Tests of the Accuracy of Indications by ARPA and AIS of the Opposite Vessel True Course, True Speed and CPA

Comaparative Study of the Accuracy of AIS and ARPA Indications. Part 2. Accuracy of the Opposite Vessel True Course and True Speed Indication

“…The exact numerical values of the average true courses and average true speeds of the vessels observed and tracked during the individual measurement series and doubled values of their standard deviations are presented in Table 5 published in Proceedings from the 19th International Radar Symposium (IRS) [6]. Table 2 summarizes this information and presents the number of meeting situations where true course and true speed indication errors (ARPA) or dispersion (AIS) were greater than their allowable values for a probability equal to 95%.…”

“…Table 2 summarizes this information and presents the number of meeting situations where true course and true speed indication errors (ARPA) or dispersion (AIS) were greater than their allowable values for a probability equal to 95%. Results of the measurements of the accuracy of ARPA and AIS indications presented in Table 5 in Proceedings from 19th IRS (the accuracy of the presentation of true motion parameters) [6] and in Table 4 in the first part of this article (the accuracy of the closest point of approach (CPA) presentation) [1] are summarized in Table 3. This table shows whether or not the accuracy requirements have been met by values of the true course, true speed and CPA of opposite ship displayed by the on board ARPA and AIS.…”

Comparative Analysis of the Usefulness of AIS and ARPA for Anti-collision Purposes

“…The ship's master and watch keeping officers (OOW) should not rely on AIS as the sole information system, but should make use of all safety-relevant information available. In general, AIS may be used to assist in collision avoidance decision-making as an additional source of information which supports radar and radar tracking aids to calculate true and relative vectors of the detected and tracked echoes on the basis of radar measurements of their distances and bearings, by assisting in [3,13]: − identification of targets by name, call sign, ship type and navigational status; − presentation of targets heading; − immediate identification of manoeuvres performed by targets; and − more accurate presentation of courses, speed over ground and rate of turn of the targets.…”

“…They were carried out over several years and some of their results have already been partly presented in publications [12][13][14][15]. The measurements were conducted by students of the Faculty of Navigation of the Gdynia Maritime University as part of their engineering thesis listed in bibliography [5,6,7,8,9,10,11,16,17,18], written under the supervision of the author of this article.…”

“…The state of the sea, expressed in degrees of the Douglas scale in the last column of this table, describes weather conditions during the test. Part of the measurements presented in this table is a repetition of information presented in the earlier publications mentioned in the bibliography [12][13][14][15].…”