HMS

Question 1

What is the purpose of HMS?

Answer 1

To provide HMCS CHARLOTTETOWN with a means of acoustically detecting and tracking surface and subsurface targets using both active and passive SONAR methods.

Question 2

What is the SONAR Control Cabinet (SCC)?

Answer 2

The SCC controls the overall operation of HMS. It can be divided into two main parts: the Sonar Control Assembly (SCA) and the Sonar Interface Assembly (SIA). The SCC also contains a separate GPS interface. It is controlled by a key switch.

Question 3

What is the SONAR Control Assembly (SCA)?

Answer 3

This set of CCAs is responsible for controlling sonar operation, storing and displaying acoustic information, detection and tracking of contacts, and interfacing with other components of the HMS and other systems. A data base of active tracks and targets is maintained here. The SCA also interfaces with CMS via I/O Processor 2 and the Nav Suite.

Question 4

What is the SONAR Interface Assembly (SIA)?

Answer 4

The SIA consists of CCAs that control transmissions and generate the active ping. It accepts the analog acoustic data that is received by HMS, performs processing and digitization, and transfers information between itself, the SCA and the Signal Processor. The SIA uses crystal oscillators to generate the active ping by producing a set of seven identical pulse waveforms. There are three types of pulse trains that can be produced: fixed frequency pulse bursts, linearly modulated pulse bursts, and continuous fixed frequency pulses.

Question 5

What is the High Speed Signal Processor (HSSP)?

Answer 5

This cabinet processes digitized acoustic data received from either the SIA (Normal Mode) or Data Recorder (Replay Mode). It can also provide simulated outputs (Training Mode). It performs FFTs, band selection, beam forming, and matched filtering. Up to 72 active beams and 36 passive beams can be formed.

Question 6

What is the Maintenance Console?

Answer 6

The maintenance console is a laptop connected to the SCC IOT run Diagnostic Mode. It also allows the techs to view the system fault logs. The maintenance console is stored in the Fwd SIS.

Question 7

What is the Junction Box Interconnect (JBI)?

Answer 7

This unit provides connections between the Sonar Transmitter Group components, the SCC, and the C5 Main Control Panel. Internal relays use transducer position indicator signals from the C5 Main Control Panel to provide the SCC with the position of the sonar transducer.

Question 8

What is the Transmitter?

Answer 8

The transmitter consists of seven drawers: one for testing (Integrated Test Equipment (ITE)), and six for transmitting (Transducer Driver Assembly drawers). Each Transducer Driver Assembly drawer contains six Sonar Power Inverters (SPIs), for a total of 36 (one per stave). Each SPI is a high-power amplifier capable of producing up to 1.2 kW of power. Each SPI receives signals from the SIA and provides a sinusoidal input to the Sonar Transducer.

Question 9

What is the Integrated Test Equipment (ITE)?

Answer 9

The ITE consists of CCAs which constantly monitor the system for faults.

Question 10

What is the Transmit/Receive (T/R) Switch?

Answer 10

The T/R switch contains 36 solid-state switches which connect the staves to either the SPIs or the six receiver CCAs inside the SIA. The T/R switch also contains connections for a dummy load which can be used to troubleshoot the system.

Question 11

What is the Transmitter Power Supply?

Answer 11

The Transmitter Power Supply cabinet receives 115 V, 400 Hz, 3-phase and 440V, 60Hz, 3-phase power. It sends the 115V power to the Sonar Transducer. The power supply uses two rectifier stacks to produce 60 and 150VDC power from the 440VAC feed. This power is used to supply the transmitter.

Question 12

What is the SONAR Transducer?

Answer 12

The SONAR transducer consists of 360 single element transducers (SETs) arranged on 36 vertical staves. The 10 SETs on each stave are connected in parallel and driven as a single unit/stave. By modifying the amplitude/time delay of the signal received by each stave, the Transducer is able to generate omnidirectional and directional beams. On reception, the bearing of the received signal is determined by comparing the amplitude/time delay in the signal received by each stave. The UWT Transducer is mounted on the bottom of the Sonar Transducer.

