EP2033010A2 - Système de navigation à haute performance généralisée - Google Patents

Système de navigation à haute performance généralisée

Info

Publication number
EP2033010A2
EP2033010A2 EP07873721A EP07873721A EP2033010A2 EP 2033010 A2 EP2033010 A2 EP 2033010A2 EP 07873721 A EP07873721 A EP 07873721A EP 07873721 A EP07873721 A EP 07873721A EP 2033010 A2 EP2033010 A2 EP 2033010A2
Authority
EP
European Patent Office
Prior art keywords
signal
navigation
leo
channels
satellite
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP07873721A
Other languages
German (de)
English (en)
Inventor
Clark E. Cohen
David A. Whelan
Robert W. Brumley
Barton G. Ferrell
Gregory M. Gutt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Boeing Co
Original Assignee
Boeing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/749,597 external-priority patent/US8296051B2/en
Priority claimed from US11/749,652 external-priority patent/US7583225B2/en
Priority claimed from US11/749,667 external-priority patent/US7554481B2/en
Priority claimed from US11/749,627 external-priority patent/US7579987B2/en
Application filed by Boeing Co filed Critical Boeing Co
Priority to EP11153732.0A priority Critical patent/EP2330441B1/fr
Publication of EP2033010A2 publication Critical patent/EP2033010A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/02—Details of the space or ground control segments
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
    • G01S19/08—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing integrity information, e.g. health of satellites or quality of ephemeris data
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/20—Instruments for performing navigational calculations
    • G01C21/206—Instruments for performing navigational calculations specially adapted for indoor navigation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
    • G01S19/05—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing aiding data
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
    • G01S19/10—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing dedicated supplementary positioning signals
    • G01S19/12—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing dedicated supplementary positioning signals wherein the cooperating elements are telecommunication base stations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/246—Acquisition or tracking or demodulation of signals transmitted by the system involving long acquisition integration times, extended snapshots of signals or methods specifically directed towards weak signal acquisition
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/31—Acquisition or tracking of other signals for positioning
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/34—Power consumption
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42—Determining position
    • G01S19/45—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement
    • G01S19/46—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement the supplementary measurement being of a radio-wave signal type
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/20—Countermeasures against jamming
    • H04K3/22—Countermeasures against jamming including jamming detection and monitoring
    • H04K3/224—Countermeasures against jamming including jamming detection and monitoring with countermeasures at transmission and/or reception of the jammed signal, e.g. stopping operation of transmitter or receiver, nulling or enhancing transmitted power in direction of or at frequency of jammer
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/20—Countermeasures against jamming
    • H04K3/28—Countermeasures against jamming with jamming and anti-jamming mechanisms both included in a same device or system, e.g. wherein anti-jamming includes prevention of undesired self-jamming resulting from jamming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/40—Jamming having variable characteristics
    • H04K3/42—Jamming having variable characteristics characterized by the control of the jamming frequency or wavelength
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/40—Jamming having variable characteristics
    • H04K3/43—Jamming having variable characteristics characterized by the control of the jamming power, signal-to-noise ratio or geographic coverage area
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/80—Jamming or countermeasure characterized by its function
    • H04K3/90—Jamming or countermeasure characterized by its function related to allowing or preventing navigation or positioning, e.g. GPS

Definitions

  • the present invention relates generally to navigation and, more particularly, to satellite-based navigation techniques.
  • navigation signals provided by various existing navigation systems often do not provide satisfactory system performance.
  • the signal power, bandwidth, and geometrical leverage of such navigation signals are generally insufficient to meet the needs of many demanding usage scenarios .
  • GPS Global Positioning System
  • a method of performing navigation includes receiving a low earth orbit (LEO) signal from a LEO satellite; decoding a navigation signal from the LEO signal; receiving first and second ranging signals from first and second ranging sources, respectively; determining calibration information associated with the first and second ranging sources; and calculating a position using the navigation signal, the first and second ranging signals, and the calibration information.
  • LEO low earth orbit
  • a navigation device in accordance with another embodiment of the invention, includes an antenna adapted to receive a LEO signal from a LEO satellite and receive first and second ranging signals from first and second ranging sources, respectively; a receiver processor adapted to downconvert the LEO signal for further processing; and a navigation processor adapted to decode a navigation signal from the LEO signal, and adapted to calculate a position of the navigation device using the navigation signal, the first and second ranging signals, and calibration information associated with the first and second ranging sources .
  • a navigation device includes means for receiving a LEO signal from a LEO satellite; means for decoding a navigation signal from the LEO signal; means for receiving first and second ranging signals from first and second ranging sources, respectively; means for determining calibration information associated with the first and second ranging sources; and means for calculating a position using the navigation signal, the first and second ranging signals, and the calibration information.
  • a method of providing a LEO signal from a LEO satellite includes providing a plurality of transmit channels over a plurality of transmit slots, wherein the transmit channels comprise a set of communication channels and a set of navigation channels; generating a first pseudo random noise (PRN) ranging overlay corresponding to a navigation signal; applying the first PRN ranging overlay to a first set of the navigation channels; combining the communication channels and the navigation channels into a LEO signal; and broadcasting the LEO signal from the LEO satellite.
  • PRN pseudo random noise
  • a LEO satellite includes an antenna adapted to broadcast a LEO signal from the LEO satellite; and a processor adapted to: provide a plurality of transmit channels over a plurality of transmit slots, wherein the transmit channels comprise a set of communication channels and a set of navigation channels, generate a first PRN ranging overlay corresponding to a navigation signal, apply the first PRN ranging overlay to a first set of the navigation channels, and combine the communication channels and the navigation channels into the LEO signal .
