# radarbudgetplot

Display link budget as waterfall plot

## Description

returns
the plot axes `hax`

= radarbudgetplot(___)`hax`

.

## Examples

### Visualize Radar Link Budget

Visualize the link budget for a radar system designed to have a probability of detection of 0.9 and a probability of false alarm of${10}^{-6}$. The radar observes a Swerling 1 target and performs M-of-N integration with M = 6 and N = 10.

Pd = 0.9; Pfa = 1e-6; M = 6; N = 10;

First, find the integration gain by comparing the detectability of a Swerling 0 target for N pulses versus one pulse.

det_1 = detectability(Pd,Pfa,1,'Swerling0'); det_N = detectability(Pd,Pfa,N,'Swerling0'); Gain_int = det_N - det_1;

Next, compute the binary integration loss.

Loss_bi = binaryintloss(Pd,Pfa,N,M);

Last, compute the target fluctuation loss.

`Loss_fluct = detectability(Pd,Pfa,N,'Swerling1') - det_N;`

Plot the radar budget.

radarbudgetplot([det_1 Gain_int Loss_bi Loss_fluct], ... {'Single-pulse steady target' 'Noncoherent integration gain' ... 'Binary integration loss' 'Fluctuation loss'})

## Input Arguments

`gl`

— Radar gains and losses

length-*N* real-valued vector

Radar gains and losses components, specified as a real-valued vector. Each entry in the vector represents a contribution to the total gains or losses. Units are in dB.

**Example: **[13.2, -7.8]

**Data Types: **`double`

`names`

— Link budget component names

length-*N* cell array of character vectors | length-*N* cell array of strings

Link budget component names, specified as a length-*N* cell array
of character vectors or length-*N* cell array of strings.

**Example: **```
{'Single-pulse steady target','Pulse integration
gain'}
```

**Data Types: **`char`

| `string`

`hax`

— Plot axes

current axes (default) | scalar

Plot axes, specified as a scalar.

**Data Types: **`double`

## Output Arguments

`hax`

— Plot axes

scalar

Plot axes, returned as a scalar.

## More About

### Radar Link Budget

Radar link budget and detectability.

A *radar link budget * is used to find the received radar signal
level based on the transmitted signal level, taking into account all the losses and gains
found along the signal path. Together with the noise level measurements, you can use the
link budget to calculate the received signal to noise ratio. The
`radarbudgetplot`

function illustrates the components of the link budget
and lets you visualize the *radar detectability factor *. The radar
detectability factor is the minimum SNR required to make a detection with specified
probabilities of detection, *P*_{d}, and false alarm,
*P*_{fa}. A waterfall chart shows the contributions
of the individual losses and gains present in the radar system to the total power required
by the radar to produce a detection.

Once the radar detectability factor is computed, you can use the radar equation to
determine the range at which the available SNR for a given target is equal to the radar
detectability factor. At ranges where the available SNR exceeds the detectability factor,
the radar can make detections with the specified
*P*_{d} and
*P*_{fa}. At the ranges where the available SNR is
lower than the detectability factor, the radar cannot achieve the required
*P*_{d} and
*P*_{fa}.

The actual SNR tells you if the combined gains and losses are sufficient to exceed the required SNR. to declare a detection. For example the required SNR to detect a Swerling 1 target is substantially higher than for a Swerling 0 target.

```
Pd = 0.9;
Pfa = 1e-6;
D0 = detectabilty(Pd,Pfs,1,'Swerling1')
```

A Swerling 0 target has a constant RCS while a Swerling 1 target has a fluctuating RCS.
The requirement to maintain a certain *P*_{d} and
*P*_{fa} for a fluctuating target requires a larger
SNR to ensure that detections are made to satisfy the
*P*_{d} level.

The waterfall chart represents each individual loss as a red bar with height equal to
the value of that loss in dB. Each gain is represented as a green bar with a height equal to
the value of that gain. Because losses increase the required signal power, losses are
represented as positive values on the chart. Gains decrease the required signal power and
are shown with a minus sign. The resulting detectability factor is shown as a horizontal
dashed line labeled with the corresponding detectability value and is equal to the sum of
the elements in the `gl`

argument.

## Version History

**Introduced in R2022b**

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