OOD PH1 2026_ ARPA Exam
what does ARPA stand for automatic radar plotting aid
what is the role of ARPA it is an automated moboard
inputs for ARPA 1. heading
2. speed
3. interfaces
heading inputs 1. gyro (minimum)
2. GPS (for stabilized)
speed inputs 1. doppler log
2. GPS
3. manual
interface inputs 1. chart
2. AIS (static and dynamic info)
Page 1 of 14
, OOD PH1 2026_ ARPA Exam
what do we lose with loss of speed inputs true vectors
if all inputs are lost, what does radar default heads up, unstabilized, RM
to
steady state tracking is required for accurate ARPA
no course/speed changes during three min window, you or
target
<1 min = scanty info
what are the three things needed for steady 1. steady course and speed of contact
state 2. your steady course and speed
3. 3 min time
Page 2 of 14
what does ARPA stand for automatic radar plotting aid
what is the role of ARPA it is an automated moboard
inputs for ARPA 1. heading
2. speed
3. interfaces
heading inputs 1. gyro (minimum)
2. GPS (for stabilized)
speed inputs 1. doppler log
2. GPS
3. manual
interface inputs 1. chart
2. AIS (static and dynamic info)
Page 1 of 14
, OOD PH1 2026_ ARPA Exam
what do we lose with loss of speed inputs true vectors
if all inputs are lost, what does radar default heads up, unstabilized, RM
to
steady state tracking is required for accurate ARPA
no course/speed changes during three min window, you or
target
<1 min = scanty info
what are the three things needed for steady 1. steady course and speed of contact
state 2. your steady course and speed
3. 3 min time
Page 2 of 14
