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ROV Locator
ROV Locator
  • ROV Locator
  • Overview
  • General Specifications Mk II
  • General Specifications Mk III
  • System Variants
  • Fundamentals Useful to System Designers
    • Sound Reflection and Absorption
    • Multipath
    • Ping Length
    • What to Do About Multipath and Other Issues
    • Clock Drift Expectations
    • Accuracy Expectations
      • Accuracy Test: Topside GPS
      • Accuracy Test: 110 Meter Slant Range
      • Accuracy Test: 295 Meter Slant Range
    • Operation in a Pool
  • Autosync Option (Mk II Only)
    • Autosync Mission Scenarios and Mission Suitability
    • Autosync Availability
    • Autosync GPS/GNSS Output
  • ROVL Channels (Autosync only; Operating Multiple Units in Proximity)
  • ROVL Coordinate Systems and Angles
    • Definitions
    • NED or “Compass” vs. ENU or “Math” Angles
    • Math to Compass Frame Conversions
    • Transducer Down Orientation
    • Transducer Up Orientation
    • Receiver/Transceiver Orientation Frames
    • Best Operating Envelope
  • Communicating With the ROVL
    • Serial Parameters
    • Packet Format
    • Messages from ROVL to Host
      • $USRTH Receiver-Transmitter Relative Angles Message
      • $USINF Information Message
      • $USERR Error Message
    • Messages from Host to ROVL
      • NMEA-Format Messages to Receiver
      • Valid Commands from Host to ROVL
  • Inertial Measurement Unit (IMU)
    • How To Tell Which IMU is Active
    • Mk II IMU Modes and Calibration
      • Mk II IMU Calibration Background
      • Mk II IMU Calibration General Procedures
    • CIMU Calibration Background
      • CIMU Magnetometer Calibration
      • CIMU Accelerometer Calibration
      • CIMU Gyro Calibration
  • Operating and Accuracy Considerations
  • Multi-Unit Operation (Swarms)
    • Multi-Unit 1:1
    • Multi-Unit 1:2
    • Multi-Unit 2x1:1
    • Multi-Unit n:1 (fixed transmitter)
    • Multi-Unit n:1 (mobile transmitter)
  • ROVL Mounting and Wiring
    • ROV/Deepside Mounting
    • Topside Mounting
    • Simple Topside Deployment Fixture
    • Wiring Notes
    • Electrical Noise
    • USB Interface using Blue Robotics BLUART Board
  • Mechanical Drawings
    • Mounting Footprint and Envelope, "S" Package
    • Mounting Footprint ("P" Package Mk II and Mk III)
    • Envelope Drawing. "P" Package ROVL Mk II Transmitter and Receiver, Mk III Transponder
  • Appendix: Math for Computing Remote Latitude/Longitude
    • Receiver & GPS at Topside and Transmitter Deepside
    • Transmitter & GPS Topside and Receiver Deepside
  • Appendix: Factory Usage Command Set
  • Troubleshooting
    • How to Tell if Your Mk II Receiver is Working
    • How to tell if your Mk II Transmitter is working
    • What to do when you find an unresolvable problem when troubleshooting
  • Copyright
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  1. Fundamentals Useful to System Designers

Accuracy Expectations

How accurate can you expect your ROVL to be?

PreviousClock Drift ExpectationsNextAccuracy Test: Topside GPS

Last updated 6 months ago

Many factors affect the accuracy of an ROVL system. In this section, we show some real data and discuss the factors in play in this test.

For this test, we took an ROVL system out on an ice-covered freshwater lake. By using an ice-covered lake, we were able to ensure the system elements were not moving around due to currents and wind. We used a Mk III system but the results for a Mk II system would be very similar.

We cut a hole in the ice for the transceiver in a place where the water was about 8 meters deep, and lowered the transceiver down about 3 meters. We then cut holes for the transponder at distances of about 110 meters, 200 meters, and 295 meters. The water depth increased slowly from the 8 meters at the transceiver to about 15 meters at the 295-meter distance. The bottom undulates along the path and there are vegetation patches to the side.

The transponder was lowered through the hole in the ice slowly to a depth of about 10 meters (with data being accumulated during the drop).

We used an inexpensive topside GPS at the transceiver location, placed on the ice and not moved during the test.

This test setup is not an ideal environment for sonar, for many of the reasons described earlier in . It does illustrate the accuracy expectations for real-world systems.

The image below is a snip of the test displayed on CeruleanMap. In the following pages we will look in more detail at each of the areas.

this section
Overall Test Results