3 Performance Standards

  3.1.1 Where a separate facility is provided for detection or targets, other than by the radar observer, it should have a performance not inferior to that which could be obtained by the use of the radar display.

  3.2.1 There should be a facility to provide for manual acquisition and cancellation for relative speeds up to 100 knots.

  3.2.2 Manual acquisition should have a performance not inferior to that which could be obtained by the user of the radar display.

  3.3.1 The "auto tracking" should be able to automatically track, process, simultaneously display and continuously update the information on at least 10 targets.

  3.3.2 The "auto tracking" should continue to track an acquired target which is clearly distinguishable on the display for 5 out of 10 consecutive scans. provided the target is not subject to target swop.

  3.3.3 The possibility of tracking errors, including target swop. should be minimised by "auto tracking" design. A qualitative description of the effects of error sources on the automatic tracking and corresponding errors should be provided to the user, including the effects of low signal-to-noise and low signal-to-clutter ratios caused by sea returns, rain, snow, low clouds and non-synchronous emissions.

  3.4.1 The display may be a separate or integral part of the ship's radar. However the "auto tracking" display should include all the data required to be provided by a radar display in accordance with the performance standards for navigational radar equipment.

  3.4.2 The design should be such that any malfunction of "auto tracking" parts producing data additional to information to be produced by the radar as required by the performance standards for navigational equipment should not affect the integrity of the basic radar presentation.

  3.4.3 The "auto tracking" facilities should be available on at least the 3, 6 and 12 nautical mile range scales, and there could be a positive indication of the range scale in use.

  3.4.4 "Auto tracking" facilities may also be provided on other range scales.

  3.4.5 The "auto tracking" should be capable of operating with a relative motion display with "north-up" and "course-up" azimuth stabilization. In addition, the "auto tracking" may also provide for a true motion display. If true motion is provided, the operator should be able to select for his display either true or relative motion. There should be a positive indication of the display mode and orientation in use.

  3.4.6 The course and speed information generated by the "auto tracking" for acquired targets should be displayed in a vector or graphic form which clearly indicates the target's predicted motion with relevant symbols^footnote. In this regard:

• .1 "auto tracking" presenting predicted information in vector form only should have the option of both true and relative vectors. There should be an indication of the vector mode selected, and if "true" is selected there should be a display of whether it is stabilized with reference to sea or ground;

• .2 an "auto tracking" which is capable of presenting target course and speed information in graphic form should also, on request, provide the target's true and/or relative vector;

• .3 vectors displayed should be time adjustable;

• .4 a positive indication of the time-scale of vector in use should be given; and

• .5 if stationary targets are being used for ground referencing then this should be indicated with the relevant symbol^footnote. In this mode, relative vectors including those of the targets used for ground referencing should be displayed when requested.

  3.4.7 The "auto tracking" information should not obscure the visibility of radar targets. The display of "auto tracking" data should be under the control of the radar observer. It should be possible to cancel the display of unwanted "auto tracking" data within 3 s.

  3.4.8 Means should be provided to adjust independently the brilliance of the "auto tracking" data and radar data, including complete extinction of the "auto tracking" data.

  3.4.9 The method of presentation should ensure that the "auto tracking" data are clearly visible in general to more them one observer in the conditions of light normally experienced on the bridge of a ship by day and by night. Screening may be provided to shade the display from sunlight but not to the extent that it will impair the observer's ability to maintain a proper look-out. Facilities to adjust the brightness should be provided.

  3.4.10 Provisions should be made to obtain quickly the range and bearing of any object which appears on the "auto tracking" display.

  3.4.11 The "auto tracking" should present in a period of not more than 1 min an indication of the target's motion trend and display within 3 min the target's predicted motion in accordance with paragraphs 3.4.6, 3.6, 3.7.2 and 3.7.3 of this Appendix.

  3.4.12 After changing range scales on which the "auto tracking" facilities are available or resetting the display, full plotting information should be displayed within a period of time not exceeding one scan.

