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Computer Assisted Search Planning
Solution: CASP 2.0
Summary of Improvements
Monte Carlo Model
Environmental Data Files
Daniel H. Wagner Associates has developed
a replacement Search and Rescue Planning System called CASP 2.0 for the U.S.
CASP 2.0 has been designed and developed to help and
assist Search and Rescue Controllers at all levels to manage
case information, plan searches, and evaluate results easily
and quickly. This section describes briefly the methods and procedures
by which watch standers can use the CASP 2.0 system to assist
in prosecuting search and rescue incidents.
||CASP 2.0 supports the planning for employment
of search and rescue units in incidents requiring search activities.
In such cases, the safety of life and property, both of the marine
public and the Coast Guard and other government and volunteer
participants, is of paramount importance. Timely, careful, and
accurate automated search planning assistance contributes to
faster locating of missing persons and vessels, lower exposure
of searchers to hazardous conditions, and lower cost of search
The Original CASP was also developed
by Wagner Associates and has been used by the U.S. Coast Guard
since 1974. Read about an exciting rescue
CASP 2.0 has certain improvements over the old CASP 1.1
- Drift predictions, probability maps, and recommended search
plans are more accurate and useful.
- OPCEN watch standers can use CASP 2.0 more frequently
and earlier in the SAR incident.
- CASP 2.0 saves watch stander time, leaving more time
for communications checks and incident analysis, and eliminating
the need for overload controllers for CASP 2.0 operation.
- CASP 2.0 information is integrated with other incident
information, making SAR case folders more complete and easy to
- CASP 2.0-generated search plans are easily and accurately
transferred to participants, eliminating the potential delays
and errors of the current voice and manual message systems.
- Locally-entered SAR case information is easily accessible
for future reference and retrieval.
CASP 2.0 provides a flexible set of tools with which
the user can define the SAR case scenario. The objectives are
to minimize the amount of data entry required for this definition
process and to model both pre-distress and post-distress conditions
in a way that permits careful handling of time-related situations.
The basic element of a CASP 2.0 scenario is a situation
composed of one or more independent location clues. Among other
things, these clues can be position reports, lines of bearing,
lines of position, hypothetical tracklines, or the results of
back-drifting objects found afloat. These independent locations
are combined by CASP 2.0 using the product method. This
means that the area of uncertainty for the situation will get
smaller with each additional independent clue.
A CASP 2.0 Case may have one or more mutually-exclusive
situations, each of which has a probability of being the true
situation. CASP 2.0 computes these probabilities from arbitrary
weights assigned by the user. Since situations are mutually exclusive,
the area of uncertainty for a Case will always increase by the
addition of different situations.
CASP 2.0 models the targets both before and after distress
by means of sample paths created by a Monte Carlo model. Each
sample path is represented by its location and target state changes
over time plus values that represents the probability that it
is consistent with information representing positive clues and
CASP 2.0 creates its probability maps by counting the replications
and their weights within each cell of a large grid. It produces
one composite map and, when appropriate, individual maps for
separate situations or targets.
CASP 2.0 supports a number of environmental data files
needed to support both drift predictions and Sweep Width calculations.
Some of these files are static (or climatic) and developed from
historical data. Static files may contain different data for
different time periods in some cycle, but they are not regularly
updated based on observations or predictions. Other data files
are dynamic, with values updated by the CASP 2.0 system
or by other data-provider organizations based on real-time observations
and computer model predictions. CASP 2.0 automatically selects
the best sources of data for each case, but the user has the
option of overriding the computer selections. The user also has
the ability to view or edit the data, with some restrictions.
CASP 2.0 treats each of the available data sources in
an appropriate manner based on known oceanographic and geophysical
models, in ways that are appropriate to accurate computer models.
The user can control the availability of various files to the
drift functions. The Monte Carlo CASP 2.0 follows the methods
from the National SAR Manual. However, CASP 2.0 always provides
a set of mean drift predictions for each location, that is based
on zero drift uncertainty, for display and evaluation by the
user. These mean drift calculations are as accurate as possible,
so that users can compare them to actual experience.
CASP 2.0 computes a total drift vector distribution database
by time, target type, and location, for an entire drift problem,
before choosing sample vectors.
CASP 2.0 models SRU search effort in a high-resolution
manner, using the SRU path and the actual paths of the sample
target replications. Each replication, therefore stores the cumulative
detection probability from all applicable searches. Sweep Width
and Probability of Detection calculations are made automatically
based on the best available SRU and weather information.
For Sweep Width calculations, if an SRU is using more than one
sensor (e.g., visual, FLIR, radar), CASP 2.0 computes a
Sweep Width for each sensor. The user may change any of the individual
SRU sweep widths for any target.
CASP 2.0 produces complete search plans that are both
feasible and optimal, within the constraints imposed by the user.
All capabilities of SRUs are taken into account automatically
after the user has specified the SRUs for a given search plan.
The complete search plan for multiple units are consistent with
standard practice and safety of flight regulations. The complete
plan is described in an automatically-composed message including
actual SRU navigation waypoints.
Obtaining an optimal search against moving targets requires
estimates of future search effort. CASP 2.0 provides an
easy way for the user to indicate the level of search effort
for several cycles into the future.
CASP 2.0 is accessed through
graphics X-Windows terminals with the ability to display coastline
maps, probability maps, and other data simultaneously. Case data
entry are accomplished through windows. All console terminals
can access data on all cases.