Method, apparatus, and system to remotely acquire information from volumes in a snowpack

• US 8,581,772 B2
• Filed: 05/31/2011
• Issued: 11/12/2013
• Est. Priority Date: 06/04/2010
• Status: Expired due to Fees

• Current Assignee: Brigham Young University (The Church of Jesus Christ of Latter-Day Saints)
• Original Assignee: Brigham Young University (The Church of Jesus Christ of Latter-Day Saints)
• Inventors: Long, David G., Preston, Stephen Joseph
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): BYTHROW, PETER M
• Application Number:
  US13/149,881
• Publication Number:
  US 20110298647A1
• Time in Patent Office: 896 Days
• Field of Search: 342/22, 342/25.R, 342/25.A, 342/25.B, 342/25.C, 342/25.D, 342/25.E, 342/25.F
• US Class Current: 342/22
• CPC Class Codes: A63B 2220/805 Optical or opto-electronic sensors
• CPC Class Codes: A63B 2225/20 with means for remote communication, e.g. internet or the like
• CPC Class Codes: A63B 29/021 Means for indicating the location of accidentally buried, e.g. snow-buried, persons
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 13/9027 Pattern recognition for feature extraction
• CPC Class Codes: G01S 13/9064 Inverse SAR [ISAR]
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values

Abstract

A method, apparatus, and system to remotely acquire information from volumes in a snowpack and to analyze the information are disclosed. Electromagnetic energy is transmitted remotely to a region of interest in a snowpack and data about reflections are processed to determine reflection values for different volumes within the snowpack. The frequency of the transmit signal is modulated and the positions from which energy is transmitted and received are changed to create a two-dimensional synthetic aperture that allows reflections from three-dimensional volumes to be discriminated and resolved. The electromagnetic energy is transmitted to ensure that it arrives at the snowpack at shallow grazing angles to maximize returns from volumes in the snow and to minimize boundary reflections from the ground.

Claims

1. A method for remotely acquiring information from volumes in a snowpack comprising:

transmitting electromagnetic energy to a snowpack from a remote location at a shallow grazing angle;

receiving electromagnetic reflections from said snowpack; and

processing data about said electromagnetic reflections with an electronic computer processor to determine reflection values for different volumes within said snowpack.

2. The method of claim 1, further comprising:

modulating a frequency of said transmitted electromagnetic energy over a sufficient bandwidth to resolve distinct volumes within said snowpack with respect to a first axis;

translating an antenna system transmitting said transmitted electromagnetic energy and receiving said electromagnetic reflections to occupy different positions with respect to a second axis substantially orthogonal to said first axis over a first distance sufficient to resolve different volumes within said snowpack with respect to said second axis; and

translating said antenna system to occupy different positions with respect to a third axis, substantially orthogonal to said first axis and said second axis over a second distance sufficient to resolve different volumes within said snowpack with respect to said third axis, wherein said positions cover an area of dimensions defined by said first distance and said second distance.

3. The method of claim 2, further comprising positioning said antenna system to maintain a relative orientation to a region of interest within said snowpack that ensures that electromagnetic energy incident upon said region of interest arrives at a grazing angle sufficiently shallow to maximize returns from volume scattering in volumes of said snowpack compared to reflections from a boundary between said snowpack and ground underneath.

4. The method of claim 2, further comprising:

transmitting electromagnetic energy from at least one additional span of the electromagnetic spectrum capable of producing a different response from said snowpack over a sufficient bandwidth to resolve distinct volumes within said snowpack with respect to said first axis; and

processing data about said different response to determine reflection values for different volumes within said snowpack.

5. The method of claim 2, wherein said reflection values are compared against expected reflection values from a reflection model for a volume comprised of a particular subject of interest.

6. The method of claim 5, wherein said reflection model takes into account a density for said volume.

7. The method of claim 5, wherein said reflection model takes into account a general shape for an average ice grain in said volume.

8. The method of claim 5, wherein said reflection model takes into account a general size for an average ice grain in said volume.

9. The method of claim 5, wherein said reflection model provides an expected response profile as a function of wavelength.

