diff options
Diffstat (limited to 'src/modules/uavcan/sensors/gnss.cpp')
| -rw-r--r-- | src/modules/uavcan/sensors/gnss.cpp | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/src/modules/uavcan/sensors/gnss.cpp b/src/modules/uavcan/sensors/gnss.cpp new file mode 100644 index 000000000..24afe6aaf --- /dev/null +++ b/src/modules/uavcan/sensors/gnss.cpp @@ -0,0 +1,173 @@ +/**************************************************************************** + * + * Copyright (C) 2014 PX4 Development Team. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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. + * 3. Neither the name PX4 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 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/** + * @file gnss.cpp + * + * @author Pavel Kirienko <pavel.kirienko@gmail.com> + * @author Andrew Chambers <achamber@gmail.com> + * + */ + +#include "gnss.hpp" +#include <systemlib/err.h> +#include <mathlib/mathlib.h> + +const char *const UavcanGnssBridge::NAME = "gnss"; + +UavcanGnssBridge::UavcanGnssBridge(uavcan::INode &node) : +_node(node), +_sub_fix(node), +_report_pub(-1) +{ +} + +int UavcanGnssBridge::init() +{ + int res = _sub_fix.start(FixCbBinder(this, &UavcanGnssBridge::gnss_fix_sub_cb)); + if (res < 0) + { + warnx("GNSS fix sub failed %i", res); + return res; + } + return res; +} + +unsigned UavcanGnssBridge::get_num_redundant_channels() const +{ + return (_receiver_node_id < 0) ? 0 : 1; +} + +void UavcanGnssBridge::print_status() const +{ + printf("RX errors: %d, receiver node id: ", _sub_fix.getFailureCount()); + if (_receiver_node_id < 0) { + printf("N/A\n"); + } else { + printf("%d\n", _receiver_node_id); + } +} + +void UavcanGnssBridge::gnss_fix_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::gnss::Fix> &msg) +{ + // This bridge does not support redundant GNSS receivers yet. + if (_receiver_node_id < 0) { + _receiver_node_id = msg.getSrcNodeID().get(); + warnx("GNSS receiver node ID: %d", _receiver_node_id); + } else { + if (_receiver_node_id != msg.getSrcNodeID().get()) { + return; // This GNSS receiver is the redundant one, ignore it. + } + } + + auto report = ::vehicle_gps_position_s(); + + report.timestamp_position = hrt_absolute_time(); + report.lat = msg.latitude_deg_1e8 / 10; + report.lon = msg.longitude_deg_1e8 / 10; + report.alt = msg.height_msl_mm; + + report.timestamp_variance = report.timestamp_position; + + + // Check if the msg contains valid covariance information + const bool valid_position_covariance = !msg.position_covariance.empty(); + const bool valid_velocity_covariance = !msg.velocity_covariance.empty(); + + if (valid_position_covariance) { + float pos_cov[9]; + msg.position_covariance.unpackSquareMatrix(pos_cov); + + // Horizontal position uncertainty + const float horizontal_pos_variance = math::max(pos_cov[0], pos_cov[4]); + report.eph = (horizontal_pos_variance > 0) ? sqrtf(horizontal_pos_variance) : -1.0F; + + // Vertical position uncertainty + report.epv = (pos_cov[8] > 0) ? sqrtf(pos_cov[8]) : -1.0F; + } else { + report.eph = -1.0F; + report.epv = -1.0F; + } + + if (valid_velocity_covariance) { + float vel_cov[9]; + msg.velocity_covariance.unpackSquareMatrix(vel_cov); + report.s_variance_m_s = math::max(math::max(vel_cov[0], vel_cov[4]), vel_cov[8]); + + /* There is a nonlinear relationship between the velocity vector and the heading. + * Use Jacobian to transform velocity covariance to heading covariance + * + * Nonlinear equation: + * heading = atan2(vel_e_m_s, vel_n_m_s) + * For math, see http://en.wikipedia.org/wiki/Atan2#Derivative + * + * To calculate the variance of heading from the variance of velocity, + * cov(heading) = J(velocity)*cov(velocity)*J(velocity)^T + */ + float vel_n = msg.ned_velocity[0]; + float vel_e = msg.ned_velocity[1]; + float vel_n_sq = vel_n * vel_n; + float vel_e_sq = vel_e * vel_e; + report.c_variance_rad = + (vel_e_sq * vel_cov[0] + + -2 * vel_n * vel_e * vel_cov[1] + // Covariance matrix is symmetric + vel_n_sq* vel_cov[4]) / ((vel_n_sq + vel_e_sq) * (vel_n_sq + vel_e_sq)); + + } else { + report.s_variance_m_s = -1.0F; + report.c_variance_rad = -1.0F; + } + + report.fix_type = msg.status; + + report.timestamp_velocity = report.timestamp_position; + report.vel_n_m_s = msg.ned_velocity[0]; + report.vel_e_m_s = msg.ned_velocity[1]; + report.vel_d_m_s = msg.ned_velocity[2]; + report.vel_m_s = sqrtf(report.vel_n_m_s * report.vel_n_m_s + report.vel_e_m_s * report.vel_e_m_s + report.vel_d_m_s * report.vel_d_m_s); + report.cog_rad = atan2f(report.vel_e_m_s, report.vel_n_m_s); + report.vel_ned_valid = true; + + report.timestamp_time = report.timestamp_position; + report.time_gps_usec = uavcan::UtcTime(msg.gnss_timestamp).toUSec(); // Convert to microseconds + + report.satellites_used = msg.sats_used; + + if (_report_pub > 0) { + orb_publish(ORB_ID(vehicle_gps_position), _report_pub, &report); + + } else { + _report_pub = orb_advertise(ORB_ID(vehicle_gps_position), &report); + } + +} |