WO2012051675A1

WO2012051675A1 - Survey airship

Info

Publication number: WO2012051675A1
Application number: PCT/AU2011/001614
Authority: WO
Inventors: Adam Kroll
Original assignee: Shift Geophysics Pty Ltd
Priority date: 2010-10-19
Filing date: 2011-12-14
Publication date: 2012-04-26
Also published as: AU2011318259A1

Abstract

A survey airship (10) comprising a non-rigid self-supporting gas envelope (12) and one or more propulsion units (22) to provide movement of the airship (10). A first magnetometer (32) is provided secured to the gas envelope (12) and a second magnetometer (34) secured to the gas envelope offset from the first magnetometer (32) in a horizontal direction. A third magnetometer (36) is secured to the gas envelope offset from the first and second magnetometers (32 and 34) in a vertical direction.

Description

"SURVEY AIRSHIP"

Field of the Invention

[001] The present invention relates to an airship to be used for geophysical surveys.

Background to the Invention

[002] Conducting geophysical surveys from the air can provide useful information for a range of fields. The data gathered from such air based surveys can be used to generate maps of information regarding subsurface features that can be used, for example, in mineral exploration.

[003] Such geophysical surveys can include gravitational, magnetic, electromagnetic and radiometric measurements. It is common to perform such measurements from an aircraft, being a plane or a helicopter, where the surveying equipment is provided on the aircraft or a towed platform. The use of such aircraft however creates problems due to the interfering signals created by the metallic bodies of the aircraft and the operating parts of the aircraft, including the engines.

[004] Airships have been proposed for some use in geophysical surveying due to the reduced noise levels during operation. The present invention relates to such a survey airship having features aimed at providing improved useful survey data.

Summary of the Invention

[005] According to one aspect of the present invention there is provided a survey airship comprising:

a non-rigid self-supporting gas envelope;

one or more propulsion units to provide movement of the airship;

a first magnetometer secured to the gas envelope; a second magnetometer secured to the gas envelope offset from the first magnetometer in a horizontal direction; an

a third magnetometer secured to the gas envelope offset from the first and second magnetometers in a vertical direction.

[006] Preferably the first magnetometer is provided on a first side of the gas envelope and a second magnetometer is located on a second opposed side of the gas envelope in the same horizontal plane.

[007] Preferably the first and second magnetometers are located generally midway between the nose and the tail of the airship. Preferably the third magnetometer is located on an upper side of the gas envelope.

[008] The third magnetometer is preferably located generally midway between the nose and the tail of the airship such that the third magnetometer is located on a plane bisecting an axis joining the first and second magnetometers.

[009] In one embodiment, an autopilot system is provided to control operation of the airship. Preferably a data acquisition system is provided to store gathered geophysical data to create a map of said data for a surveyed area.

[010] In a preferred embodiment, a gyroscope is provided to sense orientation of the airship and information from the gyroscope is stored in the data acquisition system to correct for errors introduced by the pitch, roll and yaw of the airship during the survey.

[011] In a preferred embodiment, a plurality of radiometric sensors are provided, wherein each radiometric sensor comprises an elongate sensor including a crystal sensor for detecting gamma radiation emitted from the earth and wherein the radiometric sensors are each arranged parallel to a longitudinal axis of the airship and are spaced apart down the length of the airship. [012] Preferably each of the radiometric sensors is secured to a lower side of the gas envelope. The radiometric sensors are each preferably located on a line extending under the gas envelope from the nose to the tail.

[013] In one embodiment, the propulsion units are provided on opposed longitudinal sides of a gondola supported from a lower side of the gas envelope. Each of the propulsion units preferably comprises a cylindrical housing supported from a central axle extending through the gondola such that the propulsion units can be rotated through 180 degrees to control the pitch, roll and yaw of the airship whilst draping the terrain to minimise errors related to calculating the 3D response of the earth.

[014] The airship preferably includes GPS and radar/laser altimeter to provide information regarding the position of the airship 10.

[015] A wireless communications link may be provided to communicate information to a ground control system.

[016] In one embodiment, the gas envelope is provided with a pair of horizontal fins and a pair of vertical fins on opposed thereof adjacent the tail to control pitch and yaw of the airship.

Brief Description of the Drawings

[017] The invention will now be described, by way of example, with reference to the following drawings:

[018] Figure 1 is a side view of a survey airship in accordance with the present invention; and

[019] Figure 2 is a lower perspective view of the survey airship of Figure 1.

