Operational Support
Troubleshooting & Contingency
Diagnóstico guiado pelo contexto da operação. Confirmar procedimento/OEM e autoridade operacional antes de qualquer alteração crítica.
GNSS
Heading / Gyro
INS / MRU
DVL
USBL / Acoustics
Time Sync
Network / Logging
USBL — range/quality degraded
CRITICAL
Observed symptoms
• Range unstable or excessive residuals
• Intermittent fixes
• Position jumps
Diagnostic sequence
1. Confirm active transponder/channel/frequency and interrogations
2. Check acoustic noise/interference and vessel/ROV geometry
3. Confirm transceiver installation, offsets and alignment
4. Verify heading/MRU inputs, latency/time sync and quality
5. Confirm current SVP/profile and correct application in acoustic system
6. Compare against last known-good configuration/log
Likely causes
• Wrong channel/frequency or transponder setup
• Poor geometry/shadowing/noise
• Incorrect offsets/alignment
• Heading/MRU/time-sync problem
• Invalid or stale sound velocity profile
• Hardware/cabling/power degradation
Corrective actions
• Restore verified configuration one variable at a time
• Re-test transponder at controlled geometry/range
• Correct sensor input/offset/SVP issue and repeat verification
• Record before/after evidence and residuals
Contingency
• Use verified redundant acoustic unit/sensor where approved
• Reduce operational envelope until quality is demonstrated
• Revert to last approved configuration
STOP / HOLD criteria
• Position quality cannot be demonstrated within project tolerance
• Loss of required redundancy where project/procedure requires it
• Unresolved sensor/time/offset inconsistency
GNSS — degraded/lost positioning
CRITICAL
Observed symptoms
• Position lost
• Correction age/high latency
• Solution quality degraded
Diagnostic sequence
1. Check antenna/power/cabling
2. Check satellite visibility and solution mode
3. Verify correction source/link and age
4. Compare independent GNSS where available
5. Verify datum/configuration and time sync
Likely causes
• Antenna/cable/power fault
• Correction link failure
• Masking/interference
• Wrong configuration/datum
Corrective actions
• Restore correction/data path
• Switch to approved redundant receiver/source
• Validate recovered solution against independent source
Contingency
• Use approved redundant positioning source
• Suspend tolerance-critical acquisition until quality recovers
STOP / HOLD criteria
• Required positioning accuracy/integrity cannot be demonstrated
Heading/MRU — mismatch or unstable attitude
CRITICAL
Observed symptoms
• Heading disagreement
• Roll/pitch/heave spikes
• Position/scatter correlated with attitude
Diagnostic sequence
1. Compare primary/secondary heading
2. Check alignment/lever arms/sign conventions
3. Verify MRU mounting and configuration
4. Check latency/time sync
5. Inspect power/network/data quality
Likely causes
• Alignment/offset error
• Wrong sign/convention
• Latency/time mismatch
• Sensor or installation fault
Corrective actions
• Identify trusted reference
• Correct configuration only against approved survey values
• Repeat functional verification and document comparison
Contingency
• Use approved redundant heading/MRU source
• Limit operations affected by attitude uncertainty
STOP / HOLD criteria
• Heading/attitude integrity cannot be demonstrated
Network / serial / logging — data stream missing
ATTENTION
Observed symptoms
• No data in acquisition software
• Dropped packets
• Serial feed unreadable
• Log not created
Diagnostic sequence
1. Check physical link/power and switch status
2. Verify IP/subnet/port/protocol or serial baud/parity/data/stop bits
3. Confirm source output and destination listener
4. Check firewall/interface binding and duplicate IP
5. Verify disk space/log path/time sync
Likely causes
• Cable/switch fault
• IP/port mismatch
• Serial settings mismatch
• Source output disabled
• Storage/logging failure
Corrective actions
• Trace source-to-destination systematically
• Restore one stream at a time
• Confirm timestamps and file creation after recovery
Contingency
• Record locally at source when supported
• Use approved backup network/logger or serial path
STOP / HOLD criteria
• Required raw data cannot be recorded with valid timestamps
