Method of guiding a vehicle to a position

• US 6,957,132 B1
• Filed: 06/26/2003
• Issued: 10/18/2005
• Est. Priority Date: 06/26/2003
• Status: Expired due to Fees

• Current Assignee: The United States of American As Represented By The Secretary of The Navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Hobden, Donald D., Richburg, Chris
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Application Number:
  US10/609,901
• Time in Patent Office: 845 Days
• Field of Search: 701 23- 28, 701200-201, 701207-211, 701/223, 701300-302, 362520-522, 362/238, 362/240, 362/512, 362/11, 362 36- 37, 362/41, 362/43, 362509-511, 362543-545, 340/942, 340/958, 250330-334, 250206-2063, 250/226, 250/229, 250/578.1, 250234-236, 250/559.1, 180167-169, 348/113, 348/118, 348/119, 348750-751
• US Class Current: 701/23
• CPC Class Codes: F21W 2111/00 Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G05D 1/0225 involving docking at a fixed facility, e.g. base station or loading bay parking aids B62D15/027
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/0692 specially adapted for under-water vehicles

Abstract

A method of guiding a vehicle to a position is provided. Light sources arranged in an array are placed at a position with the light sources defining a primary field-of-view (FOV) from which all of the light sources are visible. Less than all of the light sources are visible from positions outside of the primary FOV. The light sources are divided into sections with each section having a portion of the light sources associated therewith. The light sources are operated in accordance with cyclical on/off sequences so that a primary waveform of light energy is defined by the cyclical on/off sequence visible from within the primary FOV and secondary waveforms of light energy are defined by the cyclical on/off sequences visible from positions outside of the primary FOV. The light energy generated by the light sources is sensed by an approaching navigable vehicle. Based on the position of the vehicle, one of the primary waveform and the plurality of secondary waveforms is sensed. A database on the vehicle stores calibration waveforms indicative of guidance correction signals that can be used to control navigation of the vehicle. The calibration waveform that is closest to the primary and secondary waveforms so-sensed is indicative of the guidance correction signal.

Claims

1. A method of guiding a vehicle to a position, comprising the steps of:

placing light sources arranged in an array at a position with said light sources defining a primary field-of-view (FOV) from which all of said light sources are visible wherein less than all of said light sources are visible from positions outside of said primary FOV, said light sources being divided into a plurality of sections with each of said plurality of sections having a portion of said light sources associated therewith;

operating said light sources in accordance with a plurality of modes to include a search mode and a tracking mode, wherein said search mode is defined by all of said light sources flashing on and off concurrently at a predetermined rate, and wherein said tracking mode is defined by said light sources being operated in accordance with cyclical on/off sequences, each of said cyclical on/off sequences being (i) associated with a corresponding one of said plurality of sections, (ii) identical for said portion of said light sources associated with said corresponding one of said plurality of sections, and (iii) unique for each of said plurality of sections, wherein a primary waveform of light energy is defined by said cyclical on/off sequences associated with said plurality of sections and visible from within said primary FOV, and wherein a plurality of secondary waveforms of light energy are defined by said cyclical on/off sequences visible from positions outside of said primary FOV;

providing a receiver on a vehicle traveling towards said position, said receiver including at least one light sensor, a database, and a processor having an internal clock;

sensing, using said at least one light sensor, light energy generated by ones of said light sources visible thereto;

utilizing, when said light sources are operating in said search mode, said predetermined rate to set timing for said internal clock;

providing a plurality of calibration waveforms in said database, wherein each of said calibration waveforms is indicative of a guidance correction signal that can be used to control navigation of the vehicle; and

determining, using said processor when said light sources are operating in said tracking mode, which one of said calibration waveforms is closest to said one of said primary waveform and said plurality of secondary waveforms so-sensed, wherein said guidance correction signal associated with said one of said calibration waveforms can be used to control navigation of the vehicle.

2. A method according to claim 1 wherein one cycle of each of said cyclical on/off sequences includes a pulse of common duration, and wherein said one cycle associated with each of said plurality of sections is distinguishable by the timing of said pulse within said one cycle.

3. A method according to claim 1 wherein one cycle of each of said cyclical on/off sequences includes a pulse, and wherein said one cycle associated with each of said plurality of sections is distinguishable by the duration of said pulse within said one cycle.

4. A method according to claim 1 wherein each of said plurality of sections includes a portion of a periphery of said array, and wherein said method further comprises the step of excluding ones of said light sources at said periphery from said cyclical on/off sequences to reduce a cross-sectional area of said primary FOV as the vehicle gets closer to said position.

5. A method according to claim 1 wherein each of said light sources produces light energy having the same wavelength.

6. A method according to claim 1 wherein each of said light sources produces light energy having a wavelength in the range of approximately 390 nanometers to approximately 577 nanometers.

7. A method of guiding a vehicle to a position, comprising the steps of:

placing light sources arranged in an array at a position with said light sources defining a primary field-of-view (FOV) from which all of said light sources are visible wherein less than all of said light sources are visible from positions outside of said primary FOV, each of said light sources producing light energy having the same wavelength when turned on, said light sources being divided into a plurality of sections with each of said plurality of sections having a portion of said light sources associated therewith, said array being defined by concentric rings of said light sources with each of said plurality of sections having a portion of said light sources associated therewith to include portions of each of said concentric rings;

operating said light sources in accordance with a plurality of modes to include a search mode and a tracking mode, wherein said search mode is defined by all of said light sources flashing on and off concurrently at a predetermined rate, and wherein said tracking mode is defined by said light sources being operated in accordance with cyclical on/off sequences, each of said cyclical on/off sequences being (i) associated with a corresponding one of said plurality of sections, (ii) identical for said portion of said light sources associated with said corresponding one of said plurality of sections, and (iii) unique for each of said plurality of sections, wherein a primary waveform of light energy is defined by said cyclical on/off sequences associated with said plurality of sections and visible from within said primary FOV, and wherein a plurality of secondary waveforms of light energy are defined by said cyclical on/off sequences visible from positions outside of said primary FOV;

providing a receiver on a vehicle traveling towards said position, said receiver including at least one light sensor, a database, and a processor having an internal clock;

sensing, using said at least one light sensor, light energy generated by ones of said light sources visible thereto;

utilizing, when said light sources are operating in said search mode, said predetermined rate to set timing for said internal clock;

providing a plurality of calibration waveforms in said database, wherein each of said calibration waveforms is indicative of a guidance correction signal that can be used to control navigation of the vehicle;

determining, using said processor when said light sources are operating in said tracking mode, which one of said calibration waveforms is closest to said one of said primary waveform and said plurality of secondary waveforms so-sensed, wherein said guidance correction signal associated with said one of said calibration waveforms can be used to control navigation of the vehicle; and

excluding outermost ones of said concentric rings of said light sources from said cyclical on/off sequences to reduce a cross-sectional area of said FOV as the vehicle gets closer to said position.

8. A method according to claim 7 wherein one cycle of each of said cyclical on/off sequences includes a pulse of common duration, and wherein said one cycle associated with each of said plurality of sections is distinguishable by the timing of said pulse within said one cycle.

9. A method according to claim 7 wherein one cycle of each of said cyclical on/off sequences includes a pulse, and wherein said one cycle associated with each of said plurality of sections is distinguishable by the duration of said pulse within said one cycle.

10. A method according to claim 7 wherein each of said light sources produces light energy having a wavelength in the range of approximately 390 nanometers to approximately 577 nanometers.