CDD1000 Dual-Axis Doppler Log

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Product Details

China. Shanghai
1. Product Overview
1.1 Main Uses

The CDD1000 dual-axis Doppler log is a marine navigation device used to continuously measure the longitudinal and lateral velocities of a moving vessel relative to the water column, and automatically accumulate the total distance traveled. It can provide real-time speed and distance information of the vessel to various user devices.
1.2 Working Principle

According to the Doppler effect, after the device transmits a pulse signal of a certain frequency toward the seabed via a transducer, the transducer can receive echo signals reflected from both the scattering layer in seawater and the seabed. In addition to the time delay difference between the transmitted and received signals, there is also a difference in signal frequencies—the Doppler frequency shift. By processing and calculating this frequency shift using a computer system, it is possible to obtain information about the vessel’s speed and distance traveled.
1.3 System Composition

The basic system configuration consists of: one main display, one signal processing unit, one speed indicator, one transducer, and one water gate valve.

2. Main performance indicators

Power supply
Requirements	AC 220V ±10% 50Hz ±5%, 150W
Performance
Speed measurement range	-10 to +35 kN
Accuracy	±0.2 kN (for the water layer)
Navigation solution accuracy	±0.1%
Single-flight range	0 ~ 9999.99 nm;
Cumulative flight range	0~99999.99 nm;
Interface
Serial interface	6-channel RS485 interface for external speed output

3. System Model Description

4. Instrument Model Description

Serial number	Instrument Name	Model	Note
1	Signal Processing Unit	CDD1000-1
2	Main display	CDD1000-2
3	Speed indicator	CDD1000-3	Can be additionally equipped
4	Transducer	CDD1000-4
5	Water gate valve	CDD1000-5	Compatible with planar sensors

5. Examples of Main Base Products
5.1 Signal Processing Unit

Provide power to the entire system and perform calculations for speed and range, supplying speed and range information to the main display, speed repeater, and other devices.

5.2 Main Display

Displays speed and range, receives status information, and sends control commands to the signal processing chassis.

5.3 Speed Indicator

Receive speed information from the signal processing chassis via the serial port and display the speed.

5.4 Transducer

The transducer consists of four array elements and, in conjunction with the electronic subunit, enables the transmission and reception of acoustic waves. The transducer comprises array elements, a main body, and a watertight protective casing, ensuring overall pressure resistance and watertight integrity.

6. Basic Supporting Plan
Depending on the type of sensor used, there are two basic configurations: a flat-sensor configuration and a measuring-rod configuration.
6.1 Planar Sensor Supporting Solution

Serial number	Instrument Name	Model	Unit	Quantity	Note
1	Signal Processing Unit	CDD1000-1	Taiwan	1
2	Main display	CDD1000-2	Taiwan	1
3	Speed indicator	CDD1000-3	Taiwan	1	Can be upgraded to 2.
4	Transducer	CDD1000-4	Taiwan	1
5	Water gate valve	CDD1000-5	Taiwan	1

7. Supporting System Connection Diagram

8. Additional Notes: Requirements for the Installation of the Log Transducer:
a. To ensure the instrument functions properly, when installing the transducer, its radiating surface must be flush with the outer hull of the vessel.
b. The transducer should be installed at a location approximately one-third to one-quarter of the way from the ship’s bow, in an area of the hull where the influence of water flow is relatively minimal, and it must be ensured that the transducer remains submerged even when the vessel has its minimum draft and maximum roll.
c. The installation baseline of the transducer at the bow and stern shall have a deviation angle from the ship’s bow-stern line within ±1°;
d. Within a 5-meter radius near the transducer, there should be no protrusions that could disturb the water flow, as well as no suction or drainage holes.