  • a LEO satellite includes means for providing a plurality of transmit channels over a plurality of transmit slots, wherein the transmit channels comprise a set of communication channels and a set of navigation channels; means for generating a first PRN ranging overlay corresponding to a navigation signal; means for applying the first PRN ranging overlay to a first set of the navigation channels; means for combining the communication channels and the navigation channels into a LEO signal; and means for broadcasting the LEO signal from the LEO satellite.
  • a method of providing a data uplink to a LEO satellite includes determining position information using a LEO signal received from the LEO satellite, a first ranging signal received from a first ranging source, and a second ranging signal received from a second ranging source; determining a timing advance parameter using a local clock reference and a LEO satellite clock reference; preparing a data uplink signal comprising uplink data to be broadcast to the LEO satellite; synchronizing the data uplink signal with the LEO satellite using the timing advance parameter; and broadcasting the data uplink signal to the LEO satellite.
  • a data uplink device includes an antenna adapted to: receive a LEO signal from a LEO satellite, receive first and second ranging signals from first and second ranging sources, respectively, • and broadcast a data uplink signal to the LEO satellite; and a processor adapted to: determine position information using the LEO signal, the first ranging signal, and the second ranging signal, determine a timing advance parameter using a local clock reference and a LEO satellite clock reference, prepare the data uplink signal comprising uplink data to be broadcast to the LEO satellite, and synchronize the data uplink signal with the LEO satellite using the timing advance parameter.
  • a data uplink device includes means for determining position information using a LEO signal received from the LEO satellite, a first ranging signal received from a first ranging source, and a second ranging signal received from a second ranging source; means for determining a timing advance parameter using a local clock reference and a LEO satellite clock reference; means for preparing a data uplink signal comprising uplink data to be broadcast to the LEO satellite; means for synchronizing the data uplink signal with the LEO satellite using the timing advance parameter; and means for broadcasting the data uplink signal to the LEO satellite.
  • a navigation signal comprises at least a portion of a LEO signal provided by a LEO satellite
  • a method of performing localized jamming of the navigation signal includes filtering a noise source into a plurality of frequency bands to provide a plurality of filtered noise signals in the frequency bands, wherein the navigation signal is spread over a plurality of channels of the LEO signal, wherein the channels are distributed over the frequency bands and a plurality of time slots; generating a PRN sequence corresponding to a modulation sequence used by the LEO satellite to spread the navigation signal over the channels; modulating the filtered noise signals using the PRN sequence to provide a plurality of modulated noise signals; and broadcasting the modulated noise signals over an area of operations to provide a plurality of jamming bursts corresponding to the navigation signal, wherein the jamming bursts are configured to substantially mask the navigation signal in the area of operations.
  • a navigation signal comprises at least a portion of a LEO signal provided by a LEO satellite, a jamming device configured to perform localized jamming of the navigation signal includes a noise source adapted to provide a noise signal; a plurality of filters adapted to filter the noise signal into a plurality of frequency bands to provide a plurality of filtered noise signals in the frequency bands, wherein the navigation signal is spread over a plurality of channels of the LEO signal, wherein the channels are distributed over the frequency bands and a plurality of time slots; a PRN sequence generator adapted to provide a modulation sequence used by the LEO satellite to spread the navigation signal over the channels; a plurality of oscillators adapted to modulate the filtered noise signals using the PRN sequence to provide a plurality of modulated noise signals; and an antenna adapted to broadcast the modulated noise signals over an area of operations to provide a plurality of jamming bursts corresponding to the navigation signal, wherein the jamming bursts
  • a navigation signal comprises at least a portion of a LEO signal provided by a LEO satellite
  • a jamming device configured to perform localized jamming of the navigation signal includes means for filtering a noise source into a plurality of frequency bands to provide a plurality of filtered noise signals in the frequency bands, wherein the navigation signal is spread over a plurality of channels of the LEO signal, wherein the channels are distributed over the frequency bands and a plurality of time slots; means for generating a PRN sequence corresponding to a modulation sequence used by the LEO satellite to spread the navigation signal over the channels; means for modulating the filtered noise signals using the generated PRN sequence to provide a plurality of modulated noise signals; and means for broadcasting the modulated noise signals over an area of operations to provide a plurality of jamming bursts corresponding to the navigation signal, wherein the jamming bursts are configured to substantially mask the navigation signal in the area of operations.
  • Fig. 1 provides an overview of an integrated high- performance navigation and communication system in accordance with an embodiment of the invention.
  • FIG. 2 provides a further overview of the system of Fig. 1 in accordance with an embodiment of the invention.
  • Fig. 3 illustrates an overall operational configuration of the system of Fig. 1 in accordance with an embodiment of the invention.
  • Fig. 4 illustrates an approach for implementing low earth orbit signals in accordance with an embodiment of the invention.
  • Fig. 5 illustrates an autocorrelation function associated with low earth orbit signals in accordance with an embodiment of the invention.
  • Fig. 6 illustrates a process of decoding a military navigation component of a low earth orbit signal in accordance with an embodiment of the invention.
  • Fig. 7 illustrates a block diagram of a correlator of a navigation device in accordance with an embodiment of the invention.
  • Fig. 8 illustrates a process of decoding a commercial navigation component of a low earth orbit signal in accordance with an embodiment of the invention.
  • Fig. 9 illustrates an alternate process of decoding a commercial navigation component of a low earth orbit signal in accordance with an embodiment of the invention.
  • Fig. 10 illustrates a process of decoding a civil navigation component of a low earth orbit signal in accordance with an embodiment of the invention.
  • Fig. 11 illustrates a comparison between navigation components of a low earth orbit signal and GPS codes in accordance with an embodiment of the invention.
