Abstract:
A solution is described which provides an airport with the tools to accurately manage all sources of airside revenues, including operational revenues and capital programs. The system of the present invention relies on the acquisition of any and all data related to the operations, property, lease, and revenue management of an airport, including aircraft tracking data. This data is then stored in a central database where it is processed, sorted, and stored for later retrieval. The data may exist in a number of forms including real-time streams, tabular, or in the form of a database. From this data, airport revenue information can be accurately managed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation-In-Part application of U.S. patent application Ser. No. 10/743,042, filed on Dec. 23, 2003, and incorporated herein by reference; U.S. patent application Ser. No. 10/742,042 in turn is a Continuation-In-Part application of U.S. patent application Ser. No. 10/638,524, filed Aug. 12, 2003, entitled “METHOD AND APPARATUS FOR IMPROVING THE UTILITY OF AUTOMATIC DEPENDENT SURVEILLANCE”, now U.S. Pat. No. 6,806,829, which is incorporated herein by reference in its entirety, which in turn is a Continuation of U.S. patent application Ser. No. 09/516,215, filed on Feb. 29, 2000, which in turn claims priority from Provisional Application Ser. No. 60/123,170, filed Mar. 5, 1999, both of which are incorporated herein by reference in its entirety; U.S. application Ser. No. 10/743,042 is also a Continuation-In-Part of U.S. patent application Ser. No. 10/319,725, filed Dec. 16, 2002, entitled “VOICE RECOGNITION LANDING FEE BILLING SYSTEM”, Now U.S. Pat. No. 6,812,890, incorporated herein by reference in its entirety; U.S. application Ser. No. 10/743,042 is also Continuation-In-Part of U.S. patent application Ser. No. 10/457,439, filed Jun. 10, 2003, entitled “Correlation of Flight Track Data with Other Data Sources”, incorporated herein by reference in its entirety; U.S. application Ser. No. 10/743,042 also claims priority from Provisional U.S. Patent Application No. 60/343,237 filed Dec. 31, 2001, incorporated herein by reference in its entirety; 
     The present application is also a Continuation-In-Part application of U.S. patent application Ser. No. 11/031,457, filed on Jan. 7, 2005, and incorporated herein by reference, which in turn is a Continuation-In-Part application of U.S. patent application Ser. No. 10/638,524, filed Aug. 12, 2003, entitled “METHOD AND APPARATUS FOR IMPROVING THE UTILITY OF AUTOMATIC DEPENDENT SURVEILLANCE”, now U.S. Pat. No. 6,806,829, which is incorporated herein by reference in its entirety, which in turn is a Continuation of U.S. patent application Ser. No. 09/516,215, filed on Feb. 29, 2000 now U.S. Pat. No. 6,633,259, which in turn claims priority from Provisional Application Ser. No. 60/123,170, filed Mar. 5, 1999, all of which are incorporated herein by reference in its entirety; application Ser. No. 11/031,457 is also a Continuation-In-Part of U.S. patent application Ser. No. 10/319,725, filed Dec. 16, 2002, entitled “VOICE RECOGNITION LANDING FEE BILLING SYSTEM”, now U.S. Pat. No. 6,812,890, incorporated herein by reference in its entirety; application Ser. No. 11/031,457 is also a Continuation-In-Part of U.S. patent application Ser. No. 10/457,439, filed Jun. 10, 2003 entitled “Correlation of Flight Track Data with Other Data Source”, incorporated herein by reference in its entirety; application Ser. No. 11/031,457 also claims priority from Provisional U.S. Patent Application Ser. No. 60/440,618, filed Jan. 17, 2003, incorporated herein by reference in its entirety; 
     The present application is also a Continuation-In-Part application of U.S. patent application Ser. No. 10/756,799 filed Jan. 14, 2004, and incorporated herein by reference; application Ser. No. 10/756,799 is a Continuation-In-Part application of U.S. patent application Ser. No. 10/638,524, filed Aug. 12, 2003, entitled “METHOD AND APPARATUS FOR IMPROVING THE UTILITY OF AUTOMATIC DEPENDENT SURVEILLANCE”, which is incorporated herein by reference in its entirety, which in turn is a Continuation of U.S. patent application Ser. No. 09/516,215, filed on Feb. 29, 2000, which in turn claims priority from Provisional Application Ser. No. 60/123,170, filed Mar. 5, 1999, both of which are incorporated herein by reference in their entirety; application Ser. No. 10/756,799 is also a Continuation-In-Part of U.S. patent application Ser. No. 10/319,725, filed Dec. 16, 2002, entitled “VOICE RECOGNITION LANDING FEE BILLING SYSTEM”, incorporated herein by reference in its entirety, which in turn claims priority from Provisional U.S. Patent No. 60/343,237, filed Dec. 31, 2001, also incorporated by reference in its