensor performance analysis

Target assignment

Description

This is the function that determines which target each sensor point is assigned to and whether the point can be determined to be a false track. The call to target_assignment() is largely a switch that calls the target assignment subfunctions described below. After calling the subfunction it rearranges the target IDs into alphabetical order for plotting purposes and then returns a data frame with the same number of observations as the original sensor data input.

As an example, if there were four targets (A through D) that were originally input into target_track_distance, the output of that function included the distance of every sensor point (with unique number pointIndex) to all four targets. Therefore, if sensorData had N observations, the output of target_track_distance() has 4N observations, and the output of target_assignment() has N observations.

Usage

target_assignment(scenario, method, ...)

Arguments

scenario	a scenario containing either the output of target_track_distance(), or its component pieces (targetTruth, ownShipTruth, sensorData)
method	string specifying which subfunction to call. Options include: "point": point method of target assignment. Calls target_assignment.point(). Requires additional parameters "cutoff". See target_assignment.point for additional details "wholeTrack": whole track method of target assignment. Calls target_assignment.track(). Requires additional parameters "cutoff". See target_assignment.track for additional details "windowSquare": square window method of target assignment. Calls target_assignment.window(), requires additional parameters "cutoff" and "windowSize". optional parameter "parallel" will parallelize computation across multiple cores. default for this is FALSE. See target_assignment.window for additional details "windowGauss": Gaussian window method of target assignment. Calls target_assignment.gauss(). Requires additional parameters "cutoff" and "windowSize". optional parameter "parallel" will parallelize computation across multiple cores. default for this is FALSE. See target_assignment.gauss for additional details "user": user-specified method of target assignment. Calls target_assignment.user(). Requires additional parameters "userAssignedVector". See target_assignment.user for additional details
...	additional commands to be passed to each subfunction ( target.assignment.XXXXX() ). For example, all of the subfunctions require a cutoff parameter and the tho window methods (method = "windowSquare" or "windowGauss") each require the window size (windowSize) to be specified.

Value

A data frame with the same number of observations as the sensor data that was originally passed to target_track_distance(). Each sensor point in the original data set has been assigned to a target using the method specified by the user, and the output data provides the following summary statistics:

• lonError: difference in longitude between the sensor point and assigned target at the time of the sensor point

• latError: difference in latitude between the sensor point and assigned target at the time of the sensor point

• altError: difference in altitude between the sensor point and assigned target at the time of the sensor point

• bearingToTarget: bearing (azimuth) to target from ownship at the time of the sensor point

• trackNum: the track number associated with this sensor data point

• tgtAssigned: the ID of the target assigned to this sensor point

• locationError: distance between sensor point and target at the given time

• pointIndex: index referring to which of the original sensor data points this target-track pair refers. Necessary for comparisons in target_assignment()

• time: the time that this sensor point was recorded

• bearingError: difference in bearing between the sensor point and target at the time of the sensor point

• downrangeError: difference in range to ownship between the sensor point and target

• lon: longitude of the sensor point

• lat: latitude of the sensor point

• alt: altitude of the sensor point

• rangeToShip: range from target to ownship at the time of the sensor data point

• targetAspect: target aspect (as seen from ownship) at the time of the sensor data point

• meanLocationError: (only in square and gauss window methods) mean distance between sensor point and target for all of the points included in the window

• isFalseTrack: boolean indicating whether a point is outside the cutoff and therefore considered a false track

• tgtXtrack: factor expressing the truthID.trackNum interaction

• segmentNumber: an integer counting the number of times during which a single track is assigned to a particular target

@import scenarioMaker

Examples

cutoff= 2000
windowSize = 35
myScenario=target_assignment(scenario=scenarioMaker::example2_scenario,
 method='windowGauss',
 cutoff=cutoff,
 windowSize=windowSize)

battleVerse/nautilus documentation built on July 16, 2024, 4:20 a.m.