Ekahau Positioning Engine User Guide
Contents
1. 31 ACCURACY ANALYSIS Lens err eee TE GR IEEE TETTE PIGG EIG SITERT NTE EINE 32 CHAPTER 5 MAINTENANCE i aunnnnnnnnnnnnnnnnnnnnunnnnnsnnnnnnnnsnnsnnnnunnnnnnnnnnn 33 PERIODIC ACCURACY TEST vauuuununvnnnrnnennnnnnnnennnernnennnnnnnnnnunnnunnnnnnnnnunenunenn 33 DISASTER AND RECOVERY NG 33 POSITIONING MODEL MAINTENANCE 34 CHAPTER 6 CONFIGURING POSITIONING 35 WHEN TO CONFIGURE POSITIONING ENGINE MANAGER AND SDK 0005 35 TCP AND UDP PORTS USED 5 36 WORKING WITH CONFIGURATION FILES cccccesecuceeuceeeuueeuveeuveeuuueeuueeuvenuues 37 WORKING WITH POSITIONING 5 42 CHAPTER 7 INTRODUCTION TO EKAHAU SDK 43 CHAPTER 8 LICENSE UPGRADE ii nnnnnnnnnnnnnnnnnunnnnnnnnsnnsnnsnnsunnnnnnnnnnnn 44 HOW TO UPGRADE THE LIGENSE Lupen 44 APPENDIX A ACHIEVING BETTER ACCURACY s asssnnsnnnnnnnnnnnnnnnnnnnn 45 GENERAL ACCESS POINT 45 CALIBRATION FINE TUNING ACCURACY 51 Award Winning Positioning Concept The award winning concept of Ekahau Positioning Engine is to create a unique Positioning Mode2. 12 HOW TO START USING EKAHAU 12 LOADING AND CONFIGURING YOUR 14 PERFORMING SITE SURVEY WITH EKAHAU 15 DRAWING AND EDITING TRACKING 17 PERFORMING SITE CALIBRATION 19 USING REMOTE CALIBRATION CLIENT FOR HIGHER 21 MITIGATING ADAPTER DIFFERENCES WITH 5 22 DISPLAYING DEVICE LOCATIONS AND 23 DRAWING AND EDITING LOGICAL AREAS ccccccsceueeeueseeuueeuveeueeeueeneuueeunes 24 SELECTING CONTRIBUTING ACCESS POINTS cccccccccscevesuresueeteurssuvesuaueuunnens 24 SAVING AND LOADING POSITIONING 5 25 SHARING WORK BY MERGING 26 ANALYZING POSITIONING 27 CHAPTER 4 EKAHAU MANAGER 5 28 TL 28 LOCATION PROBABILITY aa a aa 30 EXPECTED POSITIONING ERROR
3. 4 After saving a Positioning Model to the Positioning Engine refer to Chapter 3 to see how to locate devices on map using Ekahau Manager Refer to the Developer Guide to find out how to use Ekahau SDK or YAXTM protocol to retrieve the location information to your application When to Configure Positioning Engine Manager and SDK In most cases the Positioning Engine default installation works well out of the box There are times however when you may need to configure some of the Positioning Engine properties For example you may need to configure Positioning Engine to use another TCP UDP port in case another application has already reserved the default port TCP and UDP Ports Used by Ekahau Products Type UDP UDP UDP TCP UDP The table below shows the TCP and UDP ports reserved for Ekahau Positioning Engine and accompanying products These ports should be opened from firewalls if they exist between Ekahau products Port 8545 8546 8547 8548 8549 NOTE Configuration entry Engine conf udp protocol port 2 Engine conf and manager conf deviceConnector clientUdpPort EkahauClientProtocol Manager conf udp protocol port EkahauClientProtocol Engine conf gatekeeper port Engine conf udp protocol port Description Ekahau Client software uses this port to send signal data to the Positioning Engine Ekahau Client listens to this port to reply to Posit
4. 5 Minimized interference noise High interference may decrease data throughput and positioning accuracy Noise can be minimized by proper channel configuration for example using 802 11b channels 1 4 8 and 11 for 4 adjacent Access Points to keep the channels as separated as possible Also try to minimize radio interference from other Wi Fi networks and radio sources 6 Strong but diversified AP signals Stronger AP signals provide better resolution and vary less than weaker signals This is why the best positioning accuracy is usually achieved closer to Access Points whereas areas with fewer and weaker signals provide lower accuracy Stronger is better but moving APs or using directional antennas to provide different RSSI for areas in close proximity will help differentiating the areas and improving accuracy 7 Site survey To ensure that your Access Point placement provides the maximum coverage perform a site survey with Ekahau Manager or Site Survey Refer to Chapter 3 of this guide 8 Quick positioning demos with Ekahau Manager laptop To quickly test positioning accuracy use dummy Access Points only Record a Positioning Model with Ekahau Manager and click the Ekahau icon in the upper right corner to display your laptop s location Walk around to test the accuracy If you need to move an Access Point after recording Positioning Model refer to Chapter 3 to disable the moved Access Points from the Pos
5. Ekahau Positioning Engine EPE 3 1 offers two ways for serving location information to local or remote applications Ekahau SDK Java API for Java developers Character based TCP protocol Ekahau YAX for any programming language that supports TCP sockets Both options utilize TCP sockets to connect to the Positioning Engine The SDK is just an easy to use Java front end for the YAX protocol After recording a Positioning Model and saving it in the Positioning Engine with Ekahau Manager use Ekahau SDK or YAX Protocol to read client coordinates Logical Areas speed heading and other information from Positioning Engine into your application For instructions on how to create location based applications with Ekahau SDK and YAX see the Developer Guide How to Upgrade the License The limited Evaluation version of EPE expires after 30 days To track up to hundreds of devices without restrictions contact Ekahau Sales to purchase your full license After purchasing your license you need to upgrade each Manager Positioning Engine and SDK installation separately To upgrade Ekahau Manager click Start gt Programs gt Ekahau gt Manager 3 1 gt License Upgrade You may alternatively click Help gt About gt Upgrade License if you are already running Ekahau Manager Browse for the license zip file and click OK The About window should now display full license information To upgrade the Positioning Engine select Start
6. you should observe the most important positioning attributes Number of detected Access Point signals at each location Accurate positioning requires at least 3 preferably 5 10 Signal strength RSSI of each AP signal Stronger is better in general however adjusting APs or using directional antennas to provide different RSSI for different areas may help differentiating the areas and improving accuracy Noise level available separately in Ekahau Site Survey Significant radio noise will decrease positioning accuracy Avoid noise with standard channel planning see Chapter 1 Performing site survey for positioning use with Ekahau Manager i Display signal strength information in the bottom view by selecting View gt Signal Strengths Take your laptop with you and walk around the area while observing the number of detected signals and their signal strengths RSSI in Ekahau Manager If necessary move existing or add dummy Access Points to have at least 3 preferably 4 or more Access Point signals blue bars available in each location Once you have at least 3 Access Point signals everywhere open a map and draw Tracking Rails as described later in this chapter 4 Take your laptop with you and walk again around the area stopping on the nearest tracking rail 5 10m 15 30 ft and clicking the rail with calibration tool selected This will associate received Access Point signals with your physical location on
7. 5 meter 15 ft average accuracy Increasing the number of AP signals increases accuracy The preferred number of signals per location is 5 10 2 Install dummy Access Points for additional signals To increase the number of AP signals per location you may install additional dummy Access Points without network connection Just power up the dummies Channel configuration is not very important as the dummies are not sending data and will not interference with data networks 3 Disable automatic power management features Disable optional power management and self healing features for reliable positioning results Enable SSID broadcasting probe responses to locate Wi Fi adapters that do not support passive scanning 4 Access point placement tips Start from the corners of the intended coverage area With 3 Access Points the test area size can be for example 20x20 m obstructed 40x40 m open If the area has low height obstructions such as office cubicles attach the Access Points using indoor antennas to ceilings or walls above the height of the obstructions Do not place the Access Points or antennas in straight lines or near one another less than 5 meters Use adhesive tape to secure the antennas for a site survey and testing before installing them permanently Depending on the desired coverage area refer to your Access Point manual to adjust the output power levels Directional antennas are recommended