Detailed Description of Preferred Embodiments

[020] Referring to Figures, there is shown a survey airship 10 for conducting geophysical surveying. The airship 10 of the present invention is configured to provide mapping of geologic data collected using magnetic surveying techniques.

[021] The airship 10 comprises a non-rigid self-supporting gas envelope 12. The gas envelope 12 is constructed of a suitable flexible material and inflated to form a cigar shaped body having a nose 14 and a tail 16. Provided about the tail 16 are a plurality of fins. A pair of horizontal fins 18 are provided on opposed sides of the airship 10 and a pair of vertical fins 19 are a provided on upper and lower sides of the airship 10. The horizontal fins 18 are provided with rudders to control the pitch of the airship 10 and the vertical fins 19 are provided with rudders to control the yaw of the airship 10.

[022] A gondola 20 is provided supported from a lower side of the gas envelope 12. The gondola 20 includes first and second propulsion units 22. The first and second propulsion units 22 are supported from opposed longitudinal sides of the gondola 20. Each of the propulsion units 22 comprises a cylindrical housing 24 supported from a central axle 26 extending transversely through the gondola 22. The housings 24 each include an internal propeller to provide propulsion and can be rotated by the central axle 26. The propulsion units 22 can be rotated by 180 degrees to allow for forward movement and vertical climb or descent.

[023] During use, the fins are provided primarily for stability. The fins will maintain pitch and yaw to obtain accurate geophysical measurements. The forward movement and climb or descent rate of the airship is controlled by the propulsion units 22 that can be rotated by 180 degrees, allowing any climb rate from vertically up to vertically down.

[024] The airship 10 is unmanned and therefore includes an autopilot system to control operation of the airship 10. The airship 10 also includes a GPS, an altimeter and a gyroscope to provide information regarding the position and orientation on the airship 10. A wireless communications link is provided to communicate this information to a ground control system which can then monitor operation of the airship 10. The airship 10 may be pre-programmed to fly a predetermined survey flight pattern which is monitored by the ground station.

[025] The airship 10 is provided with a plurality of magnetometers 30 provided to measure magnetic field readings and a plurality of radiometric sensors 28 for recording gamma ray emissions from the earth.

[026] There are provided three magnetometers 30 spaced around the gas envelope 12 for magnetic field measurements. A first magnetometer 32 is provided on a first side of the gas envelope 12 and a second magnetometer 34 is located on a second opposed side of the gas envelope 12. The first and second magnetometers 32 and 34 are both in the same horizontal plane on opposite longitudinal sides of the airship 10. In the embodiment shown, the first and second magnetometers 32 and 34 are located generally midway between the nose 14 and the tail 16 of the airship 10. This arrangement of the first and second magnetometers 32 and 34 located near the middle of the airship 10 is useful for measurements in that it provides the greatest separation between the magnetometers.

[027] A third magnetometer 36 is located on an upper side of the gas envelope. The third magnetometer 36 is therefore located vertically offset from both the first and second magnetometers 32 and 34. In the embodiment shown, the third magnetometer 36 is also located generally midway between the nose 14 and the tail 16 of the airship such that the third magnetometer 36 is located on a plane bisecting an axis joining the first and second magnetometers.

[028] The arrangement of the magnetometers 30 thereby allows measurement of gradient magnetic fields in three orthogonal directions. The difference in measurements between the mid range in values between the first and second magnetometers 32 and 34 allows measurement of the gradient in a horizontal axis perpendicular to the direction of travel of the airship. The difference in measurements between the first or second magnetometers 32, 34 and the third magnetometer 36 allows measurement of the gradient in a vertical direction. Measurement of the gradient in a horizontal direction parallel to the direction of movement of the airship 10 can be measured by any one magnetometer 30 as the airship moves through space.

[029] The airship is also provided with a plurality of radiometric sensors 28. The radiometric sensors 28 each comprise an elongate sensor including a crystal sensor for detecting gamma radiation emitted from the earth.

[030] The radiometric sensors 28 are each arranged parallel to a longitudinal axis of the airship 10 spaced apart down the length of the airship 10. In the embodiment shown, each of the radiometric sensors 28 is secured to a lower side of the gas envelope 12. The radiometric sensors 28 are each located on a line extending under the gas envelope 12 from the nose 14 to the tail 16.

