remus-rlf-reader

License: AGPL v3 Data: CC BY 4.0

Python parser for REMUS-100 AUV Run Log Files (.RLF) and companion ADCP data files (.ADC, .GPS, .rmf).

Format derived from analysis of the Makua Beach dataset (UCSD Library), collected by the REMUS-100 “Aukai” (SN 256, Hydroid Inc.) off O’ahu, Hawaiʻi, September 6–8, 2013.

⚠ Disclaimer: The binary format specification and all field decoders were derived empirically by pattern analysis — no official Hydroid/Kongsberg documentation was used. Field offsets, scaling factors, and physical interpretations may be incorrect. Verify decoded values against independent measurements before using them in analysis.

🚀 Try the Web Viewer — Browser-based interactive explorer: drag-drop RLF file upload, 12 linked Plotly plots with synced cursors and zoom, virtual-scrolled message browser with search and type filtering. All parsing runs client-side via Pyodide (Python in WebAssembly) — no data leaves your browser.

Web Viewer Screenshots

Plots tab Messages tab
Plots view Messages view

Example diagnostic plot Data quality plot

Files

File Description
remus_rlf.py RLF binary parser — decodes all known record types into NumPy arrays
remus_adcp.py ADCP companion file parser — RDI PD0 .ADC, .GPS position log, .rmf mission file
REMUS_RLF_FORMAT_SPEC.txt Empirically derived binary format specification

RLF Format

Each .RLF file is a stream of binary records with an 8-byte header:

Offset  Size  Type       Description
0       2     uint8[2]   Magic bytes: 0xEB 0x90
2       2     uint16 LE  Checksum (signed-byte sum of type+length+payload)
4       2     uint16 LE  Record type
6       2     uint16 LE  Payload length (bytes)
8       N     bytes      Payload

Decoded record types

High-rate sensor data

Type Dec Name Rate
0x044e 1102 Navigation ~18 Hz
0x041d 1053 YSI CTD ~18 Hz
0x040a 1034 Seabird CTD (SBE49) ~0.3 Hz
0x03e8 1000 ADCP/DVL (1200 kHz) ~0.35 Hz
0x03f7 1015 Sidescan (900 kHz) ~1.3 Hz
0x043e 1086 Wetlabs ECO BB2F ~1 Hz
0x03f9 1017 GPS / Acoustic Nav varies
0x041a 1050 Nav/Acoustic ~0.5 Hz
0x041f 1055 Acoustic Nav Fix ~1/4 min

Mission and configuration

Type Dec Name Description
0x03f4 1012 Vehicle Name AUV callsign (e.g. “Aukai”)
0x040d 1037 Vehicle Info Serial number, owner, firmware revisions
0x0416 1046 Manufacturer Info Manufacturer name and address
0x03ee 1006 Mission Modes Index→name mapping of all mission mode states
0x03f0 1008 Mission Legs Waypoint sequence with leg type and coordinates
0x0427 1063 Waypoints Named lat/lon waypoints with flags
0x03fc 1020 Sensor Names List of installed sensor names
0x0407 1031 Sensor Types Sensor type code→name mapping
0x040c 1036 Sensor Display Config Display name, min/max range, format string per sensor
0x041c 1052 Data Channels Channel index, name, and logging rate
0x043d 1085 ECO Calibration Scale and offset coefficients per ECO channel

Vehicle health and diagnostics

Type Dec Name Description
0x0412 1042 Battery Status LiION pack voltage, cell voltage, chemistry, serial, mfg date
0x0413 1043 Battery Cell Data Per-cell voltage counts for all 4 battery banks
0x0402 1026 Energy Monitor Battery capacity and cumulative energy consumed (Wh)
0x040e 1038 Housing Temperature Electronics housing temp (~30 C) and compass error FIFO
0x0415 1045 Compass Calibration Heading bias measurements; reference headings match .ini config
0x040b 1035 DVL Status ADCP/DVL subsystem diagnostics (logged as raw hex)
0x0408 1032 Subsystem Mode Mode/status flag register (logged as raw hex)

Mission control

Type Dec Name Description
0x03f1 1009 Objective Navigation Real-time leg progress: FROM/TO positions, RPM, speed, mode
0x0446 1094 Startup Flag Startup marker (constant, exactly 10 per mission)
0x03ef 1007 Event Marker Empty-payload phase transition marker (~9 per mission)

Event and diagnostic logs

Type Dec Name Description
0x03e9 1001 Diagnostic Log Vehicle software warnings and status messages
0x0424 1060 Acoustic Modem Log Inbound/outbound acoustic modem messages

All 32 record types observed in the data are now decoded (no unknowns remain). DVL Status and Subsystem Mode are stored as raw hex pending further analysis.

