Surface Target Surveillance Radar LW-R127

Publish Date: 2019-05-06 Views:544


1. Brief Introduction

LW-R127 radar is an independently developed surface target surveillance radar developed by Mskyeye Co., Ltd., which adopts advanced techniques such as waveguide crack antenna, solid-state transmission, pulse compression, time diversity and frequency diversity, pre-detection tracking, sea clutter and meteorological clutter suppression algorithms. LW-R127 has superior small target detection and tracking capabilities for complex sea condition systems. It is the core sensing equipment used in Vessel Traffic Service System(VTS)、Coastal Surveillance System(CSS) or monitoring system of the wind farms on the sea.

2. Main Application

VTS system is composed of communication equipment, VTS radar, ship automatic identification system(AIS), closed circuit television(CCTV), hydrometeorological equipment, data processing system and so on. As the core sensing equipment of VTS, LW-R127 radar is a product developed in strict accordance with the requirements of the International Lighthouse Navigation Association (IALAV.128 Recommendation for VTS) for radar detection performance. The LW-R127 radar is capable of tracking and monitoring the position, speed, course and other parameters of the moving vessel on the surface of water. These parameters have time information of GPS or Beidou calibration. Meanwhile, the radar can also track and monitor the position of moored vessels, lighthouses and buoys, and provide basic data for VTS system.

LW-R127 radar can also be installed at coastal observatories or outposts to monitor all kinds of illegal activities near the coastline and to enhance the vigilance of law enforcement agencies. Illegal activities may be aimed at smuggling speedboats, illegal immigration vessels, pirate boats, illegal fishing vessels, polluting ships, and so on. This radar is the core monitoring equipment of sea-air early warning system for offshore wind farm, and is widely used in offshore wind farm.

3. Technical Characteristics

3.1 Agile Configure

When LW-R127 radar is used as CSS radar or VTS radar, the hardware equipment is exactly the same, the difference is that different data processing application software needs to be configured. In addition, radar transceiver channels (including signal and data processing) can be configured as low-cost single-channel systems or dual-channel systems with better mission reliability.

In practical applications, VTS systems are divided into basic types (information services for VTS and possible navigational assistance services) and standard types (information services, navigation assistance services and traffic organization services in areas with moderate traffic density and no major navigational hazards), enhanced types (for high traffic density and specific multi-hazard area services). According to the need of practical application, LW-R127 can choose different radar products with different configuration, and obtain high cost-effective ratio.

3.2 Shaped and Circularly Polarized Antenna

The radar antenna adopts low sidelobe and low cross-polarization waveguide traveling wave array antenna, and the extremely low sidelobe can restrain the azimuth false target very well, and the antenna pitch surface is designed with reciprocal cut square shape, which effectively improves the detection coverage in the near area of radar. Circular polarization improves the performance of suppression of meteorological clutter interference.

3.3 All solid state transmitter

All-solid state transmitter overcomes the problem that magnetron transmitter needs to be replaced regularly. The high reliability of solid state transmitter effectively reduces the life cycle cost of radar system. In addition, the extremely low transmitter peak power also reduces the peripheral radio interference from  radar system.

3.4 All-phase participating pulse compression

The high stability receiver frequency source synchronous transmitter and receiver phase, through the pulse compression technology to compare the target echo phase change can obtain the corresponding target Doppler information. Through the MTI processing, it suppresses the environment clutter interference and analyses The target motion information. The superior pulse compression sidelobe performance can also restrain the false target in the range direction.

3.5 Frequency Diversity and Time Diversity

How to reduce the influence of sea clutter on target detection performance is an important function of VTS or CSS radar. LW-R127 radar transmits electromagnetic waves with different frequencies in the same beam. The reflected echo fluctuation correlation of the target is weaker than that of the target irradiated by the same frequency. The signal-to-clutter ratio of the target to sea clutter can be improved by receiving processing, so the detection performance can be improved. This method is called frequency diversity processing.

The LW-R127 radar also emits two electromagnetic waves with different frequencies in the same region in a certain time interval, and this time interval is larger than the correlation time of the sea clutter, which makes the sea clutter relatively independent, and the correlation between the sea clutter and the sea clutter in the echo becomes weaker. However, the fluctuation characteristics of the target are almost unchanged, and the signal-to-clutter ratio of the target to sea clutter can be effectively improved by the accumulation detection. This method is called time diversity processing.

