Products from Sonobuoy TechSystems

Passive Sonobuoys from Sonobuoy TechSystems

Localization, or the precise determination of a submarine's location, course, and speed, is done with passive sonobuoys whenever possible. In the 1980's, when airborne US Navy searched for submarines, passive sonobuoys typically performed the majority of initial detections. Passive tactics are used because they deny a submarine the knowledge that a tracking aircraft is present. The 'A' size sonobuoys discussed below can be air-launched since they all employ a parachute to retard their descent and provide descent stability. They can also be hand-launched over the side of a ship. All employ a battery, which is energized upon saltwater contact. Once energized, a mechanism for inflating a float with CO2 gas is activated, suspending the sonobuoy. The sensors are then released to specified depths. Passive sonobuoys use hydrophones to convert underwater sound into electrical signals, which are amplified and frequency modulated for VHF transmission. Some sonobuoys have precision-calibrated hydrophones. Most sonobuoys automatically scuttle within 8 hours of deployment. Sonobuoys are typically shipped in a Sonobuoy Launch Container (SLC) that serves as the shipping, storage, and aircraft launch container or in a gray overpack for pneumatic or free-fall launch.

For the DIFAR sonobuoys (Directional Frequency Analysis and Recording), the main sensor is a hydrophone that has directional detection capabilities. The latest generation of DIFAR sonobuoys offers various sensor types, electronic selection and post-launch control.

AN/SSQ-53D DIFAR

The AN/SSQ-53D is the most widely used sensor internationally for all phases of ASW search and tracking. Basic capabilities include three hydrophone selections (90, 400 and 1000 feet), five life selections (0.5, 1, 2, 4 and 8 hours), DIFAR sensor, and the capability to set one VHF transmitter channel out of 99 available channels. The life, depth, and channels must be set using Electronic Function Selection (EFS) prior to launch.

AN/SSQ-53F DIFAR

The AN/SSQ-53F DIFAR is the latest directional passive sonobuoy being produced for the U.S. Navy. Basic capabilities include four hydrophone depth selections (90, 200, 400 and 1000 feet), five life selections (0.5, 1, 2, 4 and 8 hours), DIFAR, Constant Shallow Omni Sensor (CSO) or Calibrated Omni (CO), sensor selection capability, DIFAR AGC (Automatic Gain Control) On/Off and the capability to set one VHF transmitter channel out of 96 available channels. Depth, life, sensor, AGC, and channel selection may be set using Electronic Function Selection (EFS) prior to launch, and all but depth selection can be changed after deployment via Command Function Select (CFS). This sonobuoy automatically scuttles after 8 hours.
 Download ANSSQ-53F Data Sheet

AN/SSQ-77C VLAD

This passive sonobuoy has the directional capabilities of the Q53 DIFAR and, additionally, a vertical line array (VLAD) of omnidirectional hydrophones for improved tracking capability in a noisy, high-traffic environment. This sonobuoy is primarily used as a deep water multi-static receiver There are five different operating life selections (0.5, 1, 2, 4 or 8 hours) and three sensor depth selections (200, 500, 1000 ft). Depth, life, and channel selection may be set via Electronic Function Selection (EFS) prior to launch, and all but depth selection can be changed after deployment via digital Command Function Select (CFS).
 Download ANSSQ-77C Data Sheet

AN/SSQ-101 ADAR

The Air Deployed Active Receiver (ADAR) sonobuoy consists of a horizontal planar array of omnidirectional sensors. The sonobuoy is primarily used as a shallow water receiver for multi-static operations. This sonobuoy transmits for a minimum of 4.5 hours over an eight hour period. Switching the VHF transmitter off when active acoustic signals are not being transmitted in the water extends the period of operation. This sonobuoy has three selectable depths (65, 325, and 500 ft.). Depth and channel selection may be set via Electronic Function Selection (EFS) prior to launch, and channel selection can be changed and VHF transmitter power can be switched on and off after deployment via digital Command Function Select (CFS).
 Download AN/SSQ-101 ADAR Data Sheet

Active Sonobuoys

Target detection of a very quiet diesel submarine or a submarine in attack mode, is very difficult, especially in extreme environmental conditions. In these situations, it is critical to localize the target quickly and accurately. This is when active sonobuoys are used. The released acoustic energy ("ping") from an active sonobuoy and the resultant return signal enable accurate positioning of the submarine in both range and bearing. When two or more fixes are obtained, the speed and the course of the submarine can be established.