8. the map 5 After covering most of the important areas click Ekahau Manager s Visualization Tab and select Signal Strength view This allows you to observe the 5 strongest Access Point signals at each location typically helping network planning At least the 3 strongest signals should provide average or strong signal strength for good accuracy For complete visualization instructions see Chapter 4 Ekahau Manager with Signal Strength RSSI display s ekahau at 7 4 as 4 at se 4B ra U tere EE TT ae bers MOTER eve Us Gen VO OE EE ee Drawing and Editing Tracking Rails Before recording data for the Positioning Model Tracking Rails must be placed on the map to indicate possible travel paths between rooms corridors floors and other locations The rails are quick to draw and provide improved positioning accuracy 1 2 Activate Rail tool by clicking its icon g Place the mouse pointer in the center of a walking path room or corridor and click the map once to create a starting point Move the pointer as far as you can on the path without crossing any wall or other obstruction Click the map again to create a curve point and continue drawing all essential paths in the area To end the current rail click the right mouse button To continue click the left mouse button NOTE You do not need to work on site while drawing the rails unless you want to observe the ar
9. to connect the polygon ends and quit drawing Right click the area in Browser View to name the area or to define custom properties for the area available for application developers via Ekahau Java SDK or YAX protocol The most probable Logical Area is displayed for each client device in the Devices Tab when the Tracking checkbox is selected for the device Logical area information can also be read from the Positioning Engine by using Ekahau SDK or YAX NOTE Make sure that you place at least one Tracking Rail and record at least one sample point inside each Logical Area the shape of the area does not affect finding it accurately but the sample points inside the area do Selecting Contributing Access Points All detected Access Points do not necessarily belong to the network under your control For example another company nearby may begin to use Wi Fi Access Points that can be observed with Ekahau Manager This causes problems if you use all detected Access Points for calibration and your neighbors change their AP locations l Prevent unwanted or unreliable Access Points from being used for positioning by de selecting them in Access Point View below the Browser View and clicking Apply Clicking Reset will undo any changes that were made before clicking Apply 2 When changing your Wi Fi network de select from your Positioning Model any Access Points that have been physically moved or uninstalled and save it back to Po
10. 5 Figure 5 Significant signal variance within an area requires multiple sample points Having more than one sample point per area may slightly increase response times One should always avoid recording sample points near shared edges of neighbouring areas Figure 6 Figure 6 Avoid recording sample points near edges of adjacent areas Fine Tuning Accuracy Errors are caused by random fluctuations in radio signals due to reflections and environmental changes causing random errors or by two or more similar sample points recorded in distinct locations causing constant errors RSSI values can also vary depending on antenna sensitivity in client devices Ekahau Manager provides a tool for statistical accuracy analysis By performing several accuracy analysis tests it is possible to identify areas where Positioning Engine fails to locate devices systematically Random Errors Random errors are caused by constant changes in radio signals Due to the nature of high frequency radio signals and limited RSSI resolution in Wi Fi devices it is very difficult to eliminate random errors completely One should concentrate on placing APs and antennas in places where random environmental changes have minimal effect Constant Errors Constant errors are usually caused by excessive correlation between two or more sample points In this scenario it may not be possible for the positioning engine to estimate an exact locati
11. Access points should be placed in corners preferably in a way which minimizes random fluctuations in signal strength caused by people moving around opening closing doors or large objects which may be moved during operation In addition one should try to avoid the above scenario Figure 1 by covering open areas with more than two Access Points Please note that walls and large objects help creating unique signal Access Point combinations and therefore may enhance the resolution Directional antennas are recommended if application requires good resolution in open areas Figures 2 and 3 Figures 2 and 3 Omni directional and directional antennas Although Ekahau s probabilistic positioning framework can estimate device s location even based on RSSI for one Access Point it is recommended that at least three overlapping Access Points were used throughout the positioning area In relatively open areas less than three overlapping channels may lead to degraded location resolution two or more sample points have very similar Access Point signal strength combinations More overlapping Access Points provide better resolution although overall accuracy will not increase significantly after exceeding six overlapping Access Points Adding Access Points Due to the nature of high frequency radio signals 2 4 GHz and limited signal strength resolution in 802 11 devices the positioning resolution and stability tends to be better near Acc
12. Description master address 127 0 0 1 Positioning Engine s address master port 8548 Positioning Engine s port This must be same as engine conf file s gatekeeper port Working with Positioning Engine Log Files Positioning Engine logging can be configured by modifying log4j properties file in conf folder under the Positioning Engine installation folder The log files are by default stored in the log folder under the installation folder To change the default folder edit this line log4j appender file File log Ekahau logfilesuffix 1log For example if you want the log files to be stored under c log directory the line should look like this log4j appender file File c log EkahauS logfilesuffix log Other important logging parameters are the maximum file size and maximum backup index The maximum file size means that when the log file has reached a certain size it will be backed up to another file and a new log file is created The maximum backup index is the maximum amount of the backup log files When this number is reached the oldest file is deleted and replaced with the second oldest In the example below we have changed the maximum file size to 2 MB and backup index to 7 log4j appender file MaxFileSize 2048KB log4j appender file MaxBackupIndex 7 If you decide not to include general INFO level messages in your logs at all change the level to WARN ERROR or FATAL as follows log4j rootLogger FATAL file
13. Save to Positioning Engine 2 IMPORTANT instruct your team to open the Positioning Model from the same Positioning Engine before adding maps or making any changes in their local copies Merging will not work unless all team members open the model from the same Engine 3 After opening the Positioning Model add the new 5 that were designated to your responsibility and go calibrate the areas It is recommended to save local backups while you proceed Select File gt Save As to save the model as a local backup 4 When ateam member has calibrated his designated area ask him to select File gt Merge from Positioning Engine This will merge the current Positioning Model in the Engine to the local model in Manager Nothing is changed in Positioning Engine s database or saved at this point You should now see your changes with everything the others may have saved in the Engine 5 The merge function will add any new maps rails sample points and Logical Areas into your Positioning Model in Ekahau Manager If the same item s exist in the Engine and your local Manager model during the merge operation your local changes will not be changed 6 After seeing that the merging was successful click File gt Save to Positioning Engine to save the merged model now including your changes in the Positioning Engine 7 Add map links between new adjacent maps or floors 8 Repeat steps 4 7 with each team member and click F
