immediate medical attention to critically ill patients and accident victims followed by transportation to a well - equipped medical facility within the golden hour saves many lives .
numbers of road accidents in india are the highest across the world . according to the national transportation planning and research center ( ntprc )
the number of road accidents for 1000 vehicles in india is about 35 while the figure is between 4 to 10 in developed countries .
there are several governmental and nongovernmental agencies like the emergency management research institute ( emri ) , located across the country , which have been dedicated to the cause of transporting critically ill patients and accident victims .
inner area of ambulance is fabricated in such a way that it houses emergency medicines , sterilizer , stretcher , and so forth . a typical inside layout of an ambulance employed for emergency patient transportation
there exists a need to augment the skill set of such paramedics with the expert doctor 's advice from the central monitoring station ( cms ) .
cms helps in identifying the nearest and appropriate hospital and coordinating with the medical personnel of that hospital .
hence there is a need for communication between the staff of the ambulance and the central monitoring station .
the doctor needs to understand the physical and physiological condition of the patient so that the right decision regarding administration of drugs and transport destination can be appropriately taken .
deploying these instruments would mean that separate communication mechanism , namely , the usage of separate sim cards and separate gsm / gprs modems , would be required resulting in increased recurring expenditure .
hence a comprehensive , cost effective system that can acquire physiological data from the patient keyed - in data from a keyboard and location data from a gps receiver as well as voice signals and send them using cellular network is needed .
have developed a real - time remote monitoring system for combining ecg data and gps data before transmitting to a central monitoring station ( cms ) .
similar systems are independently developed by researchers at the glenn research center ( nasa ) , university of akron and case western university .
khan and mishra   reported that position and velocity of vehicle can be estimated using gps receiver fitted in the vehicle and sent to the central monitoring station using gsm .
zhang and lu [ 6 , 7 ] developed an ecg telemonitoring system with gps and gprs to continuously monitor ecg of the cardiac patient along with the position and posture .
fang and lai   have developed a system to monitor the ecg of cardiac patient who is away from the hospital .
a mobile ecg telemonitoring system along with an accelerometer , to sense sudden postural changes that reflect sudden cardiac failure , has been developed .
philips company has developed systems for remote monitoring of cardiac patients from their research centers worldwide in 2009 .
exact and continuous blood pressure monitoring system along with location information and time synchronization facility to work with other measurement modules has also been proposed .
recent advances in telemonitoring systems resulted in early diagnosis and management of chronic and degenerative conditions , significantly prevalent in elderly people .
telemonitoring can also be applied on a long - term basis to elderly persons to detect gradual deterioration in their health status resulting in inability to live independently .
several digital signal processing techniques have also been employed to denoise and study gps and ionospheric studies [ 12 , 13 ] .
companies including qrs diagnostic , vivometrics , human network technology , amd telemedicine , health frontier , and cardionet have been engaged in the development of telemonitoring systems .
though all these systems are intended towards remote monitoring of cardiac patients , the concept of a unified system is not satisfied by any of the existing systems .
they do not cater to the specific requirement of acquiring the physiological data , keyed - in data , patient snapshot , and voice signals and transmitting them using cellular network .
hence , it is proposed to develop an indigenous system to meet these requirements ( figure 2 ) .
the system developed by us is a comprehensive , cost - effective system ( approximately usd 4500 ) , which can acquire the physiological data , gps data , vehicle parameters , patient information , patient snap shot , and sos messages and transmit them as a single data packet using a cellular network .  
this system has been built around arm 9/11 microcontroller based module exclusively designed for this purpose and integrated with commercially available gps and gsm modules and physiological signal acquisition systems like medicaid and gsm phone with blue tooth ( bt ) facility .
the necessary software for the embedded system has been developed using keil compiler for arm family of microcontrollers .
this system is found to be very useful for emergency patient transportation being undertaken by organizations like emri .
the designed and developed ambulance system consists of gps receiver , signal and image acquisition system , gsm / gprs modem , and microcontroller unit .
