TDOA Position Estimator

Estimate target position from time-difference of arrival

Since R2024b

• 

Libraries:
Phased Array System Toolbox / Direction of Arrival

Description

Estimate target position from time-difference-of-arrival (TDOA) measurements and anchor positions. The block also estimates the variance of the time-difference of arrival measurements.

Ports

Input

TDOAEst — Estimated time-difference of arrival (sec)

(L–1)-element real-valued vector

Estimated time-difference of arrival of signals between anchor pairs with respect to the first anchor and target, specified as an (L–1)-element real-valued vector. L is the number of anchors. Units are in seconds.

Data Types: single | double

TDOAVar — Estimated variances of time-differences of arrival (seconds-squared)

(L–1)-element real-valued vector

Estimated variances of time-difference of arrival of signals between anchor pairs with respect to the first anchor and target, specified as an (L–1)-element real-valued vector. L is the number of anchors. Units are in seconds-squared.

Data Types: single | double

AnchorPos — Anchor positions (meters)

2-by-L real-valued matrix | 3-by-L real-valued matrix

Anchor positions, specified as 2-by-L real-valued matrix or 3-by-L real-valued matrix. A 2-by-L matrix represents the anchor positions in 2-D Cartesian space, while a 3-by-L matrix represents the anchor positions in 3-D Cartesian space. Units are in meters.

Data Types: single | double

Output

TgtPosEst — Target position estimate

real-valued Q-by-1 vector

Estimated target positions, returned as a Q-by-1 vector representing the estimated target position obtained from TDOA measurements. Units are in meters.

Data Types: single | double

TgtPosCov — Target position covariance matrix

real-valued positive semi-definite Q-by-Q matrix

Target position covariance matrix, returned as a real-valued positive semi-definite Q-by-Q matrix. The covariance matrix represents the estimated target position covariance calculated from the Cramer-Rao lower bound (CRLB) of the TOA position estimator. Calculating the covariance requires the knowledge of toavar. When toavar is inaccurate, tgtposcov is also inaccurate. When toavar is accurate and small, the tgtposcov value represents the TOA position estimate CRLB. Units are in ㎡eters-squared.

Dependencies

To enable this output port, select the Output covariance of TDOA position estimate check box.

Data Types: single | double

Parameters

To edit block parameters interactively, use the Property Inspector. From the Simulink^® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Signal propagation speed (m/s) — Signal propagation speed

physconst("LightSpeed") (default) | positive real scalar

Signal propagation speed, specified as a positive real scalar. Units are in meters per second.

Example: 3e8

Output covariances of TDOA position estimates — Output covariance of TDOA position estimates

false (0) (default) | true (1)

Select the Output covariances of TDOA position estimates check box to enable the TgtPosCov output port containing the TDOA position covariances.

Data Types: Boolean

Simulate using — Block simulation method

Interpreted Execution (default) | Code Generation

Block simulation, specified as Interpreted Execution or Code Generation. If you want your block to use the MATLAB^® interpreter, choose Interpreted Execution. If you want your block to run as compiled code, choose Code Generation. Compiled code requires time to compile but usually runs faster.

Interpreted execution is useful when you are developing and tuning a model. The block runs the underlying System object™ in MATLAB. You can change and execute your model quickly. When you are satisfied with your results, you can then run the block using Code Generation. Long simulations run faster with generated code than in interpreted execution. You can run repeated executions without recompiling, but if you change any block parameters, then the block automatically recompiles before execution.

This table shows how the Simulate using parameter affects the overall simulation behavior.

When the Simulink model is in Accelerator mode, the block mode specified using Simulate using overrides the simulation mode.

Acceleration Modes

Block Simulation	Simulation Behavior
	Normal	Accelerator	Rapid Accelerator
Interpreted Execution	The block executes using the MATLAB interpreter.	The block executes using the MATLAB interpreter.	Creates a standalone executable from the model.
Code Generation	The block is compiled.	All blocks in the model are compiled.

For more information, see Choosing a Simulation Mode (Simulink).

Programmatic Use

Block Parameter: SimulateUsing

Type: enum

Values: Interpreted Execution, Code Generation

Default: Interpreted Execution

Version History

Introduced in R2024b