Other Projects

COMMUNICATIONS:

Communication is one of the biggest challenges in many underwater applications. Along with the HPRS through-wall communications system, Hydro Technologies has worked on the development of several technologies that promise to radically improve on the current state of the art capabilities in this area.

The low data rates inherent in transmission from an unmanned underwater vehicle (UUV) back to a host ship have limited the usefulness of UUVs in many applications. Hydro Technologies has been involved in several pioneering efforts to increase the data rate achievable between submerged nodes. Since the underwater acoustic channel has inherently limited bandwidth, one technique for increasing the achievable data rate is to attempt to pack more data on a given bandwidth using advanced digital communications algorithms. The leading candidate for this is known as Quadrature Amplitude Modulation (QAM). It was the application of QAM by the telephone companies that allowed for high speed DSL internet access using the same phone lines that were normally limited to dial-up speeds of 20 times slower than DSL. Many researchers are hopeful that the same speed enhancements can be applied to underwater communications.

In support of these high speed underwater communications efforts, Hydro Technologies worked with the Massachusetts Institute of Technology AUV Laboratory to help develop a custom electronics module capable of communications using advanced algorithms such as QAM. In addition to this work, Hydro Technologies assisted engineers at Woods Hole Oceanographic Institute in the design of a next generation MicroModem capable of driving underwater piezoelectric transducers with QAM signals.

                                                 

The other option for increasing the data rate of underwater communications is to increase the usable transducer bandwidth. Hydro Technologies has been developing and evaluating technologies in this area since the company was founded.  Our data acquisition and signal generation hardware is capable of evaluating the frequency response of devices under test as well as establishing a communications link using algorithms such as FM, AM, ASK, FSK, and QAM. Our custom software also allows for the full suite of acoustic characterizations such as signal-to-noise ratio and total-harmonic-distortion measurements.
 

In addition to underwater acoustic communications, Hydro Technologies has been active in optical communications. Our basic experimentation in lasers for underwater communications has led to several other applications such as a laser beam break sensor for time-of-flight measurements. One of the more esoteric applications of the optical technology developed at Hydro Technologies is a low cost optical emitter shown by the MIT Quantum Communications laboratory to generate quantum entangled photons usable in quantum cryptography research. To our knowledge, this experiment done in 2003 was the first in which a non-coherent optical source was used to generate entangled photons.

 

DATA VISUALIZATION:

Hydro Technologies develops intuitive user interfaces that bring to life data visualization, data acquisition, and controls applications. To simplify the development of these interfaces, we have created foundation software for most of the common display and processing tasks faced when developing these interfaces. This saves our customers money and allows for much quicker time to market.

Our flagship example of our design methodology is the CritterCam Dive Profiling software developed in cooperation between National Geographic and Hydro Technologies based on our D³ data visualization platform. Because the core of D³ uses our flexible inter-program communications foundation, we were able to quickly synchronize and integrate several diverse display and processing modules. In the D³ Dive Profiling application, this included a video display, linked data display, and synchronized navigatable environment based on 3D gaming technology. Since the modular architecture makes D³ easy to modify and extend, it is easy to adapt to new applications.

Hydro Technologies user interfaces for controls and data acquisition applications are designed around an intuitive look-and-feel. This is much more than just an aesthetic choice in that easy to use interfaces require less training and enhance operator immersion resulting in reduced errors. An example of this is the GUI developed for a DARPA drag reduction program. This software allowed a single operator to complete an entire configuration, hardware self-test, launch, data processing, and data archiving cycle from a single easy to use interface with minimal training.