  • Fig. 12 illustrates a block diagram of a jamming device that may be used to perform localized jamming of navigation signals in accordance with an embodiment of the invention.
  • Fig. 13 provides a frequency and time domain representation of the operation of the jamming device of Fig. 12 in accordance with an embodiment of the invention.
  • Fig. 14 illustrates a process of generating pseudo random noise in accordance with an embodiment of the invention.
  • Fig. 15 illustrates a process of constructing uniformly distributed integers of a modulo range from a channel selection pool in accordance with an embodiment of the invention.
  • Fig. 16 illustrates a process of converting a channel selection pool to a list of random non-overlapping channels in accordance with an embodiment of the invention.
  • Fig. 17 illustrates a frequency hopping pattern generated by the process of Fig. 16 in accordance with an embodiment of the invention.
  • Fig. 18 illustrates a block diagram of a receiver processor configured to receive and sample navigation signals for downconversion in accordance with an embodiment of the invention.
  • the navigation devices may be configured to blend the broadcast information and the several different types of signals together to perform high-accuracy navigation.
  • the broadcast LEO signal may be implemented with military, commercial, and civil navigation signals to permit partitioning of users among the different navigation signals and to enable infrastructure cost sharing.
  • An integrated spread spectrum, low probability of intercept and detection (LPI/D) data uplink may also be provided as also described herein.
  • FIG. 1 provides an overview of an integrated high-performance navigation and communication system 100 (also referred to as an iGPS system) in accordance with an embodiment of the invention.
  • System 100 may include a navigation device 102 (also referred to as user equipment, a user device and/or a user navigation device) implemented with appropriate hardware and/or software to receive and decode signals from a variety of space and terrestrial ranging sources to perform navigation.
  • a navigation device 102 also referred to as user equipment, a user device and/or a user navigation device
  • appropriate hardware and/or software to receive and decode signals from a variety of space and terrestrial ranging sources to perform navigation.
  • navigation device 102 may be configured to receive global positioning system (GPS) signals 106 (e.g., protected and/or unprotected GPS signals) from conventional navigation satellites.
  • GPS global positioning system
  • navigation device 102 may further receive signals 104 from various low earth orbit (LEO) satellites 108.
  • LEO signals 104 also referred to as iGPS signals
  • LEO signals 104 may be configured as a composite signal including a communication signal 104A, a military navigation signal 104B, a commercial navigation signal 104C, and a civil navigation signal 104D.
  • LEO signals 104 also referred to as iGPS signals
  • iGPS signals may be configured as a composite signal including a communication signal 104A, a military navigation signal 104B, a commercial navigation signal 104C, and a civil navigation signal 104D.
  • Such an implementation allows LEO satellites 108 to simultaneously service military, commercial, and civil users, and allows such users to share the costs of operating system 100.
  • LEO satellites 108 may be implemented by satellites of an existing communication system (e.g., Iridium or Globalstar) that have been modified and/or reconfigured to support system 100 as described herein. As also shown in Fig. 1, LEO satellites 108 may be implemented to support crosslink signals 110 between the various LEO satellites 108.
  • an existing communication system e.g., Iridium or Globalstar
  • LEO satellites 108 may be implemented to support crosslink signals 110 between the various LEO satellites 108.
  • navigation device 102 may calculate its position (and accordingly the position of an associated user) to high accuracy. Once determined, the calculated position data (and other data as may be desired) may then be uplinked to LEO satellites 108 using a spread spectrum data uplink described herein.
  • Navigation device 102 may be further configured to receive and perform navigation using broadcasts of other space and terrestrial ranging sources as may be desired in particular embodiments.
  • navigation device 102 may be configured with an inertial measurement unit (IMU) implemented, for example, as a microelectromechanical system (MEMS) device to provide jamming protection as described herein.
  • IMU inertial measurement unit
  • MEMS microelectromechanical system
  • Navigation device 102 may be implemented in any desired configuration as may be appropriate for particular applications.
  • navigation device 102 may be implemented as a handheld navigation device, a vehicle-based navigation device, an aircraft-based navigation device, or other type of device.
  • Fig. 2 provides a further overview of system 100 in accordance with an embodiment of the invention.
  • Fig. 2 illustrates LEO satellites 108 and GPS satellites 202 in orbit around the earth.
  • Fig. 2 further illustrates various aspects of infrastructure subsystems of system 100.
  • system 100 may include a reference network 204 configured to receive LEO signals 104 or other ranging signals, GPS ground infrastructure 206, and LEO ground infrastructure 208. It will be appreciated that additional spaceborne and/or terrestrial components may also be provided in various embodiments of system 100.
  • Fig. 3 illustrates an overall operational configuration of system 100 in accordance with an embodiment of the invention. It will be appreciated that although a variety of subsystems are illustrated in Fig. 3, all of such subsystems need not be provided in all embodiments of system 100.
  • LEO satellites 108 exhibit rapid angle motion relative to navigation devices 102 and various illustrated terrestrial subsystems.
  • this rapid angle motion can aid the terrestrial subsystems in solving for cycle ambiguities.
  • LEO signals 104 may be implemented with high power relative to conventional navigation signals 106. As such, LEO signals 104 may also enable penetration through interference or buildings.
  • LEO signals 104 may include a ranging and data link to the various ground terminals. As shown in Fig. 3, such terminals may include a geographically diverse reference network 204 and navigation devices 102 (illustrated in this example as a cell phone handset, MEMS device, and an automobile) .
  • GPS satellites 202 Galileo satellites 306, WAAS satellites 302, and QZSS / MSV 304 satellites, any of which may be configured to broadcast ranging and data downlinks to reference network 204 and navigation devices 102 in accordance with various embodiments .
