Radar Rescue Transponder

Principle of Operation

The SART emergency response transponder is a transceiver operating in the frequency range of 9.2-9.5 GHz marine navigation radar stations. In standby mode, only the transponder’s receiver works, when a vessel or aircraft approaches an active radar, the receiver detects its radiation and activates the built-in transmitter at the time of the next pulse, which emits a series of response pulses received by a narrowly directed radar antenna along with the reflected signal, which leads to that the defendant’s work looks on the radar screen as a series of luminous points clearly visible against the background of interference, directed from the object towards increasing range (usually 12 pcs. to block the entire frequency range, each pulse modulated transponder transmitter frequency). Thus, the operator can clearly see the emergency object on the radar screen in conditions where its identification can be very difficult, for example, during strong waves, in the dark among floating debris, etc., the radar can be of any type without any special additional devices. , the only criterion is the correspondence of the frequency range. When approaching close to the object, the responder usually begins to be activated by the side lobes of the radar antenna and the image on its screen turns into concentric circles.

Application

Under normal conditions, the radar transponder is on board the vessel in the off state. It is installed near lifeboats in order to quickly move it there during evacuation. When the defendants are 2 or more, they are installed from different sides of the vessel. In an emergency, the defendant usually turns on and, if necessary, transfers the person responsible according to the ship schedule to the boat. To increase the detection range, the transponder should be installed as high as possible, at a height of 1 meter above sea level, detection from a ship at a distance of about 5 nautical miles and from an airplane flying at an altitude of 1 km at a range of about 50 nautical miles is provided. The transponder entering the radar coverage area is signaled by a light or sound signal.

Specifications

According to the requirements, emergency responders must provide:

• manual on, off, indication in standby mode
• water resistance at a depth of 10 meters for at least 5 minutes, withstand dropping into water from a height of 20 meters, have a floating line
• visual or audible indication of normal operation and warnings that the radar is powered by radar
• standby time of 96 hours and 8 hours with continuous exposure to 1 kHz radar pulses
• maintain operability in the temperature range from −20 ° to + 55 ° С
• operate at a distance of up to 5 miles when irradiating a radar with an antenna height of 15 meters and when irradiating an aircraft radar with a power of 10 kW at a distance of 30 miles from a height of 1000 meters.

RLO hulls, as a rule, have high strength, positive buoyancy and for better visibility, are painted in bright orange colors, in addition, they may have a signal lamp that acts as a signal beacon. The power sources are disposable batteries, allowing a long shelf life of 5-10 years ^[1] .

• Radar transponder