SPAN® Heave

SPAN® Heave

The rise and fall movement of a vessel correlates directly to the returning sonar data in marine mapping applications, leading to errors in depth measurement. To compensate for these errors, select SPAN receivers feature the robust heave output option.

The images below show the ocean floor mapped with and without heave compensation. With wave motion eliminated from the data, a much more accurate and coherent image is generated.










  • Provides instantaneous and delayed heave measurements to compensate for wave effects
  • Configurable heave filter window
  • Inertial Explorer processing offers a post-processed heave filter solution
  • SPAN INS functionality

Two SPAN Heave Solutions Available

NovAtel® offers real-time and post-processing options for marine application developers.

Real-Time Measurements: SPAN receivers provide accurate, instantaneous and delayed measurements of wave motion under the most difficult marine conditions and vessel dynamics. They offer a full six degrees-of-freedom position and orientation, measuring position, velocity and attitude. The heave filter provides an asynchronous log available at 10 Hz, a synchronous log available up to the IMU data rate and a delayed log up to 10 Hz.

Post-Processed Solution: Inertial Explorer® software from NovAtel's Waypoint® Product Group, post-processes data forward and backward, ensuring the most accurate heave solution.

SPAN Technology

SPAN (Synchronous Position, Attitude and Navigation) technology brings together two different but complementary technologies: Global Navigation Satellite System (GNSS) positioning and inertial navigation. The absolute accuracy of GNSS positioning and the stability of Inertial Measurement Unit (IMU) gyro and accelerometer measurements, combine to provide an exceptional 3D navigation solution delivering full attitude and orientation.

Supporting Products

Other product categories which are required with this product to create a complete system.

SPAN® GNSS Inertial Navigation Systems

Combining GNSS receiver technology with Inertial Navigation Systems (INS) provides a superior positioning solution with 3D position, attitude (roll, pitch, yaw) and velocity. Used with commercial cards or with SAASM.


GNSS receiver performance is dependent on your choice of antenna. We offer high performance, compact, low cost and ground reference station antennas. Our anti-jam antenna is available for military or homeland security applications

Alternate Products

Other similar products which could be used instead of the product, depending on application.

Inertial Explorer®

Expands on the powerful features of GrafNav by adding support for loosely coupled and tightly coupled GNSS+INS processing

How it Works

The SPAN Heave algorithm estimates the short term, vertical displacement of a vessel, relative to the mean sea state caused by waves or swells. This allows a sonar system to compensate for the range errors caused by these effects.