# ctrectmeasjac

Jacobian of constant turn-rate rectangular target measurement model

## Syntax

``jacobian = ctrectmeasjac(state,detections)``

## Description

example

````jacobian = ctrectmeasjac(state,detections)` returns the Jacobian based on the current rectangular target `state` and `detections`.```

## Examples

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Load detections generated from a rectangular target.

`load('rectangularTargetDetections.mat','detections');`

Calculate Jacobian based on the rectangular state of the target and detections.

```tgtState = [3;48;0;60;0;5;1.9]; jac = ctrectmeasjac(tgtState,detections); jac1 = jac(:,:,1)```
```jac1 = 3×7 1.0000 0 0 0.0461 0 -0.2500 0.4330 0 1.0000 0 -0.0075 0 -0.4330 -0.2500 0 0 0 0 0 0 0 ```

## Input Arguments

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Current rectangular target state, specified as a 7-by-1 real-valued vector. The seven dimensional rectangular target state is defined as [x; y; s; θ; ω; L; W]. The meaning of these variables and their units are:

 Variable Meaning Unit x Position of the rectangle center in x direction m y Position of the rectangle center in y direction m s Speed in the heading direction m/s θ Orientation angle of the rectangle with respect to x direction degree ω Turn-rate degree/s L Length of the rectangle m W Width of the rectangle m Example: `[1;2;2;30;1;4.7;1.8]`

Data Types: `single` | `double`

Detections of target, specified as a 1-by-M cell array of `objectDetection` objects. The `MeasurementParameters` property (that specifies the transformation from the state-space to measurement-space) for each object must be the same for all the detections in the cell array.

## Output Arguments

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Jacobian of measurement model, returned as a M-by-7-by-D real-valued array. M is the dimension of each measurement specified in `detections`, and D is the number of detections specified in the `detections` input.