14. caused by some drivers use only one SSID for the dummies as well In addition it is recommended to use a different channel for the dummies this is a security measure even though the dummies are only used for transferring beacons and probes In addition the Wireless Zero Configuration option found in recent Windows versions is recommended to be disabled to remove automatic roaming to unwanted networks Calibration The purpose of Site Calibration is to map physical locations bitmap coordinates of a floor plan with signal strength values from APs which are audible at the given location Each sample point recorded with Ekahau Manager contains RSSI values for approximately twenty Access Point scans Site calibration data is fitted to a probabilistic positioning framework in Ekahau Positioning Engine The number and density of sample points depends on the application requirements If the application only uses area level information one sample point per are area might be enough If application requires more accurate location information sample points should cover the whole area Positioning Engine is able to interpolate location estimates between sample points but not outside the boundaries of sample points coverage The calibration device or external antenna should be held like it most likely will be while the device is being tracked If device s receiving antenna is blocked or covered during actual operation calibration has t
15. cess Points any 802 11a b g model Map or floor plan of the area in PNG JPG or BMP format Ekahau Positioning Engine Concept Standard 802 11 a b g and System Wi Fi Network Ekahau Manager Positioning Model creation Com ponen ts Ri maintenance analysis and live tracking on floor map 3rd Party RTLS Applications Ekahau Client Ekahau Positioning Ekahau Application Engine Suite Runs on Windows XP 2000 Award winning patented po Utilize the real time location PDAs and Ekahau Wi Fi Tag sitioning server for x y speed information with ready heading area etc examples tools and Ekahau ad SDK Installing Ekahau Positioning Engine 1 Double click Install Engine win32 exe In case of CD installation place the CD in the drive If the installation does not start automatically double click Install Engine win32 exe on the CD Follow the on screen instructions and select the components you wish to install on the target computer typically Full Install Installing Ekahau Client To locate a wireless PC or PDA you need to install the Ekahau Client service on the device and keep the Client running 1 Fully install a supported Wi Fi adapter on the device See http www ekahau com devices for supported adapters In case of Windows 2000 Windows XP Professional or Windows 2003 Server computer use the Positioning Engine installer or CD as described above but only install Ekahau Client and the inclu
16. client while ECLIENT means PC PDA with Ekahau Client software Devices which belong to this group are removed from the device list after a certain timeout Use 5 m or h postfix devices sweeper run interval deviceConnector engineName deviceConnector serverUdpPort deviceConnector clientUdpPort deviceConnector queryl nterval YAX devices 10 5 DNS name leave in comments 8545 8546 10000 ms For example 20h means 20 hours Ekahau Clients PC PDA have a small timeout because their own timeouts are checked before they end up here See deviceConnector deviceList CleanupMaxI dleTime YAX devices Wi Fi Tags are not removed before their socket connection is closed These parameters only affect devices without a new socket connection during the timeout period The former remove after parameters are checked devices removed between intervals configured here You can set a custom Positioning Engine name here Maximum length is 128 characters Positioning Engine UDP port used for receiving data from client devices Positioning Engine UDP port used for sending data to client devices Client query interval in milliseconds Positioning Engine sends AreYouAlive UDP queries to queryAddress deviceConnector queryAddress deviceConnector deviceList CleanupSweepI nterval deviceConnector deviceList CleanupMaxI dleTime database db technologies XX and devicel dentity XX errorCodeT
17. configuration file s in production use These files are located in Ekahau Positioning installation folders EPE3 1 conf and EPE3 1 db If Positioning Engine server data is lost due to hardware failure install Positioning Engine after recovering file and operating systems 1 Stop Ekahau Engine 3 1 service through Start gt Control Panel gt Administrative Tools gt Services 2 Copy backup copies of conf and db folders replacing all files created by the installer 3 Start Ekahau Engine 3 1 service Positioning Model Maintenance Methods In case of decreased average positioning accuracy there are three correction methods Before starting back up the existing Positioning Model by saving it in a file under a different filename 1 Record more sample points Record more sample points in the areas with decreased accuracy and save the Positioning Model in the Positioning Engine This is typically the fastest and easiest solution if the average accuracy has decreased by less than 20 Note that recording more sample points will not increase accuracy if the Access Point or antenna locations have been changed see option 2 below 2 Recalibrate problematic areas If adding new sample points did not help or the average accuracy has decreased by less than 30 delete the existing sample points by selecting the Edit tool and drawing a rectangle over the problematic area then right clicking a sample point and selecting Delete Sampl
18. d button Select lt custom settings gt from the drop down listbox fill in or modify the Positioning Engine details and click OK Ekahau Client Ekahau Client Properties Properties dial Status Settings Engines GPS i ae Recently discovered Engines displaying the Name Positioning SHACKLETON amundsen Engines Tab Fre h a MW Accept by default Engines with saved settings Name Accept Add How to Start Using Ekahau Manager 1 Double click the Ekahau Manager shortcut 2 When Ekahau Manager starts you are asked to provide the IP address and password of the Positioning Engine If you installed the Positioning Engine on the same computer click OK to use the local Positioning Engine and default password Otherwise enter the correct name or IP address of the computer that runs the Positioning Engine and click OK Use empty value for password unless you have manually configured Positioning Engine to use special password Positioning Engine Login in Positioning Engine Login E Ekahau Manager Address localhost startup i Pass yyorcd If You installed Postitioning Engine on this computer click OK Otherwise enter the correct name or IP address of the computer that runs the Positioning Engine Use default password Llama unless you have configured Positioning Engine to use special password 3 After Ekahau Manager has starte