Installation

Requires Python 3.8+ and NumPy. Matplotlib is optional (for --plot).

pip install numpy matplotlib

Usage

Parse an RLF file

from remus_rlf import parse_rlf, print_summary

parsed = parse_rlf('130906/RLF/130906.RLF')
print_summary(parsed)

nav = parsed['Navigation']
print(nav['lat'], nav['lon'], nav['depth'])

Command-line summary + plot

python remus_rlf.py 130906/RLF/130906.RLF
python remus_rlf.py 130906/RLF/130906.RLF --plot

--plot generates two figures saved alongside the input file:

File Contents
*_summary.png 8-panel sensor overview: track, depth profile, temperature/salinity, speed of sound, ECO backscatter/chlorophyll, vehicle attitude, sidescan bathymetry, navigation speed
*_quality.png 4-panel data quality: sensor record rate (gaps = dropouts), DVL bottom lock fraction + acoustic transponder fix events, smart battery pack voltage, acoustic modem receive quality scores

Note on acoustic modem signal quality: Modem log records carry no embedded timestamp. Timestamps are inferred by interpolating the file-byte positions of surrounding navigation records. The resulting t_hrs field is added to parsed['Acoustic Modem Log'] automatically by parse_rlf.

Parse ADCP directory

from remus_adcp import parse_adcp_directory

result = parse_adcp_directory('130906/ADCP/')
adc = result['adc']   # n_ensembles × n_cells velocity arrays
gps = result['gps']   # GPS position fixes

python remus_adcp.py 130906/ADCP/ --plot

Example Output

CLI record summary

Parsing: 130906/RLF/130906.RLF
Size: 34.9 MB

Record Type                       Hex      Count  Payload
----------------------------------------------------------
  Navigation                   0x044e     292749     46 B
  YSI CTD                      0x041d     274243     40 B
  Sidescan (900 kHz)           0x03f7      19857     55 B
  ADCP/DVL (1200 kHz)          0x03e8      17427    155 B
  Wetlabs ECO BB2F             0x043e      15681     57 B
  Seabird CTD (SBE49)          0x040a       4286     32 B
  GPS/Acoustic Nav             0x03f9       3313     59 B
  Acoustic Modem Log           0x0424       2401     36 B
  Nav/Acoustic                 0x041a       2144     57 B
  Diagnostic Log               0x03e9        422     93 B
  Data Channels                0x041c        260     24 B
  Mission Modes                0x03ee        200     21 B
  Vehicle Info                 0x040d        198     31 B
  Sensor Types                 0x0407        150     23 B
  Acoustic Nav Fix             0x041f        114    126 B
  Sensor Names                 0x03fc         90     13 B
  ECO Calibration              0x043d         80     46 B
  Battery Cell Data            0x0413         40     52 B
  Battery Status               0x0412         40    139 B
  Mission Legs                 0x03f0         60     48 B
  Waypoints                    0x0427         50     31 B
  Vehicle Name                 0x03f4         10     35 B
  Manufacturer Info            0x0416         10    108 B
  Sensor Display Config        0x040c         10     28 B

--- Navigation ---
  lat     min=  21.503  max=  21.520  mean=  21.511
  lon     min=-158.242  max=-158.232  mean=-158.237
  depth   min=   0.000  max=  10.000  mean=   2.130
  t_hrs   min=   0.000  max=   4.762  mean=   2.382

Python API examples

>>> parsed['Vehicle Name']
{'name': 'Aukai'}

>>> parsed['Vehicle Info']
{'Vehicle Serial Number': 'SN 256',
 'Vehicle Owner and ID': 'UH Aukai',
 'Vehicle rev': '(Hydroid Vehicle 256) Mar 21 2012; 10:39:16;',
 ...}

>>> parsed['Manufacturer Info']['info']
'Manufactured by Hydroid, Inc. 6 Benjamin Nye Circle, Pocasset, Ma. 02559 ...'

>>> parsed['Mission Modes']
{0: 'Manual', 1: 'Bench test', 2: 'Acoustic Test', 3: 'Hysterisis test',
 4: 'Fin wiggle test', 5: 'Abort', 6: 'Wait run', 7: 'Dead Reckon',
 8: 'DR rows', 9: 'Set position', 10: 'Wait depth', 11: 'Surface',
 12: 'Wait prop', 13: 'Compass cal', 14: 'Navigate', 15: 'Navigate rows',
 16: 'Wait magnet', 17: 'Loiter', 18: 'Get gps fix', 19: 'Reacquire'}

>>> parsed['Sensor Names']
['RDI ADCP', 'Imagenex852', 'YSI CTD', 'Seabird', 'MS Sidescan',
 'Modem', 'NMEA183 GPS', 'Wetlabs ECO', 'Smart Batt.']