entirety; application Ser. No. 10/756,799 is also a Continuation-In-Part of U.S. patent application Ser. No. 10/457,439, filed Jun. 10, 2003 entitled “Correlation of Flight Track Data with Other Data Source”, incorporated herein by reference in its entirety; application Ser. No. 10/756,799 is also a Continuation-In-Part of U.S. patent application Ser. No. 10/751,118, filed on Jan. 5, 2004, entitled “Method and Apparatus to Correlate Aircraft Flight Tracks and Events with Relevant Airport Operations Information” which in turn claims priority from Provisional U.S. Patent Application Ser. No. 60/440,618, filed Jan. 17, 2003, incorporated herein by reference in its entirety; application Ser. No. 10/756,799 also claims priority from Provisional U.S. Patent Application Ser. No. 60/440,618, filed Jan. 17, 2003, incorporated herein by reference in its entirety; application Ser. No. 10/756,799 is also a Continuation-In-Part of U.S. patent application Ser. No. 10/743,012, filed Dec. 23, 2003 entitled “METHOD AND APPARATUS FOR ACCURATE AIRCRAFT AND VEHICLE TRACKING” (Alexander E. Smith et al.), incorporated herein by reference; application Ser. No. 10/756,799 also claims priority from Provisional U.S. Patent Application Ser. No. 60/534,706, filed Jan. 8, 2004, incorporated herein by reference in its entirety; 
     The present application is a Continuation-In-Part application of U.S. patent application Ser. No. 10/830,444, filed on Apr. 23, 2004, and incorporated herein by reference; U.S. patent application Ser. No. 10/830,444 is a DIVISIONAL application of U.S. patent application Ser. No. 10/457,439, filed on Jun. 10, 2003, and incorporated herein by reference; U.S. patent application Ser. No. 10/457,439 in turn was a Continuation-In-Part application of U.S. patent application Ser. No. 09/516,215, filed Mar. 5, 1999, entitled “METHOD AND APPARATUS FOR IMPROVING THE UTILITY OF AUTOMATIC DEPENDENT SURVEILLANCE”, Now U.S. Pat. No. 6,633,259, which is incorporated herein by reference in its entirety; U.S. patent application Ser. No. 10/457,439 was also a Continuation-In-Part of U.S. patent application Ser. No. 10/319,725, filed Dec. 16, 2002, entitled “VOICE RECOGNITION LANDING FEE BILLING SYSTEM”, incorporated herein by reference in its entirety. U.S. patent application Ser. No. 10/457,439 also claims priority from Provisional U.S. Patent Application No. 60/440,618, filed Jan. 17, 2003, incorporated herein by reference in its entirety; 
     The present application is also Continuation-In-Part of U.S. patent application Ser. No. 11/111,957, filed on Apr. 22, 2005, and incorporated herein by reference; 
     The present application is also a Continuation-In-Part of U.S. patent application Ser. No. 11/145,170, filed on Jun. 6, 2005, and incorporated herein by reference. 
     The subject matter of the present application is related to the following issued U.S. Patents, assigned to the same assignee as the present invention, all of which are incorporated herein by reference in their entirety: 
     U.S. Pat. No. 5,999,116, issued Dec. 7, 1999, entitled “Method and Apparatus for Improving the Surveillance Coverage and Target Identification in a Radar Based Surveillance System”; 
     U.S. Pat. No. 6,094,169, issued Jul. 25, 2000, entitled “Passive Multilateration Auto-Calibration and Position Error Correction”; 
     U.S. Pat. No. 6,211,811, issued Apr. 2, 2001, entitled “Method and Apparatus for Improving the Surveillance Coverage and Target Identification in a Radar Based Surveillance System”; 
     U.S. Pat. No. 6,384,783, issued on May 7, 2002, entitled “Method and Apparatus for Correlating Flight Identification Data With Secondary Surveillance Radar Data”; 
     U.S. Pat. No. 6,448,929, issued Sep. 10, 2002, entitled “Method and Apparatus for Correlating Flight Identification Data With Secondary Surveillance Radar Data”; 
     U.S. Pat. No. 6,567,043, issued May 20, 2003, entitled “METHOD AND APPARATUS FOR IMPROVING THE UTILITY OF AUTOMATIC DEPENDENT SURVEILLANCE”; 
     U.S. Pat. No. 6,633,259 issued Oct. 14, 2003 “METHOD AND APPARATUS FOR IMPROVING THE UTILITY OF AUTOMATIC DEPENDENT SURVEILLANCE”; 
     U.S. Pat. No. 6,806,829, issued Oct. 19, 2004, entitled “METHOD AND APPARATUS FOR IMPROVING THE UTILITY OF AUTOMATIC DEPENDENT SURVEILLANCE”; 
     U.S. Pat. No. 6,812,890, issued Nov. 2, 2004, entitled “VOICE RECOGNITION LANDING FEE BILLING SYSTEM”; and 
     U.S. Pat. No. 6,885,340, issued Apr. 26, 2005, entitled “CORRELATION OF FLIGHT TRACK DATA WITH OTHER DATA SOURCES”. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a system and method for managing airport revenues. In particular, the present invention is directed toward a system for using aircraft tracking information to help manage airport revenues. 
