SonTek About Us

About SonTek

Founded in 1992 and advancing environmental science globally, SonTek manufactures acoustic Doppler instrumentation for water velocity measurement in oceans, rivers, lakes, harbors, canals, estuaries, industrial pipes, and laboratories. SonTek's sophisticated and proprietary technology serves as the foundation for some of the industry's most trusted flow data collection systems, such as the FlowTracker, the RiverSurveyor, and more recently, the SonTek-IQ. SonTek is located in San Diego, California, and is a division of Xylem.

Our mission has always been to advance environmental science in over 100 countries to manufacture affordable, reliable acoustic Doppler instrumentation for water velocity measurement in oceans, rivers, lakes, canals, harbors, estuaries, and laboratories. Our instruments use sound waves to tell you how fast water is moving, where it is moving, and even if it is not moving at all. Our customers are scientists, engineers, hydrologists, research associates, water resource planners, and anyone that needs to collect velocity (speed) data in every kind of body of water imaginable.

About Xylem Analytics

Xylem's analytics businesses are leading manufacturers of premium field, portable, laboratory, and online analytical instruments used in water and wastewater, environmental, food and beverage, pharmaceutical, and life science applications. The company's meters, sensors, analyzers, and related consumables are used daily by thousands of end-users worldwide to analyze and control quality in countless applications where precise measurement is required. Xylem Analytics started with the core brands of WTW, SI Analytics, Aanderaa Data Instruments, Global Water Instrumentation, Ebro, and Bellingham + Stanley and has grown through a series of successful acquisitions, including OI Analytical, YSI, MJK Automation, and most recently, HYPACK.



  • SonTek founded – In 1992, SonTek was a classic start-up—the vision of idealistic, young entrepreneurs pushing existing technology beyond its limits and answering the challenges posed by their brightest customers. As the company expanded its lineup and its customer base, it grew from its foundations in ocean research to address measurement needs in rivers, lakes, and irrigation systems. It also ventured from early acoustic Doppler technology into the cutting edge of acoustic measurement technology.


  • ADV – The first doppler systems were called Doppler Velocity Logs, used to help navigate large ships. The original SonTek ADV sensors were single-point devices used by universities and government agencies in laboratories.
  • ADV-1 – Measuring three-dimensional fluid flow at a point 5cm below the transducer, the ground-breaking ADV-1 paved the way for the development of new acoustic doppler instrumentsToday, the original SonTek ADV-1 is proudly displayed at the Army Corps Waterways Experimental Station's museum in Vicksburg, Mississippi, where it stands as a symbol of Dr. Krause's vision, which is fulfilled by innovative technology from SonTek.


  • The National Science Foundation awarded SonTek a grant to develop an acoustic Doppler profiling instrument that could be deployed in various environments, including near-shore and port areas.


  • ADP released – A robust field instrument with a three-axis array for 3D current profiling. The ADP also introduced unique design features and software to minimize side-lobe interference, a loss of data near the signal boundary—the water's surface or the bottom—that significantly reduced other profilers' accuracy and sampling field. By reducing side-lobe interference, the SonTek ADP could be used in shallow water and deeper deployments. This invention represented SonTek's first significant foray into innovations in power management, setting the stage for a wide range of instruments for field deployments lasting weeks or even months.
  • ADVOcean released


  • CurrentSurveyor released
  • Argonaut-MD released - The first Argonaut—the Argonaut-MD—was roughly the diameter of a wine bottle and slightly over two feet (60 cm) tall to enable plenty of battery capacity. The streamlined instrument tackled the challenge of measuring deep ocean currents, where the need for compact size, lengthy deployments, and reliable data had long bedeviled engineers. NOAA rapidly accepted the Argonaut to collect ocean circulation data for climate studies in the tropical Pacific.


  • MicroADV released
  • Argonaut-XR and Argonaut-SL released - The Argonaut-SL was a game-changer for SonTek. Initially designed for ports, where it could be mounted to a piling to provide current data across the width of a channel, it was quickly adopted by U.S. Geological Survey (USGS) hydrologists for measuring the speed of water flowing in rivers. Until then, SonTek was staffed by oceanographers. To meet—and understand—the emerging needs of river hydrologists, the company began hiring freshwater experts and studying flow and discharge. Argonaut-SLs were soon mounted on bridges, pilings, canal walls, and customized fixtures worldwide, fueling insight into a river, stream, canal, lake, and stormwater flows. In a few years, the Argonaut-SL became SonTek's leading product line.


  • Hydra released
  • PC-ADP released


  • Argonaut-ADV released
  • Rivercat Mini-ADP released - The inspiration was to create not just the industry's first floating instrument but one that would deliver data of unprecedented detail and accuracy in a complete, turnkey solution for measuring river discharge from a floating platform.


  • FlowTracker Handheld-ADV released
  • Triton released
  • YSI acquires SonTek


  • Argonaut-SW released
  • UK Rivercat released


  • 500 kHz Argonaut-SL (Vertical Beam) released


  • Testing Tank Construction (?)


  • International FlowTracker (WITH SmartPulse HD) released


  • SonTek HQ moves to Summers Ridge
  • Argonaut-SL 500,1500,3000 released


  • RiverSurveyor S5 & M9 released - The entire SonTek team was engaged, developing the five-beam RiverSurveyor S5 and the nine-beam M9, and the multi-frequency platform at the heart of each instrument. A giant leap from the single-point ADV or the single-frequency Argonauts and ADPs, the new RiverSurveyor S5 and M9 were the first instruments of their type to include a vertical beam. 