19. d you can create a new Positioning Model or open an existing Positioning Model either from a file or the Positioning Engine database Select New Positioning Model and click OK Ekahau Manager Startup options Positioning Model Ekahau Manager Startup Ey Mew Positioning Model I Browse 8 Open from file idean test edb O Open from Positioning Engine E Dont show this dialog again NOTE When opening a saved Positioning Model from the Positioning Engine make sure that the Positioning Engine is running 4 Select View gt Signal Strengths You should see blue bars indicating signal strength RSSI values from active Access Points You may also see gray bars indicating the last signal strengths of Access Points which are no longer detected 5 Ifyou do not see any RSSI bars ensure that your Wi Fi adapter and driver version are supported see Chapter 1 for details Update the driver if necessary and restart the computer If you still experience problems contact support ekahau com 6 Ifyou want to change the unit system between Metric and Imperial select File gt Preferences Loading and Configuring Your Map You need map image for creating the Positioning Model Supported map formats are PNG JPG and BMP 1 Use Measure tool for To import a map select New Map from the File menu Alternatively you can right click the Maps folder in the left window and select New Map f
20. ded Wi Fi drivers In case of PDA installation Pocket PC first install Ekahau Client completely on a PC and synchronize your PDA with Microsoft ActiveSync to install the Pocket PC version of Ekahau Client Accessing Ekahau Technical Support If you encounter problems while evaluating Ekahau software or if you have improvement ideas contact support ekahau com The Ekahau technical support will respond within 24 hours on business days Monday through Friday Please include the following information in your e mail Detailed description of the problem Log files from Engine Manager and Ekahau Client Operating system in use Amount of physical memory RAM and processor type Wi Fi adapter manufacturer model and driver version Access point manufacturer and models Ekahau technical support is free during the evaluation and for 30 days after purchasing a commercial license After this initial period a support package is required for further support and software updates Support packages can be purchased from Ekahau An old driver version of a Wi Fi adapter is the most common reason for not receiving signal data from Ekahau Client Please update your Wi Fi adapter driver after installing the adapter 1 Insert your Wi Fi adapter to the PC card slot and refer to its user manual to properly install the included drivers and utilities 2 After installing the Wi Fi adapter driver open any adapter utility or diagnostics tool to disp
21. del you can easily locate client devices by using Ekahau Manager s internal positioning test feature 1 To locate the Ekahau Manager laptop click the Ekahau icon in the upper right corner 2 locate any other device select Devices tab in the bottom view 3 Click the Tracking checkbox for each device on the list to test tracking in Ekahau Manager Make sure Ekahau Client software is installed and running on each PC or PDA to be located Only devices running Ekahau Client will appear on the device list 4 Right click on a device and select from context menu Properties to display many device properties such as MAC Show RSSI to display the device specific signal strengths Follow to automatically keep the device in map display Device Properties dialog for a tracked device NOTE The device list is retrieved from the Engine This is why the Engine must be running to let Ekahau Manager display the device list Ekahau Manager however uses its local model and location test feature for locating the devices Drawing and Editing Logical Areas Logical areas are user drawn areas polygons that can have a name and other location based properties Logical areas are used to determine whether a client device is within a given area 1 2 Activate the Logical Area tool by clicking the icon nn Click the map move the mouse and click again until you have drawn the desired area Double click or right click
22. e Point s Record new sample points in the deleted areas and save the Positioning Model in the Positioning Engine This method is very helpful if the area has changed only partially and neighboring areas do not need to be recalibrated 3 Recalibrate the entire positioning site If adding new sample points did not help or the average positioning accuracy has decreased by more than 50 create a new Positioning Model recalibrate the entire site and save the Positioning Model to the Positioning Engine This method is required if positioning accuracy has decreased due to structural or other major changes in the environment Ekahau Positioning Engine runs as WindowsQ NT Service All you need to do is keep the service running thus allowing Ekahau Manager to save Positioning Models in the Positioning Engine and location based applications to query client location coordinates and other information from the Positioning Engine 1 Ekahau Positioning Engine service starts automatically during the Windows startup 2 If you need to manually start or stop the Positioning Engine service on Windows 2000 Windows XP Professional or Windows 2003 Server click Start gt Control Panel gt Administrative Tools gt Services 3 save Positioning Model in the Positioning Engine select File gt Save to Positioning Engine in Ekahau Manager It takes about 10 seconds after saving to initialize and start using the new Positioning Model
23. e ekahau Ekahau ts Positioning Engine 3 Guide Contents GETTING STARTED nede 1 AWARD WINNING POSITIONING 1 POSITIONING ENGINE 5 1 EVALUATION SETUP REQUIREMENTS cccscccesccesuccncurseuresceusuueneureuuressannuursens 2 PRODUCTION SETUP REQUIREMENTS ccccceecesecseeueeeuveeueeeuueteuueeuveeueeneuenens 3 INSTALLING EKAHAU POSITIONING 4 INSTALLING EKAHAU CUHENT aed 4 ACCESSING EKAHAU TECHNICAL SUPPORT ccccsscuuscevesurscucvsaurseeresuuesuansaursens 5 CHAPTER 1 WI FI HARDWARE 6 SUPPORTED WI FI ADAPTERS 6 ACCESS POINT AND POSITIONING ACCURACY 5 7 CHAPTER 2 EKAHAU CLIENT 9 USING EKAHAU 9 CONTROLLING EKAHAU 5 11 CHAPTER 3 EKAHAU MANAGER
24. e map link s end point Continue the rail normally from the end point NOTE The location estimates depend much on the rails that you place on maps Be careful in marking only the correct paths that are accessible and used by the tracked devices Example of how to place ET Trackin TO FF TT 4 pe 9 Re Sif I a a J m at som Rails in i m DN T OF office 7 gt 1 Eg UGE OW environment Performing Site Calibration By placing Tracking Rails on the map you have successfully created an empty Positioning Model However before you can use the Positioning Model for locating devices it needs to be calibrated i e you need to record Wi Fi signal data from various map locations NOTE For the best tracking accuracy use only supported adapters for Site Calibration and tracking Ekahau also recommends using similar devices for creating the Positioning Model and tracking Please see the next headings for details 1 Take the Manager laptop with you and walk to a nearby Tracking Rail making sure that you are standing on it OE EE 2 Activate the Calibration tool by clicking its icon Move the mouse pointer to your current location on the rail and click the map to record a sample point SP Do not move away from your current location until the record dialog disappears in 10 20 s While you remain in your current location turn around slowly a full 360 to record th
25. e signals from all directions NOTE Turning around is important to collect signals from all directions without your body affecting the readings Walk about 3 5 meters along the rail and repeat Step 3 until you have calibrated the entire area Please follow the recommended sample point recording principles for maximum positioning accuracy Record a SP every 3 5 meters Record a SP in all Tracking Rail intersections Record a SP in all Tracking Rail ends Record a SP in all locations where the radio environment suddenly changes For example record one SP from both sides of a door typically from a room and corridor In case of open areas draw a grid of Tracking Rails and record a SP in the corners of each square To reach high accuracy draw and calibrate at least 5x5 3x3 meter grid To remove sample points select Edit gt Undo or alternatively select the Edit tool H right click the unwanted sample point and select Delete Sample Point from the context or Edit menu To save the calibrated Positioning Model in the Positioning Engine select File gt Save to Positioning Engine Type a filename and click OK If the Positioning Engine is not running or cannot be connected you will receive an error message Using Remote Calibration Client for Higher Accuracy For the best tracking accuracy Ekahau recommends using similar devices for creating Positioning Model and tracking For example to locate Ekahau Wi Fi Tags or certai
