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Main ❯ Underwater acoustic modems ❯ Data brief: uWave devices family

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Brief description

uWave devices family
Brief description

1. List of devices

The uWave family (μWave, pronounced: “mu-wave” or, if you like it more - “you-wave”) is specifically designed for applications that are extremely sensitive to weight and size and is presented currently by four devices:

More detailed comparison can be found in uWave modems comparison tables.

All devices within the family are fully acoustically compatible and have a common, NMEA-like protocol interfacing.

2. Features of the acoustic protocol and code channels

Acoustic Transfer Protocol uWave implements code division multiple access (CDMA) and supports 20 isolating code channels. Any device from the uWave family can be configured with any code channels for reception and transmission.

The isolating code channel ensures that data transmitted on one channel is not received by the device receiving on any other code channel.

All devices of the uWave family can receive at the same time in only one code channel.

2.1. Acoustic baud rate

The standard mode for uWave devices is 78 bps. This mode provides maximum communication range and reliability. It is in this mode that the largest number of code channels is available.

All devices in the uWave family support alternate modes, providing baud rates of 156, 314 bps and 634 bps. The higher the speed, the less noise immunity, and, accordingly, the reliability and range of communication.

Different speed modes are not compatible with each other. Transfer of the modem to another speed mode is provided by replacing its firmware.

3. Device working modes

All devices of the family can work in two modes, switching between which is carried out by the user:

These modes determine how the modem perceives data coming from the control system:

3.1. Transparent channel mode

In the transparent channel mode, the devices do not analyze the data coming from the control system and without any changes transmit them to the underwater acoustic channel, where they can be received by any device from the family that receives in the same code channel, in which the transmission was performed.

3.2. Command mode

In command mode, devices analyze data coming from the control system and interact with them within very simple NMEA-like ASCII protocol. In this mode, devices allow you to send short code requests to other devices: request of depth, temperature, power supply voltage and transmit 9 user commands. Code requests have fixed lengths of request and response signals, which allows the requesting system to estimate the propagation time (and slant range) to the requested system.

The remote modem receives and processes the code request, regardless of the mode in which it is, which frees the user from the need to monitor the status of a remote modem.

The devices uWave USBL Modem allow users to determine the horizontal angle of arrival of any incoming message from other devices of the uWave family. Including for user messages transmitted in transparent channel mode.

3.2.1. Packet mode

Packet mode allows transmitting data packets with guaranteed delivery (ALO - At-least-once), delivery notification to the addressee. In packet mode, logical addressing of up to 254 subscribers is used over each code channel (255 is a broadcast address without notification and guaranteed delivery). Packet mode can only be used when the modem is in command mode.

4. Built-in sensors

Devices uWave, uWave Max and uWave Max OEM have a built-in supply voltage measurement module. The supply voltage for all devices in the family can be remotely requested by any other devices of the family.
Starting from firmware version 1.30 with command mode enabled by default, the SVC/CMD cable core becomes a digital output. To which strobe rectangular pulses are transmitted synchronized with the moment the radiation starts and the moment the incoming message is detected. This option allows you to build navigation systems based on the uWave modems.

Devices uWave, uWave Max and uWave USBL Modem have built-in depth/temperature sensors. Depth and temperature readings can be remotely requested by any device of the family.

uWave USBL Modem devices additionally have built-in two-axis inclinometers (measure the angles of roll and pitch). The user can configure the output of this data, with a given period (from 0.5 to 60 seconds) or tandem - when any data is received from remote devices. Inclinometer readings are only available locally.

All devices equipped with depth/temperature sensors, when switched on in the air, automatically calibrate the pressure sensor, which eliminates the error in determining the depth associated with changes in atmospheric pressure and zero drift of the sensor. To achieve the maximum possible for of this precision technology, the device allows you to set an adequate value for the acceleration of gravity for the place of work (for example, according to the WGS84 Gravity model, thereby excluding the influence of its variation from geographical latitude).

The devices are designed for a maximum immersion depth of 300 meters.

4.1. Locally available parameters

Parameters that can be received locally from the device, i.e. when connected to it by cable.

  uWave uWave Max uWave Max OEM uWave USBL Modem
Pressure ✓ ✓ ✘ ✓
Temperature ✓ ✓ ✘ ✓
Depth ✓ ✓ ✘ ✓
Supply voltage ✓ ✓ ✓ ✘
Pitch ✘ ✘ ✘ ✓
Roll ✘ ✘ ✘ ✓

4.2. Remotely available parameters

Parameters that can be requested from the device remotely, i.e. via a hydroacoustic communication channel, using any other modem from the uWave family.

  uWave uWave Max uWave Max OEM uWave USBL Modem
Temperature ✓ ✓ ✘ ✓
Depth ✓ ✓ ✘ ✓
Supply voltage ✓ ✓ ✓ ✘

4.3. Measuring ranges

Parameter Min Max Units
Pressure 0 30000 mBar
Temperature -4 46 °С
Depth 0 300 m
Supply voltage 0 15 V
Pitch -180 180 °
Roll -180 180 °

4.4. Resolution of readings of built-in sensors

Parameter Resolution
locally		 Resolution
remotely
Pressure 0.1 mBar -
Temperature 0.1 °С 0.1 °С
Depth 0.01 m 0.1 m
Supply voltage 0.1 V 0.1 V
Pitch 0.1 ° -
Roll 0.1 ° -

5. Application and integration

All uWave family devices are paired with the user system using the 3.3 V UART physical interface, and by default operate in transparent channel mode. This does not require any additional integration and configuration.

To work in command mode, a simple NMEA-like ASCII protocol is used.

On our GitHub you can find examples and linbraries to interface with uWAVE devices:

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