  3.5.1 The "auto tracking" should have the capability to warn the observer with a visual and audible signal of any distinguishable target which closes to a range or transits a zone chosen by the observer. The target causing the warning should be clearly indicated with the relevant symbols' on the display.

  3.5.2 The "auto tracking" should have the capability to warn the observer with a visual and audible signal of any tracked target which is predicted to close within a minimum range and time chosen by the observer. The target causing the warning should be clearly indicated with the relevant symbols' on the display.

  3.5.3 The "auto tracking" should clearly, indicate if a tracked target is lost, other than out of range, and the target's last tracked position should be clearly indicated on the display.

  3.5.4 It should be possible for the observer to activate or de-activate the audible warning capability.

  3.6.1 The observer should be able to select any tracked target to obtain data. Targets selected should be marked with the relevant symbol on the radar display. If data is required for more than one target at the same time each symbol shall be separately identified, for example with a number adjacent to the symbol.

  3.6.2 The following data for each selected target should be clearly and unambiguously identified and displayed immediately and simultaneously in alpha-numeric form outside the radar area:

• .1 present range of the target;

• .2 present bearing of the target;

• .3 predicted target range at the closest point of approach (CPA);

• .4 predicted time to CPA (TCPA);

• .5 calculated true course of the target; and

• .6 calculated true speed of the target.

  3.6.3 The display of 3.6.2, items 5 and 6 should include an identification of whether the data uses sea or ground reference.

  3.6.4 When data for several targets is displayed, not less than two items should be displayed simultaneously for each target selected. If the items of data are displayed in pairs for each target the groupings should be: 3.6.2 items 1 with 2, 3 with 4; and, 5 with 6.

  3.7.1 The "auto tracking" should provide accuracies not less than those given in paragraphs 3.7 2 and 3.7.3 for the four scenarios defined in annex 2 to this appendix. With the sensor errors specified in annex 3 to this appendix, the values given relate to the best possible manual plotting performance under environmental conditions of ± 10° of roll.

  3.7.2 The "auto tracking" should present within 1 min of steady state tracking the relative motion trend of a target with the following accuracy values (95% probability values).

  3.7.3 The "auto tracking" should present within three minutes of steady state tracking the motion of a target with the following accuracy values (95% probability values).

  3.7.4 When a tracked target, or own ship, has completed a manoeuvre the system should present in a period of not more than one minute an indication of the target's motion trend and display within 3 min the target's predicted motion, in accordance with paragraphs 3.4.6, 3.6, 3.7.2 and 3.7.3 of this Appendix. In this context, a "manoeuvre of own ship” shall be deemed to consist of an alteration of course ± 45° in 1 min.

  3.7.5 The "auto tracking" should be designed in such a manner that under the most favourable conditions of own ship motion the error contribution from the "auto tracking" should remain insignificant compared to the errors associated with the input sensors. for the scenarios of annex 2 to this appendix.

  3.8.1 The "auto tracking" should not degrade the performance of any equipment providing sensor inputs. The connection of the "auto tracking" to any other equipment should not degrade the performance of that equipment. This requirement should be met whether the 'auto tracking' is operating or not. Additionally the "auto tracking" should be designed to comply with this requirement under fault conditions as far as is practicable.

  3.9.1 The "auto tracking" should provide suitable warnings of "auto tracking" malfunction to enable the observer to monitor the proper operation of the system. Additionally, test programmes should be available so that the overall performance of "auto tracking" can be assessed periodically against a known solution. When a test programme is being executed the relevant test symbols' should be displayed.

  3.10.1 Log and speed indicators providing inputs to "auto tracking" equipment should be capable of providing the ship's speed through the water in the fore and aft direction.

  3.10.2 If a ground stabilised input is also available from the log, from an electronic position-fixing system or from tracked stationary targets then the type of input in use should be displayed.

  3.11.1 Speed and course measuring equipment should be connected to the "auto tracking".

  3.11.2 The speed input should provide speed through the water and may, in addition, provide speed over ground.

  3.11.3 The type of measuring equipment in use should be indicated on the display.