Lawrence J. Harman and Uma Shama
GeoGraphics Laboratory, Moakley Center for Technological Applications
Bridgewater State College
Bridgewater, MA, USA
Daniel Fitch and Glen Kidwell
GeoGraphics Laboratory, Moakley Center for Technological Applications
Bridgewater State College
Bridgewater, MA, USA
The efficiency of working on any project solely depends upon three important dimensions viz. Time, Accuracy & Economy. The optimum achievement of all the three, hence, becomes vital. The use of code based hand held GPS is gaining momentum worldwide for its ease to achieve the above target. But there are certain issues which cause a deep impact on the results obtained from GPS technology. This paper throws light on such issues hence promulgating certain ways, supported by experimental results, to use the GPS technology for utmost accuracy in minimum time and economically soothing. The accuracy is often misunderstood in terms of the standard errors (S.E) as reported by the software. Studies were carried out to ascertain what is the relationship between the SE as reported by instruments and the real ground measurements. Comparison between the actual ground measurements and the SE do not bear any significant relationship between each other. The actual errors are often much more than the position errors as reported by the vendors.
This paper describes research into the application of low-cost cell phone-based location technology and no-cost web mapping services to improve the situational awareness of incident commanders responding to emergencies in rural areas. The research project was accomplished with the cooperation of innovative public safety and security professionals who needed near-real time location of specialized assets, including equipment and personnel, on very limited budgets.
Statement of the Problem.
On the rural peninsula of Cape Cod, Massachusetts, USA, the Fire Chiefs of neighboring towns depend on cooperative agreements to respond to fires, rescues, and emergency medical services with specialized equipment and personnel. For example, when there was a particular event (a national holiday celebration) that drew large crowds to a rural venue, the surrounding town’s Fire and Rescue services created an inter-jurisdictional command and control structure to stage and deploy ambulances and emergency medical technicians (EMTs). In another instance in Southeastern Massachusetts (US), rural fire departments typically join together to battle forest fires with specialized fire fighting equipment (brush breakers/tanker trucks) in state or national parks and forests that encompass several local jurisdictions. Lastly, natural disasters, such as, hurricanes, snowstorms/blizzards, and flooding often require intergovernmental coordination in rescue and evacuation. In all of these instances, it is helpful to have real-time automatic location of assets (vehicles and personnel) displayed on a web-mapping application that is accessible to all incident commanders at command posts (fire stations) and field supervisors in their mobile command vehicles (equipped with wireless laptops).
The GeoGraphics Laboratory developed a field test with the Chief of the Brewster Fire and Rescue Department in response to the mobilization of ambulances and EMTs for the festivities (including fireworks displays) associated with the a national holiday on the Fourth of July at the Cape tip community of Provincetown, Massachusetts. (See Figures 1 and 2.)
1. A-GPS Cell Phone description.
The GeoGraphics Laboratory at Bridgewater State College purchased the Motorola i355 cellular phone with A-GPS system through a state centralized purchasing contract at below retail market pricing for the cellular phones (<$80. USD) and the data-only service plan using the Nextel Integrated Digital Enhanced Network (iDEN) communications network (<$9. USD). The iDEN network is a cellular network developed by Motorola that is available in the United States from the Sprint/Nextel mobile cell phone carrier.
a. Description of the Motorola i355. The Motorola i355 is a low cost cellular phone that is constructed to military specifications to endure temperature ranges, dust and moisture found in public safety use. It is a full-feature cell phone that is capable of Internet access on the mature second generation (2G) iDEN cellular network. The i355 was one of the earliest phones with A-GPS that also supported open source (J2ME) software development.
b. Description of the Motorola/Nextel iDEN network. The iDEN network is a mobile telecommunications technology, developed by Motorola, which uses both trunked radio and cellular communications. In addition to the United States (US), where it is sold by Sprint/NEXTEL for public safety purposes and business applications, it can be found throughout the world. The features of the network that are particularly useful are the push-to-talk features of two-way radio and the full nationwide cellular communications of a cell phone. In the US, Nextel has had widespread market penetration in public safety (e.g. police and fire departments) where emergency response personnel are very familiar with the Motorola products and Nextel services. Other iDEN networks are available throughout the world including, Argentina, Brazil, Canada, Israel, Jordan, Mexico, Peru, the Philippines and Singapore.
