Patent US5859613A successfully refreshed from Google Patents.
US5859613A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for geolocating plural remote transmitters
Assignee: ORLANDO COMMUNICATIONS LLC
•
Filing: 1996-08-30
•
Granted: 1999-01-12
•
Expires: 2016-08-30
Abstract
Abstract A system and method for locating plural remote transmitters in which many, relatively inexpensive transmitters may simultaneously send identifying signals to one or more receiving stations. The receiving stations detect the signals from the remote transmitters, determine the time of arrival of the signals and decode the information (if any) contained in the signals, all without synchronization between the receiving stations and the transmitters or among the transmitters and all without a central system for polling the various remote transmitters. The system combines the signal information received from two or more receiving stations to determine the geolocation of the transmitting units.
Inventors
- 👤 James C. Otto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:35
CPC Classifications
G; G01; G01S; G01S5/00; G01S5/02; G01S5/06
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
204 words
A locating system for determining the location of a transmitter comprising: (A) plural receivers, each of said receivers comprising: (a) means for receiving a radiated signal containing digital data modulated thereon; (b) a down converter for down converting said received radiated signal to a lower frequency signal; (c) a chirp signal generator; (d) a mixer which periodically mixes said lower frequency signal with a chirp signal received from said chirp signal generator to produce a wave signal having a frequency related to the time relationship between the start of the chirp signal and the start of the digital data; (e) a filter circuit for filtering said wave signal to remove wave signals outside a predetermined range of frequencies; (f) a frequency detector for determining the frequency of the filtered wave signal; (g) a detector for decoding the digital data within the filtered wave signal from the time relationship between successively demodulated filtered wave signals; and, (B) control means comprising: (h) means to determine the time of arrival of a common one of said successively demodulated filtered wave signals received at each of said plural receivers; (i) means for determining the location of said transmitter by comparing said times of arrival at said plural receivers.
Claim 2
Dependent Claim
204 words
A locating system for determining the location of a transmitter comprising: (A) plural receivers, each of said receivers comprising: (a) means for receiving a radiated signal containing digital data modulated thereon; (b) a down converter for down converting said received radiated signal to a lower frequency signal; (c) a chirp signal generator; (d) a mixer which periodically mixes said lower frequency signal with a chirp signal received from said chirp signal generator to produce a wave signal having a frequency related to the time relationship between the start of the chirp signal and the start of the digital data; (e) a filter circuit for filtering said wave signal to remove wave signals outside a predetermined range of frequencies; (f) a frequency detector for determining the frequency of the filtered wave signal; (g) a detector for decoding the digital data within the filtered wave signal from the time relationship between successively demodulated filtered wave signals; and, (B) control means comprising: (h) means to determine the time of arrival of a common one of said successively demodulated filtered wave signals received at each of said plural receivers; (i) means for determining the location of said transmitter by comparing said times of arrival at said plural receivers.
Claim 3
Independent Claim
286 words
A system for locating a mobile transmitter, comprising: (a) plural means for receiving transmitted signals, said transmitted signals having a data signal intermittently modulated therein, each of said means for receiving being spatially diverse from each of the others of said means for receiving, each of said means for receiving comprising: (i) plural subchannel processors, each processor comprising: (A) a mixer for mixing the received signal with a periodically generated chirp signal to provide an IF signal having a frequency related to the coordination in time between the start of the periodically generated chirp signal and the data signal modulated within the received signal; (B) a filter to remove IF signals not within a predetermined bandwidth to provide a filtered IF signal; (C) a analog to digital converter to convert the filtered IF signal from analog to digital format; (D) a digital down converter to down convert the digital filtered IF signal to a baseband signal; and, (E) a fast-Fourier-transform ("IFFT") processor to identify the frequency components within the baseband signal; (ii) a chirp signal generator to periodically generate a chirp signal; (iii) a chirp signal timing control circuit to apply said generated chirp signals to said mixers within said subchannel processors in a timed sequence; and, (iv) a data demodulator which decodes the digital data within the received signal by measuring the time relationship among the modulated data within the received signal; and, (v) time of arrival detector to retain the time of arrival of the modulated data; and, (b) location determining means which utilizes the time of arrival of the modulated data at the plural means for receiving to determine the location of the transmitter relative to the location of the means for receiving.
Claim 4
Independent Claim
286 words
A system for locating a mobile transmitter, comprising: (a) plural means for receiving transmitted signals, said transmitted signals having a data signal intermittently modulated therein, each of said means for receiving being spatially diverse from each of the others of said means for receiving, each of said means for receiving comprising: (i) plural subchannel processors, each processor comprising: (A) a mixer for mixing the received signal with a periodically generated chirp signal to provide an IF signal having a frequency related to the coordination in time between the start of the periodically generated chirp signal and the data signal modulated within the received signal; (B) a filter to remove IF signals not within a predetermined bandwidth to provide a filtered IF signal; (C) a analog to digital converter to convert the filtered IF signal from analog to digital format; (D) a digital down converter to down convert the digital filtered IF signal to a baseband signal; and, (E) a fast-Fourier-transform ("IFFT") processor to identify the frequency components within the baseband signal; (ii) a chirp signal generator to periodically generate a chirp signal; (iii) a chirp signal timing control circuit to apply said generated chirp signals to said mixers within said subchannel processors in a timed sequence; and, (iv) a data demodulator which decodes the digital data within the received signal by measuring the time relationship among the modulated data within the received signal; and, (v) time of arrival detector to retain the time of arrival of the modulated data; and, (b) location determining means which utilizes the time of arrival of the modulated data at the plural means for receiving to determine the location of the transmitter relative to the location of the means for receiving.