Question 13

What are the Single Element Transducers (SETs)?

Answer 13

Each SET consists of a front radiating mass made of aluminum alloy and square in shape (but with rounded corners). There is also a rear radiating mass. Between the two radiating masses are ceramic (lead zirconate titanate) rings which have piezoelectric properties. Electrodes contact the rings to supply power. When electrical energy is applied to the ceramic rings, it causes them to deform through the piezoelectric effect, which in turn causes the aluminum and steel radiating masses to vibrate, inducing a pressure wave in the water.

Question 14

What is the C5 Hull Outfit?

Answer 14

The Hull Outfit supports the Transducer and is used to raise and lower it. It is controlled via the Alternate Control Panel (ACP) and the Main Control Panel (MCP). It is normally belt-driven by a 5hp motor, but can be operated manually using a hand wheel. It takes approx three minutes to raise or lower the Transducer with the motor, and can take hours by hand wheel. Once it is fully lowered, hydraulic down locks lock the Transducer in place. HMS is unable to transmit until it is fully down and locked in position.

Question 15

What is the sonar dome?

Answer 15

The Sonar Dome provides an acoustic window for HMS while also protecting it. It is filled with water.

Question 16

What is the Alternate Control Panel (ACP)?

Answer 16

The ACP contains one switch for raising the Transducer and another switch for lowering. A third switch is used to change between ACP and MCP control. Despite its name, this is actually the master control panel as it contains a switch that can be used to pass control to the MCP (only one panel can be in control at a given time). The ACP is located in the Sonar Trunk.

Question 17

What is the Main Control Panel (MCP)

Answer 17

The MCP contains a key switch, a raise switch, a lower switch, and a stop button. Unlike the ACP, pressing either the raise or lower switch will move the Transducer to either the fully up or fully down position. The MCP is located in the Fwd SIS.

Question 18

What is the SONAR Operator’s Console?

Answer 18

This is the main HMI for the system. It consists of two colour displays, an audio jack for headphones, trackball, joystick, keyboard, and several hard keys. A key switch is used to enable/inhibit transmission. The operator can choose several different displays to view: Amplitude Scan (shows amplitude of signals vs range), Bearing Scan (Shows range vs bearing), Passive Scan (shows passive data from the last 11 mins in 10 degree segments- same as CANTASS with time on the y-axis and frequency on the x-axis).

Question 19

What is the Instructor’s Console?

Answer 19

A laptop that is plugged into the system to allow users to create different scenarios and/or synthetic targets and then run these scenarios on the Console

Question 20

What is the Data Recorder?

Answer 20

This is a magnetic tape recorder that stores up to 24 hours of continuous unprocessed audio data. It can be played back for training purposes or further analysis. It is located to the right of the sonar operator’s console.

Question 21

What are the modes of operation for HMS?

Answer 21

Normal
Replay
Training
Diagnostic

Question 22

What are the states of HMS?

Answer 22

Active
Listen

Question 23

What is the normal mode of operation?

Answer 23

The default mode. The system collects and processes acoustic data and presents it to the operator. Data can also be recorded.

Question 24

What is the Reply mode of operation?

Answer 24

Processes and displays acoustic data stored in the data recorder.

Question 25

What is training mode?

Answer 25

Using the instructor’s console, synthetic targets/scenarios are created/run for operator training. The system acts as if it’s in normal mode, but does not transmit or listen for acoustic noise.

Question 26

What is diagnostic mode?

Answer 26

Used to perform testing for fault detection/isolation.

Question 27

What is the Active state?

Answer 27

This state is used to process returned acoustic signals from HMS’ active output, and a narrower frequency band (2.2-5.5kHz) of passive acoustic signals

Question 28

What is the Listen State?

Answer 28

This is the passive mode. It is used to process a wider frequency band (2.2-8.6kHz) of passive acoustic signals.

Question 29

What is the functional description of HMS?