c. Description of the J2ME software for A-GPS/AVL. The custom programmed J2ME application for this research acquired the latitude and longitude and related data of the particular cell phone using built in A-GPS and then sends that data stream to the GeoGraphics Laboratory’s web server. The program is able to initiate four (4) threads that collect and send the A-GPS data to the web server using Transmission Communications Protocol/Internet Protocol (TCP/IP) standards and then clears the phone memory cache and repeats the cycle. This data is then transmitted to a database server using SQL Stored Procedures on web services architecture. This provides an effective AVL in less than five seconds with an average refresh rate of 2.5 seconds. This is very high temporal resolution for AVL from a low-cost cell phone that is comparable to any purpose built AVL marketed to public safety and emergency medical services.
2. Web-Mapping Services description
a. Description of the SQL Server database. The database server uses Microsoft Windows Server 2003 Standard Edition operating system running Microsoft SQL Server 2005. The database resides on a Silicon Mechanics 2 terabyte (TB) server.
b. Description of the Microsoft VE application. A Web application that uses an Application Programming Interface (API) from Microsoft creates a web mapping service at the GeoGraphics Laboratory’s web domain (www.geolabvirtualmaps.com) for the ambulance and mobile command vehicles equipped with the Motorola i355 A-GPS AVL cell phone. This application uses the Microsoft Virtual Earth (VE) Wrapper Library Web/Ajax Service. In this case, the application centers the map on the Southeastern Region of Massachusetts, which is a geographic region designated by the Commonwealth of Massachusetts for Emergency Management and intergovernmental coordination purposes. An important feature of the VE application provides three different backgrounds for the AVL application – high quality maps that provide different information at different zoom levels, a “satellite” view that provides low-resolution Landsat or high resolution color orthophotos depending on the scale of zoom, and a hybrid background (roads and points of interest on imagery). In addition, in some areas of Massachusetts, Microsoft VE offers a “bird’s eye” view, which displays the AVL data on oblique digital imagery (45 degree angle of view) of very high resolution. The relative resolution of the AVL data, the digital maps and the digital imagery is reasonably compatible. The resultant decision support tool is useful to incident commanders for timely situational assessment and presentation.
c. Description of the reverse geocoding program. Each AVL record sent from the A-GPS equipped Motorola i355 cell phone has a field for latitude and longitude (real number format). This data is then sent to Microsoft’s MapPoint Web Service which determines the nearest street address and sends this to populate a label on the VE application in milliseconds. This label also contains data on bearing and speed. When the reverse geocoding data is added, each label tells the user where the vehicle is located, its bearing (points on the compass e.g. NW), and at what speed (miles/hour) the vehicle is traveling.
d. Web services vehicle manifest. The GeoGraphics Lab developed a Web service to add information to the label for each AVL record on the Web Mapping application. A website written in C# using ASP.NET 2.0 technology provides dispatchers (authorized by name and password) to add the type of asset (e.g. ambulance, mobile command vehicle) that the A-GPS AVL cell phone is assigned to on a computer database or manifest. This feature can be used to identify the vehicle number and regional/route assignment and the personnel (name or professional category e.g. EMT) assigned to the vehicle from a drop-down menu. There is a secure and unsecured part of this Web service powered by MS SQL Server 2005 and ASP.NET membership. Dispatchers can sign on from any Internet connected computer (including mobile command vehicles with wireless access) and obtain information about any cell phone equipped vehicle. The changed information immediately appears on the Web mapping application and anywhere else this vehicle information is being displayed (see below).
e. Personal Digital Assistant (PDA) Web publishing systems. Wireless PDAs and “smart phones” with wireless broadband access are increasingly available in the marketplace. These handheld computing and communications devices are able to display the AVL data from emergency management vehicles in a tabular format. (Web mapping AVL displays described earlier can not be operated effectively on these mass market devices with current cellular wireless broadband services.) Using C# programming language with MS ASP.NET architecture and MapPoint web services, a web site was developed that provides incident commanders with a description of every vehicle location (nearest street address), speed, bearing, vehicle ID, vehicle type, and route/region assigned. This information is similar to the legend information displayed when the cursor hovers over a vehicle icon on the AVL Web Mapping display.
