uSimCurrent: Simulating Drift Effects
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1 Overview
2 Configuration Parameters for uSimCurrent
3 Publications and Subscriptions for uSimCurrent
3.1 MOOS Variables Published by uSimCurrent
3.2 MOOS Variables Subscribed for by uSimCurrent
1 Overview
The uSimCurrent MOOS application is a newcomer in the toolbox and documentation is thin. Nevertheless it has been tested and used quite a bit and is worth a quick introduction here for those with a need for some ability to simulate water current on unmanned vehicles.
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uSimCurrent is intended to be used with the uSimMarine simulator, by generating drift vectors and publishing them to the MOOSDB. The uSimMarine simulator has a generic interface to accept externally published drift vectors regardless of the source, written to the variables DRIFT_X, DRIFT_Y, and DRIFT_VECTOR. The uSimCurrent application reads a provided current field file containing an association of water current to positions in the water. On iteration of uSimCurrent, the vehicle's current position is noted, looked up in the current-field data structure, and a new drift vector is posted. The idea is shown in Figure 1.1.
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Figure 1.1: The uSimCurrent utility: The simulator is initialized with a data file describing currents and locations. The simulator then repeatedly publishes a current vector based on the present vehicle position.
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2 Configuration Parameters for uSimCurrent
The following configuration parameters are defined for uSimCurrent. A more detailed description is provided in other parts of this section. Parameters having default values are indicated so.
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Listing 2.1 - Configuration Parameters for uSimCurrent.
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current_field: | Name of a file describing a current field. |
current_field_active: | Boolean indicating whether the simulator is active. |
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3 Publications and Subscriptions for uSimCurrent
The interface for uSimCurrent, in terms of publications and subscriptions, is described below. This same information may also be obtained from the terminal with:
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$ uSimCurrent --interface or -i
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3.1 MOOS Variables Published by uSimCurrent [top]
The primary output of uSimCurrent to the MOOSDB is the drift vector to be consumed by the uSimMarine application.
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- DRIFT_VECTOR: drift vector representing the prevailing current. See the uSimMarine documentation.
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- USC_CFIELD_SUMMARY: Summary of configured current field.
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- VIEW_VECTOR: Vector objects suitable for rendering in GUI applications.
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3.2 MOOS Variables Subscribed for by uSimCurrent [top]
Variables subscribed for by uSimCurrent are summarized below.
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- NAV_X: The ownship vehicle position on the x axis of local coordinates.
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- NAV_Y: The ownship vehicle position on the y axis of local coordinates.
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Page built from LaTeX source using texwiki, developed at MIT. Errata to issues@moos-ivp.org.
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