Abstract: The invention is a secure digital signature device which generates digital signature key pairs using a hardware random number generator. It transmits public keys to one or more smart devices and signs bit strings at the request of smart devices without exposing private keys. Requests for signatures from smart devices are not fulfilled unless the user takes action on the apparatus of the present invention: pushing a button, swiping a fingerprint, scanning their eye. The requirement for user action precludes malware issuing unintended signatures through the smart device. The private keys are maintained solely on the apparatus of the invention and are therefore not vulnerable to attack by malware on the smart device or a host server.

Abstract: Methods and systems for using W-code to extend anti-spoof capability to civilian GPS receivers for verifying locations of mobile terminals are disclosed. A system for verifying a reported location of a mobile terminal includes a receiver of the mobile terminal and a verification processor. The receiver processes the radio ranging signals to generate measured quantities related to the W-code to the verification processor. The receiver also provides the reported location of the mobile terminal to the verification processor. The verification processor generates expected quantities related to the W-code based on the reported location of the mobile terminal. The verification processor further compares the measured quantities related to the W-code to the expected quantities related to the W-code to verify the reported location of the mobile terminal.

Abstract: A system for determining the location of an object includes an interrogator remote from the object and a transponder located at the object. The interrogator receives GPS signals and transmits pre-positioning data and a tracking signal to the transponder. The pre-positioning data includes pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset while the tracking signal includes reference time and frequency information. The transponder collects RF samples of at least one of the GPS signals associated with one of the PRN code numbers and correlates the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce the correlation snapshot. The transponder transmits the correlation snapshot to the interrogator and the interrogator determines the pseudorange associated with the GPS signal using the correlation snapshot.

Abstract: Methods and systems for using W-code to extend anti-spoof capability to civilian GPS receivers for verifying locations of mobile terminals are disclosed. A system for verifying a reported location of a mobile terminal includes a receiver of the mobile terminal and a verification processor. The receiver processes the radio ranging signals to generate measured quantities related to the W-code to the verification processor. The receiver also provides the reported location of the mobile terminal to the verification processor. The verification processor generates expected quantities related to the W-code based on the reported location of the mobile terminal. The verification processor further compares the measured quantities related to the W-code to the expected quantities related to the W-code to verify the reported location of the mobile terminal.

Abstract: A local ranging system for use with GPS receivers and GPS enabled devices. A device in accordance with the present invention comprises a Radio Frequency (RF) section, the RF section adaptable to receive at least one GPS signal from at least one GPS satellite, and a baseband section, coupled to the RF section, wherein the baseband section performs calculations to determine a geoposition of the GPS receiver based on the at least one GPS signal, wherein the baseband section further comprises a Pseudo Noise (PN) output.

Abstract: A system for determining the location of an object includes an interrogator remote from the object and a transponder located at the object. The interrogator receives GPS signals and transmits pre-positioning data and a tracking signal to the transponder. The pre-positioning data includes pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset while the tracking signal includes reference time and frequency information. The transponder collects RF samples of at least one of the GPS signals associated with one of the PRN code numbers and correlates the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce the correlation snapshot. The transponder transmits the correlation snapshot to the interrogator and the interrogator determines the pseudorange associated with the GPS signal using the correlation snapshot.

Abstract: A navigation system for tracking the position of an object includes a GPS receiver responsive to GPS signals for periodically providing navigation state measurement updates to a navigation processor. The system also includes a dead-reckoning sensor responsive to movement of the object for providing movement measurements to the navigation processor. The navigation processor determines object navigation states using the navigation state measurement updates and propagates the object navigation states between measurement updates using the movement measurements.

Abstract: A system for determining the location of an object includes an interrogator remote from the object and a transponder located at the object. The interrogator receives GPS signals and transmits pre-positioning data and a tracking signal to the transponder. The pre-positioning data includes pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset while the tracking signal includes reference time and frequency information. The transponder collects RF samples of at least one of the GPS signals associated with one of the PRN code numbers and correlates the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce the correlation snapshot. The transponder transmits the correlation snapshot to the interrogator and the interrogator determines the pseudorange associated with the GPS signal using the correlation snapshot.