3.6 Target Detection and Tracking

Large dynamic receiver, medium-frequency high-speed sampling, pulse compression, CFAR processing, fine clutter map, pre-detection tracking, real aperture imaging and other technologies enable LW-R127 radar to provide clear high-resolution radar echo images. No manual radar system is required to detect and track small and large ships at different speeds at the same time.

3.7 Radar Display and Control

The radar display and control terminal has the functions of radar echo image display, target trace display, record repetition, radar equipment control, radar parameter configuration, radar fault display and so on. It provides a friendly man-machine interactive display interface.

3.8 External Interface

Radar external interface adopts standard network interface, which provides radar video, target trace, track, equipment monitoring and other information. Radar system can also provide traditional video signal interface.

4. Radar composition and configuration

4.1 Configuration of dual-channel and single-channel radar systems

LW-R127 radar can configure dual-channel system or single-channel system according to user's needs. The configuration of dual-channel system is illustrated in Figure 1. The dual-channel transceiver system is equipped with a set of antennas, turntables, servo control and display terminals, while transmitters, receivers, signal processing and data processing equipment are equipped with two sets. When one of the transceiver channels fails, it can automatically switch to the other channel and continue to work. This configuration has higher task reliability, but the cost of the system is also high.

In the single channel radar system, the antenna, turntable, servo control, transmitter, receiver, signal processing, data processing and display and control terminals are all equipped with only one set of devices, and the system configuration diagram is shown in Figure 2. The advantage of single-channel radar is that the construction cost is relatively low and the control is relatively simple. It is suitable for applications with low requirement for data support.




Figure 1 LW-R127 Dual-channel Configuration


Figure 2 LW-R127 Single-channel Configuration

4.2 Radar Antenna

The standard configuration of LW-R127 radar is 5800mm antenna (see Fig.3). When the lower azimuth resolution or precision in practical application can also meet the requirement of application, lower cost antenna can be configured with shorter length antenna. Similarly, if the requirement for near-area coverage of radar detection is not high or the influence of rain clutter can be ignored, the components such as antenna lobe shaping and circular polarization can also be removed to reduce the cost of radar system.


Figure 3   LW-R127  Radar Antenna

4.3 Antenna Turntable and Servo Control Box

The antenna turntable of the LW-R127 radar (see figure 4 to the left) is used to drive the antenna to a 360 °rotation scan, and the transmit power generated by the radar transmitter is transmitted to the antenna through the rotating joints in the turntable. The target echo RF signal is received by the antenna and transmitted to the radar receiver by rotating joint. The turntable is also equipped with azimuth encoder, oil temperature and oil level sensor and other equipment. On the right side of figure 4 is the servo control box that controls the rotation of the antenna turntable. The servo control case can be mounted in the indoor computer room by hanging the wall. The size of the chassis is: high x wide × deep=460 x 330 x 225mm³.


Figure 4 LW-R127 Schematic Diagram of Radar Antenna turntable and Servo Control Box



4.4 Transceiver cabinet

The LW-R127 radar transceiver cabinet (see Figure 5) contains indoor feeder assemblies (waveguides, loops, couplers, etc.), transmitting power, transmitting components, receiving components, signal processing, monitoring components, ventilation units, power supply units, lightning protection, satellite timing equipment, etc. The transceiver cabinet is wall-mounted. Figure 6 shows the wall diagram of the dual-channel radar transceiver cabinet.


Figure 5  LW-R127 Composition Diagram of Radar Transceiver cabinets



Figure 6  LW-R127 Transceiver Cabinet (dual channel) Wall Diagram


4.5 Radar installation

LW-R127 radar equipment also includes signal processing data processing server, radar display and control terminal, waveguide aerator, etc.. Signal processing data processing server selects commercial server with higher main frequency and larger memory, and running clutter graph within server, MTI, constant false alarm rate, trace processing, track processing and other software. The radar display and control terminal is equipped with a commercial computer with high display resolution. It runs the target display and radar monitoring software on the computer. Data communication between server, computer, transceiver cabinet and servo control box is accomplished through LAN. In addition, according to the actual situation of the radar station, the antenna tower, lightning rod and installation, spare cabins, power distribution boxes, UPS, air conditioners should be selected. The radar installation diagram is shown in Figure 7

Figure 7 LW-R127 Installation Diagram

5.Main Performance Technical Index

4.6 Main Performance Indexes

The  main performance index of LW-R127 is strictly based on

< IALAV.128 Recommendation for VTS > . See Table 1 for details.

