4.1 Performance under static conditions (Settling
of equipment)
4.1.1 When run-up in
accordance with the manufacturer's instructions, the gyro-compass should settle
within 6 h in latitudes of up to 70 °.
4.1.2 The settle point error as defined in 2.5 at any heading and at
any latitude up to 70 ° should not exceed ± 0.75 ° x secant latitude where heading
indications of the gyro-compass should be taken as the mean of 10 readings at
20-minute intervals, and the root mean square value of the differences between
individual heading indications and the mean should be less than ± 0.25 ° x secant
latitude.
4.1.3 The repeatability of
settle point error from one run-up to another should be within 0.25 ° x secant
latitude.
4.2 Performance under
operational (dynamic) conditions
4.2.1 When run-up in accordance with the manufacturer's instructions,
the gyro-compass should settle within 6 h in latitudes of up to 70 ° when rolling
and pitching with simple harmonic motion of any period between 6 s and 15 s, a
maximum angle of 5 °, and a maximum horizontal acceleration of 0.22 m/s
2.
4.2.2 The repeatability of the
settle point error of the master gyro-compass should be within ± 1 ° x secant
latitude, including variations in magnetic fields and changes in temperature as
required by resolution A.694(17), etc., likely to be experienced in the craft in
which it is installed.
4.2.3 In
latitudes of up to 70 ° N or S in craft operating within a latitude band of 10°:
- the residual steady state error, after correction for speed and course
influences at a speed of 70 knots, should not exceed ± 0.25° x secant latitude;
- the maximum error due to a rapid alteration of speed of 70 knots should
be kept to a minimum, and should not exceed ± 2 °;
- the error due to a
rapid alteration of course of 180 ° at a maximum rate of turn of 20 °/s in any
azimuth direction at a speed of 70 knots should not exceed ± 3 °; and
- the transient and steady state errors due to the craft rolling,
pitching and yawing, with simple harmonic motion of any period between 6 s and
15 s, maximum angle of 20 °, 10 ° and 5 ° respectively, and maximum horizontal
acceleration not exceeding 1m/s2, and at any course, especially at 45
°, 90 ° and 315° should not exceed ± 1° x secant latitude.
4.2.4 When subject to the environmental conditions, referred to in
resolution A.694(17) *, the error should not exceed ± 1 °.
*
Methods of testing are contained in Publications IEC 945 and ISO 8728.
4.2.5 The maximum divergence in
reading between the master compass and the steering and visual bearing equipment
under all operational conditions should not exceed ± 0.5 °.
4.2.6 The follow up rate of the transmission system
should be at least 20 ° per s.