The following 'A' size sonobuoys can be air-launched from fixed or rotary-wing aircraft, since they all employ a parachute to retard their descent and provide descent stability. These sonobuoys are also easily deployable from the deck of a surface vessel. Descent of the sonobuoy is stabilized and slowed by a parachute. They also all employ a battery, which is energized upon entry into salt water. As with the passive sonobuoys, once energized, a mechanism for inflating a float with CO2 gas is activated, suspending the sonobuoy. The sensors are then released to specified depths. These sonobuoys use a transducer to introduce acoustic energy into the water ("ping") and use the transducer to receive the return echoes, which are then amplified and frequency modulated for VHF transmission. All of the sonobuoys scuttle after a preset length of operation.

AN/SSQ-47B Range Only

This active sonobuoy, sometimes also referred to as a "Pinger" sonobuoy automatically commences to generate pings at periodic intervals after water entry. During the interval between pings, these sonobuoys receive omnidirectional acoustic data in the same frequency band as the radiated signal and transmit this data over one of twelve selectable RF channels. There are six different ping frequencies that can be specified for these sonobuoys. The sonobuoys are manufactured to the ping frequency specified by the customer. This sonobuoy is manually set prior to deployment to operate at 60 or 800 feet. These sonobuoys provide target range information, but not direction, for detected targets.
 Download AN/SSQ-47B Data Sheet

AN/SSQ-62B/D DICASS

The AN/SSQ-62 Directional Command Activated Sonobuoy System (DICASS) is currently the primary active sonobuoy used internationally. DICASS permits the operator to pinpoint a target's position in range and bearing. The AN/SSQ-62D version has been in service for a decade and offers operation on one of four acoustic frequencies (6.5, 7.5, 8.5, and 9.5 kHz) and the selection of one of two depth families. The effective source level of this sonobuoy varies with the acoustic channel between 199 and 201 dB.

AN/SSQ-62E DICASS

The current generation of the DICASS family of active sonobuoys is the AN/SSQ-62E. This sonobuoy is in use by the United States and several other countries. The major advantage of the AN/SSQ-62E over the AN/SSQ-62D is that it permits each sonobuoy to transmit on any of four acoustic channels and their respective RF channels. Optional thermal battery technology allows DICASS sonobuoys to be shipped and stored in a relatively unrestricted manner.
 Download AN/SSQ-62E DICASS Data Sheet

Other underwater Signaling and Receiving Devices

AN/SSQ-36B BT

Prior to deployment of any detection sonobuoys, it is advisable to have a vertical temperature profile of the ocean. The AN/SSQ-36B Bathythermal (BT) buoy provides a low-cost method to obtain vertical temperature profiles of water column. This approach provides near synoptic area surveys while eliminating costly vessel time. The BT is widely used for airborne Anti-Submarine Warfare (ASW) applications to evaluate local effects of seawater temperature on sonar propagation and acoustic range prediction. This sonobuoy has an operating life of approximately 12 minutes at which the temperature probe is at a depth of 800 meters (2625 ft). The sensors are calibrated for an accuracy of ± 1 degree F at a descent rate of 5 feet per second. VHF transmissions from this sonobuoy are processed to read temperature versus descent in real time. It can be air launched or over-the-side launched, is 'A' size (can be 'G' size), and is 99 channel selectable. The transmitter output is ¼ Watt.
 Download AN/SSQ-36B BT Data Sheet

MK-84 MOD 1 SUS

The Signal Underwater Sound (SUS) device is used primarily for one-way acoustic communication with submarines. The device can be set to generate one of five distinct, coded sequences. Four of these sequences consist of a continuous tone that alternates in frequency in accordance with the timing sequence defined in the Code Table (see specifications). The fifth sequence is a continuous tone at a single frequency. Third harmonics of the fundamental frequencies are also generated at levels slightly less than those of the fundamentals. A five-position switch on the side of the unit accomplishes settings. The MK-84 is designed to provide a source level of 160 dB per micro-Pascal within two (2) seconds of water entry and throughout its one-minute life.
 Download MK-84 MOD 1 SUS Data Sheet

AN/SSQ-125

The AN/SSQ-125 Coherent Source is a NATO, A-size sonobuoy manufactured by SonobuoyTech Systems for use as a source in a multi-static field. The AN/SSQ-125 is capable of generating a variety of waveforms upon command and is designed to work with the AN/SSQ-53F, AN/SSQ-77C and AN/SSQ-101 (ADAR) sonobuoys.
 Download Low Frequency Coherent Source Data Sheet