linkStatus

Status of link closure between first and last node

Since R2021a

Syntax

linkstat = linkStatus(lnk)

linkstat = linkStatus(lnk,timeIn)

[linkstat,timeOut] = linkStatus(___)

Description

linkstat = linkStatus(lnk) returns a matrix of logicals representing the link closure status history linkstat of each link in the vector link. The rows of the matrix correspond to the link objects in link and the columns correspond to the time sample.

linkstat = linkStatus(lnk,timeIn) returns a column vector of status linkstat of each link in the vector link at the specified datetime timeIn. Each element of linkstat corresponds to a link in link. If no time zone is specified in timeIn, the time zone is assumed to be Coordinated Universal Time (UTC).

[linkstat,timeOut] = linkStatus(___) returns the link closure status and the corresponding times in UTC.

Examples

Obtain Closed Downlink Status History

Create a satellite scenario object.

startTime = datetime(2020,10,13,5,30,0);
stopTime = datetime(2020,10,13,5,45,0);
sampleTime = 60;                                       % seconds
sc = satelliteScenario(startTime,stopTime,sampleTime);

Add a satellite to the scenario.

semiMajorAxis = 10000000;                               % meters
eccentricity = 0;
inclination = 0;                                        % degrees
rightAscensionOfAscendingNode = 0;                      % degrees
argumentOfPeriapsis = 0;                                % degrees
trueAnomaly = 210;                                      % degrees
sat = satellite(sc,semiMajorAxis,eccentricity, ...
    inclination,rightAscensionOfAscendingNode, ...
    argumentOfPeriapsis,trueAnomaly);

Add a transmitter to the satellite.

tx = transmitter(sat);

Add a ground station to the scenario.

latitude = 0;                             % degrees
longitude = 30;                           % degrees
gs = groundStation(sc,latitude,longitude);

Add a receiver to the ground station.

rx = receiver(gs,"MountingAngles",[0; 180; 0]);

Create a downlink.

lnk = link(tx,rx);

Obtain the link status history of the closed downlink.

s = linkStatus(lnk)

s = 1x16 logical array

   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0

Input Arguments

lnk — Link analysis

Link object vector | Link object scalar

Link analysis object, specified as a Link object vector or scalar.

timeIn — Time at which output is calculated

datetime scalar

Time at which the output is calculated, specified as a datetime scalar. If no time zone is specified in timeIn, the time zone is assumed to be UTC.

Output Arguments

linkstat — Link closure status

matrix of logical values

Link closure status, returned as a matrix of logical values representing the link closure status history linkstat of each link in the vector link. The rows of the matrix correspond to the link objects in link and the columns correspond to the time sample. The status at a given instant is 1 (true) if the link between the first and last node is closed. The link between the first and last node is closed when the link between each individual pair of intermediate adjacent nodes in the Sequence property of the link is closed.

• When both nodes of a pair belong to the same satellite or ground station, the link is considered closed.

• Otherwise, the link between the pair is closed if the directionality is from a transmitter to a receiver and the energy per bit to noise power spectral density ratio (Eb/No) at the receiver is greater than its RequiredEbNo property.

If a given node is attached to a ground station directly or via a gimbal, the elevation angle of the adjacent node with respect to the ground station must be greater than or equal to its MinElevationAngle property.

timeOut — Time samples of output link status

scalar | vector

Time samples of the output link status, returned as a scalar or a vector. If the time history of the link status is returned, timeOut is a row vector.

Note

When the AutoSimulate property of the satellite scenario is true, the link status history from StartTime to StopTime is returned. When the property is false, the link status history from StartTime to SimulationTime is returned.

Version History

Introduced in R2021a