[031] This lengthwise arrangement of the radiometric sensors provides improved measurement with increased absorption of gamma rays over conventional configurations.

[032] In the embodiment shown, there are provide four such radiometric sensors 28 with two of the radiometric sensors 28 located forward of the gondola 20 and two of the radiometric sensors located rearwardly of the gondola 20. It will be appreciated though that other numbers and configurations of the radiometric sensors 28 would be possible.

[033] Information during the survey is collected and stored by a data acquisition system. This collected information may be used to create a map of the collected geophysical data over the survey area.

[034] During operation, information regarding the orientation of the airship 10 from the gyroscope is also collected and stored over the survey area. This information regarding the orientation of the airship is then used to correct for the error in the acquired data introduced by the pitch, yaw and roll of the airship.

[035] Using an airship in this configuration provides significant advantages for collection of geophysical survey data. An airship generates lower noise levels of noise than other aircraft and provides also greater manoeuvrability, allowing the airship 10 to more effectively manoeuvre in difficult areas, such as steep hills or varied terrain. Further, as airships are more fuel efficient than other aircraft, surveys may be conducted for longer periods at lower costs.

[036] The arrangement of an airship having the propulsion units 22 rotatable through 180 degrees as shown is also advantageous in that the airship 10 will be able to climb and descend without significant pitching. This will then maintain the magnetometers generally in the same plane, thereby providing improved ability to create a 3D inversion.

[037] It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention.

Claims

1. A survey airship comprising:

a non-rigid self-supporting gas envelope;

one or more propulsion units to provide movement of the airship;

a first magnetometer secured to the gas envelope;

a second magnetometer secured to the gas envelope offset from the first magnetometer in a horizontal direction; an

2. A survey airship in accordance with claim 1 , wherein the first magnetometer is provided on a first side of the gas envelope and a second magnetometer is located on a second opposed side of the gas envelope in the same horizontal plane.

3. A survey airship in accordance with claim 2, wherein the first and second magnetometers are located generally midway between the nose and the tail of the airship.

4. A survey airship in accordance with claim 3, wherein the third magnetometer is located on an upper side of the gas envelope.

5. A survey airship in accordance with claim 4, wherein the third magnetometer is located generally midway between the nose and the tail of the airship such that the third magnetometer is located on a plane bisecting an axis joining the first and second magnetometers.

6. A survey airship in accordance with any one of the preceding claims, wherein an autopilot system is provided to control operation of the airship.

7. A survey ship in accordance with any one of the preceding claims, wherein there is provided a data acquisition system to store gathered geophysical data to create a map of said data for a surveyed area.

8. A survey ship in accordance with claim 7, wherein a gyroscope is provided to sense orientation of the airship and information from the gyroscope is stored in the data acquisition system to correct for errors introduced by the pitch, roll and yaw of the airship during the survey.

9. A survey airship in accordance with any one of the preceding claims, wherein a plurality of radiometric sensors are provided, wherein each radiometric sensor comprises an elongate sensor including a crystal sensor for detecting gamma radiation emitted from the earth and wherein the radiometric sensors are each arranged parallel to a longitudinal axis of the airship and are spaced apart down the length of the airship.

10. A survey airship in accordance with claim 9, wherein each of the radiometric sensors is secured to a lower side of the gas envelope.

11. A survey airship in accordance with claim 10, wherein the radiometric sensors are each located on a line extending under the gas envelope from the nose to the tail.

12. A survey ship in accordance with any one of the preceding claims, wherein the propulsion units are provided on opposed longitudinal sides of a gondola supported from a lower side of the gas envelope.

13. A survey ship in accordance with claim 12, wherein each of the propulsion units comprises a cylindrical housing supported from a central axle extending through the gondola such that the propulsion units can be rotated through 180 degrees to control the pitch, roll and yaw of the airship whilst draping the terrain to minimise errors related to calculating the 3D response of the earth.

14. A survey airship in accordance with any one of the preceding claims, wherein the airship includes GPS and radar/laser altimeter to provide information regarding the position of the airship 10.

15. A survey airship in accordance with claim 14, wherein a wireless communications link is provided to communicate information to a ground control system.

16. A survey airship in accordance with any of the preceding claims, wherein the gas envelope is provided with a pair of horizontal fins and a pair of vertical fins on opposed thereof adjacent the tail to control pitch and yaw of the airship.