1 Multistatic Sonar Simulation* P. Willett January, 2011 Supported by the Office of Naval Research Contract: N Program Managers: Keith Davidson & John Tague * help from R. Georgescu, S. Schoenecker, S. Coraluppi, O. Erdinc, W. Blanding

2 What is it? Most MSTWG datasets are high-fidelity but one-shot. –some need for Monte Carlo results This simulation is medium fidelity –same scenario can be run multiple times with different noises (detections and clutter) Scenario –can be specified by GUI –scenario can be specified by matfile

3 Targets motion is described via waypoints –as many as you like (e.g., “W” needs 5) as many targets as you want –presently there is no “appear” or “disappear” future work, easy –aspect dependent SNR –Gaussian-shaped pedestal,  =10 o can be set –pedestal is 10dB can be set –specify in terms of received monostatic SNR at broadside at 1 km can be set

4 Platforms as many as desired specified as waypoints, same as targets each can be a source, receiver or both platforms are acoustically observable –same model as target –can turn this off bistatic observations model –azimuth, time delay and Doppler input  ’s –attenuation with distance loss proportional to distance 2 below 1km, and to distance beyond 1km loss product of source-target and target receiver losses sound velocity must be input –no multipath future work, easy but nontrivial specify ping rates and total simulation time

5 Clutter presently three types, user-specified –Rayleigh –log-normal (choose parameter) –K-distributed (choose parameter) detection threshold input (nominally 13dB) formed in angle/delay space –more dense near receiver all resolution cells’ returns are formed and compared to the threshold –no P fa input, although it is internally calculated

6 How to use it? scenario setup mode: –invoke “multistatic_simulation” in MATLAB –decide whether want GUI or matfile input output is in “simulation_output.mat” Monte Carlo mode: –assume “parameterfile.mat” was created in scenario setup mode or is given –[newobs,newcontact,data]= … multistatic_simulation(‘parameterfile.mat’) –output given for one whole simulation run suitable to be called within loop first call simulation then call tracker compare output to truth (from parameterfile.mat)

7 What is the Output? each run (invocation of multistatic_simulation) gives three outputs –“obs” – in Cartesian space –“contact” – in time/bearing space –“data” – in NURC format that MSTWG has been using (see NURC Technical Memo RL-JUN03-01 “Abel Multistatic sonar information processing chain” by Rene Laterveer, also the presentation “New ARLUT Data Set” by Brian LaCour, MSTWG 3 rd Meeting) these are very redundant, use what you want –obs & contact are cell arrays given in form useful for a tracker

8 contact data format contact{i_scan,i_pair}.az(i_contact) –azimuth (degrees, counter-clockwise from east) contact{i_scan,i_pair}.delay(i_contact) –travel time of ping (s) contact{i_scan,i_pair}.doppler(i_contact) –bistatic Doppler (m/s) contact{i_scan,i_pair}.time(i_contact) –return time of ping from start of simulation (s) contact{i_scan,i_pair}.power(i_contact) –level of contact (dB) contact{i_scan,i_pair}.source(:,i_contact) –[x; y] values of position of source at the time of emission of ping. contact{i_scan,i_pair}.receiver(:,i_contact) –[x; y] values of position of receiver at the time of reception of return. contact{i_scan,i_pair}.provenance(i_contact) –zero if clutter, otherwise is index of target that return came from. contact{i_scan,i_pair}.truth(:,i_contact) –[x; y] values of position of reflecting target at the time of reflection. If clutter: zeros(2,1). contact{i_scan,i_pair}.number_contacts –number of threshold-exceedances for this ping/pair. contact{i_scan,i_pair}.source_platform_index(i_contact) –the index of the source platform for contact i_contact, to distinguish multistatic pairs when it is necessary to estimate (say) SNR. contact{i_scan,i_pair}.receiver_platform_index(i_contact) –the index of the receiver platform for contact i_contact, to distinguish multistatic pairs when it is necessary to estimate (say) SNR.

9 obs data format obs{i_scan}.meas(i_meas).time –return time of ping from start of simulation (s) obs{i_scan}.meas(i_meas).z(:) –[x; y; Doppler] values of centroid of contact (measurement Cartesian space). obs{i_scan}.meas(i_meas).R(:,:) –covariance matrix for z. obs{i_scan}.meas(i_meas).snr –power of contact (dB). obs{i_scan}.meas(i_meas).provenance –zero if clutter, otherwise is index of target that return came from. obs{i_scan}.meas(i_meas).truth(:,i_contact) –[x; y] values of position of reflecting target at the time of reflection. If clutter, this is zeros(2,1). obs{i_scan}.meas(i_meas).source_platform_index(i_contact) –the index of the source platform, to distinguish multistatic pairs when it is necessary to estimate (say) SNR. obs{i_scan}.meas(i_meas).receiver_platform_index(i_contact) –the index of the receiver platform, to distinguish multistatic pairs when it is necessary to estimate (say) SNR.

10 dat{i_scan,i_pair}.header.svel –sound velocity (m/s) dat{i_scan,i_pair}.buoy.compass –heading of receiver, clockwise from east in degrees dat{i_scan,i_pair}.buoy.lat(1) –latitude of receiver at time of ping (obs & contact use time of reception) dat{i_scan,i_pair}.buoy.lon(1) –longitude of receiver at time of ping (obs & contact use time of reception) dat{i_scan,i_pair}.buoy.lat(2) –latitude of source at time of ping dat{i_scan,i_pair}.buoy.lon(2) –longitude of source at time of ping dat{i_scan,i_pair}.clust.range(i_contact) –zero for all contacts dat{i_scan,i_pair}.clust.mean(i_contact).range –the time in seconds between transmission of the ping and the reception of contact number i_contact dat{i_scan,i_pair}.clust.mean(i_contact).doppler –the bistatic Doppler in m/s dat{i_scan,i_pair}.clust.mean(i_contact).beam –the angle, clockwise from east in degrees, of contact number i_contact dat data format