Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
139 words
A vehicle location system comprising: a plurality of remote relay stations, each station being capable of transmission of a predetermined relay signal and of signal reception; a plurality of transponders, each located at a corresponding vehicle, each transponder being operable upon receipt of one of said predetermined signals from at least one of said relay stations, said predetermined signal having a ranging tone impressed thereon; means at each of said plurality of transponders responsive only to a corresponding vehicle identification code in said predetermined signal for generating a reply signal within a predetermined time after initial receipt of said predetermined signal; means at said plurality of remote relay stations for receiving said reply signal; and means at each of said plurality of remote relay stations for measuring the phase difference between the original ranging tone and the reply signal.
Claim 2
Dependent Claim
139 words
A vehicle location system comprising: a plurality of remote relay stations, each station being capable of transmission of a predetermined relay signal and of signal reception; a plurality of transponders, each located at a corresponding vehicle, each transponder being operable upon receipt of one of said predetermined signals from at least one of said relay stations, said predetermined signal having a ranging tone impressed thereon; means at each of said plurality of transponders responsive only to a corresponding vehicle identification code in said predetermined signal for generating a reply signal within a predetermined time after initial receipt of said predetermined signal; means at said plurality of remote relay stations for receiving said reply signal; and means at each of said plurality of remote relay stations for measuring the phase difference between the original ranging tone and the reply signal.
Claim 3
Dependent Claim
44 words
A vehicle location system in accordance with claim 1 further comprising: means for transmitting said phase measurements from said remote relay station to a central location; and means at said central location including computing means for determining the location of said plurality of vehicles.
Claim 4
Dependent Claim
92 words
In combination: at least one transmitter for transmitting interrogating signals having at least coded interrogation portions; a plurality of transponders located in vehicles at spaced locations responsive to different identification codes of said interrogation portions for receiving said interrogating signals and for transmitting a composite reply signal, said reply signal comprising an identification portion and a tone signal; and a plurality of receiving means at a plurality of different predetermined locations for receiving said reply signal and for measuring the phase of said tone signal with respect to a phase reference signal.
Claim 5
Dependent Claim
92 words
In combination: at least one transmitter for transmitting interrogating signals having at least coded interrogation portions; a plurality of transponders located in vehicles at spaced locations responsive to different identification codes of said interrogation portions for receiving said interrogating signals and for transmitting a composite reply signal, said reply signal comprising an identification portion and a tone signal; and a plurality of receiving means at a plurality of different predetermined locations for receiving said reply signal and for measuring the phase of said tone signal with respect to a phase reference signal.
Claim 6
Dependent Claim
26 words
A combination in accordance with claim 3 further comprising: means for processing data including at least said phase measurements for determining the location of said vehicles.
Claim 7
Dependent Claim
17 words
A combination in accordance with claim 4 wherein said vehicles comprise a fleet of mobile surface vehicles.
Claim 8
Dependent Claim
63 words
A combination in accordance with claim 4 wherein said identification code in the interrogation portion of said composite transmitted signal is received by said plurality of transponders, such that only one of said transponders is responsive to said identification code; and means at said one transponder for generating a coded reply signal within a predetermined time after initial receipt of said transmitted signal.
Claim 9
Dependent Claim
16 words
A combination in accordance with claim 6 wherein said transmitted composite signal is an omnidirectional signal.