the central monitoring system has a bank of gps / gprs modems , central server and application software .
hardware design challenges include combining different commercial off - the - shelf ( cots ) devices and specifically built subsystems , design , and implementation of interprocessor communication interfaces .
software design challenges include different sampling rates on separate channels to meet the nyquist sampling rate of signals with varying bandwidths and reducing the data packet size .
the electronics system present in the ambulance consists of a powerful low cost 32 bit risc based microprocessor based system .
it acquires location , speed , and time data from gps receiver and physiological signals from an exclusively developed and built medical data acquisition module .
image from a camera , administrative data from a keyboard , and vehicle parameters from a vehicle data module are also acquired ( figure 3 ) .
all these data are combined to form a data packet , in predefined format , and transmitted using gprs module to a central monitoring station .
the central monitoring station houses call center personnel as well as trained medical personnel and expert doctors , who analyze the signals and data coming from field ambulances
.   the heart of the ambulance unit is built around arm 9 samsung processor s3c2440a operating at 400  mhz .
the unit consists of two major building blocks , namely , processor module and base module . the processor module and base module are separately designed to provide flexibility and reduction in cost .
it adopts a new bus architecture known as advanced microcontroller bus architecture ( amba ) .
the integrated on - chip functions include sdram controller , lcd controller , 4-channel dma controllers , 3-channel uarts , 2-channel spi , iic , iis , audio ac97 , 2-channel usb host controller , camera interface , and rtc calendar function .
processor module includes nonvolatile nor flash of 2  mb ( sst39vf1601 ) , nonvolatile nand flash of 256  mb ( k9f2g08u0b ) , and 32 bit sdram of 64  mb ( 2 x hy57v561626ftp - h ) , operating at a clock frequency of 100  mhz . nor flash houses bios routines for interfaces and resources .
alcor micromake usb hub ic ( au9254a ) enhances the number of usb host ports to 4 .
usb host 1 connects camera and usb host 2 connects pda system ; usb host ports 3 and 4 are used for connecting external keyboard and vehicle parameter modules , respectively .
usb device port helps in connecting to pc for downloading programs and os images from the computer .
serial port 2 is connected to gsm / gprs/3 g modem for transmitting data , voice , and images .
serial port 3 is connected to gps receiver to collect position , velocity , and time ( pvt ) information at a speed of 4800/9600  bps .
transcend make micro - sd card with necessary sd / mmc interface ( clock , command , and 4 data lines ) with a storage capacity of 4  gb is used for local storage of data and housing related file system .
. the assembled microcontroller module along with the base board is shown in figure 4 .
the sd interface consists of 4 data lines ( sddata0-sddata3 ) connected to the core module ( pa24 , pa25 , pa22 , and pa23 ) which are in turn connected to the processor through r8 , m8 , p8 , and j9 , respectively .
apart from data lines the sd interface has two control signals sdcmd and sdclk which are connected to k8 and n8 .
the transmission frequency is controlled by making the appropriate bit settings to the sdipre register .
the frequency can be changed to adjust the baud rate of the connected peripheral .  
the graphic lcd and touch screen controllers are incorporated in the samsung microcontroller itself . a 7-inch lc display ( innolux make model at070tn83 ) having a resolution of 800x3 ( rgb ) x480 along with 4 wire resistive touch screen interface is included .
the touch panel is connected using a 4-pin connector . in order to achieve energy savings , a power supply control switch to lcd
it displays several messages related to the das , gps / gprs modem , gps receiver , and patient details and forms the human machine interface .  
a 10-pin jtag programming interface is provided on the processor module to program nor flash using the programming software h flasher .
usb device is used for programming the nand flash that houses the os and application programs .
power supply circuits generate 5  vdc , 3.3  vdc , and 1.8  vdc required for peripherals and other interfaces that include camera , gps receiver , and usb hub , and so forth . switched mode regulator 2576 family ics ( lm2576 - 5  v , lm2576 - 3.3  v , and lm1117 - 1.8 for 1.8  v ) are employed .