  • Galileo satellites 306, WAAS satellites 302, and QZSS / MSV 304 satellites any of which may be configured to broadcast ranging and data downlinks to reference network 204 and navigation devices 102 in accordance with various embodiments .
  • WAAS satellites 302 Galileo satellites 306, WAAS satellites 302, and QZSS / MSV 304 satellites, any of which may be configured to broadcast ranging and data downlinks to reference network 204 and navigation devices 102 in accordance with various embodiments .
  • QZSS / MSV 304 satellites any of which may be configured to broadcast ranging and data downlinks to reference network 204 and navigation devices 102 in accordance with various embodiments .
  • all of the illustrated satellites may be configured to broadcast to all of navigation devices 102 and reference network 204.
  • a variety of ranging signals 318 from a plurality of ranging signal sources 310 may be monitored by reference network 204 and navigation devices 102.
  • Reference network 204 may be configured to characterize each ranging signal source 310 to provide calibration information associated with each ranging signal source. Such information may be passed to LEO satellite 108 over an appropriate data uplink 320, encoded by LEO satellite 108 into one or more of military, commercial, or navigation signals 104B/104C/104D of LEO signal 104, and broadcast to navigation devices 102 as part of LEO signal 104. The calibration information can then be used by navigation devices 102 to interpret ranging signals 318 in order to perform navigation in combination with a ranging measurement performed using LEO signal 104.
  • a variety of transmitters can provide timing and (and therefore ranging) data.
  • its associated ranging signal may be received by reference network 204 and navigation devices 102.
  • Reference network 204 may determine calibration information associated with the ranging signal, and telemeter such calibration information to navigation devices 102 through a data uplink with LEO satellites 108 and/or through terrestrial links to navigation devices .
  • Fig. 3 illustrates GPS signals 106 being received by one of ranging signal sources 310 implemented as a WiFi node. If the capability to measure the timing (equivalent to range if multiplied by the speed of light) of pre-defined attributes of a WiFi signal is implemented within a GPS receiver, the receiver can measure the received WiFi and GPS signal times concurrently. The difference between these quantities can be calculated, time tagged, and transferred to reference network 204 to provide calibration information associated with the WiFi node. Additional calibration information may be determined by reference network 204 in response to receiving GPS signals 106 and other types of ranging signals 318.
  • reference network 204 may telemeter real-time calibration information associated with the WiFi node to navigation devices 102 through LEO satellite 104 over uplink 320 and LEO signal 104 (e.g., over space-based links). Calibration information may also be provided to navigation devices 102 over terrestrial links.
  • each ranging signal source 310 does not necessarily need to be in view of all nodes of reference network 204 if a network 316 (e.g., the Internet) is present between the various terrestrial nodes .
  • LEO satellites 108 may be implemented as communication satellites (for example, Iridium or Globalstar satellites) that have been modified and/or reconfigured as described herein to support navigation features of system 100.
  • Tables 1 and 2 below identify various attributes of Iridium and Globalstar communication satellites, respectively, that may be used as LEO satellites 108 in accordance with various embodiments : Table 1
  • Time Slots (1) simplex down, (4) 8.28 ms duplex up, (4) 8.28 ms duplex down
  • Iridium communication satellites are used to implement LEO satellites 108
  • flight computers of the Iridium communication satellites can be reprogrammed with appropriate software to facilitate the handling of navigation signals.
  • satellite bent pipe architecture enables ground equipment to be upgraded to enable a variety of new signal formats .
  • the communication satellites may be configured to support communication signals as well as navigation signals.
  • navigation signals may be implemented to account for various factors such as multipath rejection, ranging accuracy, cross-correlation, resistance to jamming and interference, and security, including selective access, anti-spoofing, and low probability of interception.
  • Fig. 4 illustrates an approach for implementing LEO signals 104 in accordance with an embodiment of the invention.
  • blocks 410, 420, and 430 of Fig. 4 illustrate the structure of signals transmitted and received by LEO satellites 108 to provide support for communication and navigation signals, where LEO satellites 108 are implemented using existing Iridium communication satellites.
  • frequency is shown in the horizontal axis
  • time is shown in and out of the page
  • power spectral density is shown in the vertical axis.
  • some of the transmit slots 402 and receive slots 404 may be associated with existing communications (e.g., shown in Fig. 4 as telephone calls 440) .
  • the used transmit slots 402 may correspond to the data provided over communication signal 104A of LEO signal 104 transmitted by LEO satellite 108. It will be appreciated that in the embodiment shown in block 410, a plurality of transmit slots 402 remain unused. In accordance with various embodiments of the invention, the unused communication capacity of unused transmit slots 402 may be leveraged to support navigation signals as described herein.
  • a ranging overlay 422 of pseudo random noise (PRN) may be introduced in each of the remaining unused transmit slots 402.
  • Ranging overlay 422 can be run at low average power on a channel-by-channel basis, but with the aggregate ranging overlay 422 exhibiting high power to overcome jamming.
  • block 430 shows ranging overlay 422 implemented using a maximum power spot beam provided by LEO satellite 108.
  • ranging overlay 422 may be implemented using a combination of frequency hopping and direct sequence PRN.
  • frequency hopping component a subset of frequencies may be chosen on a pseudo-random basis each burst. Then, within each burst, the data bits are also chosen on a pseudo-random basis.
  • telephone calls 440 may be given priority in transmit slots 402 over ranging overlay 422, with ranging overlay 422 being little affected by occasional missing or corrupted bursts.
  • ranging overlay 422 may be given priority in transmit slots 402 over telephone calls 440, with telephone calls 440 similarly being little affected by occasional missing or corrupted bursts.
