Sonic 2024 User Manual

Graph 4: Along-track position error caused by 1.0° error in yaw patch test error
11.4 Solving for the Patch Test
Depending on the data collection software that is employed and how it solves for the patch test,
there will be a distinct order that the tests will be solved for, but this does not influence the data
collection for the patch test. In general, latency will be solved before pitch; roll will be solved for
before yaw. It is not uncommon that a larger than expected error in one of the tests will make it
necessary to go back and resolve for all previous values. This can be the case with a large yaw offset,
as this will influence to a greater degree the accuracy of the latency and pitch computations if done
using a slope.
The resultant patch test values are corrections that are entered in the data collection software and
not in the Sonic 2024/2022 software, as the values are used for process data.
11.5 History
Since the advent of commercial multibeam echosounders there has been the need to measure
the
angular offsets between the multibeam sonar head and the auxiliary sensors that provide
attitude
and heading information. Another measurement is made to determine the latency, in
the GPS
receiver. Multibeam data is collected that is used to determine (1) latency, (2) roll offset,
(3) pitch
offset and (4) heading or yaw offset
What has been developed is called the Patch Test; this is the multibeam calibration. During the
development of the data collection criteria, for the Patch Test, there has only been a basic
description for the manner of the data collection; providing little, if any, directions that would
help
create a high degree of confidence in the results of the various tests. This section will
-10
-8
-6
-4
-2
0
2
4
6
8
10
-100 -50 0 50 100
Along-track Position Error in Metres
Angle from Nadir
Position Error with a Heading Error of 1.0°
200 metres
150 metres
100metre
50 metre
25 metres
10 metres
Water Depth
Page 136 of 210
Version 5.0 Rev r002
Date 05-08-2014
Part No. 96000001

Sonic 2024 Specifications

General

Brand	Sonic
Model	2024
Category	Marine Equipment
Language	English