10. The method of claim 5, wherein said reflection model takes into account a water content distribution.

11. The method of claim 2, further comprising:

transmitting electromagnetic energy to a region of interest of said snowpack wherein a victim of an avalanche may be buried; and

analyzing said reflection values to determine a location for said victim.

12. The method of claim 2, further comprising:

transmitting electromagnetic energy to a region of interest of said snowpack with a potential for including avalanche debris; and

analyzing said reflection values to determine a three-dimensional distribution for said avalanche debris.

13. The method of claim 2, further comprising:

transmitting electromagnetic energy to a region of interest of said snowpack important to determining snow-water equivalencies for a watershed; and

analyzing said reflection values to determine snow-water equivalencies.

14. The method of claim 2, further comprising:

transmitting electromagnetic energy to a region of interest of said snowpack from which avalanche formation may occur; and

analyzing said reflection values for properties relevant to avalanche prediction.

15. The method of claim 14, wherein said bandwidth, and said first distance and said second distance with respect to said second and said third axes are sufficient to achieve a resolution commensurate with a thickness for a layer of interest to avalanche prediction in said snowpack regardless of a direction of propagation relative to said snowpack.

16. An apparatus for remotely acquiring information from a snowpack comprising:

a signal conditioning module modulating electromagnetic energy across various frequencies within at least one bandwidth sufficiently large to resolve different volumes within said snowpack with respect to a first axis, defined by a direction of propagation directed along a shallow grazing angle relative to the snowpack, and with sufficient power to transmit said electromagnetic energy to a remote area of interest in a snowpack and to produce detectible reflections;

an antenna system electrically coupled to said signal conditioning module, wherein said antenna system transmits said electromagnetic energy, to arrive at a shallow grazing angle relative to the snowpack, and receives said reflections from said snowpack;

a memory coupled to said signal conditioning module, wherein said memory stores data about values for said reflections generated by said signal conditioning module; and

a processor communicatively coupled to said memory, wherein said processor determines reflection values for different volumes within said snowpack.

17. The apparatus of claim 16, further comprising infrastructure for translating said antenna system substantially orthogonal to said first axis, wherein said infrastructure translates said antenna system to occupy different positions with respect to a second axis and with respect to a third axis substantially orthogonal to said first axis and substantially orthogonal to one another over an area sufficient to resolve different volumes within said snowpack.

18. The apparatus of claim 16, wherein an orientation of said antenna system relative to said snowpack is maintained to ensure that electromagnetic energy incident upon said region of interest of said snowpack arrives at a grazing angle sufficiently shallow to maximize returns from volume scattering in volumes of said snowpack compared to reflections from a boundary between said snowpack and ground underneath.

19. A system for remotely retrieving information from a snowpack comprising:

a signal conditioning module modulating electromagnetic energy across various frequencies within at least one bandwidth sufficiently large to resolve different volumes within said snowpack with respect to a first axis, defined by a direction of propagation directed along a shallow grazing angle relative to the snowpack, and with sufficient power to transmit said electromagnetic energy to a remote area of interest in a snowpack and to produce detectible reflections;

an antenna system electrically coupled to said signal conditioning module transmitting said electromagnetic energy, to arrive at the shallow grazing angle relative to the snowpack, and receiving said reflections from said snowpack;

infrastructure for translating said antenna system substantially orthogonal to said first axis, wherein said infrastructure translates said antenna system to occupy different positions with respect to a second axis and with respect to a third axis substantially orthogonal to said first axis and substantially orthogonal to one another over an area sufficient to resolve different volumes within said snowpack, and wherein said infrastructure maintains an orientation of said antenna system relative to said area of interest to ensure that electromagnetic energy incident upon said snowpack arrives at a grazing angle sufficiently shallow to maximize returns from volume scattering in volumes of said snowpack compared to reflections from a boundary between said snowpack and ground underneath;

a memory coupled to said signal conditioning module storing reflection data indexed to reflection frequencies and positions of said antenna system at which reflections are received; and

a processor communicatively coupled to said memory determining reflection values for different volumes within said snowpack.

20. The system of claim 19, wherein:

said memory also stores at least one volume scattering coefficient that provides an expected reflection value for a particular volume that potentially exists in the snowpack; and

said processor compares the at least one volume scattering coefficient to the reflection data to determine the presence of the particular volume in the snowpack.