WO2012051676A1

WO2012051676A1 - Survey airship

Info

Publication number: WO2012051676A1
Application number: PCT/AU2011/001615
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: AU2011318260A1

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 transmitting coil (32) extends around the gas envelope in a horizontal plane. A second transmitting coil (34) extends around the gas envelope (12) in a vertical plane parallel to the longitudinal axis of the airship (10). A third transmitting coil (36) extends around the gas envelope (12) in a vertical plane perpendicular to the longitudinal axis of the airship (10). One or more geophysical survey systems provided to collect geophysical survey data based on the sensed ground response to signals transmitted by the transmitting coils (30).

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 transmitting coil extending around the gas envelope in a horizontal plane;

a second transmitting coil extending around the gas envelope in a vertical plane parallel to the longitudinal axis of the airship;

a third transmitting coil extending around the gas envelope in a vertical plane perpendicular to the longitudinal axis of the airship; and

one or more geophysical survey systems provided to collect geophysical survey data based on the sensed ground response to signals transmitted by the transmitting coils.

[006] Preferably, the first and second transmitting coils extend around the gas envelope of the airship from the nose to the tail perpendicular to each other and the third transmitting coil is located generally midway between the nose and the tail.

[007] Preferably the gas envelope is generally cigar shaped and the first and second transmitting coils are generally elliptical in shape and the third transmitting coil is generally circular in shape.

[008] Preferably, the geophysical survey systems include a three component receiver provided to measure the ground response to signals generated by the transmitting coils in three orthogonal directions such that the conductivity of the earth may be generated in three dimensional space.

[009] In a preferred embodiment, there is provided a data acquisition system to store gathered geophysical data to create a map of said data for a surveyed area.

[010] Preferably, an autopilot system is provided to control operation of the airship.

[011] 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. [012] The propulsion units are preferably provided on opposed longitudinal sides of a gondola supported from a lower side of the gas envelope.

[013] Preferably 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 terrain to minimise errors related to calculating the 3D response of the earth.

[014] Preferably a plurality of receiver sensors are provided for collecting signals for use with the active electromagnetic systems, the sensors comprising one or more of an induction coil, a fluxgate magnetometer and a SQUID magnetometer.

[015] In one embodiment, the airship includes GPS and radar/laser altimeter to provide information regarding the position and orientation on the airship.

[016] A wireless communications link is preferably provided to communicate information to a ground control system.

[017] The gas envelope is preferably 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

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

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

[020] Figure 2 is a lower perspective view of the survey airship of Figure 1 ; and

[021] Figure 3 is a block diagram of the components of the systems provided on the survey airship. Detailed Description of Preferred Embodiments

[022] 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 electromagnetic surveying techniques.

[023] 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.

[024] 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.

[025] 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.

[026] Figure 3 shows a block diagram representation of the systems provided within the airship 10, including geophysical survey systems. The airship 10 comprises is unmanned and therefore includes an autopilot system 144 to control operation of the airship 10. The airship 10 includes GPS 146, radar/laser altimeter 148 and gyroscope 150 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 142 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 142.

[027] In one embodiment, a single ground station 142 may be used to simultaneously control a plurality of the airships 10 each having an independent flight pattern. In a further embodiment, all or some of the operations performed by the grounds station 142 may be performed from an aircraft-based control station or a ship-based control station.

[028] A range of geophysical survey equipment is provided in the airship 10. A central acquisition system 162 is provided to collect data from a plurality of geophysical survey systems including one or more magnetometers 154 and a passive electromagnetic sensor in the form of an AFMAG (audio frequency magnetic) system 160 for measuring low frequency electromagnetic fields caused by a natural electromagnetic sources. The geophysical survey systems also include a ground penetrating radar 152 and active frequency domain 158 and time domain 156 electromagnetic survey systems.

[029] A plurality of sensors are provided for collecting signals for use with the active electromagnetic systems 156 and 158, the AFMAG 160 and the ground penetrating radar 152. These sensors include one or more induction coils 164, a fluxgate magnetometer 166 and a SQUID magnetometer 168: The sensors may be located either inside or outside the gas envelope 12.

[030] The airship 10 includes three transmitting coils 30 provided to generate signals for the electromagnetic systems. Each of the transmitting coils 13 comprises a coil of wire extending around the gas envelope 12 of the airship 10. A first transmitting coil 32 is oriented in a horizontal plane extending around the envelope 12 of the airship 10 from the nose 14 to the tail 16. A second transmitting coil 34 is oriented in a vertical plane extending around the envelope 12 of the airship 10 from the nose 14 to the tail 16. A third transmitting coil 36 is oriented also in a vertical plane extending around the envelope 12 of the airship 10 transversely to the longitudinal axis of the airship 10. The third transmitting coil 36 is located generally midway between the nose 14 and the tail 16.

[031] The first and second transmitting coils 32 and 34 are therefore generally elliptical in shape and the third transmitting coil 36 is generally circular in shape.

[032] The sensors provided on the airship 10 to measure the ground response from the transmitting coils 30 include a three component receiver. The use of a three component receiver, along with the orientations of the transmitting coils 30 thereby allow collection of data in three different orthogonal directions, being vertically perpendicular to the direction of flight, vertically parallel to the flight direction and horizontally.

[033] This particular arrangement of the transmitting coils 30 provides greater geological information that is expected to be of significant value. The use of the three transmitting coils 30 and a three component receiver allows a 3D inversion to be derived in which the conductivity of the subsurface of the earth is represented in three dimensional space over the surveyed area.

[034] Information during the survey is collected and stored by the data acquisition system 162. This collected information may be used to create a map of the collected geophysical data over the survey area.

[035] During operation, information regarding the orientation of the airship 10 from the gyroscope 150 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.

[036] 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.

[037] 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 provide an improved ability to gather accurate data in three dimensions.

[038] 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 transmitting coil extending around the gas envelope in a horizontal plane;

2. A survey airship in accordance with claim 1 , wherein the first and second transmitting coils extend around the gas envelope of the airship from the nose to the tail and the third transmitting coil is located generally midway between the nose and the tail.

3. A survey ship in accordance with claim 1 or 2, wherein the gas envelope is generally cigar shaped and the first and second transmitting coils are generally elliptical in shape and the third transmitting coil is generally circular in shape.

4. A survey ship in accordance with any one of the preceding claims, wherein the geophysical survey systems include a three component receiver provided to measure the ground response to signals generated by the transmitting coils in three orthogonal directions such that the conductivity of the earth may be generated in three dimensional space.

5. 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.

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 claim 6, 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.

8. A survey ship in accordance with any one of claims 1 to 7, wherein the propulsion units are provided on opposed longitudinal sides of a gondola supported from a lower side of the gas envelope.

9. A survey ship in accordance with claim 8, 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 terrain to minimise errors related to calculating the 3D response of the earth.

10. A survey airship in accordance with any one of the preceding claims, wherein the geophysical survey systems include an active time domain electromagnetic system.

11. A survey airship in accordance with any one of the preceding claims, wherein a plurality of receiver sensors are provided for collecting signals for use with the active electromagnetic systems, the sensors comprising one or more of an induction coil, a fluxgate magnetometer and a SQUID magnetometer.

12. 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 and orientation on the airship.

13. A survey airship in accordance with claim 12, wherein a wireless communications link is provided to communicate information to a ground control system.

14. A survey airship in accordance with any of the preceding claims, wherein the gas envebpe 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.