  • CastAway-CTD released - SonTek has continued to innovate, making it easier and more reliable than ever to gather rich data with ever-smaller instruments. The novel, palm-sized CastAway-CTD provides university researchers, consultants, and others with conductivity, temperature, and depth data to support their other measurements. The CastAway-CTD also empowers citizen scientists, like Inuit pack ice hunters in Canada, tracking changes in the Hudson Bay or long-distance sailors gathering data along their routes.


  • ITT Acquires YSI & SonTek and Forms ITT Analytics; Spins Off ITT & Becomes Xylem Inc.
  • SonTek-IQ released


  • SonTek’s 20th Anniversary
  • SonTek-IQ Pipe released


  • HydroSurveyor released


  • FlowTracker2 released – An upgrade from SonTek's first blockbuster product with a state-of-the-art graphical user interface to streamline measurement collection and improve data quality—is being used by technicians and scientists of all stripes from northern California to Nepal. And the SonTek-IQ brings the latest technology to irrigation canals, shallow streams and rivers, and pipes for measurements even in extremely shallow water and low-flow conditions.

A Brief History of SonTek

Since its founding in 1992, SonTek has been an innovation leader in measuring the physical movement of water—depth, velocity, waves, and flow. Building on the use of acoustic Doppler signals to measure the movement of water, founders Ramon Cabrera and Atle Lohrmann created a culture of innovation and set the stage for SonTek's global success.

Decades before, naval engineers first harnessed the ability to send out an acoustic signal, bounce it off the seafloor, and read its return signal to establish the speed and direction of ships traveling on the ocean. Following the advent of those Doppler Velocity Logs, advances in microelectronics and digital signal processing significantly improved the transmission, reception, and interpretation of acoustic signals. Those advances enabled scientists to start reading acoustic signals as they bounced off particles and bubbles suspended in the water column rather than just off the bottom of the sea. That allowed them to apply acoustic Doppler technology to profile water currents for scientific and other practical applications. The Acoustic Doppler Current Profiler (ADCP) was born.

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Going with the Flow: The FlowTracker

As SonTek gained familiarity with the surface water hydrology market, the company sought to apply its instrumentation insight and innovation to develop new solutions to old problems. Driven by the pent-up demand for an electronic alternative to the classic propeller flow meter—used for over a century to measure river discharge—SonTek created the FlowTracker Handheld ADV system, which married SonTek's original ADV innovation with the ultra-flexible Argonaut platform.

Unlike the mechanical propeller meter—which required the operator to count clicks in a headset, convert the clicks to an estimate of velocity, and, ultimately, calculate discharge on paper—the FlowTracker included a handheld interface and powerful calculation software in a portable, field-ready instrument.

Handheld or mounted on a wading rod, the FlowTracker delivered robust 2D and 3D flow measurements and automatically calculated and recorded discharge. The user-friendly system also introduced SonTek's SmartQC software, a series of built-in data quality checks and automatic calibration checks that heralded SonTek's entry into enhanced user interface development.

Easy to use—new technicians could master it after a few hours of training and practice—the FlowTracker was an international hit and disrupted the worldwide use of mechanical current meters for streamflow. SonTek adapted its software package to include ISO and USGS discharge calculations and interfaces in English, Spanish, French, Italian, and German. FlowTracker sales exceeded projections and lifted the company to the next level, solidifying the SonTek brand name as a leader in innovation.

In 2007, the company moved to its present location—a more significant, newly built, better-appointed facility. Promoting a research-grade testing tank, improved workspaces for the engineers, and more commodious office space for the marketing and customer service teams that had grown to cover a global market. Staying close to its San Diego roots, SonTek had grown over the years from its experimental, "skunkworks" atmosphere into a global high-tech company in a space that encouraged further growth. 

All Aboard

The RiverSurveyor S5/M9 brought a unique combination of vertical beam and 25-degree slant-angle beams that provided the capacity to profile water velocity and measure depth using bottom tracking, bottom detection, incoherent, pulse coherent, and broadband pulses and processing. SonTek's revolutionary SmartPulseHD technology provided:

  • Dynamic selection and optimization.
  • It allowed the S5 and M9 to automatically switch frequency and pulsing schemes for each sample based on velocity and depth to deliver seamlessly.
  • It provided high-definition data over a wide range of environmental conditions.

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With a RiverSurveyor S5/M9, operators could measure shallow to deep sections of a river with a single system, a task that previously required two separate instruments with different frequencies to achieve the same performance.

While programmers were developing the pinging and processing software—and making them user-friendly—other SonTek engineers developed the integrated DGPS and RTK GPS systems, batteries, telemetry packages, and hulls that supported the RiverSurveyor.

The result was revealed when the RiverSurveyor S5 and M9 were launched in 2009—rich, detailed visualizations of depth, velocity, and direction in vivid colors processed by RiverSurveyor Live software. From irrigation canals to the churning Amazon to Arctic glaciers, hydrologists could dive into mysteries of current and flow that had been buried deep beneath the surface. 

As the RiverSurveyor market propelled SonTek to new heights, the company delved into the specific needs of the irrigation market. SonTek had the opportunity to collaborate with the Irrigation Training and Research Center (ITRC) at California State Polytechnic Institute and work on projects from the arid western U.S. to Spain's agricultural heartland. SonTek hosted its first user conference in Nevada and made inroads into China and other Asian markets.

Adaptations and Growth

With its SmartPulse HD technology and leadership in acoustic Doppler signaling, software, and visualization, SonTek fine-tuned and upgraded many of its instruments, integrating SmartPulse HD technology into other systems.

 In laboratories and irrigation systems, from pure glacial melt to stormwater overflow, SonTek instruments have become the gold standard in a wide range of applications. And from its roots as an ocean-tech start-up to its current role as an integral part of Xylem Analytics—a global leader in analytical instrumentation—SonTek has built a reputation for innovation, quality, and a never-ending focus on the needs of its customers around the world.

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