battery backup to the unit is provided using a 7.5  v 4000  mah nickel cadmium battery .
the linux kernel source code used is linux 2.6.29 and it is configured and cross - compiled using the cross - platform development tool chain arm - linux - gcc 4.3.2 .
the application code interacts with the hardware device through the device driver associated with the corresponding hardware and accesses the device .  
gps receiver , camera module , vehicle parameter module , gsm / gprs/3 g module , patient information module , and sos messaging module are connected to the system using appropriate interfaces as discussed below .
the gps receiver used in the system is a 12-channel gps receiver module eb818 from compass systems .
it is built around sirf - star iii ( gsc3f / lp base band processor with integrated flash memory , and rf front end ) chipset technology .
the module has the advantage of fast acquisition hardware , integrated rf filtering , and a tcxo .
the camera captures the image of the patient and surroundings ( in the case of an accident ) .
logitech / emprex camera with a resolution of 5 megapixels is connected using usb host 1 interface to the arm processor .
it provides the functionality of a single - chip camera and image processor in a small footprint package and outputs full - frame , subsampled , or windowed 8-bit/10-bit images . timing generator , analog signal processor ,
a / d converters , digital signal processor , output formatter , and serial camera control bus ( sccb ) interface are the main blocks present in the image sensor .
camera is controlled through the sccb interface and can provide up to 15 frames per second ( fps ) .
sccb provides a programming interface for all required image processing functions including image quality , formatting , and output data transfer that can be controlled .
vehicle parameter acquisition module is built around a low cost pic family microcontroller 18f452 with a multichannel 10-bit adc and usb interface for transferring the vehicle data to the microcontroller system .
wavecom make gsm / gprs/3 g modem is chosen for transmission of voice , data , and images .
this is connected to the arm board through rs 232 with a connection speedup to 19,200  bps .
in addition to the standard at commands , the module supports an extended set of at commands .
this facilitates tasks like reading , writing , deleting sms messages , and sending sms messages .  
kbd2 is a regular qwerty keyboard connected using usb host 3 to enter administrative and patient information data , mainly alphanumeric .
paramedic staff present in the ambulance can key in any data related to the patient including condition and particulars like his / her name , age , address , and so forth through the keyboard .
this message is transmitted to the central monitoring station ( cms ) for the medical advice from the doctors .
apart from sending patient information , the staff details like leave , present , or absent can be sent to cms to notify the authorities .
kbd1 , a 5x5 matrix keyboard , is used to initiate transmission of precanned messages like start of the ambulance from its base station , reaching the site of patient , start of ambulance after picking up the patient , and so forth .
fifteen such messages are provided presently , leaving the other 10 buttons for future expansion .  
physiological data acquisition system acquires the patient 's physiological data like ecg , respiration , and temperature through separate modules .
the outputs from these modules are connected to an lpc 1788 based data acquisition module through a 200 ksps , 16-bit resolution , and 8-channel adc ( linear technologies make ltc1867 ) .
they are processed in the system and are transferred to microprocessor based system which in turn transmits to cms for further processing and action initiation .  
an accident victim or patient in emergency or an attendant dials a toll free , predesignated number belonging to the central monitoring station being managed by an ngo .
the call is answered by the call center executive , who obtains details like the nature of emergency , assesses the help needed , and then transfers the call to a medical expert , emergency response care physician ( ercp ) in the call cenetr .
based on the information related to the location , an ambulance in the vicinity of the site is dispatched .
once the ambulance reaches the site , the emergency medical technician ( emt ) provides prehospital care to the victim at the scene .
he then connects the physiological data acquisition to the patient , which acquires required data from the victim and transfers the data ( including patient 's image , previous history , etc . ) to the call center ercp 's computer system , where the doctor is available .
these extracted parameters include ambulance position , patient 's physiological parameters , and patient 's image .
the precise position of the ambulance and its movement is also displayed on the monitor with the help of mapping software on pc at the cms .
because of this mapping interface the dispatch officer ( do ) at the cms has a chance to know the position of ambulance exactly and guide that ambulance to the accident location on receiving the accident call .