Claim 5
Dependent Claim
34 words
The system of claim 2 wherein said FFT processor develops plural frequency bins, each of said bins being associated with signals having a different frequency within the bandwidth of signals passed through said filter.
Claim 6
Dependent Claim
39 words
The system of claim 3 wherein valid digital data are present in the frequency bins if successive decoded digital data occur within a predetermined frequency offset within the frequency bins from the bin holding the first decoded digital data.
Claim 7
Dependent Claim
28 words
The system of claim 3 wherein said FFT produces 10,000 frequency bins and wherein valid data occurs within a window of 128 frequency bins of successive chirp signals.
Claim 8
Dependent Claim
17 words
The system of claim 2 wherein plural digital bits of information are encoded within each modulated signal.
Claim 9
Dependent Claim
29 words
The system of claim 2 wherein the frequency of said baseband signal is related to the time relationship between the periodic chirp signals and the intermittently modulated data signals.
Claim 10
Dependent Claim
48 words
The system of claim 2 wherein five successive chirps form a frame of data, each frame having a base chirp and four successive chirps, the timing between the start of the base chirp and each of the successive chirps indicating the digital data being represented by said frame.
Claim 11
Dependent Claim
32 words
A transmitter location system comprising: at least one transmitter for radiating a signal containing digital data modulated thereon; receiving means for receiving said signal, said receiving means comprising a chirp signal generator.
Claim 12
Dependent Claim
32 words
A transmitter location system comprising: at least one transmitter for radiating a signal containing digital data modulated thereon; receiving means for receiving said signal, said receiving means comprising a chirp signal generator.
Claim 13
Dependent Claim
14 words
The system of claim 9 wherein said signal comprises a plurality of chirp signals.
Claim 14
Dependent Claim
54 words
The system of claim 10 wherein said receiving means further comprises: a plurality of antennae for receiving said signal; a demodulator for downconverting and decoding each of said chirp signals contained within said signal; and, a data processor for further decoding said signal based on the timing of successive ones of said chirp signals.
Claim 15
Dependent Claim
93 words
The system of claim 11 wherein said demodulator comprises: a plurality of subchannel processors, each processor comprising: a mixer for mixing the downconverted chirp signals with a reference chirp signal from said chirp generator to produce a continuous wave (CW) signal; a filter for filtering said CW signal; an analog to digital converter to convert said filtered CW signal from analog to digital format; a digital down converter to down convert the digital filtered CW signal to a baseband signal; and, a fast-Fourier-transform (FFT) processor to identify the frequency of said baseband signal.
Claim 16
Dependent Claim
22 words
The system of claim 12 further comprising means for generating multiple offset signals of a reference signal provided from said chirp generator.
Claim 17
Dependent Claim
43 words
The system of claim 13 wherein said demodulator comprises means for determining a timing relationship between each of said chirp signals and one of said reference signals generated by said chirp generator such that said timing relationship is indicative of said digital data.
Claim 18
Dependent Claim
22 words
The system of claim 11 further comprising means for generating multiple offset signals of a reference signal provided from said chirp generator.
Claim 19
Dependent Claim
43 words
The system of claim 15 wherein said demodulator comprises means for determining a timing relationship between each of said chirp signals and one of said reference signals generated by said chirp generator such that said timing relationship is indicative of said digital data.
Claim 20
Dependent Claim
47 words
A locating system for determining the location of a transmitter comprising: at least one transmitter for radiating a signal containing digital data modulated thereon; receiving means for receiving said signal, said receiving means comprising: a chirp signal generator; and, a demodulator for downconverting and decoding said signal.
Claim 21
Dependent Claim
47 words
A locating system for determining the location of a transmitter comprising: at least one transmitter for radiating a signal containing digital data modulated thereon; receiving means for receiving said signal, said receiving means comprising: a chirp signal generator; and, a demodulator for downconverting and decoding said signal.
Claim 22
Dependent Claim
14 words
The system of claim 17 wherein said signal comprises a plurality of chirp signals.
Claim 23
Dependent Claim
30 words
The system of claim 18 wherein said receiving means further comprises a data processor for further decoding said signal based on the timing of successive ones of said chirp signals.
Claim 24
Dependent Claim
27 words
The system of claim 19 wherein said timing of successive ones of said chirp signals is referenced from the start of a first of said chirp signals.
References Cited (Backward Citations)
US5173710A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-01-11 | 2002-07-13 | 2003-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-01-11 | 2006-07-13 | 2007-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-01-11 | 2010-07-13 | 2011-01-12 | $7700.00 | Window Closed / Lapsed |