Low cost ocean surface drifter for satellite tracking

Abstract

An ocean floating drifter, which can be very quickly assembled at low cost in urgent situation, can accurately trace ocean surface currents with help of global positioning device to transmit periodically data and position information to satellites. The drifter includes a cylinder shape made of materials which can protect the electronic GPS tracker device in it. A conical shape at lower end is used to lower the impact during air drop. The weight amount at the bottom can be pre-adjusted to simulate different the wind effect during the drifting. The drifter can be kept relatively stable position during its drifting to let its GPS device reliably communicate with satellites. The drifter has special provisions to sustain impact during air drop, resist corrosion, fish-bite damage and biological fouling.

Claims

1. An ocean drifter used to follow ocean surface currents comprising: a hollow cylinder shape body with sealed caps on both the top and bottom ends; a conical shape made with the same materials as the cylinder is attached to the bottom; weighing materials, foam, GPS and foam slice are subsequently inserted into the cylinder from the bottom to the top; a global positioning tracker device is sitting above the foam at near the top inside of cylinder and can transmit its location to satellites periodically;

2. The drifter assembly according to claim 1 where the hollow cylinder, caps at the two ends and conical shape at the bottom are all made of PVC;

3. The drifter assembly according to claim 1 where the conical shape attached to the bottom is optional for non air drop uses, it is required in the case of air drop.

4. The drifter assembly according to claim 3 where the conical shape at the bottom is also acting as weighing material. It is made of solid but the same materials as its cylinder body in claim 1.

5. The drifter assembly according to claim 1 where the caps and conical are attached to the cylinder using PVC solvent cement, which is mainly tetrahydrofuran;

6. The drifter assembly according to claim 1 where the weighing materials is crushed stones and/or sand;

7. The drifter assembly according to claim 6 where the weight materials is adjusted to control how much body floating above water to take wind effect.

8. The drifter assembly according to claim 1 where the foam materials is polyethylene or polyurethane;

9. The drifter assembly according to claim 8 where the foam is used to support and hold electronic satellite tracker device at the top of the drifter;

10. The drifter assembly according to claim 1 where a range from 5 mm to 20 mm thick foam is placed between the GPS or electronic device and the cap.

11. There is no space remaining among these items inside the cylinder body, including weighing materials, foam, GPS and caps in claims 8, 9 and 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] A further understanding of the nature and advantages of the present invention may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Furthermore, various components of the same type may be distinguished by following the reference label with a dash and a second label distinguishing between similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0018] FIG. 1 is a simplified block diagram illustrating a perspective 3-D view of a drifter;

[0019] FIG. 2 is a simplified block diagram illustrating a side view of the drifter;

[0020] FIG. 3 is a simplified block diagram illustrating a top view of the drifter including a global positioning device without the top cap;

[0021] FIG. 4 is a simplified block diagram illustrating a perspective 3-D view of a cap of the drifter, which can be either the top cap or bottom cap.

DETAILED DESCRIPTION OF THE PREFFERRED EMBODIMENTS

[0022] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described.

[0023] Refer to FIG. 1 and FIG. 2, an ocean drifter 100 according to a preferred embodiment of the invention is provided. The shape of a drifter in FIG. 100 is generally a cylinder shape body 104 with two caps 102 and 107 at the top and at the bottom respectively. Attached to the bottom is a conical 108 made with the same solid material as the cylinder. The outside diameter of the cylinder is either 3.5 inches (88.900 mm) or 4.5 inches (114.300 mm) while the height is the cylinder is between 12-24 inches which doesn't include the conical part at the bottom. The height of the conical is at least the same as its diameter or greater. The caps 102 and 107 have the exact the same inner diameter as the outside diameter of the cylinder 104, so the caps can tightly fit and cover the cylinder.

[0024] The materials used for the cylinder 104, the caps 102 and 107, the conical are all schedule 40 PVC (Polyvinyl Chloride). Typically, the wall thickness of the cylinder or the pipe is 0.216 inches and 0.237 inches respectively for 3.5 inches and 4.5 inches cylinder respectively. The conical is also made of the same PVC material. This conical is optional when the drifter is deployed in low attitudes such as from the boat, but it is necessary if dropped from the air.

[0025] The cap and the cylinder are sealed using PVC solvent cement. The conical and the bottom cap can be attached together using general water-resistant glue.

[0026] The bottom cap will be first sealed using PVC solvent cement. The bottom conical shape is attached at the bottom when the drifter to be dropped from high altitude. This conical shape can help to decrease the impact force to prevent damaging the GPS device when the drifter is entering the water from high altitude. Otherwise the conical part is not necessary.

[0027] Inside the cylindrical PVC shell, heavy weight materials 106 such as small crushed stones or sand are put in the bottom of the drifter after the bottom cap is sealed and cured. For the first drifter to be built, it is needed to test the volume of the weight to be added. The amount of weight to be added is depending on how much of the drifter needs to be floating above the water. The more space the drifter needs to be above the water, the less weight needs to be added.

[0028] Above the weight materials 106, a light foam 105 is inserted inside the cylinder. The materials can be like polyethylene or polyurethane. The foam should occupy the whole space with minimal space remaining, in other words, the diameter of the form is the same or near the inside diameter of the cylinder.

[0029] The volume of the weighing material 106 can be adjusted depending on how much body of the drifter needs to be floating above the water line 109.

[0030] At the top of the foam 105, cutting a space on the foam to fit GPS 101. The GPS is put inside the cutting space above the foam 106. The GPS may need to face up according to the GPS specification or its operation requirement. A thin slice of foam 103 with its thickness of 5-20 mm is put above the GPS.

[0031] After the weight materials, the form, the GPS and the thin foam above the GPS are all in their positions, the top cap 102 is cemented and sealed to the cylinder.

[0032] The assembled drifter can be dropped to the water for use almost immediately after a 15-20 minutes cure time.