  • ranging overlay 422 may be implemented with as wide a bandwidth as possible subject to spectrum regulations.
  • all available channels may be used, and various methods of frequency, time, and code division multiple access (CDMA) may be employed to create a downlink signal that tends to look like flat white noise unless the user knows the code.
  • CDMA code division multiple access
  • the flatness provides a signal that is well suited for accuracy, jam resistance, and multipath rejection. Cross correlation can be minimized by using an appropriate encryption algorithm made possible by fast digital signal processing in navigation device 102.
  • LEO signal 104 may be implemented as a complex signal s(t) versus time t as shown in the following equation:
  • A is the signal amplitude
  • n is the symbol index
  • p is the direct-sequence pseudo-random noise value given as ⁇ 1
  • h is the symbol impulse response
  • m is the channel frequency index
  • f0 is the spread spectrum broadcast span
  • N is the number of channel frequencies forming the spread spectrum broadcast span.
  • a low-power direct- sequence code may be provided on each of the 1.25 MHz channels that is orthogonal to telephony traffic.
  • Fig. 5 provides plots 504 and 510 of autocorrelation function 502 using different scales.
  • an envelope 506 of autocorrelation function 502 is shown as being formed by the effective correlation length of the 25ksps direct sequence data.
  • autocorrelation is formed by the aggregation of the broadband channels separated by 41.667 kHz.
  • the effective direct sequence chip length may be that of Y code, namely 30m.
  • an example GPS coarse / acquisition (C/A) code 512 and an example GPS military (M) code 514 are also shown superimposed on plot 510.
  • the side lobes of autocorrelation function 502 are as readily manageable as those for GPS M-code 514. In this regard, the side lobes of autocorrelation function 502 are either highly attenuated or clearly distinguishable.
  • Fig. 6 illustrates a process of decoding military navigation signal 104B of LEO signal 104 in accordance with an embodiment of the invention. It will be appreciated that the process of Fig. 6 may be performed by navigation device 102 in response to receiving LEO signal 104.
  • LEO signal 104 may include several parallel channels 602 (shown as 12 channels in Fig. 6) configured to carry military navigation signal 104B.
  • a pseudo-random process may be used to determine the particular channels 602 activated for each broadcast burst from LEO satellites 108.
  • a string of quadrature phase-shift key (QPSK) symbols 604 are illustrated for each parallel burst on channels 602, with time going into the page.
  • QPSK symbols 604 are modulated with the PRN direct sequence encoding and also exhibit bias and rotation based on their frequency offset in LEO signal 104.
  • step 2 of Fig. 6 the PRN encoding is despread by rotating each burst to baseband, subtracting off inter-channel bias, and stripping off the PRN direct sequence pattern to provide a set of bursts carrying data associated with military navigation signal 104B, as represented by modified QPSK symbols 606.
  • step 3 of Fig. 6 low-bit rate data is demodulated according to a set of M possible orthogonal macro symbols 608. If quarter cycle ambiguities from the QPSK modulation are present, the combined ambiguities and macro symbols may not be perfectly orthogonal. Once the data is estimated, a hard decision algorithm strips off the estimated data leaving only unmodulated carrier 610.
  • step 4 of Fig. 6 the carrier is averaged over the entire burst and then over each channel.
  • an in phase and quadrature measurement 612 of the instantaneous tracking error can be provided.
  • a phase locked loop (PLL) of navigation device 102 is then used to track the satellite carrier.
  • Fig. 7 illustrates a block diagram of a correlator of navigation device 102 that may be used to perform the process of Fig. 6 in accordance with an embodiment of the invention.
  • a numerically controlled oscillator 702 generates a carrier that downconverts the incoming LEO signal 104 (e.g., received through an antenna of navigation device 102) to a baseband signal 714.
  • Baseband signal 714 is provided to an upper path 704 that performs punctual code carrier tracking.
  • Baseband signal 714 is also provided to a lower path 706 that performs early minus late detection.
  • a bank of synthesizers 708 and PRN generators 710 replicate each channel of LEO signal 104.
  • replicated signals 712 are mixed with baseband signal 714 to remove all code and phase rotation for each channel separately.
  • a hypothesis generator 716 computes the signal associated with each of the possible macro symbols 608 and quarter cycle ambiguities, if any.
  • a processor 718 uses a maximum a posteriori (MAP) algorithm to provide a data estimate 720 identifying which of the macro symbol hypotheses is most likely. As shown, data estimate 720 is passed to lower path 706 for use in early minus late detection. To perform punctual detection in upper path 704, processor 718 strips off the data and outputs the resulting bursts to summing block 722 that integrates the aggregate bursts over time to arrive at the in phase and quadrature tracking error 724.
  • MAP maximum a posteriori
  • each counter value 1402 may include a type flag 1412 that identifies each counter value 1402 as specifying either a channel selection (e.g., if type flag 1412 is set to a "1") or direct sequence chips (e.g., if type flag 1412 is set to a "0"). If type flag 1412 is set to channel selection, then other bits of counter value 1402 may specify which channels of a channel selection pool 1408 through which to broadcast data burst chips.
  • a type flag 1412 that identifies each counter value 1402 as specifying either a channel selection (e.g., if type flag 1412 is set to a "1") or direct sequence chips (e.g., if type flag 1412 is set to a "0"). If type flag 1412 is set to channel selection, then other bits of counter value 1402 may specify which channels of a channel selection pool 1408 through which to broadcast data burst chips.
  • type flag 1412 is set to direct sequence
  • other bits of counter value 1402 may correspond to a chip block index 1414 (e.g., specifying a particular one of direct sequence chips 1410 to be broadcast) and a burst count 1416 (e.g., specifying a frame number of the particular direct sequence chip 1410 to be broadcast) .
