In modern hydrography, all measurements from the array of on-board sensors are processed by computers.This necessitates that all sensors provide their measured data in digital form. In echo sounding, in particular, a large number of analogue echoes are converted into a single depth value. However, in this automatic conversion the user losses informations about the echoes reflected by the top of the soil, by buried sediment layers and by additional reflectors in the water. This information in the form of the graphical deciption of all the echoes has to be used frequently in postprocessing to verify the depth values automatically determined by the echo sounder system.

To ensure the verifiability of the measured data, the new surveying echo sounders LituSystem / LituGraph have internal computers and show the recorded echoes on a LCD screen instead of using the conventional echo registration on electro-sensitive or thermo-sensitive paper. The modern display reduces paper usage and eliminates wear problems of the registration mechanics.

Special interface electronics converts the complete echo sequence, including all echoes due to intermediate and sediment reflectors, into a serial digital data stream, which can be received by any convential desktop or notebook computer of sufficient capacity.

The echo sequence can be displayed on screen in real time without delay using the Fz software LituPlot. The screen shows the familiar graphical echo registration plot that used to be printed onto paper with all the echoes generated in nature. For each sounding, a depth value is determined from the analogue echo sequence and is displayed on the screen instantaneously. If the LituSystem or LituGraph has several sounding frequencies depth values are determined for all frequencies and are displayed on the screen.

At the same time the graphical deciption is displayed on the screen the complete data stream of the echo sequence is archived on the hard disk of the built-in computer. The depth value of the main soil echo is saved as well and it can be transferred to ean external analysis module - if one exists. The data format can be adapted to be compatible with an existing surveying system.

A positioning or annotation system such as differential GPS receivers, laser distance measurements units or external computers can be connected to the LituSystem / LituGraph. The data strings are marked on the display and are saved onto the hard disk with the echo data.

The data saved on the hard disk can be transferred to any computer using diskettes, ZIP diskettes, CD-ROM or other mobile media. Furthermore, the built-in computer offers additional possibilities to work with the data or to transfer them, e.g. by radio transmission.

In the replay mode, a recorded echograph can be analyzed or verifies on the display of the on-board computer or checked at a computer at the office.

The LituSystem / LituGraph is connected to the ship's power supply (12 / 24 Vdc).