     BACKGROUND OF THE INVENTION 
     Most airports derive revenue from a variety of sources, and it is becoming more common for airports to finance operations from a combination of usage fees and to finance capital programs through grants, such as the Federal Airport Improvement Program (AIP) and Passenger Facility Charges (PFCs). (See, e.g., www.faa.gov). All of these revenue sources are based on the activity at the airport. AIP grant amounts are based on the passenger throughput and landed cargo weight. Approved PFC collection amounts are based on passenger throughput. In order to receive such government revenues or subsidies, however, an airport must be able to accurately track the number of passengers and amount of cargo passing through the airport. Manually tallying such data, or relying upon reported data from airlines can be cumbersome and inaccurate. 
     Traditional usage fees were generally limited to landing fees based on an aircraft maximum certified gross take-off weight. Airports would like to be able to more accurately bill for actual airport usage, which includes landing fees, use of gates, facilities and parking of aircraft, rather than just using flat fees based on gross aircraft weight. Traditionally, due to lack of technical solutions, airports used an honor system, whereby the airport relied on users to self-report their activity at the airport, such as landings, parking, cargo landed, and the like. However, when such data is carefully audited, many airports have found inadequacies in the honor system. Therefore, it remains a requirement in the art to provide a revenue management system that can track airport usage, passenger flow and landed cargo weight would maximize operational revenues as well as capital financing from AIP/PFC and other sources. 
     Airports operate using one of two accounting methods; residual costing or compensatory approaches. The main difference is risk allocation. The residual approach places the risk with the airlines, as their usage fees may need to increase to cover costs of airport operations. The compensatory approach may result in insufficient airport operational revenues, which would be an operating loss for the airport. In either case, airports have found that an independent accurate source of revenue management would be beneficial. For cost accounting, it benefits the users, (mainly signatory airlines) and the airport. Regardless of the accounting model used by the airport, an independent revenue management system would enhance operating revenues and capital program financing by more accurately tracking costs and usage. 
     Although all airports are somewhat different, it is important to point out that the sources of revenue at one of the “average” top 200 airports in the U.S. may be comparable to other, similar airports. For example, airport operational revenues usually may be derived from landing fees, automobile parking, and property management. Automobile parking usually accounts for 20 to 30% of revenue, landing and use fees usually account for 20 to 30%, and the remaining revenue is generally derived from property leases (e.g., for airlines and retail). 
     By comparison, capital program revenues are generally of the same order. For example, a typical landing fee for passenger aircraft may be in the region of $200-$400. The PFC entitlement, at $3 per paying passenger is therefore $300 for an aircraft carrying 100 or so passengers. Therefore the revenue entitlements being tracked are of similar magnitudes and should be managed appropriately. 
     With regard to tracking capital program entitlements, in a presentation titled “Optimizing Management of Airport Revenues,” one of the present inventors, Mr. A. E. Smith, presented a summary of airport revenues at the 2005 Airport Finance &amp; Administration Conference Sponsored by AAAE and Southeast Chapter AAAE, Jan. 30-Feb. 1, 2005. This presentation is incorporated herein by reference. 
     That presentation stated that 3300 airports in the U.S. national system received an average of $12 B per year for planned capital development. The largest source is bonds, followed by AIP, then PFCs, and estimates of airport capital developments range from $9 B-$15 B per year. AIP entitlements are based on cargo activity (landed cargo weight) and the number of enplaned passengers, which is based on a stratification of entitlements, with a minimum total of $1 M and a maximum of $26 M as follows: $7.80 for each of the first 50,000, $5.20 for each of the next 50,000, $2.60 for each of the next 400,000, $0.65 for each of the next 500,000, and $0.50 for each additional enplanement. 
     PFCs may be used in lieu of 50%-75% AIP entitlements. For more information on the PFC program refer to FAA Order 5500.1 (www.faa.gov), incorporated herein by reference. Other background documents include: AIP101, presented by FAA at the FAA Southwest Region Capital Planning Conference, Oct. 19, 2004, Fort Worth, Tex., and GAO-03-497T, Tuesday, Feb. 25, 2003, AIRPORT FINANCE, Past Funding Levels May Not Be Sufficient to Cover Airports&#39; Planned Capital Development, both of which are incorporated herein by reference. 
     There are also many background documents written by Airport Council International (ACI) and the American Association of Airport Executives:
         www.aci-na.org/docs/pfcfinaldraft.doc;   www.aaae.org/_pdf/_regpdf/040318pfc.doc;   www.aci-na.org/docs/Hotlights02-16-04.pdf;   www.commerce.senate.gov/hearings/212pla.htm;   www.house.gov/transportation/aviation/04-01-04/barclay.html; and   www.aaae.org/government/200_Regulatory_Affairs/100_What&#39;s_New;
 
all of which are incorporated herein by reference. Other related information may be found on the websites of the respective organizations, www.aci-na.org and www.aaae.org, both of which are also incorporated herein by reference.
       

     Air carriers must collect and refund PFCs where necessary. PFCs are collected for each one-way trip in U.S. at either $3 or $4.50. PFCs are collected only for revenue passengers. Carriers collect PFCs and manage the money as a trust fund. Airlines are compensated for PFCs remitted (either $0.08/$0.11 per PFC). As of January 2005, the FAA approved over 350 airports, including over 90% of the top 100 airports, to collect PFCs. Over half of the airports are collecting at the higher $4.50 level. By the end of 2004, FAA had approved over $47.5 B in PFCs. 