later this software helps the staff at the central monitoring station to guide the ambulance to the appropriate , nearest hospital .
emt is advised by the ercp , who assesses the patient with the available clinical information made available to him , regarding the care and drugs to be administered to the patient .
this is followed by the shifting of the emergency victim to the nearest and appropriate hospital .
the ambulance is equipped with a variety of medical equipment , medical consumables , and disposables to ensure the victim is stabilized ( prehospital care ) by the time the ambulance reaches the hospital for further treatment .
once the patient is handed over to the hospital , the ambulance returns to its predesignated base location and is ready for attending next emergency .
the individual modules of the developed system are tested separately for their independent satisfactory performance .
the power supply is tested for regulation , ripple , load regulation , and line regulation .
the required dc voltages are 5.01  v , 3.29  v , and 1.79  v with a ripple content less than 2  mv .  
the values are found to be 1000 , 0.03150  hz , and 100  db , respectively .
the temperature measurement is calibrated using a standard clinical thermometer and water bath for the temperature range 25c to 50c .
the respiratory module is tested for the impedance variation . as the respiratory activity results in a small change of transthoracic impedance
a voltage variation of 0.5  v is obtained for a resistance change of 0.1   for a base resistance of 1500  .   clock and reset circuits are tested using an oscilloscope .
adc is tested for a proper conversion by applying variable dc voltage to analog input pins of the board .
then , a sinusoidal waveform with a varying frequency ( 0.05  hz to 200  hz ) is applied and the values are again read and presented on pc screen .
the parameters monitored in this module are ignition status ( digital input ) , fuel level , and engine oil level ( analog inputs ) .
the analog voltages vary from 0 to 3.3  v for minimum to maximum levels .  
as the receiver output is available through serial interface , at 4.8  kbps , the module is tested for accuracy and update frequency by running hyperterminal program on pc .
gsm functionality is tested by making a voice call to another cell phone whereas gprs functionality is tested by connecting to a website on the net .
the patient details as required by the central monitoring station are entered using the qwerty keyboard and checked for successful transmission .
the programming interfaces are tested by connecting serial and usb cables between arm9 unit and a pc running flash magic and dnw software .
this is tested by pressing the keys on the matrix keyboard for successful transmission to the microcontroller arm9 unit and subsequent transmission to cms .
this is tested by transferring lcd test code from pc to arm9 board and running the program .
the communication between the ambulance unit and cms computer is tested using the developed diagnostic software .
an investigation using the developed physiological data acquisition module and gps receiver has been carried out to explore the possibility of relationship between physiological parameters and geographical location .
first location is the department of biomedical engineering , university college of engineering , osmania university and the second one is the rangapur observatory .
the recording is repeated three times for the same subject and the average value of these three recordings is considered .
three parameters , namely , heart rate , body temperature , and respiration rate are computed from these recordings .
the data are recorded from the subjects of different age groups ranging from nineteen years to fifty - nine years and the mean age is twenty - five years .
students and staff of the department of biomedical engineering , university college of engineering and navigational electronics research and training unit of the osmania university , volunteered to be subjects .
the base board pcb is designed and fabricated . the circuit is assembled and tested for its power supply functioning as per specifications .
h - jtag - dongle is connected to the j - tag connector on the core module and the other side to pc 's parallel port interface . using the software h flasher boot loader ( super vivi128 . ) is loaded into the nor flash .
the boot loader ( super vivi128 ) , kernel ( zimage_a70 ) , and file systems ( root_qutopia128  m ) are subsequently downloaded loaded into the 256  mb nand flash using dnw software . the application is developed using gnu gcc compiler .
application software , after thorough testing , is also downloaded into the nand flash . the use of the processor s3c2440 resulted in compact design of the system .
the software modules h - jtag flasher , dnw , and gnu gcc compilers are employed in the development of software . with user friendly software development tools , the development and change management at site are relatively simpler .
the system facilitated acquisition of gps data ( pvt ) , images , physiological signals , vehicle fuel tank level , keyboard entered administrative data , and sos messages .
