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Halberd Instrument Works — Drawing Office Application No. 18/447,209 · Filed 04 March 2026 · 3 Sheets, 5 Figures

United Instrument Registry · Class G01S 7/52

Apparatus and Method for Continuous Sonic Cartography of Subsurface Water Columns

US 12,884,317 B2 Utility Granted 19 Jul 2026

Abstract — A buoyant survey apparatus is disclosed comprising a pressure-tolerant hemispherical dome coupled by a compliant collar to a ballasted instrument barrel. A radially distributed hydrophone ring samples an acoustic field while a gimballed reference mass corrects for wave-induced tilt. A sampling controller assembles successive frames into a continuously refreshed depth map without interrupting the drift path of the apparatus, permitting single-operator survey of channel beds, submerged structures, and sediment plumes over extended deployments.

Bibliographic Data

[54]: Sonic Cartography Apparatus
[75]: M. Okonjo-Reyes; A. Vasari; T. Lindqvist
[73]: Halberd Instrument Works, Ltd.
[22]: 04 March 2026
[51]: G01S 7/52 · G01S 15/89 · B63B 22/00
[58]: Field of Search: 367/87–131
[56]: 11,402,996 · 10,884,102 · GB 2 447 118 A
[57]: 17 Claims, 3 Drawing Sheets

Examiner R. Halloway Art Unit 3645

Sheet 1 of 3US 12,884,317 B2

Fig. 1Exploded perspective view of survey apparatus 100

Sheet 2 of 3US 12,884,317 B2

Fig. 2Sectional elevation taken along line II–II of Fig. 1

Fig. 3Schematic block diagram of signal chain 110

Sheet 3 of 3US 12,884,317 B2

Fig. 4Plan view of transducer ring 112, beam sectors 130 indicated

Fig. 5Enlarged detail V of Fig. 2 — compliant collar coupling

Index of Reference Numerals — hover a row to locate it on the sheets

No.	Element	Appears In
100	Survey apparatus	Fig. 1
102	Telemetry mast	Fig. 1
104	Pressure dome	Fig. 1, 5
106	Compliant collar	Fig. 1, 5
108	Instrument barrel	Fig. 1, 2
110	Sampling controller	Fig. 1, 2, 3
112	Hydrophone ring	Fig. 1, 3, 4
114	Transducer element	Fig. 1, 4
116	Gimbal cradle	Fig. 2
118	Reference mass	Fig. 2, 3
120	Ballast keel	Fig. 2, 4
122	Pressure hull wall	Fig. 2, 5
124	Pre-amplifier stage	Fig. 3
126	Frame assembler	Fig. 3
128	Depth map product	Fig. 3
130	Beam sector	Fig. 4
132	Elastomeric web	Fig. 5

Detailed Description — of the preferred embodiment

[0001]

Brief Description of the Drawings

[0002]

Fig. 1 is an exploded perspective view of a survey apparatus 100 according to a first embodiment. Fig. 2 is a sectional elevation taken along line II–II. Fig. 3 is a schematic block diagram of the signal chain. Figs. 4 and 5 are, respectively, a plan view and an enlarged detail.

[0003]

Structure of the Apparatus

[0004]

Referring now to Fig. 1, the survey apparatus 100 comprises a pressure dome 104 of drawn acrylic having a wall thickness of between 9 and 14 millimetres. A telemetry mast 102 rises from the crown of the dome and carries a radiating element above the mean waterline, so that surface reflections do not shadow the uplink during heavy chop.

[0005]

The dome 104 is seated upon a compliant collar 106, best seen in the enlarged detail of Fig. 5. The collar is formed as an elastomeric web 132 vulcanised between two annular flanges, and is dimensioned to accept a differential expansion of up to 2.4 millimetres without transmitting shear into the pressure hull wall 122.

[0006]

Depending from the collar is an instrument barrel 108 containing the sampling controller 110. As shown in Fig. 2, the controller is carried on a gimbal cradle 116 together with a reference mass 118, the latter being free to swing about two orthogonal axes so as to establish a local vertical independent of wave-induced tilt of the barrel.

[0007]

A ballast keel 120 of cast lead is fixed to the lower closure of the barrel 108. In the embodiment illustrated, the keel represents approximately 41 per cent of the displaced mass, which the inventors have found to yield a righting period of 3.1 seconds — long enough to avoid coupling with the dominant swell band of coastal channels.

[0008]

The Transducer Ring

[0009]

The hydrophone ring 112 comprises eight transducer elements 114 distributed at equal angular intervals, as shown in plan view in Fig. 4. Each element subtends a beam sector 130 of nominally 52 degrees, the sectors overlapping so that no azimuth is left unsampled at survey depth.

[0010]

Signals from the ring 112 pass to a pre-amplifier stage 124 which applies a time-varied gain law before digitisation. The corrected stream is delivered to the frame assembler 126, which combines the attitude solution derived from the reference mass 118 with successive returns to produce the depth map product 128.

[0011]

It is a particular advantage of the arrangement that the map 128 is refreshed continuously rather than in discrete survey passes; the drift path of the apparatus 100 need never be interrupted, and a single operator may hold station from a small tender.

Claims — what is claimed is

A survey apparatus 100 for sonic cartography of a water column, comprising:

a pressure dome 104 defining a sealed upper volume;
a compliant collar 106 coupling said dome to an instrument barrel 108;
a hydrophone ring 112 carried below said barrel and comprising a plurality of transducer elements 114; and
a sampling controller 110 configured to assemble successive returns into a continuously refreshed depth map 128.

The apparatus of claim 1, wherein said sampling controller 110 is carried upon a gimbal cradle 116 within said barrel 108.

The apparatus of claim 2, further comprising a reference mass 118 pendulously suspended within said cradle 116 and arranged to establish a local vertical.

The apparatus of claim 1, wherein said compliant collar 106 comprises an elastomeric web 132 vulcanised between opposed annular flanges.

The apparatus of claim 1, wherein said transducer elements 114 are eight in number and are distributed at equal angular intervals about said ring 112, each subtending a beam sector 130 overlapping that of an adjacent element.

The apparatus of claim 1, further comprising a ballast keel 120 constituting not less than 35 per cent of the displaced mass of the apparatus.

A method of surveying a water column, comprising: sampling an acoustic field by means of a hydrophone ring 112; deriving an attitude solution from a reference mass 118; and combining said samples with said solution in a frame assembler 126 without interrupting a drift path of the apparatus 100.

— 17 claims, remainder omitted from this specimen sheet —