     The amount and type of funding varies depending on airport size. For example, as illustrated in the chart of  FIG. 1 , large- and medium-hub airports depend primarily on bonds, while the smaller airports rely principally on AIP grants. Passenger facility charges are a more important source of revenue for the large- and medium-hub airports because they have the majority of commercial-service passengers. 
       FIG. 2  is a chart compiled by the General Accounting Office (GAO), illustrating various types of airport projects financed through the PFC programs. The reporting requirements imposed by the Government for PFC programs are fairly onerous. Airports must compile quarterly reports to provide oversight of PFC revenue to the FAA and the airlines. Airlines collecting PFCs from over 50,000 enplanements must conduct annual independent audits. The quarterly reports are monitored to see how well revenues track to the approved program. Excessive revenue accumulation may result in a revision of charge expiration, or a decrease in the PFC fee. For shortfalls, an increase of project total is possible (up to 15%) by extending the program expiration date. 
     In tracking use fees, airports have been constrained to available technologies and manual procedures that have been on the market. Flight tracking systems and associated systems are now available (see www.rannoch.com) for tracking aircraft in the vicinity of an airport and on the ground. One such system is described in the aforementioned U.S. Pat. No. 6,812,890, entitled “VOICE RECOGNITION LANDING FEE BILLING SYSTEM”. The system of that Patent can track takeoffs and landings of aircraft using aircraft tracking data, transponder and other electronic data sources, as well as voice recognition of Air Traffic Control (ATC) communications. The system of that Patent has been installed at various airports with demonstrated success. After installation, billing for landing fees increased by as much as one third, clearly illustrating that previous manual reporting systems were inadequate. 
     It would be desirable to expand such a system (and it is one object of the present invention) to implement comprehensive billing systems to bill for airport usages, such as: Landing fees, Parking fee management, (By location/time period, and Overnights), Stratified user fees for signatory &amp; non signatory users, FBO and GA fees, De-ice facilities, Ramp/apron/gate use, Maintenance facilities, Noise fee surcharges, Curfew violation fees, and the like. One method to achieve this is by the use of 2-D zones, as illustrated in  FIG. 3 , in combination with an airport&#39;s GIS systems and accurate aircraft tracking and identification. While there are several technologies available for tracking aircraft on the airport surface, none have been used in any real operational capacity to manage billing for usage, such as time on gate. 
       FIG. 4  is a diagram illustrating the Aerobahn system offered by Sensis Corporation of Dewitt New York. (See, e.g., www.sensis.com). KLM Royal Dutch Airlines (KLM) will begin an evaluation of Aerobahn Service at Amsterdam Airport Schiphol to assess the value of Aerobahn in improving the management of traffic into and out of the apron area. KLM is the second SkyTeam Alliance member to use Aerobahn. Sensis recently announced that Northwest Airlines has contracted for 60 months of Aerobahn Service for its Minneapolis-St. Paul International and Detroit Wayne County Metropolitan hub airports. Aerobahn provides airlines and airports with comprehensive operational information which positions users to more efficiently manage and measure airside operations. At Schiphol, ATC coordinators in KLM&#39;s Operations Control Center will use the data to help manage flight status and to closely coordinate movements with air traffic control to maximize efficiency and capacity. While this system may be able to track aircraft, it does not appear to be able to use such aircraft tracking data to manage airport revenue. 
     Accurate measurement of time on gate by specific aircraft would allow the airport to bill for use. Additionally, it would allow the airport to manage limited assets more efficiently. However, current systems do not utilize this data to enhance airport revenue management. Most existing aircraft billing and revenue management systems are manually intensive and rely on data inputs from disparate sources. Many of the datasets are incomplete, inaccurate, and result in less than perfect solutions. 
     One example of such a Prior Art system is the system in use at the Port Authority of New York and New Jersey as illustrated in  FIG. 5 . The system is called CATER, for Collection and Analysis of Terminal Records System. The system is described in the Port Authority&#39;s Request for Proposal 0000007548, Electronic Collection and Analysis of Terminal Records System and Itinerant Aircraft Billing System, dated Jan. 13, 2005. 
     Data sources include schedule information, such as the Official Airline Guide (OAG), the FAA&#39;s flight strips and also Airline Service Quality Performance Reports (ASQP). On first review, the approach appears to be comprehensive, but it lacks several key data items, and many of the data elements are incomplete. For more information on Airline Service Quality Performance Reports (ASQP) refer to http://web.mit.edu/aeroastro/www/labs/ICAT/ and Documentation for the Consolidated Operations and Delay Analysis System, September 1997, Office of Aviation Policy and Plans Federal Aviation Administration Washington, D.C. 20591, both of which are incorporated herein by reference. 
     The FAA document states that ASQP data are collected by DOT to calculate on-time performance for its monthly Air Travel Consumer Report. Major air carriers are required by regulation to report this information. However, the reporting requirements apply only to air carriers with more than one percent of total domestic scheduled passenger revenues; the 10 carriers that must file include: Alaska Airlines, Northwest Airlines, America West Airlines, Southwest Airlines, American Airlines Trans World Airlines, Continental Airlines, United Airlines, Delta Air Lines, and USAir. 