the acquired signals are made in to a data packet and sent to a central monitoring station using gprs .
the data are stored locally , when there is connection loss to the internet and transferred as soon as the connection is restored .
the application code interacts with camera , data acquisition system , keyboards , gps receiver , and gsm / gprs modems through their respective drivers .
the developed ambulance electronics system with all peripherals ( figure 9 ) is installed inside an ambulance .  
the image of the surroundings as captured by the camera is also transmitted to the cms .  
it is clearly noted that heart rate increased at rangapur observatory compared to that at the department of bme .
the mean heart rate increased from 83 at the department of bme to 90 at rangapur observatory .
thus the percentage increase in heart rate between these two locations is 8 . out of the 46 subjects ,
the heart rate increased for 33 subjects and it decreased for 13 subjects ( figure 11 ) .
the maximum increase is 43 beats per minute and the minimum increase is 2 beats per minute ; while the maximum decrease is 32 beats per minute , the minimum decrease is 1 beat per minute .  
the increase in respiratory rate ranged from 114 breaths per minute while the decrease ranged from 113 breaths per minute .
as seen from figure 12 , there is no change in the mean value of respiratory rate between the two locations .
though the mean values of heart rate , respiration rate of female subjects are slightly higher than those of male subjects at both locations , the difference between male and female subjects is different at the two locations as shown in table 3 . there is no significant change in the body temperature between the two locations
the ambulance electronics system consisting of arm 9 microcontroller has been designed , fabricated , and tested .
the prototype has proved that it is possible to integrate and deploy an integrated medical data acquisition system , administrative data collection system , and communication system that is cost effective as well as life saving . an engineered model based on this prototype can be built and installed in the ambulances engaged for patient transportation .
engineered models , when installed in the ambulances , will enhance the capability of emergency patient transportation organizations in terms of reduction in time to reach the nearest hospital and extending timely prehospital medical care .
the features of the system can be enhanced to meet the requirements from time to time based on the experience gained while using the system .
there has been a significant change in the heart rate of the subjects between the two locations .
the changes in physiological parameters might be attributed to the difference in altitude ( about 150 meters ) between the two locations . as the data has been recorded from a small and healthy group of subjects , further work on a much larger database is required to establish the results obtained in this study regarding the effect of location on physiological parameters . hence to derive more useful conclusions , larger group of subjects , both normal and abnormal , with different age groups have to be studied .
diagnostically significant information could be extracted and the effect of location ( as obtained by gps receiver ) on physiological parameters could be identified more successfully .
the system developed here is a product of extensive need - based research projected by government and nongovernment organizations engaged in emergency patient transportation .
one can not employ systems from different manufacturers in the same project , as interoperability becomes difficult .
they do not provide the data that can be easily read by scientific software for further processing .
the system , as it provides data in text format , alleviates all such problems .
such a system will also avoid dependence on proprietary software to store and process the data .
 telemonitoring during the golden hour of patient transportation helps to improve medical care . 
 presently there are different physiological data acquisition and transmission systems using cellular network and radio communication links . 
 location monitoring systems and video transmission systems are also commercially available . 
 the emergency patient transportation systems uniquely require transmission of data pertaining to the patient , vehicle , time of the call , physiological signals ( like ecg , blood pressure , a body temperature , and blood oxygen saturation ) , location information , a snap shot of the patient , and voice . 
 these requirements are presently met by using separate communication systems for voice , physiological data , and location that result in a lot of inconvenience to the technicians , maintenance related issues , in addition to being expensive . 
 this paper presents design , development , and implementation of such a telemonitoring system for emergency patient transportation employing arm 9 processor module . 
 this system is found to be very useful for the emergency patient transportation being undertaken by organizations like the emergency management research institute ( emri ) . 
1. Introduction
2. Design Aspects of the System
3. Ambulance Electronics Unit
4. Testing and Evaluation/Validation
5. Data Acquisition
6. Results and Discussion
7. Conclusion