PPC-Dataset-ROS2

Unofficial ROS 2 conversion of the PPC-Dataset by Taro Suzuki. Please cite the original dataset when using these recordings.

The bags use the message definitions of gnss_ros_standardization. Build the release of that package that matches this dataset; the message definitions must be identical for the bags to deserialize.

Contents and time convention

Topic	ROS type	Nominal rate	Source
/gnss/observation	gnss_ros_standardization/msg/GnssObservations	5 Hz	rover.obs
/base/gnss/observation	gnss_ros_standardization/msg/GnssObservations	1 Hz	base.obs
/gnss/ephemeris	gnss_ros_standardization/msg/GnssEphemerides	at transmission time	base.nav
/gnss/imu/data_raw	sensor_msgs/msg/Imu	100 Hz	imu.csv
/gnss/reference/solution	gnss_ros_standardization/msg/GnssSolution	5 Hz	reference.csv
/gnss/reference/solution_odom	nav_msgs/msg/Odometry	5 Hz	reference.csv

Header stamps and bag timestamps use GPST, not UTC. GNSS week/TOW is also GPST. Each bag includes gnss_time_basis.yaml; do not interpret the timestamps as UTC without a time-scale conversion. Source gaps are kept; missing epochs are not interpolated.

IMU acceleration is in m/s², angular velocity in rad/s (converted from deg/s), in the source axes (imu_link), without lever-arm correction. The reference solution keeps the source LLH/ECEF position and ENU velocity. The reference Odometry uses the first reference position as the ENU map origin; attitude is in map (from roll, pitch and heading clockwise from North), linear twist in base_link.

Runs

Run	First observation (GPST)	Duration	Messages	MCAP bytes
nagoya_run1	2024-08-03 08:53:00	1530 s	177,457	27,257,971
nagoya_run2	2024-07-20 10:22:00	1890 s	219,263	33,828,047
nagoya_run3	2024-08-03 09:50:00	1040 s	120,656	18,241,015
tokyo_run1	2024-07-23 04:04:30	2390 s	277,244	39,049,486
tokyo_run2	2024-07-23 01:10:00	1830 s	212,447	35,394,985
tokyo_run3	2024-07-23 01:51:00	3060 s	355,244	59,654,591

bags/<run>/ contains one MCAP file (lossless Zstandard chunk compression), the metadata and the time-basis sidecar. Each MCAP file is below 100 MB.

Navigation messages

Each navigation record is published at its transmission time (RINEX ttr; GLONASS tof), as a receiver stream delivers it in real time. Records transmitted before the first observation epoch are published together 1 s before the first observation, so that playback delivers them before the first epoch. Records transmitted after the last observation epoch are omitted.

Each message also carries the ionosphere parameters of the base.nav header (GPS, Galileo, QZSS, BeiDou). The topics carry legacy Kepler GPS/Galileo/QZSS/BeiDou ephemerides and GLONASS ephemerides: 8,256 records across the six runs. The source files contain 20,712 records (a file shared by several runs is counted once for each run). Not published are the 5,698 SBAS records, which the message types cannot represent; records without an orbit, which receivers publish as "unhealthy, no orbit"; and records transmitted after the last epoch.

What was checked

• Observations: all 12 RINEX observation files were parsed independently of RTKLIB's obs_t selection. 70,380 epochs and 8,345,592 signal observations matched the topics: satellite/signal identity, week/TOW, P/L/D/CN0, missing components, LLI bits and GLONASS frequency channels. BeiDou C51–C63 are kept. P and L use absolute tolerance 1e-6; float32 D/CN0 use max(1e-6, abs(source) * 6e-8). Identifiers, flags and counts match exactly.
• A zero measurement value in these bags comes from a zero (missing) field in the source RINEX files; treat it as missing.
• Navigation: every published record matched the fields of its source record.
• IMU and reference: every CSV row matched its message (header time within 1 µs).
• Playback: each compressed bag was played into a new recorder; all topic counts and ordered payload hashes matched.

Replay

source /opt/ros/jazzy/setup.bash
source /path/to/gnss_ros_standardization/install/setup.bash
ros2 bag info bags/nagoya_run1
ros2 bag play bags/nagoya_run1 --rate 1

Use reliable subscriptions; the navigation topic uses transient-local durability. Start subscribers before playback if every message must be received.

Reproduce

Each run was converted with the software's rinex_to_rosbag (default --eph-mode transmission):

ros2 run gnss_ros_standardization rinex_to_rosbag \
  --obs rover=/path/to/run/rover.obs --obs base=/path/to/run/base.obs \
  --nav /path/to/run/base.nav \
  --topic-obs rover=/gnss/observation --topic-obs base=/base/gnss/observation \
  --timestamp-scale gpst --storage mcap --out /path/to/new-bag \
  --imu /path/to/run/imu.csv --imu-frame raw --reference /path/to/run/reference.csv

It was then compressed with ros2 bag convert and this configuration:

output_bags:
  - uri: /path/to/compressed-bag
    storage_id: mcap
    storage_preset_profile: zstd_small
    all_topics: true

ros2 bag convert -i /path/to/new-bag mcap -o compression.yaml
cp /path/to/new-bag/gnss_time_basis.yaml /path/to/compressed-bag/

Compressed bytes can vary with library versions. To compare a regenerated bag, compare the decoded payloads and timestamps, not the file hash. To produce sqlite3 instead, use storage_id: sqlite3 and omit storage_preset_profile.

License

MIT. See LICENSE. Derived from PPC-Dataset, Copyright (c) 2025 Taro Suzuki. No upstream endorsement is implied.