     However, ASQP does not contain any information on the operations of smaller air carriers, commuters, air taxis, or on general aviation, cargo, military and international flights. The percentage of total operations for which ASQP has data varies depending on the mix of traffic at each airport. At those airports where a significant proportion of operations are not reported, the ground movement and flight times may be biased. In addition, ASQP does not provide any information on the aircraft type used for a flight. 
       FIG. 6  describes the data fields available from ASQP:  FIG. 7  is a screenshot from January 2005 of statistics for the ASQP data from the Bureau of Transportation Statistics web site. As illustrated in  FIG. 7 , the tail number data is missing over 30% of the time. Other variables such as Airtime, TaxiOut, TaxiIn, WheelsOff, WheelsOn, and statistics related to the cause of delay show similar results. Therefore these existing sources of data for airport revenue management, while very useful, are incomplete, inaccurate, and offer a significant delay in data timeliness. 
     Another area of automation of financial management for airports is in Lease Management Systems. As stated above, a substantial portion of an airport&#39;s operating revenue may be derived from leases of property, for example to airlines and retail companies. In the past, most airports had limited facilities (“concessions”) for airport travelers. These concession stands were usually badly overpriced and offered limited poor quality goods and services. In recent years, many airports such as the recently renovated and renamed Washington Reagan National Airport have created virtual shopping malls within the airport itself. 
     Airports have realized that air travelers are willing to spend money in airports on quality services and products, and moreover are unwilling to tolerate the high-priced and poor quality “concession stands” of the past. As such, airports have discovered they are sitting on valuable retail space, which can be leased for a generous profit. However, many airports may not be as comfortable with this new role as retail space landlord, and may be ill equipped to manage such retail leasing operations. 
     For a retailer operator in an airport, income may depend directly upon the number of flights (and passengers) travelling in and out of a particular gate or section of the airport. Thus, a lease for space in a busy portion of the airport terminal may be worth much more than one in a lesser-used portion of the airport. A retailer may be willing to pay more for retail space where it can be demonstrated that more passengers will be passing by. Similarly, a retailer may be less willing to pay top dollar for retail space in a lesser-used portion of the terminal. Quantifying actual passenger traffic and basing leasing prices for retail space based upon such traffic could optimize revenues for all portions of the airport. 
     More traditionally, airports have managed leasing of space to airlines for gates, ticket counters, and other space within the airport. Managing leasing of such space traditionally has relied upon flat fees for use of a particular space over a period of time. Traditional leasing techniques may not have correlated costs with income and usage. Gates that are not in use by one airline may sit vacant and could be leased to another airline on an as-needed basis. Tracking such use of airport facilities can be cumbersome and costly. It would be desirable to provide a system for dynamically tracking airport usage for leasing purposes. 
     An airline at the airport may receive invoices for rent as well as aircraft activity. This can be summarized as static and dynamic billing; where the airline receives bills for rental of space (static) and landing fees (dynamic). There are several existing packages on the market for management of leases at airports—or the static part of the equation. These existing programs include:
         AirIT&#39;s Propworks (www.airit.com);   Aeroware, (http://www.aeroware.com/property.htm);   Airport Corporation of America, (http://www.airportweb.com);   Kelar (http://www.kelar.com/gis);   the Bowman Group (www.thebowmangroup.com/bgclients2.html); and   Maximo, (www.mrosoftware.co.nz/pdf/SydAir.pdf),   All of which are incorporated herein by reference.       

     An example of a typical standalone lease management system is described in Official Notice #6064, Invitation to Submit Proposal for Airport Property and Revenue Management Software System, published in February 2005 by General Mitchell International Airport, Milwaukee, Wis., and incorporated herein by reference. There are also solutions on the market aimed at capturing airport landing fees, such as Megadata&#39;s Passur (www.passur.com) and Lochard&#39;s SkyTrac (www.lochard.com), both of which are incorporated herein by reference. 
     Other relevant Megadata references include Published U.S. patent applications 20040243302, System and method to display operational and revenue data for an airport facility; 20040104824, Simplified flight track display system; 20040054550, System and method for the distribution of information during irregular operations; 20030009267, Apparatus and method for providing live display of aircraft flight information; and 20050021221, System and method for the correlation of multiple data feeds, all of which are incorporated herein by reference. 
     However, there are no comprehensive approaches that combine the static lease management with the dynamic aspects including landing fees, taxi usage, and overall facility usage including gates. Thus, it remains a requirement in the art to provide such a system. 
     When billing automation is introduced into a business, one of the main reasons is to improve the collection of revenue. A system that is more comprehensive in identifying usage may increase amounts collected. Costs may be reduced through automation and reduction of manually intensive activities. More accurate and automated client billing may reduce the cost to some clients, while increasing costs to other clients, but more importantly the system would provide detailed information on usage charges. 
     Most airports use unsophisticated methods to charge for airport usage. Peak time pricing is based on hourly blocks of time and client fees are assessed based on basic aircraft registration weight. Parking fees are usually charged to the nearest hour and ramp use fees are assessed based on the scheduled use of ramps at the airport. The reason for the approximations and basic rules is because existing (legacy) billing collection techniques are rudimentary and cannot support a more sophisticated set of rules. 
