Module: simpleInstrumentController

Executive Summary

This module generates a command in the form of a DeviceCmdMsgPayload that turns on a Module: simpleInstrument if the spacecraft a.) has access to a Module: groundLocation and b.) the associated attitude error and attitude rate error from an attitude guidance message is within the given tolerance.

Message Connection Descriptions

The following table lists all the module input and output messages. The module msg connection is set by the user from python. The msg type contains a link to the message structure definition, while the description provides information on what this message is used for.

Module I/O Messages

Msg Variable Name

Msg Type

Description

locationAccessInMsg

AccessMsgPayload

input msg containing the ground location access

attGuidInMsg

AttGuidMsgPayload

input message containing the attitude guidance

deviceStatusInMsg

DeviceStatusMsgPayload

(optional) input message containing the device status

deviceCmdOutMsg

DeviceCmdMsgPayload

output message with the device command

Detailed Module Description

This module writes out a DeviceCmdMsgPayload to turn on an instrument, i.e. Module: simpleInstrument.

Note

This module assumes that the simulated data is generated instantaneously. Therefore, the baudRate of the simpleInstrument must be sized as such.

The module first checks if the instrument controller is active using the controllerStatus variable. This variable defaults to 1 (active), but the user may set the variable to 0 (inactive) with the deviceStatusInMsg or controllerStatus variable. Then, the module checks if target has already been imaged. If the target has not been imaged, the module then checks if the norm of the attitude error is less than the user specified tolerance and if the Module: groundLocation is accessible. If both are true, the module sets the deviceCmd to 1. Otherwise, the deviceCmd is set to 0.

User Guide

Two variables must be set. The variable attErrTolerance is the norm of the acceptable attitude error in MRPs. It must be set at the beginning of the sim.

The imaged variable is always initialized to 0 (i.e. the target has not been imaged). However, if the simulation is stopped and restarted again this variable should be reinitialized to 0 in between. If it is not and the previous target was imaged, the new target will not be imaged.

Optionally, attitude rate error checking may be enabled by setting useRateTolerance to 1. If enabled, rateErrTolerance should be set to the norm of the acceptable attitude rate error in rad/s when imaging.

If the user desires to make the instrument controller inactive, the controllerStatus variable should be set to 0. This may be done if the controller is to match the status of corresponding instrument data and power modules. This may also be accomplished by writing out a DeviceStatusMsgPayload to the deviceStatusInMsg.


Functions

void SelfInit_simpleInstrumentController(simpleInstrumentControllerConfig *configData, int64_t moduleID)

This method initializes the output messages for this module.

Parameters
  • configData – The configuration data associated with this module

  • moduleID – The module identifier

Returns

void

void Update_simpleInstrumentController(simpleInstrumentControllerConfig *configData, uint64_t callTime, int64_t moduleID)

Add a description of what this main Update() routine does for this module

Parameters
  • configData – The configuration data associated with the module

  • callTime – The clock time at which the function was called (nanoseconds)

  • moduleID – The module identifier

Returns

void

void Reset_simpleInstrumentController(simpleInstrumentControllerConfig *configData, uint64_t callTime, int64_t moduleID)

This method performs a complete reset of the module. Local module variables that retain time varying states between function calls are reset to their default values.

Parameters
  • configData – The configuration data associated with the module

  • callTime – [ns] time the method is called

  • moduleID – The module identifier

Returns

void

struct simpleInstrumentControllerConfig
#include <simpleInstrumentController.h>

Data configuration structure for the MRP feedback attitude control routine.

Public Members

double attErrTolerance

Normalized MRP attitude error tolerance.

unsigned int useRateTolerance

Flag to enable rate error tolerance.

double rateErrTolerance

Rate error tolerance in rad/s.

unsigned int imaged

Indicator for whether or not the image has already been captured.

unsigned int controllerStatus

dictates whether or not the controller should be running

AccessMsg_C locationAccessInMsg

Ground location access input message.

AttGuidMsg_C attGuidInMsg

attitude guidance input message

DeviceStatusMsg_C deviceStatusInMsg

(optional) device status input message

DeviceCmdMsg_C deviceCmdOutMsg

device status output message

BSKLogger *bskLogger

BSK Logging.