26. ea when placing the rails To select a rail or a curve point activate the Edit tool and click the desired rail or curve point You can select several objects by holding down the left mouse button To move a rail press down the left mouse button and drag the rail to another location To delete a rail select it and select Edit gt Delete or right click the rail and select Delete from the context menu To continue on an existing rail or to create junctions place the pointer on an existing rail or curve point and left click once To draw rectangular rails that are always in a 45 angle hold down the Shift key and left click once 8 connect two adjacent maps or floors draw rail curve point for example in front of an elevator door or staircase but do not end the rail Select another map by clicking it in the Browser View When you move the mouse pointer back on the other map you will notice a round map link icon with a thumbnail map of the starting point Move the cursor in front of the other floor s elevator doors and click the map to create a two way tracking rail between the two floors or adjacent maps 1 Starting point of a map link in front of an elevator Do not end the tracking rail but select another map 2 Select another map another floor or adjacent map by clicking it in the Browser View Move the mouse pointer back on map to see a thumbnail of the first map 3 Click the correct location to place th
27. edge length of the visualization Use coarser setting when you do not have much sample points but want to display as wide coverage as possible Use finer level when you have more sample points and need more accurate visualization NOTE The visualization settings such as the grid size do not affect positioning in any way Signal Strength displays the coverage area of all enabled Access Points in the Positioning Model Leger ne Anatom PE digest tirana fee Tee GE By switching the view between different Access Points areas with poor network coverage can be spotted Displaying the accuracy analysis error vectors on the coverage areas provides insight to network planning problems that might cause decreased accuracy For example poor network coverage typically correlates with decreased positioning accuracy in the area To solve the problem change Access Point locations or antenna directions or add more Access Points in the problematic area Location Probability 1 Select the Visualization tab from the bottom view 2 Select the Location Probability view 3 Optionally select Positioning Mode NOTE Make sure you have selected only one device from the Devices Tab Selecting multiple devices will cause imprecise results Location probability displays the probability for a single device to be located wit
28. espective coverage in a simplified way Actual signal propagation is a very complex issue due to environmental factors like reflecting and absorbing materials walls furniture people or large moving object etc Symmetric Coverage Ekahau s positioning framework is based on the fact that the received signal strength indicator values RSSI for surrounding Access Points in a Wi Fi client device vary with respect to the physical location where the measurement is done As the result of Site Calibration process positioning framework is initialized with a site specific set of calibration data Each sample point contains a set of RSSI values for each Wi Fi Access Point which has responded to client s scan requests at the given location Every sample point should be somewhat different If two sample points that have not been recorded in immediate vicinity of each other contain similar data RSSI values and Access Points match the probabilistic framework will have to compromise between these two points which can lead to positioning error Therefore to eliminate the possibility of having two or more identical sample points combined coverage areas for all Access Points should not be symmetric In Figure 1 below sample points in top left and bottom right corners would presumably be similar Figure 1 Symmetric coverage two omni directional antennas are located in opposite corners or an open space Asymmetric Coverage
29. ess Points Ekahau recommends placing an Access Point in each area where high resolution is required It may also be possible to re arrange the existing APs in way which increases resolution in significant areas If APs or antennas are moved after calibration their coverage areas have to be recalibrated All sample points which are within original and new coverage area of the moved Access Point s have to be selected deleted and recorded again Sometimes removing Access Points from Positioning Model may improve accuracy After calibration Ekahau Manager allows user to see coverage area contours for each Access Point from which calibration device has received signals If Access Point s coverage looks flat or if it has more than one peak it probably degrades accuracy several distant sample points have similar signal values In addition APs which are administered by outside parties should not be used since location antenna placement or transmit power may be changed without notice The Accuracy Analysis tool can also be used to select the optimal Access Point combination Adding Dummy Access Points The APs used only to improve positioning accuracy do not have to be connected to the backbone network as long as the client devices are able to communicate with the Positioning Engine When placing these so called dummy APs make sure they do not share the same SSID as the AP s that are used for transferring data To avoid confusion
30. gt Programs gt Ekahau gt Engine 3 1 gt License Upgrade Browse for the license zip file and click OK The Positioning Engine license is now upgraded To upgrade Ekahau SDK select Start gt Programs gt Ekahau gt SDK 3 1 gt License Upgrade Browse for the license zip file and click OK The SDK license is now upgraded General This Appendix provides information and guidelines for increasing positioning resolution using Ekahau Positioning Engine Ekahau s positioning technology is based on probabilistic positioning framework which utilizes the latest advances in decision theory probabilistic modeling and information theory Access Point Placement chapter describes advantages and disadvantages of various network topologies in respect to potential positioning resolution Calibration Chapter examines this issue further from application s requirement perspective The last chapter describes methods for improving resolution once the hardware infrastructure is in place Access Point Placement Access point density and antenna placement orientation are the most important factors regarding overall positioning resolution To achieve repeatable and consistent positioning resolution Access Points should be placed to provide unique signal strength and Access Point combination for each significant location Every site is unique in terms of actual network coverage this section merely describes Access Point antenna placement and r
31. hin the grid Square Pee ms He ri a Faker byen Wadi cers Positioning Mode Description Accurate Displays the probability for a single device to be located within the grid square using device history of around 5 seconds location update interval x 2 5 s Real Time Same as above with 1 s device location history No History Same as above without device location history This view is similar to the Expected Error Expected Positioning Error 1 Select the Visualization tab from the bottom view 2 Select the Expected Positioning Error view The Expected Error view is not using devices history information meaning that the accuracy is typically lower than in reality The Engine utilizes location history by default for higher accuracy Expected Error displays the estimated location error at each location without using device s location history 31 Accuracy Analysis 1 Select the Visualization tab from the bottom view 2 Select the Accuracy Analysis view Accuracy Analysis view displays the recorded statistical average positioning error in colors for each location You must have at least one analysis case visible and calculated to display the visualization Click the Accuracy Analysis tab right click the analysis case and select Update from the context menu after opening an existing model from a file or Positioning Engine Accuracy analysis displays the recorded ave
