Integrated radio location and communication system
First Claim
1. A radio location and communication system of the phase ranging type comprising:
- a stationary broadcast means for transmitting a continuous RF carrier signal, said stationary broadcast means including means for generating a carrier range tone signal synchronized with said continuous RF carrier signal and for transmitting, on said continuous RF carrier signal, a periodic carrier rang tone signal comprising a carrier range tone signal burst,one or more mobile locator transmission means phase-locked to the RF carrier signal from said broadcast means for continuously generating a transmitter range tone signal periodically synchronized by said periodic carrier range tone signal burst from said stationary braodcast means, and for transmitting said transmitter range tone signal at specific times between the periodic carrier range tone signal bursts, anda plurality of stationary receiving means, each for detecting the carrier range tone signal burst from said stationary broadcast means and generating a continuous receiving means range tone signal synchronized by said periodic carrier range tone signal burst from said stationary broadcast means and for detecting said transmitter range tone signal from said locator transmission means and phase comparing said receiving means range tone signal and said transmitter range tone signals from the mobile unit for the computation of the location of said locator transmission means, whereby the mobile locator transmission means and the plurality of stationary receiving means are periodically resynced by the stationary broadcast means, and may be used a plurality of times thereafter to determine the location of the mobile locator transmission means prior to the next resyncing thereof.
1 Assignment
0 Petitions
Accused Products
Abstract
An integrated radio location and communication system comprising a plurality of radio locator-transmitter devices which may be fixed to vehicles and/or carried by persons and which are capable of transmitting the position and identity of said devices to two or more centrally located fixed receiver sites. Each of said locator-transmitters is continuously phase-locked to the RF carrier of a nearby commercial broadcast station, which station is modified slightly to provide periodic transmission of a "range-tone" which is on the order of a few kilohertz in frequency and is phase-locked to the RF carrier. An identical phase-locked range-tone is likewise generated within each locator-transmitter. The two centrally located fixed receivers are also phase-locked to the broadcast station RF carrier and likewise generate a range-tone. Thus the broadcast station, the plurality of locator-transmitters and the two fixed receiver sites all generate identical range-tones and these are continuously kept in synchronism with each other by virtue of a phase-lock loop arrangement wherein all range-tones are derived from (and locked to) the RF carrier of the AM broadcast station signal. The fixed receiver sites can compute the position of each locator-transmitter by comparing the phase of the range-tone sent to them directly by the locator-transmitter with the phase of the range-tone received directly from the broadcast station. A novel frame synchronization method is disclosed whereby the position (i.e., "time-slot") of each locator-transmitter emission and its RF subchannel uniquely identifies the emitting source and thus the location as well as identity of each of the many locator-transmitters.
360 Citations
24 Claims
-
1. A radio location and communication system of the phase ranging type comprising:
-
a stationary broadcast means for transmitting a continuous RF carrier signal, said stationary broadcast means including means for generating a carrier range tone signal synchronized with said continuous RF carrier signal and for transmitting, on said continuous RF carrier signal, a periodic carrier rang tone signal comprising a carrier range tone signal burst, one or more mobile locator transmission means phase-locked to the RF carrier signal from said broadcast means for continuously generating a transmitter range tone signal periodically synchronized by said periodic carrier range tone signal burst from said stationary braodcast means, and for transmitting said transmitter range tone signal at specific times between the periodic carrier range tone signal bursts, and a plurality of stationary receiving means, each for detecting the carrier range tone signal burst from said stationary broadcast means and generating a continuous receiving means range tone signal synchronized by said periodic carrier range tone signal burst from said stationary broadcast means and for detecting said transmitter range tone signal from said locator transmission means and phase comparing said receiving means range tone signal and said transmitter range tone signals from the mobile unit for the computation of the location of said locator transmission means, whereby the mobile locator transmission means and the plurality of stationary receiving means are periodically resynced by the stationary broadcast means, and may be used a plurality of times thereafter to determine the location of the mobile locator transmission means prior to the next resyncing thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 19, 20)
-
-
8. A radio location and communication system of the phase ranging type, comprising:
-
stationary broadcast means for transmitting a continuous RF carrier signal from a predetermined location, said stationary broadcast means including means for generating a carrier range tone signal synchronized with said continuous RF carrier signal and for transmitting, on said continuous RF carrier signal, a periodic range tone signal comprising a carrier range tone signal burst, one or more mobile locator transmission means phase-locked to said RF carrier signal from said broadcast means for continuously generating a transmitter range tone signal, for generating between said periodic carrier range tone signals a pair of RF transmitter frequencies wherein the differnce of said pair of frequencies equals the periodic carrier range tone frequency, and for relaying said pair of RF transmitter frequencies, and a plurality of stationary receiving means for detecting the carrier range tone signal from said broadcast means and said pair of frequencies from said locator transmission means and phase comparing said transmitter range tone signal and the difference of said pair of RF transmitter frequencies to compute the location of said locator transmission means, whereby the mobile locator transmission means and the plurality of stationary receiving means are periodically resynced by the stationary broadcast means, and may be used a plurality of times thereafter to determine the location of the mobile locator transmission means prior to the next resyncing thereof. - View Dependent Claims (9, 10, 11, 12, 13, 14, 21, 22)
-
-
15. A radio location and communication system, of the phase ranging type, comprising:
-
stationary conventional AM boradcast means for transmitting ordinary program material on a continuous RF carrier signal from a predetermined loation, said stationary broadcast means including means for generating a carrier range tone signal phase-locked to said continuous RF carrier signal and for transmitting, on said continuous RF carrier signal, a periodic carrier range tone signal comprising a carrier range tone signal burst, mobile locator transmission means phase-locked to receive the broadcast signal from said predetermined location, for generating a continuous transmitter range tone frequency identical to said carrier range tone frequency as received, and a pair of RF transmitter frequencies in such a manner wherein the frequency difference between said pair of RF transmitter frequencies equals the periodic carrier range tone frequency, and for relaying said transmitter range tone frequency and said pair of RF transmitter frequencies, and a plurality of stationary receiving means for detecting said periodic carrier range tone signal from said broadcast means at said predetermined location and said pair of RF transmitter frequecies from said locator transmission means, for generating a continuous receiving means range tone signal synchronized by said periodic range tone signal from said stationary broadcast means, and phase comparing said signals to compute the location of said locator transmission means, whereby the mobile locator transmission means and the plurality of stationary receiving means are periodically resynced by bhe stationary broadcast means, and may be used a plurality of times thereafter to determine the location of the mobile locator transmission means prior to the next resyncing thereof. - View Dependent Claims (16, 17, 18, 23, 24)
-
Specification