3. Testing the hardware and software.
While the principal hardware and software components of the A-GPS AVL cell phones, Web databases and Web Mapping Services are mass market items, this particular service design and much of the integration software was original. Therefore, considerable testing, redesign, redeployment and retesting have been a constant in this research application.
a. Geographic coverage of i355 and iDEN. Initial tests of the A-GPS AVL cell phone focused on verifying coverage in rural areas of Cape Cod and in rural areas leading to Cape Cod as a part of the Cape Cod Transportation Partners Technology Project. This included post processing of AVL locations with geographic information systems (GIS) and real-time situational assessment using Web Mapping Services and the custom AVL mapping described above. An interesting data set that supports this analysis is the location (latitude/longitude) of the cellular tower transmitting the AVL data from the i355 handset. These tower data can be mapped along with the AVL data using a desktop mapping program to determine if the internal antenna on the Motorola i355 is sufficient for reliable coverage or whether an external antenna is necessary to increase the signal from the handset. Tests of the i355 coverage also were conducted in the “urban canyons” of Manhattan Island in New York City (US), on the mountain passes of New Hampshire, Vermont, California and Nevada (US) with good results. Using a powerful external antenna on the i355 cell phone, coverage was maintained on passenger ferries traveling from Boston to Provincetown, Massachusetts (US) and from Hyannis to Nantucket Island, Massachusetts (US).
b. Web Databases and Web Mapping Services. The original Microsoft Research award to the GeoGraphics Laboratory provided high-end hardware and software that promoted the research applications using very large geo-spatial data sets that led to this project. These hardware and software systems and the original communications software required considerable testing and modification. In some cases, where legacy AVL systems is integrated with the i355 AVL data, it is particularly necessary to have very stable databases on the Server side as the quality of the Client side could not be relied on for continuous operation.
c. Situational Awareness and Geo-spatial Analyses. Web mapping displays that provide AVL situational awareness in a near real-time (under 5 seconds) context were developed and tested using Google Maps, Microsoft Virtual Earth and Google Mapplet APIs. In each case, trial and error testing led to a more stable mapping application for the consumer. To analyze archival AVL data, SQL queries were developed and tested to extract records relating to vehicle ID, regional application, or geography. These data sets were imported into a desktop mapping (Maptitude™ by Caliper Corporation) and high-end GIS program (TransCAD™ by Caliper Corporation). For spatial analysis, the GeoGraphics Laboratory used these desktop mapping and GIS programs to display the AVL data on high-resolution (.5 meter) color digital orthophotos with very satisfactory results.
4. Conduct of exercise.
The GeoGraphics Laboratory developed an informal cooperative relationship with the Chief of the Town of Brewster (Massachusetts, US) Fire and Rescue Department to field test the Motorola i355 A-GPS AVL cell phone and a Web Mapping Service for Southeastern Massachusetts Emergency Management (See www.geolabvirtualmaps.com). Co-incidentally, Chief Roy Jones, the Brewster Fire Chief, was also the commander of a regional mobilization of emergency medical services in response to the Fireworks Display on the national July 4th celebration on the Cape tip Town of Provincetown. The Chief offered to test the A-GPS AVL/Web Mapping Service as a near real-time situational awareness demonstration for the location and display of ambulances and mobile command vehicles.
a. Description of Provincetown July 4th Celebration Mobilization. The GeoGraphics Laboratory was able to provide the Brewster Fire Chief with ten (10) Motorola i355 A-GPS AVL cell phones for the field test. The Command Post (CP) and staging area for the mobilization was the Town of Truro Fire Station in the Lower Cape village of North Truro. The Chief met each ambulance as it arrived from cooperating towns at the North Truro staging area. He explained the field test to the ambulance driver and placed a cell phone operating as an A-GPS AVL unit on the dash of each vehicle and sent the vehicle to its assigned deployment (in most cases the parking area of the Town of Provincetown Fire Station). The chief used his laptop with Internet access and a large screen auxiliary display in the North Truro Fire Station to monitor the location of vehicles as they responded to medical emergencies associated with the fireworks celebration transporting injured or ill persons to the regional hospital in the Mid-Cape town of Barnstable. The large screen display of the Web Mapping Service served as a means for the cooperating towns to achieve multi-jurisdictional situation awareness of all ambulances and mobile command vehicles participating in the exercise. Literally, every ambulance was on the same web page/web map. A screen shot of the Web Mapping Service emergency management display taken during the exercise can be found in Figure 3.
