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Survey Strategy

Jonathan Capone edited this page Apr 11, 2026 · 1 revision

Survey Strategy

This page describes how to operate the system to produce accurate and usable maps.

Map quality is determined as much by how data is collected as by how it is processed.


1. Core Principle

The system samples depth along a path.

The map is built from:

  • where the ROV travels
  • how measurements are spaced
  • how consistently the system is operated

Better movement → better data → better maps


2. Path Planning

Recommended Pattern: Parallel Transects

Move the ROV in straight, parallel lines across the survey area.

→ → → → →
← ← ← ← ←
→ → → → →

This produces:

  • even coverage
  • consistent spacing
  • minimal gaps

Spacing Between Lines

Line spacing should be based on depth and desired resolution.

  • shallow water → tighter spacing
  • deeper water → wider spacing

General guideline:

  • spacing ≈ 2–5× expected depth

3. Speed Control

Maintain a consistent, slow speed.

Why it matters

  • faster movement → larger gaps between samples
  • inconsistent speed → uneven sampling density

Recommendation

  • move slowly and steadily
  • avoid sudden acceleration

4. Orientation Stability

Keep the ROV as level as possible.

Effects of tilt

  • pitch and roll distort depth measurements
  • angled sonar increases error

Best practice

  • avoid sharp turns
  • allow system to stabilize before collecting data
  • maintain consistent orientation during passes

5. GPS Quality Awareness

Monitor GPS conditions during operation.

Important factors

  • satellite count
  • HDOP
  • fix stability

Best practice

  • wait for a strong GPS fix before starting
  • avoid areas with obstruction
  • pause data collection if GPS quality drops

6. Coverage Strategy

Ensure full coverage of the survey area.

Common mistakes

  • leaving gaps between paths
  • uneven spacing
  • incomplete edge coverage

Recommended approach

  • overlap edges slightly
  • extend beyond area of interest
  • verify coverage visually when possible

7. Sampling Density

Sampling density determines map resolution.

High density

  • more detail
  • better interpolation

Low density

  • smoother results
  • less accuracy

8. Depth Considerations

Depth affects both sensor behavior and mapping strategy.

Shallow water

  • higher resolution possible
  • tighter spacing recommended

Deep water

  • lower resolution acceptable
  • wider spacing possible

9. Error Reduction

To improve accuracy:

  • maintain steady speed
  • minimize tilt
  • ensure consistent spacing
  • avoid noisy environments
  • verify sensor operation

10. Practical Workflow

Before Survey

  • check all sensors
  • confirm SD logging
  • wait for GPS fix

During Survey

  • follow planned path
  • maintain steady motion
  • monitor system status

After Survey

  • review coverage
  • check data quality
  • re-run areas if needed

11. Conceptual Understanding

The system does not map an area directly.

It builds a representation from:

  • sampled points
  • spatial distribution
  • interpolation

The quality of the final map depends on how well the survey path captures the structure of the environment.


Summary

Good maps come from:

  • consistent movement
  • controlled spacing
  • stable measurements
  • complete coverage

The system provides the tools, but the survey strategy determines the result.

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