zerorate.cpp

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//=================================================================================================
// Copyright (c) 2011, Johannes Meyer, TU Darmstadt
// 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 the Flight Systems and Automatic Control group,
//       TU Darmstadt, nor the names of its contributors may be used to
//       endorse or promote products derived from this software without
//       specific prior written permission.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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#include <hector_pose_estimation/measurements/zerorate.h>
#include <hector_pose_estimation/system/imu_model.h>
#include <hector_pose_estimation/filter/set_filter.h>

namespace hector_pose_estimation {

template class Measurement_<ZeroRateModel>;

ZeroRateModel::ZeroRateModel()
{
  parameters().add("stddev", stddev_, 90.0*M_PI/180.0);
  parameters().add("use_bias", use_bias_, std::string("gyro_bias"));
}

ZeroRateModel::~ZeroRateModel() {}

bool ZeroRateModel::init(PoseEstimation &estimator, Measurement &measurement, State &state)
{
  if (!use_bias_.empty()) {
    bias_ = state.getSubState<3,3>(use_bias_);
    if (!bias_) {
      ROS_ERROR("Could not find bias substate '%s' during initialization of zero rate pseudo measurement '%s'.", use_bias_.c_str(), measurement.getName().c_str());
      return false;
    }
  } else {
    bias_.reset();
  }

  if (!bias_ && !state.rate()) {
    ROS_WARN("Pseudo updating with zero rate is a no-op, as the state does not contain rates nor biases.");
    // return false;
  }

  return true;
}

void ZeroRateModel::getMeasurementNoise(NoiseVariance& R, const State&, bool init)
{
  if (init) {
    R(0,0) = pow(stddev_, 2);
  }
}

void ZeroRateModel::getExpectedValue(MeasurementVector& y_pred, const State& state)
{
  y_pred(0) = state.getRate().z();

  if (!state.rate() && bias_) {
    y_pred(0) += bias_->getVector().z();
  }
}

void ZeroRateModel::getStateJacobian(MeasurementMatrix& C, const State& state, bool)
{
  if (state.rate()) {
    state.rate()->cols(C)(0,Z) = 1.0;
  } else if (bias_) {
    bias_->cols(C)(0,Z) = 1.0;
  }
}

const ZeroRateModel::MeasurementVector* ZeroRateModel::getFixedMeasurementVector() const
{
  static MeasurementVector zero(MeasurementVector::Zero());
  return &zero;
}

} // namespace hector_pose_estimation