b. Problems and opportunities. While the opportunity to test the A-GPS AVL cell phones and Web Mapping Service was fortunate for this applied research project, the timing of the mobilization precluded any advance planning, purchasing accessory equipment or modification of Web Mapping Services. For example, while there was enough DC battery chargers for the mobile command vehicles, there were not enough for many of the ambulances. The cell phones were constantly sending AVL locations at intervals of 2 – 4 seconds – a draw on the cell phone’s battery. The mobilization exercise was conducted between 6 pm (EDT) to midnight. In most cases, the battery ran out in four to five hours. Also, in some areas on the Cape tip, the A-GPS cell phone lost connectivity with the Nextel tower. An inexpensive external antenna would have ensured continuous Nextel reception. Despite these minor problems, the Chief reported that, when the Web Mapping Service was displayed on the large screen; it held the attention of the command staff for the next five hours during the mobilization. Further, the use of the high resolution “Bird’s Eye” view feature was well received by staff at the CP. (See Figure 4.)
1. Use of low-cost A-GPS cell phones for AVL is very affordable for very high temporal resolution and reasonable spatial resolution.
2. 2G Motorola/iDEN cellular network for low-cost transmission of minimal locational data at high refresh rates is very sustainable for long-term public service applications on a regional and national basis.
3. Use of Web mapping services and open source applications by Microsoft Virtual Earth and Google provide de-facto standards of software development, communications protocols, and rapid extensibility for regional, national and global applications.
4. Open source software and hardware systems provide the opportunity for the immediate deployment of these A-GPS AVL systems to respond to regional and multi-national disasters and terrorist attacks.
5. A secure mounting kit for the A-GPS phone, wired directly to the vehicle’s battery, equipped with an external antenna, and mounted away from direct sunlight would improve reliability of operation.
Recommendations for Future Research.
1. Deployment of equipment for fighting forest fires in rural U.S. Specialized fire fighting assets (e.g. brush breakers and tanker trucks) from multiple jurisdictions equipped with A-GPS AVL cell phones displayed on a regional web mapping service, such as the Southeastern Massachusetts Emergency Management AVL web mapping display, would provide coordination of Fire Services providing mutual aid in response to a regional forest fire.
2. Deployment of equipment for mutual aid response to rural highway mass casualty incidents or terrorist attacks in rural and small urban U.S. Winter weather conditions produce highway hazards that cause multiple car crashes with mass casualty potential. Town-based emergency medical services respond to these mass casualty incidents (MCIs) through cooperative agreements in rural areas. Use of Web Mapping Services could greatly assist in coordinating these responses at local, regional, statewide and national levels. In addition, to natural disasters, response to terrorist attacks require similar near real-time situation awareness coordination and coordination.
The authors are greatly appreciative of the public safety professionals that have encouraged this research and provided wise counsel in the application of these geo-spatial technologies to emergency management. In particular, we would like to acknowledge the support provided by: Chief Roy Jones, Town of Brewster (MA, US) Fire and Rescue Department; Chief Craig Weston, Town of Carver (MA, US) Fire Department; Chief George Rogers of the Town of Bridgewater Fire Department; Chief Robert Crosby, Barnstable (MA, US) Fire Department and Chairman of the Southeastern Massachusetts Homeland Security Regional Advisory Committee; Reinald Ledoux, Administrator of the Brockton Area Transit Authority and Vice Chair of the Southeastern Massachusetts Homeland Security Regional Advisory Committee and COL David Gavigan, Commander of Special Operations for the Bristol County (MA) Sheriff. We would also like to thank Dr. Jim Gray and Dan Fay from Microsoft Research for their financial and intellectual support of the GeoGraphics Laboratory.