?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Novel+Environmental+Features+for+Robust+Multisensor+Navigation&rft.creator=Walter%2C+DJ&rft.creator=Groves%2C+PD&rft.creator=Mason%2C+RJ&rft.creator=Harrison%2C+J&rft.creator=Woodward%2C+J&rft.creator=Wright%2C+P&rft.description=Many+navigation+techniques+have+now+become+so+reliant+on+GNSS+that+there+is+no+back+up+when+there+is+limited+or+no+signal+reception.+If+there+is+interference%2C+intentional+or+otherwise%2C+with+the+signal%2C+navigation+could+be+lost+or+become+misleading+%5B1%5D.+Other+navigation+techniques+harness+different+technologies+such+as+Wi-Fi+%5B2%5D%2C+eLoran+and+inertial+navigation.+However%2C+each+of+these+techniques+has+its+own+limitations%2C+such+as+coverage%2C+degradation+in+urban+areas+or+solution+drift+%5B3%5D.+Therefore+there+is+a+need+for+new+navigation+and+positioning+techniques+that+may+be+integrated+with+GNSS+to+increase+the+reliability+of+the+system+as+a+whole.+This+paper+presents+the+results+of+a+feasibility+study+to+identify+a+set+of+novel+environmental+features+that+could+be+used+for+navigation+in+the+temporary+absence+of+GNSS+or+degradation+of+the+signal.+By+measuring+these+features+during+times+of+GNSS+availability+a+map+can+be+produced.+This+can+be+referred+to+during+times+of+limited+reception%2C+a+principle+already+used+for+some+Wi-Fi+positioning+techniques+%5B2%5D.+Therefore+a+%E2%80%9Cmeasurable%E2%80%9D+can+be+defined+as+a+feature+either+man-made+or+natural+that+is+spatially+distinct+and+has+limited+temporal+variation.+Possibilities+considered+include+magnetic+anomalies+%5B4%5D%2C+light+intensity+and+road+signs.+Firstly%2C+a+brainstorming+exercise+and+a+literature+study+were+conducted+to+generate+a+list+of+possible+environmental+features+that+was+assessed+for+the+viability+of+each+candidate.+The+features+were+ranked+according+to+three+criteria%3A+practicality%2C+precision+and+coverage.+The+definition+of+practicality+for+each+measurable+was+that+a+suitable+detector+must+be+installable+on+a+road+vehicle%2C+particularly+an+emergency+vehicle%2C+at+a+reasonable+cost+with+minimal+alterations+to+the+vehicle.+Precision+was+defined+in+terms+of+the+spatial+variation+of+the+environmental+feature+and+thus+the+accuracy+with+which+position+information+might+be+derived+from+it.+Coverage+was+assessed+in+terms+of+the+availability+of+the+feature+over+a+range+of+different+environments.+Continuous+coverage+is+not+required+because+the+new+measurables+may+be+used+in+combination+and+integrated+with+dead+reckoning+techniques%2C+such+as+odometry+and+inertial+navigation+%5B3%5D.+The+outcome+of+the+viability+study+was+used+to+determine+which+features+are+to+be+experimentally+tested.+Magnetic+anomalies%2C+road+texture+and+a+dozen+other+environmental+features+were+found+to+be+worth+investigation.+Features+which+were+discounted+include+wind+speed+and+pulsars+%5B5%5D.+The+initial+experiment+was+carried+out+on+foot+in+Central+London.+The+same+tests+were+repeated+on+two+separate+days%2C+with+a+closed+loop+circuit+walked+three+times+on+each+occasion.+This+experiment+used+an+Inertial+Measurement+Unit+(IMU)%2C+comprising+accelerometer+and+gyro+triads%2C+together+with+a+barometer%2C+three-axis+magnetometer+and+GNSS+receiver.+The+experiment+was+also+recorded+using+a+camcorder+from+the+point+of+view+of+a+pedestrian%2C+enabling+visual+and+audio+features+of+the+environment+to+be+assessed.+Magnetic+anomalies+were+found+to+be+a+promising+source+of+position+information.+Peaks+in+the+magnetometer+data+were+observed+on+all+rounds+at+approximately+the+same+positions.+There+were+also+similarities+seen+in+the+temperature+profiles+after+correcting+for+the+temporal+variation+of+the+background+temperature.+Another+potential+source+of+position+information+was+found+to+be+text-based+signs.