>>> parsed['Waypoints'][:2]
[{'lat': 21.5198, 'lon': -158.2323, 'flags': 2, 'name': 'Compass Cal.'},
 {'lat': 21.5103, 'lon': -158.2323, 'flags': 0, 'name': 'Turn at 2.0 M'}]

>>> parsed['ECO Calibration'][:3]
[{'channel': 'Ref470',       'units': 'Counts',     'calibrated': False, 'scale': 1.0,    'offset':  0.0},
 {'channel': 'Beta470',      'units': 'B/m/sterad',  'calibrated': True,  'scale': 2.4e-5, 'offset': 50.0},
 {'channel': 'Chlorophyll A','units': 'ug/liter',    'calibrated': True,  'scale': 0.016,  'offset': 75.0}]

>>> parsed['Acoustic Nav Fix'][:2]
[{'datetime': '2013-09-06 21:17:50', 'lat': 21.5195, 'lon': -158.2321,
  'heading': 190.7, 'range_m': 173.2, 'speed': 0.412},
 {'datetime': '2013-09-06 21:17:51', 'lat': 21.5195, 'lon': -158.2321,
  'heading': 193.1, 'range_m': 150.9, 'speed': 0.669}]

>>> parsed['Battery Status'][:2]
[{'batt_id': 2723, 'chemistry': 'LiION', 'serial': '102455',
  'mfg_date': 'Dec  2 2009', 'capacity_mAh': 5500,
  'cell_mv': 3071, 'pack_mv': 27736},
 {'batt_id': 2724, 'chemistry': 'LiION', 'serial': '102455',
  'mfg_date': 'Dec  2 2009', 'capacity_mAh': 5500,
  'cell_mv': 3076, 'pack_mv': 27733}]

>>> parsed['Diagnostic Log'][:2]
[{'source_file': 'DIAGNOSE.CPP',
  'message': 'Warning: Verify transponder range test disabled in mission file, line 69'},
 {'source_file': 'SCAN_VEH.CPP',
  'message': 'Warning, objective 4 is not in altimeter mode'}]

# Acoustic modem log — direction '>' = modem→vehicle log, '<' = vehicle→modem command
# Message categories observed across the dataset:
>>> ml = parsed['Acoustic Modem Log']

# Modem firmware revision broadcast (most common — continuous heartbeat)
>>> next((m for m in ml['message'] if m.startswith('Rev:')), None)
'Rev: AUV13 (0.90.0.39)'

# Startup self-query: modem address, detection threshold, frequency band
>>> [m for m in ml['message'] if m.startswith('Query')]
['Query Self Address (SRC)', 'Query Detection threshold (PTH)', 'Query Modem freq band (BND)', ...]
>>> [m for m in ml['message'] if m.startswith('Response')]
['Response:SRC is 8', 'Response:PTH is 50', 'Response:BND is 3', ...]

# Data transmission cycle (surface comms)
>>> sorted(set(m for m in ml['message'] if any(k in m for k in ['Cycle','Tx','Data ready'])))
['Cycle Init Ack (8->0)', 'Cycle init (talk)', 'Data ready for transmission', 'Tx begin', 'Tx end']

# Acoustic ranging pings — one every ~4 minutes, timestamped
>>> [m for m in ml['message'] if m.startswith('Ranger')][:3]
['Ranger data (automatic 21:20:04.7)',
 'Ranger data (automatic 21:24:04.8)',
 'Ranger data (automatic 21:28:04.9)']

# Receive quality metric (only on successful receives)
>>> sorted(set(m for m in ml['message'] if m.startswith('Data quality')))
['Data quality: (2) 177', 'Data quality: (2) 180', 'Data quality: (2) 190',
 'Data quality: (2) 191', 'Data quality: (2) 195', 'Data quality: (2) 198']

# Errors
>>> sorted(set(m for m in ml['message'] if 'Error' in m or 'BAD' in m))
['Error 13: $ not found', 'Error 6: Undocumented error', 'Msg:BAD_CRC']

Dataset

The raw .RLF and .ADC files are not included in this repository. Download from the UC San Diego Library Digital Collections:

Amador, A. (2020). REMUS-100 AUV data, Makua Beach, O’ahu, 2013. UC San Diego Library Digital Collections. https://library.ucsd.edu/dc/object/bb9937198n doi:10.6075/J09P3042

Licensed under CC BY 4.0.

Expected directory layout after download:

130906/
  RLF/130906.RLF
  ADCP/130906.ADC  130906.GPS  130906.txt
130907/
  ...
130908/
  ...

References

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