Kongsberg TTC / transponder — deck test or communication failure
CRITICAL
Observed symptoms
• Transponder does not reply during deck test
• Unexpected channel/frequency
• Intermittent acoustic response
• Battery/status concern
Diagnostic sequence
1. Verify transponder identity, model and serial against inventory
2. Confirm battery/status indication and service history
3. Confirm configured channel/frequency/code against approved plan
4. Check TTC transducer/cable/interface and test geometry
5. Repeat controlled deck test away from competing acoustic sources
6. Save test result and configuration as evidence
Likely causes
• Wrong transponder selected
• Battery depleted or maintenance overdue
• Channel/code/frequency mismatch
• TTC interface/cable problem
• Acoustic interference or unsuitable test geometry
Corrective actions
• Correct configuration against approved frequency plan
• Replace/service suspect battery or unit under applicable OEM procedure
• Repeat deck test and capture evidence
• Update inventory status before installation
Contingency
• Use tested spare transponder with approved configuration
• Reallocate an approved spare channel/code without creating acoustic conflict
STOP / HOLD criteria
• Unit cannot pass required pre-deployment functional test
• Identity/configuration cannot be reconciled with inventory/frequency plan
PIES + Dunker — connection / data harvesting failure
ATTENTION
Observed symptoms
• Unable to establish Dunker communication
• PIES does not respond
• Data harvest incomplete or interrupted
Diagnostic sequence
1. Confirm PIES identity and expected acoustic configuration
2. Verify Dunker/transceiver connection, power and selected mode
3. Confirm compatible channel/address and communication settings
4. Establish controlled geometry and minimize competing acoustic traffic
5. Attempt status/query before data harvest
6. Preserve downloaded file and verify completeness before ending session
Likely causes
• Wrong address/channel or mode
• Poor acoustic geometry/noise
• Dunker/interface setup problem
• PIES power/status issue
• Interrupted transfer
Corrective actions
• Re-establish verified configuration one parameter at a time
• Retry communication at controlled range/geometry
• Harvest data and validate file before clearing/ending any session
• Record PIES ID, time, file and result in Evidence & Audit
Contingency
• Retry from alternate approved Dunker/transceiver configuration
• Schedule another harvesting opportunity if operational constraints prevent reliable transfer
STOP / HOLD criteria
• Any action would risk deleting/unrecoverably altering PIES data
• PIES identity cannot be positively confirmed
DVL — bottom lock / velocity degraded
CRITICAL
Observed symptoms
• Bottom lock lost
• Velocity noisy or intermittent
• INS aiding degrades with DVL
Diagnostic sequence
1. Check DVL power, communications and health/status
2. Verify altitude/range and seabed suitability
3. Check beam status and individual beam quality
4. Confirm mounting alignment, lever arms and frame convention
5. Verify sound-speed/input configuration where applicable
6. Check time sync and INS aiding status
Likely causes
• Altitude outside operating envelope
• Poor seabed return or aeration
• Beam obstruction/failure
• Alignment/frame error
• Time/configuration mismatch
Corrective actions
• Restore valid geometry/altitude when operationally possible
• Correct approved mounting/configuration values
• Validate velocity against independent navigation solution
• Document beam/status evidence after recovery
Contingency
• Use approved alternate aiding source
• Operate within reduced navigation envelope until DVL integrity returns
STOP / HOLD criteria
• Required navigation integrity cannot be maintained without valid DVL aiding
MBES — coverage / data quality degraded
CRITICAL
Observed symptoms
• Poor swath quality
• Outer beams noisy
• Depth mismatch or artifacts
• Coverage gaps
Diagnostic sequence
1. Verify sonar health, frequency/mode and acquisition settings
2. Check GNSS, heading, attitude, heave and latency inputs
3. Confirm offsets, patch/alignment values and reference frames
4. Confirm valid sound-velocity input/profile
