Patent Application
20130054138
The present invention relates to integrated global positioning system (GPS) communications networks, and particularly to communications and automated global positioning determination of racing vehicle information indications.
The start of a sailboat race is unlike the start of any other racing event. Several variable factors contribute to this uniqueness; and these factors, both individually and in combination with each other, introduce problems that need to be considered and addressed by sailors at the start of each race.
Sailboat races typically have running starts. That is, unlike, say, a foot race or a swim race where each runner or swimmer starts from a dead stop, sailboat races start with each boat moving toward the starting line, building up momentum long before the starting signal is given. Ideally, the boat reaches the starting line at full speed an instant after the starting horn is blown. Should the boat cross the starting line before the starting signal is given, the boat will be penalized, typically requiring that the boat circle back and re-cross the starting line and effectively forfeit several seconds, if not minutes, of valuable race time. On the other hand, should the boat delay in crossing the starting line until long after the starting signal has been given, an advantage in both time and position may be ceded to the other boats in the fleet.
Accordingly, it is advantageous in sailboat racing to be able to estimate time of traversal over the start line with great accuracy.
There are, however, several factors, almost none of which is present in other types of racing events, that make it difficult to accurately predict the time of transversal over the start line in sailboat races.
Unlike races that are conducted over land, in sailboat racing there is no actual visible painted, printed or otherwise inscribed line that extends across, and easily identifies, the start line. The starting line in a sailboat race typically comprises two physical structures, between which a virtual line extends across the open water, indicating the start line. In a typical racing format, a race committee boat (or more particularly, a flag pole affixed to an anchored race committee boat) constitutes one end of the starting line; and an anchored buoy (the “pin”) constitutes the other end of the starting line. Typically, determination as to when a boat crosses the starting line is made by a person (the “starter”) stationed on the race committee boat, sighting along the starting line to the pin at the opposite end of the starting line. A boat is considered to have reached the starting line when its bow crosses the line of sight of the starter who is sighting from the committee boat, along the start line, to the pin.
At the beginning of a race, when numerous boats may be crossing the starting line at about the same time, it can be difficult for a racer to discern when the boat has crossed the start line, as other boats may be blocking the racer's sight lines up and down the start line.
Additionally, because a racing boat is necessarily positioned at the beginning of a race between the structures (i.e., the race committee boat and the pin) that mark the opposite ends of the starting line, it is impossible for a person on a racing boat to be looking at both end structures simultaneously as the boat crosses the starting line.
In order to overcome these problems, a common pre-race practice is to sail beyond an end of the starting line, then position the boat such that the sailboat, the pin and the race committee boat are in a straight line. If possible, notice is made of a landmark (typically onshore, often far beyond the end of the starting line) that appears to be in line with the starting line. This is referred to as taking a “line shot”. This landmark is then used, along with either the committee boat or the pin, as a reference to indicate when one's boat has crossed the starting line at the beginning of the race. If possible, it is usually desirable to take a line shot from beyond each end of the starting line, as one or the other of the landmarks may be blocked from sight (such as by other competitors' boats) when the race actually begins. This strategy is problematic because there is not always a nearby landmark, much less a perfectly aligned landmark, to use for this purpose.
Accordingly, it would be desirable to have a method or apparatus by which a sailor can determine when his boat has crossed a starting line that does not rely on such, often distant, landmarks for line shots.
Another characteristic that is unique to sailboat race starts is that the racers in sailboat races almost never leave the starting line going in a direction that is at an angle (i.e., other than perpendicular) to the starting line. In virtually every other type of sporting race, racers leave the start line initially on a course that is perpendicular to the start line. In a typical sailboat race, the first leg of the race is upwind. That is, the first mark that must be rounded by the racers is generally located upwind of the starting line. Since sailboats cannot sail directly into the wind, it is therefore necessary for the racers to leave (and approach) the starting line at an angle (i.e., other than perpendicular to the starting line).
The distance between a first point and a reference line is usually taken to be the shortest distance between the first point and the line. This corresponds to a distance from the first point, to a point on the reference line, measured along a second line that is perpendicular to the reference line. The time it takes to travel from the first point to the reference line, then, can be simply calculated by dividing the distance to the line by the speed of travel toward the line. However, because sailboats almost never approach starting lines at a right angle, the perpendicular distance from the boat to the finish line is largely irrelevant. In sailboat racing, it is therefore difficult to accurately determine the time it takes to travel (from a given point on the water) to an arbitrary location along the starting line, even when the structures marking the opposite ends of the starting line are visible and the approximate speed of the boat is known.
Another characteristic that is unique to boat races is that the precise geographic location and orientation of a starting line (that is, the precise location of the committee boat and the pin that mark the opposite ends of the starting line) is almost never known well in advance of a race; and, in any event, the location and/or orientation of the starting line may well change from race to race, depending on many variables (notably wind speed and direction).
Since there is a virtually infinite number of possible geographic locations and orientations for starting lines, even for sailboat races that are repeatedly held in the same waterways, it has been found impractical to pre-program starting lines into marine-based navigation systems.
Another characteristic that is unique to sailboat races is that variables such as changing wind conditions, and changing positions, tacks (starboard or port), bearings and speeds of other competitors, influence the speed, angle of approach and/or location along the starting line at which a racer may choose to cross the starting line. Since the speed, angle of approach and/or the location along the starting line may change at any time (and, in fact, may change several times) before, and up until, the boat crosses the starting line, the time- and distance-to-crossing the starting line can vary considerably and be difficult to estimate during the starting sequence of a sailboat race.
U.S. Pat. No. 5,731,788 to Reeds discloses a global positioning and communications system for race and start line management that purports to overcome some of the aforementioned problems in the prior art.
Differential GPS systems and methods are generally known. Such systems and methods are summarized in a survey article by Earl G. Blackwell, “Overview of Differential GPS Methods,” 32 Journal of The Institute of Navigation, (No. 2, Summer 1985). The article describes, among other things, how a local GPS reference receiver (RR) can be employed to eliminate common errors in the GPS navigation solution of other nearby receivers. As is well known, GPS systems permit users equipped with suitable receivers to make accurate position, velocity, and time determinations worldwide with reference to GPS satellites, which are in 12 hour (19,000 km) orbits about the earth. Such satellites continuously broadcast their identification, position, and time using specially coded signals.
In the Reeds system, a first Global Positioning System (“GPS”) transceiver is advantageously positioned (for example on a race committee boat) at one end of a starting line; a second GPS transceiver is advantageously positioned (for example on a fixed buoy) at the opposite end of a starting line; and a third GPS transceiver is advantageously positioned on at least one racing sailboat. In the Reeds system, the location of the start line is calculated based on data received from the first and second GPS transceivers, which communicate their respective locations to a receiver (or receivers) which may be located on the committee boat and/or on the racing sailboat(s). Those receivers are in communication with processors that calculate the location of the starting line. The third GPS transceiver communicates its position (and, consequently, the position of the sailboat on which it is mounted) at predetermined time intervals to the processors. Based on the data received from the first, second and third GPS transceivers, the processor can monitor and display the sailboat's position, bearing, speed relative to the starting line, and can calculate and display such additional information as distance from boat to starting line, location at which boat will cross the starting line, and time at which boat will cross the starting line.
One disadvantage of the Reeds system is that a minimum of three GPS transceivers (namely, one fixed at each end of the starting line and one on a racing sailboat) are necessary for operation of the system. This means that, not only must the racing competitor bear the financial costs associated with outfitting his boat with GPS equipment, but the race organizers must procure and maintain at least two of their own transceivers (namely, one for the committee boat and one for the pin).
Another disadvantage of the Reeds system is that control of the system is out of the hands of individual racers. If the race committee boat and the starting line buoy are not each outfitted (e.g., by the race committee) with the necessary GPS-based transceiver equipment, then an individual racer cannot access the data that the operational Reeds system could provide.
Another disadvantage of the Reeds system is that, even if the race committee boat and the starting line buoy are each outfitted with GPS-based transceiver equipment, an individual racer still may not have access to the data that the operational Reeds system purports to provide, unless the individual racer is equipped with a GPS-based transceiver that is compatible with and tuned to the race committee boat's equipment.
Accordingly it would be desirable to enable the development of global positioning information which is of use in the correct setting of course and speed of sailboats nearing a race start line, and which information could be obtained by individual racers without reliance on any third party.
It is a common, though certainly not uniform, occurrence that the starting line of a sailboat race also serves as the finish line for the race. The racing boat is allowed to cross the finish line at any location between the ends of the line (which are typically marked by the committee boat at one end and a pin at the other end). Often there is a preferred end, or a preferred intermediate point along the line, at which to cross the finish line. Generally, the end that is closest to the approaching sailboat is the preferred end. However, it is often difficult to tell from several hundreds of yards (or more) away from the finish line, which end of the line is closest, and therefore which end is preferred.
Accordingly, it may be desirable to enable the development of global positioning information which is of use in the correct setting of course of sailboats nearing a race finish line.
In light of the foregoing background, the present invention provides a position control and management system and method for monitoring and controlling boat or vehicle activities at a race start-line, during a race, and at the traversal of the race finish line by using an automated global positioning network to track at least one race boat or vehicle.
Further, the system according to the present invention provides for the development of global positioning information which is of use in the correct setting of course and speed of sailboats nearing a race start line, and which information could be obtained by individual racers without reliance on any third party.
Further, the system according to an embodiment of the present invention determines actual and anticipated crossing times for boats and vehicles at a race start line or finish line and provides for user friendly display of information indicating anticipated and actual line crossing times, estimated times of arrival (ETA) at a selected line crossing, positions, courses and velocities, and tracks of movement of one or more selected boats or vehicles prior to, during and after a race.
To accomplish position control and management, the communications network according to one embodiment of the present invention includes at least one racing boat having a GPS communication controller, and passive first and second physical structures disposed at opposite ends of a starting line.
According to one embodiment of the present invention, a GPS communication controller is located at or on the racing boat. The communication controller is adapted to contemporaneously record and store a first location, that location preferably corresponding to a position of the racing boat when the boat is located at a first point on (or on an extension of) the start line; and the communication controller is adapted to contemporaneously record and store a second location, that location preferably corresponding to a position of the racing boat when the boat is located at a second point on (or on an extension of) the start line, such that the controller can determine and record the geographic location of the start line (and extensions thereof).
The racing boat-carried GPS communication controller additionally monitors and displays the racing boat's varying position and velocity as a function of time.
According to one embodiment of the present invention, the racing boat carries data processing equipment to establish a formulation of the start line, and for calculation and display presentation of position and direction information relating to the start-line, and the racing sailboat preferably being established on a boat-positioned display to permit the skipper and crew members including but not limited to helmsman, tactician, and navigator to make decisions regarding velocity, tack, and positioning relative the start line, to monitor race progress and, for example, to avoid premature start-line crossage.
According to one embodiment of the present invention, the racing boat carries data processing equipment to establish a formulation of the finish line, and for calculation and display presentation of position and direction information relating to the finish line, and the racing sailboat preferably being established on a boat-positioned display to permit the skipper and crew members including but not limited to helmsman, tactician, and navigator to make decisions regarding velocity, tack, and positioning relative the finish line, to monitor race progress and, for example, to select an optimal location for crossing the finish line.
It is another object to provide an embodiment a racing boat-carried GPS communication controller of the character described that is portable and hand-held.
It is another object to provide an embodiment a racing boat-carried GPS communication controller of the character described that comprises a downloadable application (“app”) for hand-held “smart phones” and similar devices.
Other objects, features and advantages of the present invention will become readily apparent from the following detailed description of the preferred embodiment when considered with the attached drawings and the appended claims.
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
Referring now to
The race control GPS device 15 additionally comprises a location selection user interface 24 and data storage memory 26 in communication with the GPS processor 22. When the location selection user interface 24 is activated, for example by operator input, the race control GPS device 15 records the then-current location (e.g., longitude and latitude) of the device in the data storage memory 26.
In the preferred embodiment of the invention, the race control GPS device 15 is adapted to store coordinates for a first selected position P1 and a second selected position P2 when the location selection user interface 24 is activated at two different positions (e.g., positions P1 and P2).
Referring now to
The race control GPS device 15 continuously monitors the location (e.g., longitude and latitude) of the unit. The GPS processor 22 and data storage memory 26 records the then-current location of the unit at timed intervals. By comparing a first recorded location (Pb) to a second recorded location (Pa), and determining the distance between the two locations, then dividing that distance by the time interval between which the two were recorded, the GPS processor calculates the location, bearing and speed (S) at which the unit is traveling at any given time. In
The GPS processor preferably receives and records then-current position data at regularly timed intervals. In the preferred embodiment of the invention, at least the last two recorded positions (Pa, Pb) are stored in the data storage memory 26. The data processing unit 23 converts the global position data for at least the most recent last two recorded positions (Pa and Pb), as well as the global position data for the previously selected and stored positions (P1 and P2), to respective coordinates in the same planar coordinate system.
In the preferred embodiment of the invention, the GPS data processing unit 23 converts global position data (e.g., longitude and latitude) for the last two recorded positions (Pa, Pb) to Cartesian (i.e., x-y) coordinates. For any two such points (Pa, Pb), the data processing unit 23 then calculates the equation of the straight line that passes through those two points. Such a line, which corresponds to the course line (C) along which the unit is currently traveling, can be mathematically expressed in the form y=mcx+bc, where “mc” is the slope of the line and “bc” is point above the x-y origin at which the line intercepts the y axis.
In the Cartesian system, the last such positioning point (Pa) will have a location designated Pa(Xa, Ya); and the next-to last such positioning point (Pb) will have a location designated Pb(Xb, Yb). The bearing (mc) at which the unit is currently traveling corresponds to the slope of the line that extends between these two points Pb, Pa, namely mc=[Ya−Yb]/[Xa−Xb].
Referring now to
Referring now to
Referring again to
By simultaneously solving the equations of course path (C) [where y=mc+bc] and the target line 40 [where y=mt+bt], the GPS data processing unit 23 calculates the coordinates of the point (the “Start Point”, Ps) at which the course path (C) intersects target line 40.
Once the coordinates of the Start Point Ps have been calculated, GPS data processing unit 23 calculates the distance (D) from the sailboat's current position Pa to the Start Point Ps. Mathematically, this distance (D) equals
Square Root [(Xs−Xa)2+(Ys−Ya)2]
where,
Once the distance (D) from the sailboat's current position Pa to the Start Point Ps has been calculated, GPS data processing unit 23 calculates the time it takes to traverse that distance at the sailboat's current speed. Mathematically this can be calculated by the equation
T=D/S
where,
The actual satellite information taken in by the receiver is the same as in the prior art. The system invented requires the registration of a sufficient plurality of pseudorange information sets from available global positioning satellite vehicles in orbit above the receiving station having an antenna to receive satellite information relevant to global positioning. As in the prior art, each of the information sets includes a predetermined block of information with respect to both the transmitting satellite and the receiving station listening for the information. The information registered may be stored locally or transmitted in raw or modified form to another receiving station (not shown).
Local data storage could be accomplished within the actual GPS receiver or in an on-board computer. Alternatively, a separate computing device or system could be externally connected to accomplish the same result.
According to one embodiment of the present invention, at the beginning of a race start sequence (e.g., ten minutes before the start), a start gun is fired and a flag or shape is raised on a committee boat. The same or another gun is fired with five minutes to go before the start of the race. During the start sequence, the racing boats will compete for optimal position with respect to the remaining boat, with the intent of traversing the start line just as the race start gun goes off.
The information provided to data processing unit 23 and display 28 is preferably transmitted via hard wire connection between the GPS processor 22 and the data processing unit 23. In an alternative embodiment of the invention information provided to data processing unit 22 and display 28 may be sent via radio transmission.
In the preferred embodiment of the invention, the display 28 graphically portrays the relative angle of approach 0 of the current path (C) of the sailboat 3 (graphically represented by sailboat icon 31) and the target line 40, in a given X-Y plane, as well as the sailboat's current speed 38 and its distance (graphically represented by D1) to the point of its projected intersection (i.e., start point Ps) with the target line 40. Accordingly, it will be understood that, in the preferred embodiment of the invention, it is neither necessary nor desired to display the target line on the display screen 28 at the start line's actual compass orientation (e.g., such that North is toward the “top” of the screen); nor is it necessary or desirable to graphically display the sailboat's 3 actual compass orientation (e.g., relative to North). All that is necessary in this regard is that the relative orientations of the target line 40 and the boat's course (C) be accurately illustrated.
In a preferred embodiment of the invention, as shown in
Also, in a preferred embodiment of the invention, the start point Ps (that is, the point at which the sailboat's current path (C) intersects the target line 40) is displayed on the display screen 28 in a fixed location on the screen, preferably approximately laterally centered, as shown in
The scale of the graphics on the display screen 28 is preferably chosen such that distances from P1 to P2 and from the sailboat icon 31 to the start point Ps both can fit within the screen. The distance from the sailboat 3 to the start point Ps may be graphically displayed on the screen 28 to the same scale as the distance from P1 to P2. As the sailboat 3 approaches the start point Ps the length (D1) of the line from the sailboat icon 31 to the target line 40 decreases correspondingly.
As discussed above, in order to establish a target line 40 corresponding in orientation and position to a start line 11, two user selected points (P1, P2) must be input to the GPS device 15. This is accomplished by the user's interaction with a user interface device 24, which is in communication with the GPS processor 22. In the preferred embodiment of the invention, the user interface device 24 comprises a graphical user interface (GUI), whereby the user identifies a selected position (e.g., P1 or P2) by cursor placement and “clicking” on an appropriate menu item shown on the display screen 28, or, alternatively, by touching an appropriate menu item on a “touch screen” enabled display screen. In alternative embodiments of the invention, the user interface 24 may comprise a user-interactive keyboard or toggle switch for identifying the selecting positions P1, P2.
The position and residuals information received by data processing unit 23 produces indications such as position indications for sailboat 3 relative to target line 40, a historical track indication (not shown, but implementable as the track of prior positions of sailboat 3 relative to target line 40), a current speed 38 over ground, the intercept angle θ between the sailboat's current course (C) and the target line 40, and an estimated time of arrival (ETA) 42 at the intercept between the course of sailboat 3 and the target line 40. As shown in
On the display screen 28, the icons representing user selected positions P1 and P2 can be connected by a dashed line indicating the target line 40, which in accordance with the present invention corresponds, insofar as angle of intercept and distance to sailboat 3, to start line 40. Display screen 28 may be a conventional cathode ray tube (CRT) or liquid crystal display (LCD) or any of a number of currently used display types.
It will be understood from the preceding description of the present invention that, by viewing the display, the skipper, navigator, or strategist onboard sailboat 3 (or all of them) are provided with a symbolic status representation including essential stationing information with regard to sailboat 3 and start line 11. The skipper may accordingly produce change of station or velocity instructions to the crew to ensure timely crossing of start line 11. As shown in
As described above, the present invention a graphic display screen 28 is employed for showing time, distance, angle of approach and other information that may be useful for managing start line approach of a racing sailboat. In a preferred embodiment of the invention, global positioning data is received by a GPS receiver 20, and global positioning data is converted by GPS data processing unit 23 to Cartesian coordinates, whereby various identified locations (namely, P1, P2, Pb, Pa, Pb) can all be plotted in a common plane.
Various methods of converting global coordinates (such as longitude and latitude) to Cartesian coordinates are know in the prior art. One such Cartesian coordinate system that is widely used for plotting locations of points on the Earth's surface is called the “Universal Transverse Mercator System” (or, UTM). In this system the globe is subdivided into narrow longitude zones, which are projected onto a transverse Mercator projection. A grid is constructed on the projection and used to locate points in an X-Y (so called “easting” and “northing”) format.
Equations for converting latitude and longitude coordinates to UTM, although fairly complicated and somewhat tedious, are well known in the prior art. One method of converting latitude and longitude to UTM is given below. In the following equations, the following symbols have the following meanings:
First, the meridional Arc (M) through the point in question, (i.e., the distance along the earth's surface from the equator) is calculated. All angles are in radians.
M=A′lat−B′ sin(2lat)+C′ sin(4lat)−D′ sin(6lat)+E′ sin(8lat)
Where lat is in radians and
The latitude and longitude of the point in question can now be calculated as follows:
All angles are in radians, and easting x is relative to the central meridian.
y=northing=K1+K2p2+K3p4, where
x=easting=K4p+K5p3, where
In the case of each of the embodiments noted or suggested herein, differential GPS corrections can be applied according to techniques well-known in the art, to improve the absolute accuracy of the position information determined. As is well known, differential GPS corrections can be obtained by use of a reference station, which is positioned at a known location. When reference station makes a GPS measurement which deviates from its known location value, the difference between known and measured values constitutes a correction which can be applied in the GPS calculations of other GPS receivers within several hundred miles of the reference station. According to one embodiment of the present invention, referring to a GPS measurement shall include reference to a differentially corrected GPS measurement.
The present invention has been described herein above with respect to management and control of a racing vehicle, such as a sailboat, as it approaches the start line of a race. It will it will be appreciated by those skilled in the art that the present invention can similarly be used in some instances with respect to management and control of a racing vehicle as it approaches the finish line of a race.
For example, as a sailboat approaches a finish line on its final tack, there is often a preferred end at which to cross the line. Generally, the “preferred” end of the line is the end that the boat can sooner cross. This is often, by not always, the end that is closest to the approaching sailboat. In any event, it is often difficult to visually determine, from several hundreds of yards or more away from the finish line, which part of the line is closest (either in time or in distance) to the sailboat.
In a preferred method of using the present invention, prior to starting a race, a pair of line shots are taken from positions (e.g., P1, P2) on an extension of the finish line. The finish line may be the same as the start line (as illustrated in
In various advantageous embodiments, portions of the system and method of the present invention include a computer program product. The computer program product includes a computer-readable storage medium, such as the non-volatile storage medium, and computer-readable program code portions, such as a series of computer instructions, embodied in the computer-readable storage medium. Typically, the computer program is stored and executed by a processing unit or a related memory device, such as the GPS processor 22, data processing element 23 or data storage memory 26 as depicted in
In this regard,
Accordingly, blocks or steps of the block diagram, flowchart or control flow illustrations support combinations of means for performing the specified functions, combinations of steps for performing the specified functions and program instruction means for performing the specified functions. It will also be understood that each block or step of the block diagram, flowchart or control flow illustrations, and combinations of blocks or steps in the block diagram, flowchart or control flow illustrations, can be implemented by special purpose hardware-based computer systems which perform the specified functions or steps, or combinations of special purpose hardware and computer instructions.
Modified embodiments of the invention. Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. For example:
Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.