     With a more sophisticated system, the billing could be exact, and peak pricing could be based on actual landing time, parking time, ramp usage, type of ramp, and departure. Fees could be based on the specific aircraft weight for the individual aircraft, which would be equitable to users with different aircraft configurations. A system with this level of accuracy and fidelity would benefit the airport as well as the airport users. Users could have detailed information as feedback showing the billing accuracy and they could use this information to streamline their operations and planned use of the airport in peak and non-peak periods. 
     Increasingly sophisticated data feeds and the integration of multiple data streams allow an airport to get closer to the ideal billing methodology, one based on the economic cost of use. Every aircraft and passenger that arrives or departs an airport requires a certain amount of resources be available for that operation. Some aircraft require more resources than others based on their size, weight, and use (cargo vs. passengers). An ideal billing system would charge a fee based on the actual costs associated with accommodating that aircraft at that airport at that time. 
     For instance, an Airbus A380 will consume more of the airport&#39;s resources than a Canadair Regional Jet, but the difference in resources consumed by each of these two aircraft is only grossly approximated by the ratio of their maximum gross weights, which is how most billing systems are configured to charge landing fees. The Airbus carries over 500 people and may require that other gates be closed to accommodate the size of the large aircraft. These additional gates are then denied to other aircraft and have a cost associated with the lost opportunity, even if the Airbus was not using them. The lost opportunity cost represents an economic cost that should be recovered by the airport. 
     Thus, it remains a requirement in the art to provide an airport revenue management system which can track airport revenues and costs by determining the actual location, track, size, and type of aircraft travelling through the airport, as well as accurately tracking the number of passengers, amount of cargo, and the like, and to do so in an automated fashion, without relying unduly on manually entered data or self-reporting by airlines. 
     SUMMARY OF THE INVENTION 
     The system of the present invention acquires any and all data related to the operations, property, lease, and revenue management of an airport, including aircraft tracking data, and combines this data in a data fusion process to provide an accurate tracking of airport revenues and expenses. This data is then stored in a central database where it is processed, sorted, and stored for later retrieval. The data may exist in a number of forms including real-time streams, tabular, or in the form of a database. From this data, airport revenue information can be accurately managed. 
     The Data Acquisition Unit (DAU) acquires airport operation data. This system is designed to have a large number of channels of data flowing into it from conventional data sources, including manually entered data, data from other databases, aircraft tracking data, and other automated data entries relating to airport operation. The DAU acquires and assembles these multiple channels of data and forwards them to the data correlation and assembly unit (DCAU). The DAU is designed to work in real-time and has the capacity to acquire all the data available from any source. The output of the DAU is a single stream of un-correlated data. 
     The Data Correlation and Assembly Unit (DCAU) processes uncorrelated data. The DCAU system has software that simultaneously evaluates the multiple channels of data and prioritizes, filters, sorts, and assembles the data. Correlation includes the process of combing data elements for like events or occurrences. Thus, for example, airline schedule information, or self-reported schedule information may indicate when an aircraft is supposed to arrive at a gate, and how long the aircraft will be parked at the airport, but actual tracking data may provide more accurate data as to how long the aircraft was parked, what gate it arrived at, take-off weight of the aircraft, number of passengers, and the like. The system will use whichever data source is deemed to be most accurate, or whatever data source is available, to build a complete and accurate picture of airport operations. 
     Correlation also eliminates double reporting of the same event. Thus airline schedule information may be correlated with flight track information so that an airline flight is not reported as two flights if the flight is late or the like. This system readies the processed data for insertion into the data storage systems, the AirScene Data Warehouse (ADW). The output of the DCAU is a stream of data that is imported into a relational database by the ADW. 
     The AirScene Data Warehouse (ADW) is a relational database for storing the processed data. The ADW stores all of the data in an industry standard relational database and has sufficient capacity to respond in a timely fashion when queried. This database is accessed by a number of different processes and users including automated reporting engines, web-based query engines, user-initiated queries from software such as Access, Excel, Crystal reports, AirScene NOMS, AirScene Property and Revenue Management System, GIS, CAD, accounting, billing and other software tools. The ADW can be a stand-alone system or it can work in concert with other database servers to provide data and data services to the airport. The data flow for the ADW is bidirectional. Queries come into the ADW and those queries are processed and the results of the query are sent to the requester. 
     From the ADW, data on airport operations can be retrieved through manual inquiries via a user interface, or may be retrieved by other accounting software programs or packages through automated queries. Invoicing for airport operations, such as take-off and landing fees can be automated, and more accurately based upon actual takeoff weight, number of passengers on board, and the like. Actual passenger counts (enplanements) can be readily determined to qualify for government subsidies and also to assist in airport planning and operations. Leasing of gate space, as well as retail space, can be optimized based upon actual passenger traffic, as opposed to flat-rate fee schedules, passenger traffic projections, retail sales, or the like. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a chart illustrating how the amount and type of funding varies depending on airport size. 
         FIG. 2  is a chart compiled by the GAO, illustrating various types of airport projects financed through the PFC programs. 
