The channels contained in this library come from various experiments. The experiments differ by geographical location, transmission distance, water depth, transmitter/receiver mobility, acoustic bandwidth and the size of the recording array. The channels are color-labeled, and a detailed description of relevant parameters is given below for each. To download the channels, click here.

Each channel is estimated from the experimental data and stored in a matrix ${\bf C}$ of complex-baseband impulse responses evolving over time. If a recording array is available, there is one such matrix for each array element. Each row of this matrix represents an instantaneous channel response as a function of delay. Different rows correspond to different, equi-spaced instants in time. Any motion-induced delay drifting is suppressed in the channel matrix to enable compression for efficient storage. A separate vector $\theta$ is provided which contains the uncompressed time-varying channel phase that is directly related to the delay. To fully reconstruct the channel, the matrix ${\bf C}$ needs to be uncompressed, and the phase/delay needs to be imparted to re-introduce phase shifting and delay drifting. Details of this process, along with the ready-to-use code, are given in the User’s Guide.

For the Green channel, $M$ denotes the number of time-diversity channels formed from repeated transmissions on a single hydrophone, and $\ell$ denotes the inter-transmission interval.