Answer 29

In this scenario, the system is operating in Normal mode, Active state with DT-Narrow transmit and CW ping at 8kHz selected. Inside the SCC, the SIA generates a master pulse waveform with a frequency of 16 kHz (twice the desired frequency). Six other pulses are generated and time delays are applied to achieve the required beam forming. The pulses are sent to the SPIs in the Transmitter. ITE monitors the outputs for faults. Inside the Transmitter, the SPIs amplify the signals and send them to the T/R Switch. As it is time to transmit, the T/R Switch routes the transmit signals to the Transducer. The electrical signals travel to their respective SETs and cause the ceramic rings to expand and contract in syn with the signal. The front and rear radiating masses vibrate which cause the front radiating mass to induce a pressure wave in the water. Positive and destructive interference from the other staves cause the acoustic signal to be beam formed in the desired direction with the desired beamwidth. As the acoustic signal travels through the water, it experiences transmission losses. It reflects off of a target and travels back to the transducer. The pressure wave impacts some SETs, which causes them to vibrate creating an electrical signal. As the pressure wavefront is approximately a flat plane, the different staves generate electrical signals at different times and with different amplitudes. The electrical signals travel to the T/R switch, which is now set to receive, and routes the signals to the SIA. Inside the SIA, the six receivers amplify, filter, and digitize the signals. They are then sent to the HSSP for processing. Inside the HSSP, the signals are processed for targets. The previously mentioned time delays and amplitude differences are used to beam form the returned signals, yielding the bearing to the contact. The time between transmission and reception is used to determine range. FFTs are performed, converting the received signals to the frequency domain for spectrum analysis. The information is then sent to the SCC. Inside the SCC, the SCA performs ADT on the contacts. It also converts the audio from the HSSP and converts it back to an analog signal for the operator’s headset. The display processor generates the video for the displays on the console. The operator, sitting at the console, is then able to see graphs of the returned echoes and hear the received signals. The operator notices a track of interest, reports it to the SCS, and orders HMS to pass the track to CMS. This command is sent from the console to the display processor in the SCC. The SCA then forwards the track to CMS via I/O Processor 2.

Question 30

What are the system interfaces for HMS?

Answer 30

- EPG&D - HVAC - CMS via I/O Processor 2 - Nav Suite via the DDU for GPS data and non- critical ship’s attitude data - UWT for blanking and to provide a mount for the UWT transducer - Bridge panel to indicate dome status to OOW - SWS to fill and empty the dome

Question 32

What are some redundancy and survivability factors for HMS?

Answer 32

- If CMS is INOP, HMS can operate in standalone - Up to two SETs can fail per stave and the system will still operate - Up to 35 SETs can fail before HMS is considered INOP - Hand wheel in the event of C5 Hull Outfit motor failure - takes hours as ~43 rotations = 1 inch of movement

Question 33

What are some tests & trials for HMS?

Answer 33

- Integrated Test Equipment (Constantly monitoring the system) - BITs - FITs - Sonar Performance Figures (“SPIFFs”)

Question 34

What are SPIFFs?

Answer 34

This is a series of tests performed by FMF to predict the sonar range for specific acoustic conditions. It is split up into 3 parts. Part 1 is alongside to test the operation of the transducer. Part 2 is in the Bedford Basin using a special boom to test beam patterns, source levels and intensity. Part 3 is conducted at sea and measures own-ship sound levels WRT speed.

Question 35

What are the safety factors WRT HMS?

Answer 35

- High voltage precautions - Safety interlock switches inside the transmitter cut power off to all components if any drawers are opened. - Additional safety interlock switches prevent HMS from transmitting unless the Transducer is fully down and locked. - Divers down precautions. Three keys are locked in the divers down LOTO box IAW NAVORD 3136-4 - The 3 keys are the C5 key in the MCP, HMS1 key in the SCC, and HMS2 key in the SOC. All need to be in and switched on for the system to work - Marine mammal mitigation IAW NAVORD 4003-6