+It+is+relatively+simple+to+extract+text+from+camera+images+and+it+is+easily+stored+in+a+feature+database.+However%2C+methods+of+dealing+with+identically-worded+signs+in+close+proximity+will+need+to+be+developed.+Sound+levels+were+analysed+in+10s+intervals+for+the+mean%2C+minimum+and+maximum+sound+volume.+There+was+no+clear+correlation+observed+between+the+different+rounds+of+the+experiment.+Due+to+the+pedestrian+experimental+results+sound+levels+of+the+surroundings+will+not+be+used+in+further+experimentation.+An+alternative+area+of+enquiry+for+using+sound+(in+the+vehicular+experiments)+is+using+microphones+to+indirectly+measure+road+texture+based+on+the+noise+from+the+wheel+contact+with+the+road+%5B6%5D.+The+paper+will+also+present+results+of+road+vehicle+experiments.+Multiple+circuits+of+the+same+routes+will+be+compared.+Different+environments+will+be+assessed+including+rural%2C+dual+carriageways%2C+suburban+and+urban+roads.+Sensors+to+be+used+include+the+IMU+and+3-axis+magnetometer+from+the+pedestrian+experiment%2C+a+barometer%2C+gas+sensors%2C+a+microphone%2C+an+axle-mounted+accelerometer%2C+an+ambient+light+sensor+and+a+thermometer.+These+will+be+placed+either+on%2C+inside+or+under+the+vehicle+as+determined+by+the+individual+needs+of+the+sensors.+The+results+will+be+used+to+determine+which+of+these+sensors+could+be+potentially+used+for+a+multisensor+integrated+navigation+system+and+also+the+environments+in+which+they+work+optimally.+Using+the+results+of+the+three+feasibility+study+phases+(literature+review%2C+pedestrian+and+road+experiment)+the+next+project+stage+will+be+to+produce+a+demonstration+system+that+uses+the+most+feasible+features+of+the+environment+and+creates+a+map+database+during+times+GNSS+is+present.+This+database+will+then+be+used+for+navigation+in+times+of+need.+In+the+long+term%2C+it+is+envisaged+that+this+technique+will+be+implemented+cooperatively%2C+with+a+batch+of+vehicles+collecting+feature+data+and+contributing+it+to+a+common+shared+database.+%2F+References+%5B1%5D+Thomas%2C+M.%2C+et+al.%2C+Global+Navigation+Space+Systems%3A+Reliance+and+Vulnerabilities%2C+London%2C+UK%3A+Royal+Academy+of+Engineering%2C+2011.+%5B2%5D+Jones%2C+K.%2C+L.+Liu%2C+and+F.+Alizadeh-Shabdiz%2C+%E2%80%9CImproving+Wireless+Positioning+with+Look-ahead+Map-Matching%2C%E2%80%9D+Proc.+MobiQuitous+2007%2C+Phildaelphia%2C+PA%2C+February+2008%2C+pp.+1-8.+%5B3%5D+Groves%2C+P.D.%2C+Principles+of+GNSS%2C+Inertial%2C+and+Multisensor+Intergrated+Navigation+Systems%2C+Second+Edition%2C+Artech+House%2C+2013.+%5B4%5D+Judd%2C+T.%2C+and+T.+Vu%2C+%E2%80%9CUse+of+a+New+Pedometric+Dead+Reckoning+Module+in+GPS+Denied+Environments%2C%E2%80%9D+Proc.+IEEE%2FION+PLANS%2C+Monterey%2C+CA%2C+May+2008%2C+pp.+120%3F128.+%5B5%5D+Walter%2C+D.+J.%2C+%22Feasibility+study+of+novel+environmental+feature+mapping+to+bridge+GNSS+outage%2C%22+Young+Navigator+Conference%2C+London%2C+2012.+%5B6%5D+Mircea%2C+M.%2C+et+al.%2C+%E2%80%9CStrategic+mapping+of+the+ambient+noise+produced+by+road+traffic%2C+accordingly+to+European+regulations%2C%E2%80%9D+Proc.+IEEE+International+Conference+on+Automation%2C+Quality+and+Testing%2C+Robotics%2C+Cluj+Napoca%2C+Romania%2C+May+2008.&rft.publisher=The+Institute+of+Navigation&rft.date=2013-09-30&rft.type=Proceedings+paper&rft.language=eng&rft.source=+++++In%3A++Proceedings+of+the+26th+International+Technical+Meeting+of+The+Satellite+Division+of+the+Institute+of+Navigation+(ION+GNSS+2013).++(pp.+488+-+504).++The+Institute+of+Navigation%3A+Manassas%2C+US.+(2013)+++++&rft.format=application%2Fpdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F1394971%2F1%2FION_GNSS13_debbie_walter.pdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F1394971%2F&rft.rights=open