imu_compass.h

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/*imu_compass.cpp
Authors: Prasenjit (pmukherj@clearpathrobotics.com)
Copyright (c) 2013, Clearpath Robotics, Inc., All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following
   disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
   disclaimer in the documentation and/or other materials provided with the distribution.
 * Neither the name of Clearpath Robotics nor the names of its contributors may be used to endorse or promote products
   derived from this software without specific prior written permission.
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Description:
Header file for IMU Compass Class that combines gyroscope and magnetometer data to get a clean estimate of yaw.
*/

#include "ros/ros.h"
#include "tf/tf.h"
#include "tf/transform_listener.h"

#include "sensor_msgs/Imu.h"
#include "geometry_msgs/Vector3Stamped.h"
#include "std_msgs/Float32.h"

//typedef boost::shared_ptr<sensor_msgs::Imu const> ImuConstPtr;

class IMUCompass {

private:
  ros::NodeHandle node_;
  ros::Subscriber imu_sub_;
  ros::Subscriber mag_sub_;
  ros::Subscriber decl_sub_;
  ros::Publisher imu_pub_;
  ros::Publisher mag_pub_;
  ros::Publisher compass_pub_;
  ros::Publisher raw_compass_pub_;

  tf::TransformListener listener_;
  ros::Timer debug_timer_;

  void imuCallback(sensor_msgs::ImuPtr data);
  void declCallback(const std_msgs::Float32& data);
  void magCallback(const geometry_msgs::Vector3StampedConstPtr& data);
  void debugCallback(const ros::TimerEvent&);
  void repackageImuPublish(tf::StampedTransform);

  //Heading Filter functions
  void initFilter(double heading_meas); //initialize heading fiter
  bool first_mag_reading_; //signifies receiving the first magnetometer message
  bool first_gyro_reading_; //signifies receiving the first gyroscope message
  bool filter_initialized_; //after receiving the first measurement, make sure the filter is initialized
  bool gyro_update_complete_; //sigfnifies that a gyro update (motion model update) has gone through

  double mag_zero_x_, mag_zero_y_, mag_zero_z_;

  sensor_msgs::ImuPtr curr_imu_reading_;

  //Heading Filter Variables
  //State and Variance
  double curr_heading_;
  double curr_heading_variance_;
  double sensor_timeout_;

  //Motion Update Variables
  double heading_prediction_;
  double heading_variance_prediction_;
  double heading_prediction_variance_;
  double mag_declination_;
  double last_motion_update_time_;
  double last_measurement_update_time_;

  //Measurement Update Variables
  double yaw_meas_variance_;

public:
  IMUCompass(ros::NodeHandle &n);
  ~IMUCompass() {
  }
};