32. ile gt Save to Positioning Engine Analyzing Positioning Accuracy 1 statistically analyze positioning accuracy select the Analysis tool by clicking its icon Cu Open the map where you are located inside the calibrated area Start walking at a constant restful speed across the areas that you wish to include in the accuracy analysis Stay inside the calibrated area and always click the map in your current location when changing your direction or speed Right click the map to end the analysis and display the error vectors in the Map View and statistical analysis on Accuracy Analysis Tab Each arrow on the map describes the difference between the actual clicked location and a calculated estimate constructed from the signal data in the open Positioning Model recorded for the same clicked location Right click the accuracy analysis to access its context menu You can rename or delete the analysis update the analysis to visualize it after opening an existing model or after you have changed Positioning Options display error charts or export the analysis data as a text file Should the average error be worse than 5m the likely reason is an insufficient number of available AP signals suboptimal placement of Access Points or antennas or too high radio interference Please see Appendix A to modify Access Point or antenna locations so that at least 3 AP signals can be detected throughout the positioning area a
33. ioning Engine broadcasts to find all Ekahau Clients in a subnet and for positioning requests Ekahau Clients use this port to send signal data to Ekahau Manager Java SDK YAX Wi Fi Tags Applications and Manager use this port to connect to the Positioning Engine Ekahau Wi Fi Tags use this port to send signal data to the Positioning Engine When using Ekahau Client with Network Address Translation NAT the implementation needs to support 1 1 translation Address translations between many to one are not supported Working with Configuration Files Positioning Engine Ekahau Manager and Java SDK can be configured by modifying the engine conf and manager conf files with a text editor The configuration files are located in the conf directories under the Positioning Engine Manager and SDK installation folders Save a backup copy of the original file before making changes and remember to restart Positioning Engine Ekahau Manager or SDK application to apply the new settings The Positioning Engine and Manager Configuration files are in hierarchical XML format For example Ekahau Client s UDP port setting is defined in hierarchy conf gt deviceConnector gt clientUdpPort You can see what the hierarchy looks like in the engine conf sample below If a configuration file does not exist or contains incorrect values the system default values are automatically applied If you modify the UDP communication settings betwee
34. itioning Model or re calibrate the affected area Using Ekahau Client Ekahau Client allows Ekahau Manager to retrieve signal data for Site Calibration typically from a Wi Fi adapter installed on a local computer and allows the Positioning Engine to retrieve signal data from client devices for positioning This is why Ekahau Client must be installed and running on the Ekahau Manager laptop and on each client device that is to be tracked The Windows 2000 Windows XP Professional and Windows 2003 Server version of Ekahau Client provides Ekahau Client Controller Properties dialog that can be used for Viewing the Client status Starting and stopping the Ekahau Client service Configuring the allowed or restricted Positioning Engines Enabling or disabling the writing of an Ekahau Client log file To access Ekahau Client Properties dialog click the Ekahau icon Se in Windows system tray If the icon is not displayed start the Client Controller by selecting Start gt Programs gt Ekahau gt Client gt Ekahau Client Controller If you need to view start or stop Windows services manually click Start gt Control Panel gt Administrative Tools gt Services NOTE Red Client icon 2 on system tray means the Client service is not running A yellow exclamation mark n means an error Click the icon to view error status Ekahau Client Ekahau Client Properties RE Status Settings Engines GPS dialog s
35. l EPE components on a light laptop PC You will need the following items for the evaluation setup Light laptop PC with at least Windows 2000 Windows XP Professional or Windows 2003 Server 1 GHz processor 512 MB RAM and 200 MB HD space Ekahau Positioning Engine Full Install A supported Wi Fi adapter and driver see http www ekahau com devices for supported versions At least 3 standard Wi Fi Access Points any 802 11a b g models The positioning area should have at least 3 preferably 5 or more Access Point signals at each location Map or floor plan of the area in PNG JPG or BMP format NOTE Please see the Positioning Engine Quick Guide to locate your own laptop using Ekahau Manager Production Setup Requirements For production use install the Positioning Engine on a dedicated server and use a laptop PC for the Manager application Install Positioning Engine on a server with at least Windows 2000 Windows XP Professional or Windows 2003 Server 1 GHz processor 1 GB RAM and 200 MB HD space Install Ekahau Manager and Ekahau Client on a light laptop PC with at least Windows 2000 Windows XP Professional or Windows 2003 Server Pentium III 512 MB RAM 200 MB HD Install Ekahau Client on all tracked PC or PDA devices with at least Windows Pocket PC 2002 or 2003 Supported Wi Fi adapters for the Ekahau Manager laptop PC and each client device to be tracked At least 3 Wi Fi Ac
36. l for the positioning site such as a hospital office or warehouse by recording Wi Fi network signals from various locations This patented process is called Ekahau Site Calibration and it provides significantly higher positioning accuracy than any other method such as predicted signal propagation or triangulation that does not consider the actual radio environment Positioning Engine Components Component Ekahau Positioning Engine Ekahau SDK Ekahau Manager Ekahau Client Description Java based server that calculates and provides the Wi Fi device locations via Ekahau API Ekahau APIs include the SDK J ava package Javadoc and code examples for reading location information Programmers using other than Java language can alternatively use the Ekahau YAX protocol to read the location information via TCP socket Application for creating Positioning Models Saving them in the Positioning Engine drawing Logical Areas testing live positioning and analyzing accuracy Ekahau Client must be installed and running on each PC or PDA that is to be tracked Also required by Ekahau Manager Supported Platforms Windows 2000 XP Professional and 2003 Server Windows 2000 XP Professional and 2003 Server Windows 2000 XP Professional and 2003 Server requires a laptop Windows XP 2000 Pocket PC 2002 and 2003 Evaluation Setup Requirements For quick evaluation install al
37. lay the driver version 3 If the driver version number is lower than the one supported you need to update the driver For update instructions see Start gt Programs gt Ekahau gt Drivers gt Readme 4 After installation open any adapter utility or diagnostics tool to confirm that the driver was updated properly If you have trouble updating the driver please refer to the adapter and driver documentation before contacting Ekahau support Supported Wi Fi Adapters Ekahau Client and Positioning Engine have been tested on Windows 2000 Windows XP Professional and Windows 2003 Server with more than 40 leading Wi Fi adapters drivers and PDA devices from Agere Avaya Buffalo Cisco D Link Enterasys IBM Nortel Networks Proxim and other manufacturers Click Start gt Programs gt Ekahau gt Client gt Device Support or visit http www ekahau com devices for the latest list of supported Wi Fi adapters drivers and devices If you find out that an untested adapter works please send its model and driver version to support ekahau com Access Point and Positioning Accuracy Guidelines Ekahau Positioning Engine supports all 802 11a b g Wi Fi Access Points Follow these steps for good positioning results 1 Provide at least 3 Access Point signals at each location EPE can locate a device with only one AP signal buta minimum of 3 signals must be detected by the client device in each location for better than
