Navigation system
First Claim
1. A navigation system for determining the location of a vehicle from the radio transmissions of two or more radio signal sources of known frequency and location in proximity of the vehicle comprising:
- means for entering and storing the frequencies and longitude and latitude positions of the at least two selected radio sources;
a rotatable directionally sensitive antenna;
means for rotating said directionally sensitive antenna through 360°
in a step-wise fashion and providing signals representative of the angular position of said antenna in relation to the heading of the vehicle;
means for detecting the heading of the vehicle and generating heading signals representative of said heading;
means for detecting the stored frequencies of the at least two selected radio signal sources and causing said means for rotating to rotate said directionally sensitive antenna until said directionally sensitive antenna is positioned in a signal null position for each of said radio signal sources;
means for comparing said angular position signals representative of the signal nulls with the heading signals to provide compass null headings for each of said radio signal sources;
means for differentiating between real null headings and false null headings for each of said radio signal source;
means for converting the point of intersection of said real null headings into corresponding longitude and latitude values for said vehicle;
means for visually displaying said longitude and latitude values for the location of said vehicle.
1 Assignment
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Accused Products
Abstract
Disclosed is a navigational system for accurately determining the position of a vehicle, such as a boat, truck, automobile or airplane in relation to two or more commercial AM radio transmission antenna or other signal sources of known longitude and latitude. The frequencies and exact coordinates (longitude and latitude) of the radio antenna are entered by keyboard input into the memory of the system. The null angles from the vehicle to the radio antenna are determined automatically by a computer controlled radio direction finder antenna mounted on the vehicle. The heading of the vehicle is determined and the relative null angles (in relation to the heading of the vehicle) are converted to standard null headings (North, 0°) by the system. The known positions of the stations are automatically compared by the system to the respective true and false (180° opposite) null headings and the correct angles are selected according to the proper trigonometric relationship (the sum of the internal angles of a triangle must equal 180°). Once the system has selected the proper null headings, the exact position of the vehicle can then be determined automatically and the coordinates displayed on a visual display. The system can also be adapted to allow input of one or more sets of destinational or navigational coordinates and the system will display the correct compass heading to be steered to reach the selected coordinates. The coordinates of hazards can also be entered and the system will provide a warning if the vehicle comes too close to the hazards.
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Citations
22 Claims
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1. A navigation system for determining the location of a vehicle from the radio transmissions of two or more radio signal sources of known frequency and location in proximity of the vehicle comprising:
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means for entering and storing the frequencies and longitude and latitude positions of the at least two selected radio sources; a rotatable directionally sensitive antenna; means for rotating said directionally sensitive antenna through 360°
in a step-wise fashion and providing signals representative of the angular position of said antenna in relation to the heading of the vehicle;means for detecting the heading of the vehicle and generating heading signals representative of said heading; means for detecting the stored frequencies of the at least two selected radio signal sources and causing said means for rotating to rotate said directionally sensitive antenna until said directionally sensitive antenna is positioned in a signal null position for each of said radio signal sources; means for comparing said angular position signals representative of the signal nulls with the heading signals to provide compass null headings for each of said radio signal sources; means for differentiating between real null headings and false null headings for each of said radio signal source; means for converting the point of intersection of said real null headings into corresponding longitude and latitude values for said vehicle; means for visually displaying said longitude and latitude values for the location of said vehicle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A navigational system for determining the location of a vehicle comprising:
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a central processing means for manipulating data; a key input means for entering data into the system; a memory means for storing data entered by the key input means or manipulated by the central processing means; a rotatable directionally sensitive antenna; means for causing said antenna to rotate until a signal null is sensed for at least two preselected radio signal sources whose transmission frequency and location data had been previously entered by the key input means; means for providing to said central processor means data indicative of the relative angle between the heading of the vehicle and said directionally sensitive antenna at a radio signal null position for each radio signal source sensed by said antenna; said central processing means including means for manipulating vehicle heading data and said data indicative of the relative angle of the radio signal null to provide null heading data for each of said radio signal sources; said central processing means also including means for manipulating said location data of the radio signal source and the null heading data to determine the coordinates of the location of said vehicle and causing those coordinates to be displayed on the display means. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification