Since the inception of the global positioning system (GPS) in the 1980's many useful military and civilian applications have been developed to utilize its positioning capabilities. Since GPS is primarily a military system, the civilian signals have been previously degraded in a mode called Selective Availability (SA). Typically, positions could be determined to a radius of 100 meters. For many applications that was sufficient and acceptable. For other applications, greater accuracy was required and numerous methods were developed to diminish the effect of SA and increase the accuracy level of the civilian signal. Many of these methods required post processing of the signal data and thus could not be used in real time applications. Other methods required the use of Differential GPS (DGPS) equipment to increase the accuracy of the signal in real time. These systems typically produced an accuracy of 1 to 5 meters but required additional receivers, communications links and antennas. They were portable systems but not easily handheld.
In May of 2000 the Department of Defense authorized the general cessation of SA on the civilian signal. This has diminished intentional errors to the signal and has increased the accuracy of commercial GPS receivers to generally 1 to 10 meters. This range of accuracy greatly enhanced existing applications and will create many opportunities for new applications.
During the period when SA was turned on, the error introduced by the government was the major error in the GPS civilian system which required various techniques such as DGPS to sufficiently correct distances for use on a golf course. With SA turned off, DGPS is no longer necessary for sufficiently accurate distance calculations over short periods of time where environmental conditions remain essentially unchanged for a GPS system tuned for the motion dynamics of a golfer. However, over longer periods of time, the changes in the ionosphere and troposphere now make up the major error in the GPS civilian system when determining locations and distances on a golf course. By applying the processes of the present invention, these changes can be filtered out and the GPS tunable parameters can be set by the golfer for a specific course to produce accuracies necessary for the golf course environment.
The present invention provides a personal, independent handheld device for the mobile golfer. Some prior systems use a base station installed on the course with radios to transmit correction data. This invention does not require any centralized equipment or radios to be installed at the golf course. Some systems require transmitters to be installed on the pin on the green. This invention does not require any transmitters to be installed at the course. Some systems require survey zones to be pre-defined and course images generated by professionals and then provided to the golfer. Although this invention can use surveys developed by others, the owner of the device can perform his own personal surveys using a simple target-based user interface with specialized objects and descriptors tailored for golf. Some systems require error corrections to be obtained and applied on a per satellite basis. This invention can adjust for differences in environmental conditions from the time the original survey was performed and the current playing conditions for a set of targets grouped as a networked data set without having to apply corrections to individual satellites. If DGPS is used to apply corrections to individual satellites, the processes described by this invention can be applied to further improve system accuracy. Many systems require specific cart mounted equipment to determine the ball's approximate position and compute distance to targets. This invention allows the mobile golfer to walk up to the ball and hold the device immediately above the ball location to determine the ball's position and the distance to various targets. Cart-based systems are typically dedicated to a specific course and shared by many golfers. This invention can be used on a variety of courses and can be adjusted for the personal mobile golfer dynamics of each course using tunable GPS parameters.
A common drawback of existing golfing related devices that operate in conjunction with a GPS is that the data and information presented to the golfer or user on the device display screen is typically presented in a limited and/or fixed format that has limited use for the viewer. For example, the data and information displayed on the screen may be static and not subject to any real time user screen modifications. The user may not be able to manipulate the display screen in real time to obtain further data or different data that that originally presented. Also, some golfing related devices with a GPS systems may be completely text based, some may not provide display of environmental conditions, some may not include displays of statistical golfer information. Further, some golfing related devices with a GPS may not have the ability to survey and collect golf course survey data, upload collected survey, process uploaded survey data, and download golf course related maps, data or information. There is thus a need for a way to graphically display distances to targets, elapsed time, club statistics, wind direction and other golf related information, and a method for collecting, processing and distributing golf course geographic information services (GIS) data and information, including golf course survey data and information.