Table 1  LW-R127 Main Performance Indexes


Index Name

Constraint Condition

VTS Requirement

LW-R127 Index

Detection Range

Weather:clear

Sea Condition:level 4

Radar Antenna:20m Altitude:1mRCS=1m2

Basic:none

Standard:none

Enhanced:5nm/9.26km

5.4nm/10km

Weather:clear

Sea Condition:level 6 Radar Antenna:20m Altitude:3mRCS=10m2

Basic7nm/13km Standard8nm/15km

Enhanced9nm/16.7km

15nm/27.78km

Range Accuracy &

Resolution Ratio

<5nm/9.26km

Display15m

Track25m

Display6m

Track18m

Horizontal Beam Width

-3dB

Basic:≤0.7°

Standard:≤0.45°

Enhanced:0.4°

≤0.44°

Antenna Sidelobe

Suppression

First sidelobe suppression

Basic-26dB

Standard-27dB

Enhanced-28dB

-27dB



5.2 Main technical index of product

LW-R127 main technical index, see Table 2.


Table 2 LW-R127 Main Technical  Index


Name

Index

Main Technical Index

Service Frequency

9140 MHz 9470 MHz

Gain

≥35 dB

Azimuth Sidelobe

≤-27 dB-5°-1.5°& 1.5°

Azimuth Beamwidth

≤0.44°

Pitching Beamforming

Reciprocal Cut Square(-40° +1°

Polarization Mode

Circular Polarization

Circular Polarization ICR

≥15 dB

Feeder Standing Wave

≤1.5

Antenna Size

5800×727×300mm3

Antenna Weight

180kg

Speed

24 RPM

Launching

Transmitting Power

≥50 W

Duty Cycle

≤20%

Pulse Top Drop

≤5%

Pulse Top Wave

≤3%

Pulse Front and Back Edge

≤20 ns

Input Excitation

10 dBm

Harmonic Output

≥45 dBc

Signal to Noise Ratio

≥60 dBc

Transmitter Efficiency

≥20%


Name

Index

Service Frequency

9140 MHz9470 MHzinterval 40 MHz

Noise Factor

≤3.5dB

IF-FRE

120MHz-60dBm+10dBm

Receiving Bandwidth

35MHz3dB tape width

Linear Dynamic Range

≥70dB

Receiving

Sampling Clock

160MHz≥10dBm

Timing Clock

80MHz≥10dBm

Waveform Clock

400MHz≥10dBm

Pulse front and back edge

20ns

Local Phase Noise

-105dBc/Hz@1kHz

Output Excitation Power

≥10dBm50Ω

Signal to Noise Ratio

≥70dBc

Out-of-band Interference Suppression

≥45dB

Stray Suppression

≥60dB

Signal Processing Form

MTI+ real aperture imaging

Signal Processing

Processing Range

120m32km

Pulse Repetition Rate Ratio

1.1

Average Repetition Rate

3600Hz

Data Transfer Rate

2.5 Seconds/Fram

Pulse Pressure Ratio

35dBnarrow)、45dBwide

Spot Processing Capability

≥5000 Points / Fram

Track Processing Capability

≥300 Batch / Fram

Data Handling

Predictive Tracking Determination Time

≤1 min

Track Determination to Specified Precision Time

≤2 min

Data Loss to Track Automatic Termination Time

≥1 min

Tracking Target Velocity

≤70 knots(35m/s)

Tracking Target Speed

≤20°/s

Control

Radar system switch / Parameter setting / Channel switching

Monitor

Status / Diagnostics / Alert report data item

Data source identification, data reception system identification, time, supervisor measurement and control data

Name

Index

Communication Function

Send control commands and configuration parameters to receive radar data

Monitoring Function

Subsystem control, status monitoring, fault alarm, recording and querying syslog

Terminal

Display Function

A display, PPI, display area operation, display area settings, record and repeat data

User Management

User rights setting

Control

Antenna drive motor stop control

Servo

Receive and Transmit

Turntable sensor signal, support UDP protocol, communicate with monitoring terminal and execute control command

Power Distribution

Power Supply Form

380 V±10%50Hz±5%Three-phase five-wire system