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`=(+$ B H %(G ' '.5 ' >(+ 1a $%() %*+$ , 6 2 6*P./ 9 $ ! 9 Q ;( $%(Q! *) ;() # % 3]?@$9 9 b '$%():# >( (+$9 ' N 4 O <:6:# *U <:#1O <:# $9 K 6 c?G$9 $%(d #./, 6 6 3' '$%() * $ , 6 3B?G$9*C K 9 ;( (J(+1 () #.2D 1. INTRODUCTION e $ 9 fRg]hW$%(c, 6:6 .a$ , $9i $9 ' >(= + *= ,H() ' b! (+$9 $9 9 :B $9 N$ j k?G$9 l <* $9 6 17 / ! ! $9:B $9 H()3P$ =.2 1A(+1 () #.2( 9 6* > < 9$ Z! (+$9 $9 ' m 9 :; < $9 ' m.5 6 (n <*) V B(+$9*C 6 " ' V fLgohBp (I() # H(+$9 $ '$9 1R 5q9 ./.a$ 3 $9 (J*) 6i $9*) #.5 # ] * I:K 9 ; <*F '$9 #? r s(+ '1O *4 '! 6*U < $9 ' 3F$9 (r $ ./$9 6 7*C ;() $9 ' 3J c$9 (4:6 () tD J $%(L!H ! 6*L! *) ' '$9 B(5 & 6* '$9 K?m R 9 6*+ H < $ S ' 9 :B $9 .5 6:# > $%(+.2(8 H < /.2 1N, = >() 6 W, 1n #./, 6 6 V(+1 () #.2(S H < ' 1Y*) 6i $9*) u*) # % < $ ! (+$9 $9 ' v 9 :B $9 3b?G$9 w " 6 $ 9 B():6* $ ! $9 ' x y*C ;(+ 9 (u +*C . z$ ./! 9 #.5 # < $9 ' { H(+$ <:6 ' >() $9:s(+$ B H $ '3F, $ 9 '$ O ' = 8(+ ,H() $% J, 12 |?} *+ ?G $9:# / H #(F, 6 # /! , $%(+ R$ 5 $%(P <*C ; | % / /~ 6C#)D _J K % $ k! (+$9 9$9 O 9 :; < 9$9 + *r #./, 6 6 l?G$9*) # 9 ;( (r '$%() *+$ , % (+1 () #.2()3/ $ VfLgohB35 # m ;(A 8*) 6i $9*) K
6*+ H $ H +* () *+ :6 *C 63F S.2 1/ ] 6 6 O @ B 9 ',> F*C ; + 6*) # :4! (+$9 $9 ' HD E+ N $%(Q!> ! 6*R $%():# H( (+$9 N Q 8*) # % < 9$ S.5 6*+$9 (4 4 :9$ S_ ` X :' H() $9:0(+$ B H $ T % -* ./$ * ' ' *N B 9 ;( , 9?r 6 # A K.a, 6 6 S?G$9*) # 9 ;( (| ;(|$%(I! *C '$9 6 3 #(I?r # d #(r #( () ;( (+.5 # @ r:# *C*) # @ % -:# ' 9 ' B18:; !H , $ $9 $9 ;( DFg] <*C $9:# % *+ 1;3J :6 .a!> <* $%() 2$%(P.2 < Q, 6 ?} # s $ .5 R I *)*+$ 93> B 9 R I *)*+$ 93 !H < j 9 ( (k.5 # $ =.5 6 (5 n 6 6* ./$ A A*) # % < $ 9 :B $9 H( 7 #./, 6 6 ?G$9*) # 9 ;( ( ;()3/, T '$% n_I` <:6 ' >() $9:N(+$ ; > $ D}E+ % K * R % W $%(k$%(8 #( () ;( (+.5 # R 9 $ ./!H <:6 4 R K '$9*) ' .5 # 4 =./ 9 9$9t!H < & 6*)*) * (L?G$9 $ N B :K .5 6 ' 9 ;1B3w :; !H , $ $9 $9 ;(*C 6i $9*) 6 + * 9 (+16 :# *) ' $9^; < 9$9 8 6:;( ( <* 1/$ A <:6 ' >() $9: 8_ `7 $ .5 / G <*)* $ * ;$ Dl P 5() # 6*) 4$ ./!H <:6 ] d.a 9 $9 !H < l(+$ B H >! *C !H $9 v K! # # :6 u T(+$ ; > j!H < v 9 ( ( # '$9*C .5 # <* $% < $9 ' k # 6* 14 '$9:t < ;(d 9 G >() } ] I $ .5 } ] *)*+$ *] $ .5 '$% ) + 6*C K :6 c / <*C*+$ G,H #() 6 .5 6 ' 9 ;1;3I #$9 6*a 9 ' 8 *Q$ :6 :6 6*) ?G$9 2 9 6*] 6:# $9i' 63 + *] ; ) -:6 $ G ' 6 ' 9 :; < $9 ' HD To demonstrate the capabilities of a relative position location system for wireless embedded nodes, details are provided on an implementation of a hybrid acoustic RF ranging technology. This technology leverages an RF 2.4GHz wireless communications channel to provide internode synchronization, and coordination between nodes, while determining the distance between nodes through acoustic signaling. This system is similar in concept to the recently developed USC and UCLA [1,2], the active bat, [3], and the active cricket [4,5] acoustic location systems. It operates in a purely peer-to-peer system, as one component within the DARPA/ATO Self Healing Minefield prototype communication and control system [9]. The acoustic signal consists of chaotic sequence emitted from four speakers on each node and received on other nodes in the system through their four microphones. The time of arrival at each microphone, synchronized over the RF channel with the acoustic transmit time, enables a range measurement at each microphone, which is then used to triangulate the source position, or reception angle. Collaboration between nodes over the RF channel is also accomplished to ensure reception of enough range and angle measurements to characterize the position of each node to a desired accuracy. Details are provided on the accuracy of this robust distributed system, which determines both angle and range between wireless nodes autonomously, then uses this information to compute a relative position for each node. Details on the performance of this system in both indoor and outdoor environments are presented. Individual range accuracy of less than one meter over tens of meters for up to twenty nodes is shown. 2. COMPARISON OF POSITION LOCATION METHODS :; < $9 ' {.5 6 ()3W?G 6 6*",H #() 6 { ' x :' H() $9:z *m_ ` (+$ B H $ V.2 1 , W, *) ' K T !$ 0 *C 6 , *) < :; < % K * $9 ;( D J ;() 4 *) @ J$ .5 } ] <*C*+$ )3BG B 9 6 r*C*+$ } 'IC3 (+$ B H () *) # ' z.5 ; #(+ *) #.5 # DcG 9 6*+ H < T! (+$9 $9 ' 9 :B $9 .5 6 ' 9 ;$9 B(@$ :# 5 ; < O*) 6:# ' $ s(+1'() % K.k(Q .5 ; #(+ *+$ s :# > Q$ 2! (+$9 $9 ' 'G k$ H + 6*C*) 6 k 9 :; < $9 ' 8 ' R /! *C
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