Method of recording sonar data

Abstract

A sonar system comprising a sonar transmitter, a very large array two dimensional sonar receiver, and a beamformer section transmits a series of sonar pings into an ensonified volume of fluid at a rate greater than 5 pings per second, receives sonar signals reflected and scattered from objects in the ensonified volume, and beamforms the reflected signals to provide a video presentation and/or to store the beamformed data for later use. The parameters controlling the sonar system are changed so that the beamformer section treats the data from the receiver section with more than one set of parameters per ping and/or neighboring pings. The stream of data is treated either in parallel or in series by different beamforming methods so that at least one beam from the beamformer has more than one value.

1 . A method of recording sonar data measured by a sonar system having sonar system parameters, comprising;
 a) transmitting a first set of sonar pings into a first volume of sonar signal transmitting material, the sonar pings transmitted from a sonar ping transmitting device, wherein the sonar ping transmitting device is controlled by a first set of ping transmitting parameters chosen from a predetermined list of ping transmitting parameters;   b) receiving sonar acoustical signals reflected or scattered from objects in the first volume of sonar signal transmitting material, wherein the received acoustical sonar signals are received by a sonar receiving device array controlled by a first set of receiver parameters selected from a predetermined list of receiver parameters to convert the received sonar acoustical signals into digital data signals which are transmitted to a sonar beamforming device and/or a digital processing device for further processing of the digital data signals,   c) beamforming and/or further processing the received sonar signals wherein the step of sonar beamforming is performed by a sonar beamforming device controlled by a first set of beamforming parameters chosen from a predetermined list of beamforming parameters, and wherein the digital processing device for further processing is controlled by parameters chosen from a predetermined list of processing device parameters; then   d) changing at least one sonar system parameter to provide at least two significantly different three dimensional (3D) sonar data sets for each ping of the first set of pings, the at least two (3D) sonar data sets for describing the objects reflecting or scattering the transmitted sonar signals, wherein a sonar system parameter is defined as any parameter chosen from the predetermined lists of ping transmitting parameters, receiver parameters, beamforming parameters, and processing device parameters.   
     
     
         2 . The method of  claim 1 , wherein the at least two significantly different sonar data sets are used to provide at least two significantly different beamformed sonar images. 
     
     
         3 . The method of  claim 2 , wherein step d) further comprises changing at least one of the sonar beamforming device parameters for each ping of the first set of pings during the step of beamforming. 
     
     
         4 . The method of  claim 1 , wherein step d) further comprises; changing at least one of the sonar receiving device parameters during the step of receiving for each ping of the first set of pings. 
     
     
         5 . The method of  claim 4 , wherein two different gain profiles are used to provide two significantly different data sets for each ping of the first set of pings. 
     
     
         6 . The method of  claim 1 , wherein the sonar system parameters are set to provide sonar data to reconstruct a consolidated image from the requested eyepoints of a more than one user. 
     
     
         7 . The method of  claim 1 , wherein the image resolution is changed during the sonar signal receiving step from higher resolution for the first arriving ping reflection to lower resolution for the later arriving ping reflections. 
     
     
         8 . The method of  claim 1 , wherein features identified in two or more data sets for each ping are matched with corresponding features identified in at least one further data set to provide a mosaic data base. 
     
     
         9 . The method of  claim 8 , wherein the at least one further data set for a ping is produced from preceding and/or succeeding pings, and where in the sonar device parameter changed is a digital processing device parameter, wherein the digital processing device parameter changed is a sidelobe clipping parameter and/or a thresholding parameter. 
     
     
         10 . The method of  claim 9 , wherein the at least one digital processing device parameter changed is chosen to reduce unwanted acoustic artefacts. 
     
     
         11 . The method of  claim 1 , wherein one of the at least two significantly different sonar data sets for each ping of the first set of pings is a full-time series 3D volume data set or a partial series 3D volume data set. 
     
     
         12 . The method of  claim 11 , wherein two of the at least two significantly different sonar data sets are a full-time series 3D volume data set and a partial series 3D volume data set. 
     
     
         13 . The method of  claim 1 , wherein the at least one digital processing device parameter is changed from a first sidelobe filter to a second sidelobe filter. 
     
     
         14 . The method of  claim 13 , wherein the sonar data set produced using the first sidelobe filter is monitored in real-time to ensure no wanted objects are being removed. 
     
     
         15 . The method of  claim 1 , wherein the image resolution is changed during the sonar signal receiving step from higher resolution for the first arriving ping reflection to lower resolution for the later arriving ping reflections. 
     
     
         16 . The method of  claim 1 , wherein features identified in the two or more data sets are matched with a Simultaneous Localization and Mapping (SLAM) technique. 
     
     
         17 . The method of  claim 1 , wherein an absolutely positioned mosaic is created. 
     
     
         18 . The method of  claim 17 , wherein the two or more data sets for each ping are matched with models. 
     
     
         19 . The method of  claim 18 , wherein the models represent known physical entities. 
     
     
         20 . The method of  claim 18 , wherein the models may be moving and/or updated in real-time. 
     
     
         22 . The method of  claim 18 , wherein the models are volume 3D binned data 
     
     
         23 . The method of  claim 1 , wherein the two or more data sets for each ping are compared with at least one previously generated data set. 
     
     
         24 . The method of  claim 23 , wherein the previously generated data set may be from a previous survey of the same physical location. 
     
     
         25 . The method of  claim 24 , wherein the comparison is used to determine dredging progress and/or to check for scouring around structures in areas with high underwater currents and/or to check for changes in infrastructure. 
     
     
         26 . The method of  claim 23 , wherein the two or more data sets for each ping are matched with data from previously surveyed areas to find to determine dredging progress and/or to check for scouring around structures in areas with high underwater currents and/or to check for changes in infrastructure such as quay wall damage and/or explosive devices placed underwater. 
     
     
         27 . The method of  claim 1 , wherein the range of at least one of the at least two significantly different data sets is divided into a number of sections, and the range of zero or one object for each section is recorded and/or shown as a partial time-series. 
     
     
         28 . The method of  claim 27 , wherein at least one of at least two significantly different beamformed sonar images is a custom view. 
     
     
         29 . The method of  claim 28 , wherein the custom view is a cross section or a plan view. 
     
     
         30 . The method of  claim 1 , wherein the first set of sonar pings forms part of a series of sets of sonar pings transmitted at a rate of at least 5 pings per second. 
     
     
         31 . The method of  claim 30 , wherein the least two significantly different sonar data sets representative of the first set of sonar pings are displayed as at least one video stream at a frame rate of at least 5 frames per second. 
     
     
         32 . The method of  claim 30 , wherein two sets of sonar data are recorded and/or shown. 
     
     
         33 . The method of  claim 1 , wherein at least two significantly different sonar data sets for each ping of the first set of pings are used to simultaneously provide a far-field obstacle avoidance view and a high-resolution seabed view. 
     
     
         34 . The method of  claim 33 , wherein the far-field obstacle avoidance view and the high-resolution seabed view are used in autonomous navigation. 
     
     
         35 . The method of  claim 1 , wherein at least one of the at least two significantly different sonar data sets for each ping comprises raw data.