cartographer/sensor/fixed_frame_pose_data.h

Overview

FixedFramePoseData represents an absolute pose measurement in a fixed frame — for example GPS position, or an external pose estimate. Unlike relative sensor data (IMU, odometry), it is used directly in the global optimization: the pose graph adds residuals that pull each node’s global pose toward the fixed-frame measurement, which helps bind the map to the world frame.

Struct: cartographer::sensor::FixedFramePoseData

struct FixedFramePoseData {
  common::Time time;
  absl::optional<transform::Rigid3d> pose;
};

  • time — Timestamp of the measurement.

  • pose — Optional pose in the fixed frame. The absl::optional allows a measurement with no usable pose (e.g. a GPS fix with no lock) to be delivered without discarding the timestamp.

Serialization

proto::FixedFramePoseData ToProto(const FixedFramePoseData& pose_data);
FixedFramePoseData FromProto(const proto::FixedFramePoseData& proto);

proto::FixedFramePoseData stores the timestamp and an optional transform.proto.Rigid3d:

message FixedFramePoseData {
  int64 timestamp = 1;
  transform.proto.Rigid3d pose = 2;
}

ToProto omits pose when it is not set; FromProto reconstructs the absl::optional from has_pose().

Usage

sensor::FixedFramePoseData pose_data{time, pose};  // or {time, absl::nullopt}
trajectory_builder->AddFixedFramePoseData(sensor_id, pose_data);

Role in the SLAM Pipeline

  • Trajectory builder interface — AddFixedFramePoseData accepts these measurements; they are stored per trajectory in the optimization problem.

  • Optimization — During Solve, each trajectory with fixed-frame pose data has a fixed_frame_origin_in_map transform computed and residual blocks (in OptimizationProblem2D/OptimizationProblem3D) pull the trajectory’s nodes toward the measured poses, constraining the map to the fixed frame.

  • Serialization — per-trajectory fixed-frame pose data is stored in the serialization format via proto::FixedFramePoseData in serialization.proto.

See Also