  • cipher 1406 can be used to select a value from a channel selection random number pool 1408 that directs frequency hopping. In another embodiment, cipher 1406 can be used to select direct sequence chips 1410 that fill up the QPSK data bits.
  • Fig. 16 illustrates a process of converting channel selection pool 1408 to a list of random non-overlapping channels in accordance with an embodiment of the invention.
  • the process of Fig. 16 can be used for military navigation signal 104B, commercial navigation signal 104C, and civil navigation signal 104D, by selecting different parameters for M and N (shown in Fig. 16) in accordance with values provided in the following Table 4:
  • Fig. 17 illustrates a frequency hopping pattern generated by the process of Fig. 16 in accordance with an embodiment of the invention.
  • various random channel selections (associated with corresponding transmission frequencies) are provided for successive transmission bursts.
  • each frequency and chip is generated in a pseudo random manner using a common key (for example, a 128-bit key) known in advance by LEO satellite 108 and navigation device 102.
  • Figs. 18-21 illustrate various aspects of navigation device 102 that may be implemented in accordance with various embodiments of the invention.
  • Fig. 18 illustrates a block diagram of a receiver processor 1800 of navigation device 102 configured to receive and sample signals for downconversion in accordance with an embodiment of the invention.
  • navigation signals received by an antenna 1802 are filtered by multi-band filters 1804 (to preselect desired frequency bands), amplified by amplifier 1806, and sampled by sample and hold circuitry 1808 to provide raw digital RF samples 1816.
  • Receiver processor 1800 also includes an oscillator 1810 and synthesizer 1812 that may be used to synchronize sample and hold circuitry 1808.
  • the sample rate of sample and hold circuitry 1808 may be chosen to prevent overlap among aliased, pre-selected frequency bands.
  • Fig. 21 illustrates a block diagram of one of tracking modules 1906 in accordance with an embodiment of the invention.
  • Tracking module 1906 receives feed forward commands 1908 to preposition both the code and carrier phase for the particular ranging signal being tracked by tracking module 1906.
  • Downconverter 1950 rotates the carrier provided in complex samples 1904 to baseband as a first processing step.
  • the downconverted signal 1952 signal is split and passed to a matched early minus late filter 1954 and a matched punctual filter 1956.
  • filters 1954 and 1956 provide in-phase and quadrature representations of early minus late tracking errors 1958 and punctual tracking errors 1960, respectively.
  • the signal reference waveform is encoded as an impulse response parameter whose time origin is tied to the broadcast clock.
  • the broadcast frequency is the carrier frequency of the ranging source.
  • the broadcast location is encoded as a precision ephemeris for space vehicles and as a Cartesian static coordinate for terrestrial ranging sources.
  • a clock correction calibrates the ranging source against system time based on Coordinated Universal Time (UTC) (e.g., provided by the United States Naval Observatory (USNO) ) .
  • UTC Coordinated Universal Time
  • USNO United States Naval Observatory
  • appropriate ground stations may be configured to decipher new ranging signal codes employed by LEO satellites 108 in near real-time.
  • such ground stations may provide the deciphered codes to navigation devices 102, thereby permitting navigation devices 102 to perform navigation using virtually any signal, cooperative or not.
  • Figs. 22-29 illustrate various uses of system 100 to perform navigation in different environments services in accordance with various embodiments of the invention.
  • Fig. 22 illustrates the use of system 100 to provide indoor positioning in accordance with an embodiment of the invention.
  • navigation device 102 may be positioned inside a building or other structure.
  • navigation device 102 may receive LEO signal 104 either directly from LEO satellite 108 and additional ranging signals 318 from nodes 310.
  • reference stations of reference network 204 may also receive ranging signals 318.
  • reference network 204 may be configured with appropriate hardware or software to determine calibration information associated with each ranging signal source 310, passed to LEO satellite 108 over data uplink 320, encoded by LEO satellite 108 into LEO signal 104, and broadcast to navigation device 102 as part of LEO signal 104. The calibration information can then be used by navigation devices 102 to interpret ranging signals 318 in order to perform navigation in combination with a ranging measurement performed using LEO signal 104.
  • navigation device 102 may utilize LEO signal 104 and ranging signals 318 to perform navigation.
  • Military navigation signal 104B (e.g., provided by LEO satellite 108 as part of LEO signal 104) as well as ranging signals 318 (e.g., provided by ranging signal sources 310 such as cellular or television signal sources) may be implemented as high power signals capable of penetrating building materials to reach navigation device 102 when positioned in indoor environments. Accordingly, by using such high power signals in the approach shown in Fig. 22, navigation device 102 may perform navigation indoors and acquire quickly from a cold start.
  • Fig. 23 illustrates the use of system 100 to provide indoor positioning in accordance with another embodiment of the invention. It will be appreciated that the implementation shown in Fig. 23 generally corresponds with the implementation of Fig. 22 previously discussed. However, in the embodiment shown in Fig. 23, navigation device 102 may also optionally communicate with reference network 204 or nodes 312 or 314 through network 316.
  • navigation device 102 may determine its final position fix by forming a vector of pseudoranges for each ranging source, k, then linearizing about an initial guess for user position, x, and user clock bias ⁇ .
  • the method of least squares is used to refine the user position estimate:
  • system 100 may be implemented to provide high-accuracy, high-integrity navigation.
  • Fig. 24 illustrates the use of system 100 to perform navigation using GPS signals 106 and dual band LEO signals 104 and 104' in accordance with an embodiment of the invention.
  • Fig. 24 shows how a single-frequency Ll GPS signal may be used with two different LEO signals 104 and 104' (e.g., different LEO signals in different frequency bands from different LEO satellites 108 and 108') to provide a high level of navigation performance.
