Marine Radar Technology
Marine Radars typically operate at S-Band and X-band. Pulsed tube devices are typically used for detection along coastal lines, fixed harbor objects, and other ships and boats especially in low visibility coastal fog to avoid collision. Marine radars use a relatively narrow 360-degree scanning horizontal beam looking for targets while the radar range returns provide the target distance. A narrow horizontal beam provides better target resolution. A shorter range resolution provides better target separation. Marine radars are essentially a 2-D, range and angle, scanning reporting system. In a pulsed radar, target range is based on time difference between the transmitted pulse and the detected returned pulse. Since it takes more time for the pulse to return from a long range target, the time between any two generated pulses must be longer. The average radar transmitted power is defined as Peak Pulse Power x (pulse width / time between pulses). For example, a high power X-band radar with 25 KW peak power and 4.5 microsecond pulse width and a time between pulses = 1/180 second is equivalent to an average radar transmitted power of 20.25 Watts. This X-band radar has a detection range of 240 nautical miles. If the pulse width is reduced, the average power on target will also be reduced, and target detection range will be dramatically reduced by a factor of (average power)^1/4. This radar can be replaced with a solid-state continuous power radar of 20.25 Watt transmitter power. However, continuous power radars may be subjected to continuous “jamming” or self-jamming which must be handled carefully. A continuous power radar has the following advantages:
- Solid-state construction for extended operational life
- Reduced DC power requirements
- Reduced equipment size and weight
- Lower overall cost
CHANG has been conducting continuous power radar development and applications for more than 20 years in frequencies from 1 GHz to 100 GHz (microwave to millimeter wave). We decided to enter the Marine Radar business based on the following capabilities:
- Programmable digital waveform generation that can maintain a fine range resolution (in the order of 1 ft or less) at maximum detection range
- State of the art digital signal processing based on FPGA (Field Programmable Gate Array)
- Small to large size metal-coated ultra lightweight and rugged graphite reflector antenna
- Capability with pan/tilt gimbal systems
- Capability of stabilization platform for a gimbaled radar
Coastal radars are facing extreme challenges in detecting small boats such as Rubber Inflated Boats and jet-ski type vessels in an effort to counter illegal drug traffic and terrorists in high sea clutter environments. Sea clutter is difficult to handle statistically. However, a high-resolution coastal radar, with small horizontal scanning beam and small range resolution provides better sea clutter rejection in contrast to small target detection. Sea clutter rejection techniques in addition to using high-resolution have also been examined at CHANG. We have submitted a white paper to the Department of Homeland Defense regarding a Harbor Surveillance Radar.
We hereby solicit partners and investors to join us as we enter the marine radar business. Please contact us at generalinquiry@changind.com.