         FIG. 3  illustrates one method of tracking aircraft using 2 D zones, in combination with airport GIS systems and accurate aircraft tracking and identification. 
         FIG. 4  is a diagram illustrating the Aerobahn system offered by Sensis Corporation of Dewitt, N.Y. 
         FIG. 5  is a block diagram illustrating an example of a Prior Art ASQP system in use at the Port Authority of New York and New Jersey. 
         FIG. 6  describes the data fields available from ASQP. 
         FIG. 7  is a screenshot of January 2005 statistics for the ASQP data from the Bureau of Transportation Statistics web site. 
         FIG. 8  is a diagram illustrating data flow through the AirScene system of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 8  is a block diagram illustrating the major components of the AirScene™ Airport Revenue Management System and the types of data utilized by the system. The AirScene™ Airport Revenue Management System utilizes this data to quantify airport revenue and expenses based upon, in part, individual aircraft movement. This cumulative data allows AirScene™ to manage airport revenues. This information can be displayed through AirScene™ in the form of tables, graphs, or graphically represented on an airport diagram. Other programs, including 3rd party accounting software, may use the data from the AirScene™ system to more effectively manage airport income and expenses more effectively. Government agencies, the general public or other parties, may use the data to accumulate and analyze airport usage statistics and data, if desired. Such data may be published to a website or the like for public or government use, if desired. 
     Referring to  FIG. 8 , the system draws on data from the AirScene™ Data Warehouse (ADW)  702 . DW  702  represents a single repository for all the information acquired from a number of different data sources. These data sources may include Operational Databases  102 . Databases  102  may include the Official Airline Guides (OAG) databases, SSID (Supplemental Structural Inspection Document), the aforementioned ASQP system, the FAA CATER (Collection and Analysis of Terminal Records) system, FAA Flight Strips, and Aircraft Registration Database. Resultant data  202  from Operational Databases  102  may include airline flight schedules, future anticipated operations, owner information, aircraft movement records, and the like. 
     Databases  104  may include Flight Information and may include Aircraft Communication Addressing and Reporting Systems (ACARS) data, Aircraft Situation Display to Industry (ASDI), Automatic Dependent Surveillance—Broadcast (ASD-B), Controller-Pilot Datalink Communication (CPDLC), Mode-S transponder data, and the like. This data generated from aircraft by radio signals may include relevant data  204  such as aircraft type and weight, cargo, fuel weight, time on gate, off gate, on wheels, off wheels, air traffic controller (ATC) communication recording, and the like. From this data, it is possible to determine aircraft weight, type, number of passengers, and other data relevant to airport revenue management. For example, number of passengers on each airplane can be collected to determine total number of enplanements for the airport. 
     Databases  106  may include Airport Data Sources, including Common Use Terminal Equipment (CUTE), Local Departure Control System (LDCS), (See, http://www.damarel.comlproducts, incorporated herein by reference) Property/lease management systems, Geographic Information Systems (GIS), Computer Aided Design (CAD) data of airport terminals and facilities, Noise and Operations Monitoring System (NOMS), and the like. Databases  106  may produce data  206  such as gates used, time on gate, off gate, passenger counts, revenue passengers, property and concession revenues, resource tracking, noise levels, and aircraft service records. This airport information, for example, when correlated with other data, such as aircraft tracking data, can indicate which gate an aircraft is parked at, which runways were used, and the like. 
     Aircraft Multilateration Flight Tracking Systems  108  may comprise, for example, Rannoch Corporation&#39;s AirScene™ Mlat (Multilateration) system, which is capable of identifying and tracking aircraft both in the air and on the ground using multilateration of radio signals. Other aircraft tracking systems may also be used, including aircraft sensors mounted in taxiways and runways (e.g. conductive loops or the like) or other types of systems. Examples of such systems includes various models of Airport Surface Detection Equipment (ASDE), such as ASDE-X (see www.asdex.net, incorporated herein by reference), ASDE-3, and ASDE, as well as Airport Movement Area Safety System (AMASS), SITA Information Networking Computing (SITA INC), Short Messaging Service (SMS) (See, http://www.sita.aero/default.htm, incorporated herein by reference), the aforementioned ADS-B, and the like. Data  208  from such systems can produce actual aircraft positions or tracks (paths followed). Position and speed of aircraft can also be determined from such data. In addition, data  208  may include flight corridors, runways, taxiways, and gates used by aircraft, as determined from vehicle ground track, position and speed, along with other aircraft information and communications. 
     Other data sources  110  may describe airport conditions and may include digital ATIS (digital Automatic Terminal Information Service, see, http://www.arinc.com/products/voice_data_comm/d_atis/, incorporated herein by reference), Automated Surface Observation System (ASOS), METAR (Aviation Routine Weather Reports, available from the FAA and other sources), TAF (Terminal Aerodrome Forecast) the aforementioned SMS, Internet weather sources, and the like. These sources may produce data  210  indicating which runways are preferred, meteorological data, surface conditions, precipitation,/icing, coefficients of friction, and the like. 