  • the carriers of GPS signals 106 and LEO signals 104 and 104' are sufficient for navigation--the code phases from the signals need not be used.
  • both code and carrier are used to derive maximum information from the available observables.
  • stations of reference network 204 may monitor GPS signals 106 and LEO signals 104 and 104', and gather continuous carrier phase information to carry out precise orbit determination of GPS satellites 202 and LEO satellites 108.
  • LEO signals 104 and 104' effects of the ionosphere can be removed, yielding a carrier phase signal that is ionosphere free.
  • Cycle ambiguities of all GPS satellites 202 and LEO satellites 104 and 104' e.g., shown by ellipsoids 2402
  • the position of navigation device 102 (e.g., an aircraft in this embodiment) can be determined in Fig.
  • the following notation provides the kth pseudorange measurement to determine the user position, x, at epoch m, and the tropospheric zenith delay, DZ, along with all the satellite range biases, modeled as continuous variable, b.
  • the method of least squares is used to solve the system of equations for the position adjustments, time biases, and vector of range biases. Even though measurements using GPS signals 106 are single frequency and subject to ionospheric bias, the resulting solution does not have an ionospheric dependence. Because measurements using LEO signals 104 and 104' are ionosphere free and because LEO satellites 104 and 104' exhibit rapid angle motion (compared with the virtually static motion of GPS satellites 202), the geometry matrix is full rank with the exception of a common mode between the clock and the ranging biases. This means that the bias estimates for GPS satellites 202 take on values that position the user correctly based on the ionosphere-free measurements using LEO signals 104 and 104' .
  • Fig. 25 illustrates the use of system 100 to perform navigation using GPS signals 106 and a single LEO signal 104 in accordance with an embodiment of the invention.
  • the orbit geometry of a single LEO satellite 108 in view tends to place the LEO satellite 108 on a trajectory that aligns a position uncertainty ellipsoid 2502 with the local horizontal.
  • a third signal 2504 e.g., from Galileo satellite 306 or another satellite
  • navigation device 102 e.g., an aircraft in this embodiment
  • the integrity of a navigation system can be measured by the system's ability to provide timely warnings to users when it should not be used.
  • the integrity risk of a navigation system can be characterized as the probability of an undetected hazardous navigation system anomaly.
  • system 100 can be implemented to provide high integrity using Receiver Autonomous Integrity Monitoring (RAIM) .
  • RAIM Receiver Autonomous Integrity Monitoring
  • navigation device 102 can be configured to monitor measurement self-consistency to detect navigation errors associated with a variety of failure modes.
  • the rapid motion of LEO satellites 108 can facilitate such measurements.
  • the residual of the least squares fit is used to carry out a chi-square hypothesis detection of a system fault.
  • the following equation may be used:
  • ⁇ corresponds to ranging measurements
  • H corresponds to a satellite geometry matrix
  • x corresponds to a position estimate.
  • navigation device 102 maybe configured to calculate measurement residual R. If R is less than a threshold value, then system 100 is deemed to be operating properly. If R is greater or equal to a threshold value, the navigation device 102 may issue an integrity alarm.
  • Fig. 26 shows the effect of a ranging error on a position solution in accordance with an embodiment of the invention.
  • the ranging measurements are self consistent. However, should one or more of the measurements be corrupted and biased, the error could push the output solution away from the truth.
  • RAIM is able to detect the error because the inconsistency among measurements is highly correlated with the actual position error.
  • Fig. 28 illustrates the use of system 100 to perform navigation using signals received directly from LEO satellite 108 and GPS satellites 202 in accordance with an embodiment of the invention.
  • Fig. 29 illustrates a similar implementation of Fig. 28, but with network 316 and ranging signals 318 added to preclude momentary interruptions in LEO signals 104 and GPS signals 106 from affecting the continuity of service.
  • system 100 may be configured to support data uplink 320 from reference stations of reference network 204 to facilitate navigation performed by navigation devices 102 using navigation signals 104B/104C/104D.
  • Data uplink 320 may also be supported by appropriately-configured navigation devices 102.
  • data uplink 320 may also be used to pass any desired data from reference network 204 and/or navigation devices 102 to LEO satellite 108 for subsequent broadcast as part of communication signal 104A of LEO signal 104.
  • GPS Time and UTC are available from a precision timing function of system 100, it is possible to establish a one-way uplink protocol that allows data uplink 320 to occur without direct two-way synchronization.
  • the time and frequency phasing of data uplink 320 can be pre-positioned to arrive at LEO satellite 108 to exactly match the satellite's instantaneous carrier phase and frame structure on a symbol-by-symbol basis.
  • data uplink 320 may be configured as a spread spectrum uplink with anti-jamming and low probability of intercept and detection (LPI/D) characteristics.
  • LPI/D low probability of intercept and detection
  • low power signals of data uplink 320 may be summed over many symbols to pull an aggregate macro symbol out of the noise and provide an LPI/D uplink.
  • Fig. 30 illustrates a generalized frame structure for data bursts 3002 of uplink 320 to LEO satellite 108 in accordance with an embodiment of the invention.
  • data uplink 320 may be configured to support uplink bursts on approximately 240 channels with 414 bits per burst.
  • the frame structure of LEO satellite 108 may be pre-positioned in a rest state (e.g., no time shift and no frequency shift relative to a master clock of LEO satellite 108) .
  • a reference station of reference network 204 may be configured to generate an appropriate synchronization signal for data uplink 320 to LEO satellite 108. The effect of this synchronization signal is to pre-align the frame structure for the data symbols in a burst against the UTC or GPS Time reference.
  • the demodulator is treated as a hard limiter.
