234
12 Radar Systems of Maritime Transport
Information processing algorithms, implemented in ARPS, impose additional
limitations. The main ones are the following:
• None of the existing ARPS provides guaranteed detection and lock-on for autotracking of all targets, including the critical ones. Therefore, the use of ARPS only
in automatic acquisition mode cannot be considered as proper radar surveillance.
• If the echo signal is unstable (small vessels, tracking in conditions of strong
interference), the target may be reset and information on it will not be displayed.
With a close divergence of two targets, the loss of one target is possible. In this
case, the other target will have two vectors, one of which will be false;
• Signals from the radar, gyrocompass and log come to the ARPs with errors. With
the roll of the vessel, the presence of interference, maneuvering and yaw of own
ship, the errors of the sensors increase. Therefore, when calculating the elements
of target movement and the parameters of the approach situation, the “smoothing”
is used, which leads to a delay in the output of reliable data up to three minutes
from the moment the target is taken for tracking;
• Errors of the calculated elements of target movement and situation parameters
can reach the following values:
• true course of the target—±5 ÷ 7°;
• true target speed—±1.2 knots;
• distance of the shortest approach—±0.7 miles;
• time of the shortest approach—±1 min.
• The target maneuver is detected with a significant delay, and the data generated
by the ARPS on the maneuvering target will be unreliable for 3 ÷ 4 min after its
completion.
• When maneuvering own ship, the ARPS output information for all tracked targets
will be unreliable.
12 Radar Systems of Maritime Transport
Information processing algorithms, implemented in ARPS, impose additional
limitations. The main ones are the following:
• None of the existing ARPS provides guaranteed detection and lock-on for autotracking of all targets, including the critical ones. Therefore, the use of ARPS only
in automatic acquisition mode cannot be considered as proper radar surveillance.
• If the echo signal is unstable (small vessels, tracking in conditions of strong
interference), the target may be reset and information on it will not be displayed.
With a close divergence of two targets, the loss of one target is possible. In this
case, the other target will have two vectors, one of which will be false;
• Signals from the radar, gyrocompass and log come to the ARPs with errors. With
the roll of the vessel, the presence of interference, maneuvering and yaw of own
ship, the errors of the sensors increase. Therefore, when calculating the elements
of target movement and the parameters of the approach situation, the “smoothing”
is used, which leads to a delay in the output of reliable data up to three minutes
from the moment the target is taken for tracking;
• Errors of the calculated elements of target movement and situation parameters
can reach the following values:
• true course of the target—±5 ÷ 7°;
• true target speed—±1.2 knots;
• distance of the shortest approach—±0.7 miles;
• time of the shortest approach—±1 min.
• The target maneuver is detected with a significant delay, and the data generated
by the ARPS on the maneuvering target will be unreliable for 3 ÷ 4 min after its
completion.
• When maneuvering own ship, the ARPS output information for all tracked targets
will be unreliable.