US4879713A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Satellite-based vehicle communication/position determination system
Assignee: NEC Corp
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Filing: 1988-09-27
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Granted: 1989-11-07
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Expires: 2008-09-27
Abstract
Abstract A satellite-based vehicle communication/position determination system constituted by N (N≧3) geostationary satellites, a plurality of vehicle stations for performing radio-wave exchange with the satellites using a low-directivity antenna, and a base station having high-directivity antennas for independently performing radio-wave exchange with the N geostationary satellites is disclosed. The base station has a communication FDM receiver, N chirp signal receivers for receiving and pulse compressing chirp signals from a vehicle station, which are obtained via the N geostationary satellites, and a circuit for determining the position of the vehicle station based on time differences of compressed pulses from the chirp signal receivers. Each vehicle station has a communication FDM receiver, a transmitter, a chirp signal generator, and a switching control circuit for controlling to selectively output a transmitting signal or the chirp signal.
Inventors
- 👤 Osamu Ichiyoshi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:59
CPC Classifications
G; G01; G01S; G01S19/00; G01S5/00; G01S5/02; G01S5/06; H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/204; H04B7/216
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
444 words
A satellite-based vehicle communication/position determination system comprising: N geostationary satellites, N being an integer greater than or equal to 3; at least one vehicle station; and a base station, each of said vehicle station comprising: a low-directivity antenna for performing radio-wave exchange with said N geostationary satellites; vehicle station FDM (frequency division multiplex) receiving means for frequency-selectively receiving a signal in a communication frequency channel assigned to the self station from various signals in a plurality of communication frequency channels received at said low directivity antenna; vehicle station receiving control means for transmitting a signal output of said vehicle station FDM receiving means as a receiving signal to a following circuit, and detecting a base station control signal from the signal output; chirp signal generating means for generating a chirp signal for performing frequency sweep over all the bandwidth of a satellite network at a predetermine sweep rate for a predetermined period of time in response to a frame sync signal detected and formed by said vehicle station FDM receiving means; and vehicle station transmitting means for transmitting a communication signal including a position determination start signal from said low-directivity antenna to said N geostationary satellites in the communication frequency channel assigned to the self station, interrupting the transmission of the communication signal for a period of time designated by a control signal from said base station and transmitting the chirp signal from said low-directivity antenna during the interruption period, and said base station comprising: N high-directivity antennas for respectively performing radio-wave exchange with said N geostationary satellites; base station FDM transmitting means for transmitting, from at least one of said N high-directivity antennas to the corresponding geostationary satellite, signals in one or a plurality of communication frequency channels in which the communication signal including the base station control signal for designating a time period for which the chirp signal is to be transmitted is inserted; base station FDM receiving means for receiving and demodulating signals in one or a plurality of communication frequency channels received at one of said N high-directivity antennas; base station reception control means for transmitting the signal output from said base station FDM receiving means to a following circuit as a receiving signal, and detecting a start signal from the signal output; N chirp signal receiving means including chirp filters for performing pulse compression processing of the chirp signals received at said N high-directivity antennas; and time difference detecting means for detecting time differences among N compressed pulses sent from said N chirp signal receiving means in response to the detection of the start signal, and forming a position determination signal for calculating the position of the vehicle station.
Claim 2
Dependent Claim
444 words
A satellite-based vehicle communication/position determination system comprising: N geostationary satellites, N being an integer greater than or equal to 3; at least one vehicle station; and a base station, each of said vehicle station comprising: a low-directivity antenna for performing radio-wave exchange with said N geostationary satellites; vehicle station FDM (frequency division multiplex) receiving means for frequency-selectively receiving a signal in a communication frequency channel assigned to the self station from various signals in a plurality of communication frequency channels received at said low directivity antenna; vehicle station receiving control means for transmitting a signal output of said vehicle station FDM receiving means as a receiving signal to a following circuit, and detecting a base station control signal from the signal output; chirp signal generating means for generating a chirp signal for performing frequency sweep over all the bandwidth of a satellite network at a predetermine sweep rate for a predetermined period of time in response to a frame sync signal detected and formed by said vehicle station FDM receiving means; and vehicle station transmitting means for transmitting a communication signal including a position determination start signal from said low-directivity antenna to said N geostationary satellites in the communication frequency channel assigned to the self station, interrupting the transmission of the communication signal for a period of time designated by a control signal from said base station and transmitting the chirp signal from said low-directivity antenna during the interruption period, and said base station comprising: N high-directivity antennas for respectively performing radio-wave exchange with said N geostationary satellites; base station FDM transmitting means for transmitting, from at least one of said N high-directivity antennas to the corresponding geostationary satellite, signals in one or a plurality of communication frequency channels in which the communication signal including the base station control signal for designating a time period for which the chirp signal is to be transmitted is inserted; base station FDM receiving means for receiving and demodulating signals in one or a plurality of communication frequency channels received at one of said N high-directivity antennas; base station reception control means for transmitting the signal output from said base station FDM receiving means to a following circuit as a receiving signal, and detecting a start signal from the signal output; N chirp signal receiving means including chirp filters for performing pulse compression processing of the chirp signals received at said N high-directivity antennas; and time difference detecting means for detecting time differences among N compressed pulses sent from said N chirp signal receiving means in response to the detection of the start signal, and forming a position determination signal for calculating the position of the vehicle station.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-06 | 1993-05-08 | 1993-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-06 | 1997-05-08 | 1997-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-06 | 2001-05-08 | 2001-11-07 | $7700.00 | Window Closed / Lapsed |