  • the center Gaussian curve shown in Fig. 32 is representative.
  • the presence of a signal i.e., a data bit
  • LEO satellite 108 can detect the emergence of a signal. Calculations known to those skilled in the art place the loss of a hard limiter at about 2 dB. In other words, but for a 2 dB effective analog to digital conversion loss, the input signal is completely preserved—even if LEO satellite 108 was originally implemented as communication satellite.
  • the above approach is not limited to particular implementations of LEO satellite 108.
  • the timing advance parameter then governs the synthesis of the signal in the baseband processor.
  • the data to be uplinked is encoded and encrypted in block 3304 according to user preference.
  • Data modulator block 3306 generates 40% root raised cosine pulses that are modulated by the appropriate data bit,
  • PRN direct sequence code and channel frequency offset provided by PRN generator block 3310 and synthesizer block 3312. Any desired number of channels can be concurrently processed in parallel.
  • the signals are summed, upconverted (in this case by 100 MHz) , converted to real form, converted from digital to analog, and upconverted to RF for broadcast as shown by blocks 3316 through 3324 of Fig. 33.
  • the baseband component may be implemented to reside in the modified baseband real estate of a DAGR or cellular handset.
  • antenna 3324 may also be used for GPS signals in a DAGR or cellular handset.
  • the power consumption and form factor of the data uplink broadcast hardware may be implemented for handset or compact use.
  • such transmit hardware may be implemented by a RF2638 chip available from RF Micro Devices that provides 10 dBm of RF output power and draws 25 mA at 3V.
  • Waveforms associated with the various macro symbol hypotheses are mixed with the incoming signal and then processed by a processor 3412 (e.g., in the manner previously described with regard to processor 718) to provide the resulting data message 3414.
  • orthogonal encoding provides excellent bit energy per noise spectral density (Eb/NO) performance for data uplink 320.
  • system 100 may be implemented to support communications navigation and surveillance-air traffic management.
  • navigation devices 102 may be implemented in aircraft (e.g., in place of the antenna and GPS card in an aircraft's Multi-Mode Receiver (MMR)) to enable Cat III landing, a built-in communication link, integrated automatic dependent surveillance, and integrated space-based air traffic control .
  • system 100 may be implemented to support search and rescue.
  • navigation devices 102 may be configured to provide global E911 features for both military and civil purposes. The LPI/D characteristics of the military version of data uplink 320 could qualify a modified DAGR to be employed under hostile conditions.
  • system 100 may be implemented to support battle damage assessment.
  • information gathered in human or sensor form, including position information can be quickly aggregated via data uplink 320.
  • system 100 may be implemented to support weather information correlated by position can be aggregated in real time.

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Abstract

L'invention concerne un système de navigation à haute performance généralisée qui utilise des satellites à orbite basse (LEO). Dans un mode de réalisation, un procédé consistant à effectuer une navigation comprend la réception d'un signal LEO provenant d'un satellite LEO, le décodage du signal de navigation à partir du signal LEO, la réception des premier et second signaux de mesure de distance à partir de première et seconde mesures de distance, respectivement, la détermination des informations de calibrage associées aux première et seconde sources de mesure de distance, et le calcul d'une position en utilisant le signal de navigation, les premier et second signaux de mesure de distance et les informations de calibrage. Dans un autre mode de réalisation, un procédé consistant à fournir un signal LEO provenant d'un satellite LEO comprend la fourniture d'une pluralité de canaux de transmission sur une pluralité de fentes de transmission, les canaux de transmission comprenant un ensemble de canaux de communication et un ensemble de canaux de navigation, la production d'une première superposition de mesure de distance et de bruit pseudo-aléatoire (PRN) correspondant à un signal de navigation, l'application de la première superposition de mesure de distance et du PRN à un premier ensemble de canaux de navigation et la combinaison des canaux de communication et des canaux de navigation en un signal LEO. Le procédé comprend aussi la diffusion du signal LEO à partir du satellite LEO. Une liaison montante de données de satellite à orbite basse (LEO) est aussi proposée. Un procédé comprend la diffusion du signal montant de données vers le satellite LEO. Diverses approches d'un brouillage des signaux de navigation locaux sont en outre proposées. Des signaux de bruit modulés sont diffusés sur une zone d'opérations pour fournir une pluralité de salves de brouillage correspondant au signal de navigation. Les salves de brouillage sont configurées pour masquer sensiblement le signal de navigation dans la zone d'opérations.
EP07873721A 2006-05-18 2007-05-17 Système de navigation à haute performance généralisée Withdrawn EP2033010A2 (fr)

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US11/749,597 US8296051B2 (en) 2006-05-18 2007-05-16 Generalized high performance navigation system
US11/749,652 US7583225B2 (en) 2006-05-18 2007-05-16 Low earth orbit satellite data uplink
US11/749,667 US7554481B2 (en) 2006-05-18 2007-05-16 Localized jamming of navigation signals
US11/749,627 US7579987B2 (en) 2006-05-18 2007-05-16 Low earth orbit satellite providing navigation signals
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JP2010506138A (ja) 2010-02-25
CA2647582A1 (fr) 2008-09-04
WO2008105778A3 (fr) 2009-03-12
WO2008105778A2 (fr) 2008-09-04
EP2330441B1 (fr) 2014-03-05
KR20090013760A (ko) 2009-02-05
IL194338A (en) 2014-12-31
IL220751A0 (en) 2012-08-30
AU2007347851A1 (en) 2008-09-04
IL194338A0 (en) 2009-08-03
EP2330441A1 (fr) 2011-06-08
JP5253388B2 (ja) 2013-07-31
KR101378272B1 (ko) 2014-03-25

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