Category: Uncategorized

Hydrographic Equipment and Their Uses (and Where to Buy Them)

Understanding the underwater world begins with the right tools. Hydrographic equipment helps surveyors, engineers, and environmental professionals measure, map, and monitor water bodies accurately. From bathymetric surveys to offshore construction, these instruments ensure reliable and high-quality data. Below is a complete guide to the most important hydrographic equipment, their uses, and where to buy them in Nigeria and across Africa. 1. Echo Sounders (Single Beam and Multibeam) The echo sounder is the heart of every hydrographic operation. It works by transmitting sound pulses to the seabed and recording their return time to determine depth. Types and Uses Single Beam Echo Sounder (SBES): Ideal for rivers, lakes, and small-scale dredging projects. Multibeam Echo Sounder (MBES): Provides high-resolution 3D seabed mapping for ports, offshore platforms, and navigation channels. 2. Side Scan Sonar A side scan sonar creates detailed acoustic images of the seabed surface. It’s widely used to identify objects, seabed types, and underwater hazards. Applications Detecting shipwrecks and submerged debris Seafloor classification and habitat mapping Pipeline and cable route surveys Explore durable side scan sonar systems and accessories at Geossotech — designed for both shallow and deepwater mapping. 3. Sub-bottom Profiler The sub-bottom profiler looks below the seabed to reveal layers of sediment and subsurface structures, essential for geological and offshore engineering studies. Applications Sediment thickness analysis Offshore foundation investigations Geological and geotechnical surveys 4. GNSS / RTK Positioning Systems Accurate positioning is critical in hydrography. GNSS and RTK systems provide real-time coordinates of the vessel and sonar for precise georeferencing. Applications Real-time navigation Bathymetric mapping Tide correction 5. Tide Gauge A tide gauge records water level fluctuations over time to support depth correction and tidal analysis. Applications Establishing mean sea level Coastal and port monitoring Flood and climate studies 6. Sound Velocity Profiler (SVP) / CTD Sensor The SVP or CTD sensor measures conductivity, temperature, and depth, helping to correct sonar data for accurate depth readings. Applications Oceanographic studies Water quality monitoring Bathymetry correction 7. Motion Reference Unit (MRU) / IMU The MRU or IMU captures vessel motion (pitch, roll, and heave) to correct sonar readings affected by waves or instability. Applications Motion compensation in sonar data High-accuracy offshore surveys 8. Unmanned Surface Vessel (USV) USVs are autonomous or remotely operated survey boats used for shallow or dangerous waters where manned boats can’t go. Applications Shallow water bathymetry Port and reservoir mapping Hazardous area data collection 9. Acoustic Doppler Current Profiler (ADCP) An ADCP measures the speed and direction of water currents using the Doppler effect. Applications Sediment transport studies River and estuary monitoring Ocean current analysis 10. Hydrographic Data Processing Software After field data collection, processing software turns raw readings into detailed maps and charts. Applications Bathymetric chart production Volume and dredging computation Data analysis and reporting Conclusion Hydrographic equipment enables professionals to understand and manage the world beneath the water. From echo sounders and side scan sonars to GNSS systems and USVs, each tool plays a vital role in producing accurate and dependable results. For reliable hydrographic equipment in Nigeria and Africa, Geossotech is your one-stop destination. We provide top-tier instruments, accessories, software, and technical support to ensure your project runs smoothly from start to finish.

Why Does My Coordinates Keep Shifting, Even with RTK Fix?

You’re using RTK. You’ve got FIXED. Everything looks fine… but your coordinates still shift. If you’ve ever walked back to a site only to find your points in the wrong place, even with FIX , you’re not alone. RTK coordinates don’t just shift by accident. Let’s break down the real reasons this happens, and how you can stop losing data. 1. Lost Correction Link Without Knowing  It might be because your GNSS receiver quietly lost connection with its correction source. RTK relies on real-time corrections from a base station or CORS. If your mobile data drops or your radio link weakens for just a few seconds, your receiver may continue logging but without valid corrections, you’re logging garbage. Monitor correction status at all times Use strong SIM cards or robust radio links Only allow point logging with a FIxed Status. 2. FIX Isn’t Always Accurate Don’t be fooled by the word “FIXED or “FIX’ as it may appear.” Not all FIX are good.You can still get wrong coordinates from a Fixed solution if satellite geometry is poor (e.g., high PDOP), or signal strength is low.  Because that FIX was weak to begin with. What to do: Only log when PDOP < 2 Wait 5–10 seconds after getting FIX before logging Monitor satellite quality in your field app 3. Pole Tilt = Horizontal Error Even a slight lean in your GNSS pole  especially one not using tilt compensation  causes shifts in horizontal position. At 2 meters height, a few degrees of tilt = 10–30 cm error or more. What to do: Initialize tilt sensors before you begin Use a bipod for stable pole positioning Watch your bubble constantly , especially on uneven terrain 4. Wrong Coordinate System = Huge Shifts Mixing up WGS84, UTM Minna Zone 32N, and Zone 31N is a common but costly mistake in Nigeria. Most GNSS receivers default to WGS84, but many projects, especially cadastral and engineering work, require coordinates in UTM Minna. If you log data in WGS84 and compare it to Minna-based plans, your coordinates can be 100 to 200 meters off. Worse still, using the wrong UTM zone, like Zone 31N in Port Harcourt instead of Zone 32N, can shift your data by hundreds of kilometers. The Easting values in each zone start from different origins, so the same point will appear in two completely different locations. What to do: Confirm your coordinate system before logging Match your system to project specs Ask your team: Are we using the same datum and projection? 5. Multipath Error: When Signals Bounce Nearby buildings, tree canopies, vehicles, even metal rooftops  all of these can bounce GNSS signals and create false positions. Your receiver might show FIX, but the signal it fixed on was reflected. What to do: Avoid reflective surfaces and dense trees Use receivers with strong multipath rejection Consider external antennas when working near structures 6. You Logged While in FLOAT Without Realizing It happens more often than you’d think. You believe you’re in FIX… but your app fell back to FLOAT mode and never warned you. What to do: Lock point collection to FIX only Use apps with clear FIX/FLOAT indicators Review point status logs before leaving site 7. Glitches: Firmware, App, and Compatibility Issues Some coordinate shifting comes from firmware bugs or outdated apps. Even with FIX, bad software can ruin your survey quietly. What to do: Keep your GNSS firmware updated Use recommended software from your GNSS provider Partner with a reliable local dealer (like Geossotech) for hands-on support Need Help Troubleshooting? At Geossotech, we help surveyors all over Nigeria and  Africa with the right equipment and technical help they need. Whether you bought your equipment from us or not, we’re happy to help. visit https://geossotech.com/ 📞 Call us: +234 706 176 9934📍 Visit our office @ N0 3 Bello close, Chevvyview Estate, Chevvydrive, Lekki-Epe Expressway🛠️ Book a setup check or demo Contact us: https://geossotech.com/new-contact/ Final Reminder: FIX is Not Enough If you walk away with one thing from this article, let it be this: FIX means nothing… if the rest of your system isn’t solid. IF your GNSS is not fixing then this  https://geossotech.com/gnss-not-fixing-causes-fixes/  is a must read To know more about the brand of GNSS we sell visit https://www.comnavtech.com/

Precision Delivered, Solutions Empowered.

Copyright 2024 © GEOSSO Technologies Ltd. All Rights Reserved.

Scroll to Top

Free Guide:

HOW TO START A DRONE MAPPING BUSINESS IN NIGERIA

Click on the link below to register now!!