38. le using the Tag s belt clip 7 Take your laptop and perform the Site Calibration record data for your Positioning Model as described in the previous sections Mitigating Adapter Differences with Adapter Models Wi Fi adapter manufacturers use different radio hardware and software in Wi Fi adapters Even individual adapters from same manufacturer typically have slightly incompatible scales for observing the RSSI values This can cause positioning inaccuracy if the calibration and tracking steps are performed using different Wi Fi adapters The positioning inaccuracy caused by different adapter scales is typically 1 5 meters 3 15 ft depending on the adapter without using any mitigation technology Ekahau s patented technology minimizes the positioning inaccuracy caused by RSSI measurement differences Ekahau Client and Manager use method called Ekahau Adapter Models to automatically apply the correct adapter model to mitigate the differences The card models can be found from functions cfg under Ekahau Manager s conf directory NOTE In case of low accuracy for a specific device open the Devices tab right click on the problematic device and select Properties from its context menu Make sure the device s Wi Fi adapter and driver are supported The conversion function for the specific technology should display OK Displaying Device Locations and Properties After drawing Tracking Rails and calibrating the Positioning Mo
39. n Ekahau Manager Positioning Engine and Ekahau Client in the configuration files you will also have to change those accordingly in Ekahau Client engine conf and manager conf files can be found under the conf folders in the Positioning Engine installation directory NOTE Always save a backup copy of the configuration files before making changes and remember to restart Positioning Engine after making the changes The following attributes can be changed or added in the Positioning Engine configuration file The XML hierarchy is described with dots Name authentication password gatekeeper port tag udp port gatekeeper timeout devices default remove after devices groups group name devices groups group remove after Default Llama 8548 8549 10000 ms 2 min YAX and ECLIENT 10s for Ekahau Clients 10min for Description The password used to authenticate with the Positioning Engine Positioning Engine listens to this TCP port for Ekahau Manager SDK YAX and Wi Fi Tag communication Ekahau Wi Fi Tag UDP port Timeout for the server socket to wait for authentication TALK and HELLO messages before disconnecting the client socket You may have to adjust this if you test YAX over Telnet for example Device is removed from the device list after 2 minutes These devices do not belong to either YAX or ECLIENT group These are the default groups of devices YAX means Ekahau Tags and Palm
40. n PDA devices only you should record the data for your Positioning Model using Tag or the PDA not just any Wi Fi adapter Ekahau Card Models will automatically minimize the differences between any supported Wi Fi adapters and devices but using similar adapter or device for calibration and tracking phases is always the best option 1 Make sure the Tag PDA or other device can communicate with the Wi Fi network 2 In case of a PDA make sure you are using a supported Wi Fi adapter and driver see http www ekahau com devices for the list 3 In case of a PDA install Ekahau Client software and make sure it is running properly 4 Incase of a Ekahau Wi Fi Tag open a terminal program and connect to the Tag via your laptop s terminal program see the Tag s user guide for instructions then type in calibrate lt Enter gt This makes the Tag send data as fast as possible for Site Calibration use If you hit ESC or the Tag drops off from the calibration mode for some reason you will see this if the status LED is not blinking constantly anymore just repeat the calibrate command and continue 5 Open Ekahau Manager select File gt Preferences gt Calibration Client and choose the IP address or friendly name of the device This allows Ekahau Manager to retrieve signal data from the selected remote device for creating the Positioning Model 6 Attach or hold the Tag or PDA similarly to the most typical user for examp
41. nd re calibrate Contact support ekahau com in case of consistent low accuracy NOTE When opening a previously saved model file edb that includes Accuracy Analyses right click on the analysis name and select Update Analysis to visualize the analysis results display the visualizations you first need to draw Tracking Rails on a map and record some sample points Note that the selected de selected Access Points for each map will affect the visualizations Signal Strengths 1 Select the Visualization tab from the bottom view 2 Select the Signal Strength view 3 Optionally select Viewed Signal Viewed Signal Description Strongest Displays the RSSI of the strongest Access Point of all recorded at each map location This can be any selected Access Point that has the strongest signal at that map location 2 Strongest Displays the 24 strongest RSSI at each map location Useful to see what happened if the strongest Access Point would crash IS there a backup and how would it cover the area 3 Strongest Displays the 3 strongest RSSI at each map location Useful to see what happened if the 2 strongest typically a backup would crash Is there another backup Access Point and how would it cover the area 4 Strongest See above 5 Strongest See above 4 Optionally select the preferred color scale from the drop down color listbox 5 Optionally configure the visualization s grid Grid affects to the
42. o be performed under similar circumstances Positioning resolution is good when every sample point in the Positioning Model is different to some extent and signal information received from the device being tracked can be mapped to a sample point or a group of sample points which has been recorded in vicinity of device s actual physical location Sample points should be recorded at every significant location while avoiding irregular distribution High sample point density provides more potential resolution given that the environment walls large objects etc Access Point placement and number of overlapping channels provide favourable variation in signal intensities Calibrating two or three sample points per specific location sometimes increases the accuracy by giving the Positioning Engine more certainty of the signal strength combinations in the location in question Logical Areas Each Logical Area has to contain at least one sample point otherwise the area will not get any location probability even if the estimated coordinate would be inside the boundaries of the Logical Area When using relatively small less than 10 m 100 ft adjacent areas one sample point in the middle of the Logical Area will provide best resolution between the areas Figure 4 Figure 4 Small adjacent areas Sometimes one sample point is not enough to represent whole area due to large size awkward shape or Access Point placement Figure
43. on and therefore the location estimate is a compromise between several locations Another cause can be a significant change in the environment To correct this kind of errors first try replacing or adding sample points in problematic locations If problems persist throughout the area the only solution is to recalibrate the whole area If recording or replacing sample points does not help the problem resides in the Access Point topology The only solution for this problem is adding APs near the problematic areas Latency The coordinate information produced by Ekahau Positioning Engine is not based on just one RSSI sample Stabile and accurate tracking is achieved by combining latest RSSI observation with previous observations This is why accurate location estimate is produced with a few seconds delay High sample point density provides better potential resolution but it may increase latency particularly in open areas If the devices are moving quickly sample point density should be lower for optimal latency accuracy ratio e ekahau i West coast 12930 Saratoga Avenue Suite B 9 Saratoga CA 95070 Tel 1 866 4EKAHAU Fax 1 408 725 8405 East coast 620 Herndon Parkway Suite 200 Herndon VA 20170 Tel 1 866 4EKAHAU Fax 1 703 481 9834 Europe Tammasaarenlaituri 3 00180 Helsinki Finland Tel 358 20 743 5910 Fax 358 20 743 5919 Asia Suite 1002 Ghuang s Tower 30 32 Connaught Road Cent
