Patent Application
20080065628
The present invention correlates Master Street Address Guide (MSAG)-validated street address data with real-world geographic (e.g., latitude/longitude) data. According to the invention, conventional MSAG-validated street address data is processed, or geocoded, into an additional (or integrated) database that associates latitude/longitude information with a particular entry in the existing MSAG-validated database. The association of the lat/lon data may be direct, or indirect using link ID or other unique tags indicating a particular entry in the MSAG-validated database.
Ideally the geocoding need be performed only once by a service provider, e.g., as part of the deployment of an emergency service system. Of course, updated geocoding may be performed from time to time as the content of the MSAG-validated street address database changes or is otherwise revised. In this way, the closest public service answering point (PSAP) to a given latitude/longitude position of a wireless or VoIP device may be determined quickly, providing emergency services with the smallest possible reliable response time.
In particular, as shown in
The geocoder 160 may be any suitable computer, and need not be performed via a network. Preferably the geocoder 160 is operated by a third party software provider rather than by a wireless or VoIP carrier. However, operation of the geocoder 160 by a wireless or VoIP provider is entirely within the present invention.
The lat/lon association database 100 is shown in
The disclosed geocoder 160 geocodes, or divides each road in a given area into lengths, or links, and associates each link with a given ID. The number of links for any given street-addressable road is preferably determined by the number of intersections therewith by other streets, the number of driveways, and/or any other relevant points of distinction. Another factor for dividing a street into links are the places on that street where the street address number changes.
It is entirely possible and feasible that more than one link will be associated with a same entry in the MSAG-validated street address database 150. For instance, multiple intersections may occur on a street in front of a single street addressed home or business. In this case, the multiple intersections would each associate to a same entry in the MSAG-validated street address database 150 for that single home or business.
A dataset contained in the MSAG-validated street address database 150, and/or in the lat/lon association database 100, may describe a small region, state, or even the entire country. In any event, it is import that each link have an identifier that's unique in a given geographic data set. But again, it's entirely possible that multiple identifiers point to a same entry in the MSAG-validated street address database 150.
Geocoding 160 of the MSAG-validated street address database 150 takes each street address entry in the MSAG-validated street address database 150 as input, and outputs an associated latitude/longitude for each input street address entry.
The exact latitude/longitude designated for any given link is preferably that of a central point of the link. The central point may be determined in any suitable mathematical method for determining a center of an area. As another example, the central point for which the lat/lon data is assigned may be a 2-dimensional calculation measured as a midpoint of a linear line drawn along the pathway of the centerline of the street link. If the link is rectangular, the center point may be the cross-point of two straight lines drawn from opposing corners of the rectangle. The central point may also be calculated in 3-dimensions using not only the geographic shape of the length and width of the link, but also variation in altitude.
The lat/lon assigned to any given link may be a range of lat/lon values, though such implementation adds significantly to complexity of the lat/lon association database 100.
In addition to the exact latitude/longitude, the geocoding also determines a unique link ID for each link in the lat/lon association database 100. The format of the link ID may be any suitable format for a database. In the preferred embodiment, the link ID is uniquely assigned for each entry in the lat/lon association database 100.
Each MSAG record in the MSAG-validated street address database 150 associates an address range with an emergency services number (ESN), and therefore a particular public safety answering point (PSAP) responsible for that geographic location. The present invention associates MSAG record entries with IDs for all links in the address range, thus solving the conventional problem of reliably locating the closest PSAP to a given lat/lon position as a simple lookup of the link ID for a given lat/lon position.
In particular, as shown in step 202 of
In step 204, the lat/lon of the 911 caller is determined. This determination may be performed in any conventional manner, including cell site location, global positioning satellite (GPS), etc.
In step 206, the closest street link ID entry in the lat/lon association database 100 is determined, based on the latitude/longitude data determined in step 204.
In step 208, using the closest link ID determined in step 206, a look up is performed in the MSAG-validated database 150, to find the associated MSAG-validated record in the MSAG-validated database 150.
In step 210, the emergency services number (ESN) of the PSAP assigned to the location of the wireless or VoIP 911 caller is extracted from the associated MSAG-validated record matched in step 208.
Thus, each MSAG address range in an otherwise conventional MSAG-validated street address database 150 is geocoded to find associated link IDs and corresponding latitude/longitude data for each link ID, and that association is stored in a data table. Then, when an emergency call arrives, the link ID is determined based on a lat/lon of a calling wireless or VoIP party via look up in a lat/lon association table. If it is present in the lat/lon association database 100, the link ID of that match in the lat/lon association table is used in a look up in the MSAG-validated street address database 150 to find the relevant MSAG-validated record nearest to the current position of the wireless or VoIP 911 caller. The emergency services number (ESN) is extracted from the matched MSAG-validated record.
If the emergency caller's link ID isn't found in the lat/lon association table, it would indicate that the data contained in the MSAG-validated street address database 150 is incomplete. To this end, the geocoding process of each MSAG record in the MSAG-validated street address database 150 helps to validate the MSAG data. If a particular MSAG record fails to geocode, it indicates that something is inconsistent between the MSAG and the real-world geographic data. It is also possible for MSAG records to overlap. Thus, the present invention not only provides reliable MSAG-validated street address information to emergency services for wireless and/or VoIP 911 callers, it actually improves the quality and reliability of the MSAG-validated database 150 itself, by way of resolution of any inconsistencies in the geocoding process.
Since geocoding in accordance with the present invention occurs early in the process, it is possible to resolve these inconsistencies ahead of time, before any negative impact to emergency calls can occur, again not only equaling the reliability of wireline emergency calls with wireless and/or VoIP callers, but actually improving upon it.
The present invention has particular applicability to providers of E911 emergency services for wireless devices, especially mobile phones.
While the invention has been described with reference to the exemplary embodiments thereof, those skilled in the art will be able to make various modifications to the described embodiments of the invention without departing from the true spirit and scope of the invention.