5. Inspect vessel speed, sea state, aeration and acoustic interference
6. Compare reciprocal/overlap data where available
Likely causes
• Sensor input or latency problem
• Bad sound velocity
• Incorrect offsets/alignment
• Aeration/noise/sea-state effect
• Unsuitable sonar settings
Corrective actions
• Identify whether defect is sonar, navigation, motion or SV related before changing settings
• Restore approved configuration
• Repeat verification line/overlap check and document result
Contingency
• Reduce speed/swath where project method permits
• Re-run affected coverage after quality is restored
STOP / HOLD criteria
• Survey specification/coverage cannot be demonstrated
• Systematic bias remains unresolved
Time sync — timestamp / latency inconsistency
CRITICAL
Observed symptoms
• Sensors disagree in time
• Position/attitude artifacts
• Logs have offset timestamps
Diagnostic sequence
1. Identify authoritative time source
2. Check NTP/PTP/PPS/serial time distribution as applicable
3. Compare host and sensor clocks
4. Verify configured latency/delay values
5. Check reboot/startup sequence and loss of sync alarms
Likely causes
• Time source unavailable
• Wrong time server/interface
• Latency configured twice or omitted
• Host clock drift
• PPS/network distribution fault
Corrective actions
• Restore approved master time source
• Correct only verified latency values
• Restart/re-sync according to controlled procedure
• Capture before/after timestamp evidence
Contingency
• Use approved alternate master/time path
• Suspend precision acquisition until common time base is proven
STOP / HOLD criteria
• Common time base cannot be demonstrated for required sensors
ROV sensor installation — mounting / reference problem
CRITICAL
Observed symptoms
• Sensor position inconsistent after installation
• Unexpected heading/offset effect
• Intermittent cable or data after launch
Diagnostic sequence
1. Confirm correct sensor/transponder serial and assigned ROV/location
2. Inspect bracket, mechanical security and orientation
3. Confirm measured offsets/lever arms and sign convention
4. Verify cable routing, connectors, strain relief and wet-mate condition
5. Perform deck functional test after final installation
6. Photograph installation and record position reference
Likely causes
• Wrong unit/location
• Mounting orientation error
• Incorrect measured offset
• Cable/connector stress
• Configuration not updated after physical change
Corrective actions
• Correct physical installation before compensating in software
• Update approved offsets/configuration to match measured installation
• Repeat functional check and preserve photo/test evidence
Contingency
• Move to approved alternate mounting position and re-survey offsets
• Use verified spare sensor/cable where applicable
STOP / HOLD criteria
• Mechanical integrity is uncertain
• Installation/reference cannot be reconciled with configuration
• Required sensor cannot pass post-installation functional test
Sensor failure / redundancy — primary source lost
CRITICAL
Observed symptoms
• Primary sensor offline
• Automatic source switch
• Primary/secondary disagreement
Diagnostic sequence
1. Identify failed/degraded source without disabling healthy redundancy
2. Compare independent source quality/status
3. Confirm backup configuration, offsets, datum/frame and time sync
4. Verify acquisition/QC software is consuming intended source
5. Assess project requirement for redundancy
Likely causes
• Hardware/power/network failure
• Configuration mismatch between primary and backup
• Automatic failover selected an unverified source
• Common-mode failure
Corrective actions
• Transfer to verified backup under approved procedure
• Validate output against independent reference before resuming
• Record failure, source change and validation evidence
• Quarantine failed unit from operational use until assessed
Contingency
• Continue on single source only where project procedure/risk assessment explicitly permits
• Reduce operational scope while redundancy is degraded
STOP / HOLD criteria
• Mandatory redundancy is lost
• Backup source cannot be independently validated
• Common-mode fault affects both primary and backup