44. rage error in colors for each location View accuncy tnes TE ens We Acareer Asha Crordratez X Vi Particring Enga Zadar Cpen Periodic Accuracy Test Positioning model inconsistency the difference between recorded calibration data and actual radio environment increases with changes in the environment such as new walls cubicle changes large containers or furniture and so on Extensive tests in various dynamically changing environments have proved that during a continuous 30 day field testing the average positioning accuracy may decrease up to 5 10 in areas with dynamic changes manufacturing area 10 20 in areas with significant dynamic changes shipping amp receiving area Despite of the good robustness Ekahau recommends testing active Positioning Models 3 times a year Periodic testing can be performed quickly by opening the Positioning Model from the Positioning Engine activating the tracking feature and walking around while comparing the actual location to location estimate A more accurate and recommended method is to record new sample points 5 10 of the number of points in the Positioning Model to be analyzed against the original Positioning Model in Ekahau Manager For detailed instructions on how to use Ekahau Manager for positioning accuracy analysis see Chapter 4 Disaster and Recovery Ekahau recommends making backup copies of positioning model and
45. ral Hong Kong Tel 852 3426 4770 Fax 852 3426 4061 www ekahau com sales ekahau com support ekahau com Legal Notice Ekahau the Ekahau logo Ekahau Site Survey Ekahau Positioning Engine Ekahau Manager Ekahau T201 and Ekahau Client are trademarks or registered trademarks of Ekahau Other product and company names may be trademarks or trade names of their respective owners The enclosed software contains implementations of Ekahau s patent pending inventions Under no circumstances shall Ekahau or Ekahau be responsible for any loss of data income or any direct special incidental consequential or indirect damages howsoever caused Copyright Ekahau Inc 2000 2005 All rights reserved
46. ranslations XXX access rights XX 255 255 255 255 10000 ms 30000 ms db every n milliseconds Engine sends AreYouAlive UDP queries to this address Positioning Engine s device list gets cleaned up from old not responding clients every n milliseconds If the device has been idle n milliseconds the next device list cleanup will mark Ekahau Client device for removal The engine database path Used to format and identify data for example BSIDs Usually there is no need to edit these Internal parameters no need to edit By default all Ekahau Managers with correct password can update the model database Here you can create read only managers which can only browse the model and track devices Take app id from your manager s license xml for example manager 42 and change lt attr name app id value manager gt to lt attr name app id productionParameters XX value manager 42 gt After this modification and restarting Engine only Ekahau Manager with app id manager 42 can save a model in the Engine The production parameters are described in the Developer Guide These production parameters in engine conf override the system defaults but any YAX protocol or Ekahau SDK user can override these with their own values check the developer guide to see how Below are the definitions for attributes in manager conf that differ from engine conf Name Default
47. rom the context menu Click Browse to select suitable map image To ensure that Ekahau Positioning Engine functions accurately you must define the correct map scale for each map image If you already know how many map pixels equal the map s selected distance unit meter foot you can type the value in the Map Scale field and click OK If you do not know the pixels map unit ratio of the map leave the field as zero and click OK The map should shortly appear Click the blinking Measure tool and click point on the map for example the corner of a wall or another measurable object Then click another point on the map at least 3 meters 10 feet apart from the starting point Next walk to the marked location on site and measure the real world distance between the two points with a measuring tape Type the real world distance in the lower text field and click Set Map Scale setting map scale After Measure setting the scale you can use the Measure tool for measuring on the map distances set Map Scale Performing Site Survey with Ekahau Manager When setting up Wi Fi network the Access Point and antenna locations are typically selected for maximum coverage and data throughput before installing the Access Points and antennas permanently This process is called site survey and it is also recommended before recording data for Positioning Model When performing a site survey for positioning
48. sitioning Engine 3 The restrictions apply for all maps in the Positioning Model Selected All A Access Point View below the Browser View 2 3 Aldrin 00 A0 F8 8F 8C FO 00 40 F 8 90 F8 09 00 40 F 8 9D 82 B2 ENE 9 00 40 F8 9D F8 54 E Apinakiikku E Apple Network e990b1 00 03 93 E9 90 B1 Apple Network ea47e1 00 03 93 E4 47 E1 E Baldrin Data from all Access Points is processed and saved in the Positioning Model but only the selected Access Points are used for positioning and accuracy analyses This makes it possible to quickly test positioning and accuracy analyses with different Access Point combinations without a need for re calibration Saving and Loading Positioning Models Ekahau Manager can save models either as Ekahau Database files edb or directly in the Positioning Engine s internal database Typically the best Positioning Model is always saved in the Engine while test calibrations and exercises are saved as files After saving a Positioning Model in the Positioning Engine it takes a few seconds before the Engine reads the new model into memory and starts using it for tracking As the tracking history queue is emptied positioning accuracy can slightly decrease for the next 5 20 seconds Sharing Work by Merging Positioning Models 1 Open Ekahau Manager and create a Positioning Model with at least one map image then click File gt
49. status Ekahau Client 3 2 build 196 is running tab amp Centrino is connected NOTE You can install more Ekahau Clients on PC or PDA devices than your EPE license permits You might run into tracking problems if the wrong client devices register into Positioning Engine before the preferred right ones This can be avoided by installing as many Ekahau Clients as the license allows NOTE Ekahau Client s GPS settings are for Ekahau Site Survey only and are not supported by Ekahau Manager or Engine 3 1 Controlling Ekahau Client Visibility Ekahau Client users can select the Positioning Engines that are allowed or disallowed to locate them When using the default Positioning Engine settings set automatically during the installation all available Positioning Engines typically appear in the Recently Discovered Positioning Engines listbox You can then uncheck the Accept checkbox to block positioning requests from that specific Positioning Engine To allow requests from known Positioning Engines only uncheck the Accept by default checkbox If you want to save the Positioning Engine settings click the Add button select the name of the Positioning Engine from the drop down listbox modify the settings as appropriate and click OK If you have manually modified Positioning Engine communication settings see Chapter 6 to see why and how to do this you may need to manually configure the Positioning Engine by clicking the Ad
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