     Note that all of the data sources  102 ,  104 ,  106 ,  108 , and  110  do not need to be used in order to produce a satisfactory airport revenue tracking system. Some or all of these sources may be used, and/or additional sources of relevant data may also be applied. Each source of data may generate data, which may be relevant to airport revenue or expenses. Missing data may be filled in by other sources. In addition, data from different sources may be used to correlate data to increase accuracy of data reporting. For example, airport subsidies may be based upon enplanements (passengers loaded), which in the past may have been determined solely by manual reporting by airlines. The present invention may correlate that data (as set forth below) with passenger data from automated sources such as flight information  104 . 
     Similarly, tracking gate usage and parking usage may have been a manual task relying upon self-reporting by airlines and/or manual reporting by air and ground traffic controllers or other airport personnel. Airlines may tend to underreport gate and parking usage, and airport personnel may be too busy with other jobs to accurately track such usage. The automated system of the present invention can track aircraft automatically and report down to the minute (or even second) where an aircraft is parked or particular gate usage. This data may be used to invoice airlines for airport services, as well as in planning gate usage. Similarly, landing fees can be more accurately based upon actual aircraft weight, passenger load, and use of airport facilities, rather than upon some flat-rate schedule. Thus, from the data sources described in  FIG. 8 , numerous useful data can be derived which may be useful to tracking airport revenue and expenses. 
     Data acquisition unit  302  acquires data  202 ,  204 ,  206 ,  208 , and  210  from data sources  102 ,  104 ,  106 ,  108 , and  110  to produce a single stream of raw uncorrelated data. The data acquired and stored by AirScene™ is the key to accurately tracking airport revenues and expenses. Data correlation and Assembly Unit  502  takes this stream of raw uncorrelated data and produces a single stream of fully correlated and calculated data  602 . Correlation involves identifying which data elements represent the same or similar items (e.g., with regard to aircraft weight and track) and eliminating duplicate entries. 
     It is important that data from two sources indicating the track of the same aircraft are not counted as two aircraft tracks, otherwise, aircraft tracking data might be doubled, giving a false impression of actual airport traffic. Calculations may include weight calculations based upon aircraft weight (calculated from direct data, or inferred from aircraft type, cargo weight, fuel, and souls on board, or the like). 
     The Air Scene™ Data Warehouse  702  then stores this correlated and calculated data in a usable database. Workstations  902  connected to warehouse  702  may edit data or send queries  802  and receive results  804  which may be displayed  1002  in graphical, tabular, or visual form, illustrating aircraft revenue sources and income. The system can be interfaced with existing revenue management systems, and may also generate, in an automated fashion, invoices, checks, government forms, and the like to pay bills, invoice customers, and request subsidies based upon airport usage. 
     The AirScene™ Airport Revenue Management System can combine all the data sources into a single calculation of airport income and expenses. Historic data can also be accessed to make predictions about the future income and expense trends. Also, scheduled airline operations data from sources such as the Official Airline Guide (OAG), can be utilized to anticipate future airport operations for the purpose of calculating the future income and expenses. The OAG website database (see, www.oag.com) and other data includes data on aircraft weights, types, codes, and other aircraft, flight, airline, and schedule information. 
     In another alternative embodiment, a landing fee billing system may be implemented whose fees are based on the airport usage, including pavement wear. Aircraft known to place more stress on the pavement could be assessed higher landing fees to compensate the airport operator for the additional wear and tear. Aircraft weight can be readily determined by knowing aircraft type, souls on board, cargo weight, fuel weight, or even reported weight data (or even weight sensors embedded in pavement). Such a landing fee embodiment may be incorporated into the Rannoch Corporation Landing Fee system (described in the Patents and Pending Applications previously incorporated by reference) such that an aircraft owner can be automatically assessed a landing fee based upon aircraft weight, and billed accordingly. 
     The system and method of the present invention can thus be used to automatically calculate the amount of subsidies due from PCF and AIP grants based upon passenger throughput and/or cargo weight, based upon accurate data correlated from multiple sources. 
     In addition, the database created by the present invention can be used to audit other airport operations and systems to determine whether accurate data is being reported. For example, as noted previously, automobile parking is a substantial source of revenue for an airport. Yet many airports subcontract parking operations to one of a number of large parking companies who have an interest in underreporting parking revenues to the airport. Passenger throughput data can be used to audit parking revenues, as the number of cars parked will generally be proportional to overall passenger throughput. 
     Similarly, taxi surcharges and revenues can be audited based upon passenger throughput. Moreover, data for passengers entering taxis at the airport can be automated through the use of electronic data inputs at taxi stands and the like. Rental car company airport surcharges can be similarly input electronically, and/or monitored and audited using the system of the present invention. Rental car company databases may be queried by the system of the present invention and the data fed to the AirScene™ Data Warehouse. 
     The system may also be used for security purposes by authorized law enforcement authorities to track individual passenger flow through an airport. Data reported from a number of sources throughout the airport can track a passenger based upon check-in, security checkpoints, boarding operations, and even use of credit cards at airport concessions. In addition the use of RFID tags and other devices may be used to track passenger and baggage data for financial auditing and/or security purposes. Privacy concerns can be easily met by limiting access to the database regarding individual queries to authorized personnel. 
     While the preferred embodiment and various alternative embodiments of the invention have been disclosed and described in detail herein, it may be apparent to those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope thereof.