Abstract: A system for determining the location of an object includes an interrogator remote from the object and a transponder located at the object. The interrogator receives GPS signals and transmits pre-positioning data and a tracking signal to the transponder. The pre-positioning data includes pseudorandom noise (PRN) code number, Doppler frequency offset and code phase offset while the tracking signal includes reference time and frequency information. The transponder collects RF samples of at least one of the GPS signals associated with one of the PRN code numbers and correlates the RF samples of the GPS signal against code replicas of the GPS signal based on the Doppler frequency offset, code phase offset and reference time and frequency information for that GPS signal to produce the correlation snapshot. The transponder transmits the correlation snapshot to the interrogator and the interrogator determines the pseudorange associated with the GPS signal using the correlation snapshot.

Abstract: A navigation system for tracking the position of an object includes a GPS receiver responsive to GPS signals for periodically providing navigation state measurement updates to a navigation processor. The system also includes a dead-reckoning sensor responsive to movement of the object for providing movement measurements to the navigation processor. The navigation processor determines object navigation states using the navigation state measurement updates and propagates the object navigation states between measurement updates using the movement measurements.

Abstract: A navigation system for tracking the position of an object includes a GPS receiver responsive to GPS signals for periodically providing navigation state measurement updates to a navigation processor. The system also includes a dead-reckoning sensor responsive to movement of the object for providing movement measurements to the navigation processor. The navigation processor determines object navigation states using the navigation state measurement updates and propagates the object navigation states between measurement updates using the movement measurements.

Abstract: A communications system for determining the position and velocity of an object using a plurality of GPS signals transmitted by a plurality of GPS sources includes an interrogator remote from the object and responsive to the plurality of GPS signals. The interrogator transmits an RF signal including GPS source information and at least one of frequency information and time and code phase information of at least one of the GPS signals. The system also includes a transponder positioned on the object and responsive to the RF signal and the plurality of GPS signals. The transponder tracks one of the plurality of GPS signals in response to the GPS source information and the frequency information and time and code phase information. The transponder generates a correlation snapshot and transmits the snapshot to the interrogator.

Abstract: A communications system for determining the position and velocity of an object using a plurality of GPS signals transmitted by a plurality of GPS sources includes an interrogator remote from the object and responsive to the plurality of GPS signals. The interrogator transmitts an RF signal comprising GPS source information and at least one of frequency information and time and code phase information of at least one of the GPS signals. The system also includes a transponder positioned on the object and responsive to the RF signal and the plurality of GPS signals. The transponder tracks one of the plurality of GPS signals in response to the GPS source information and the frequency information and time and code phase information. The transponder generates a correlation snapshot and transmits the snapshot to the interrogator.

Abstract: A communications system for determining the position and velocity of an object using a plurality of GPS signals transmitted by a plurality of GPS sources includes an interrogator remote from the object and responsive to the plurality of GPS signals. The interrogator transmitts an RF signal including GPS source information and at least one of frequency information and time and code phase information of at least one of the GPS signals. The system also includes a transponder positioned on the object and responsive to the RF signal and the plurality of GPS signals. The transponder tracks one of the plurality of GPS signals in response to the GPS source information and the frequency information and time and code phase information. The transponder generates a correlation snapshot and transmits the snapshot to the interrogator.

Abstract: A rescue radio system includes a radio frequency tag, which is carried by and remains with an aircraft, and a rescue radio, which is carried by and remains with an aircrew member. The rescue radio includes an accelerometer that generates an actuation signal in response to the rescue radio being accelerated at a rate that is at least as great as the minimum amount of acceleration that the rescue radio can experience while the rescue radio is being carried by an aircrew member who is ejected from the aircraft. In response to the actuation signal, an interrogator of the rescue radio is activated so that it transmits an interrogatory signal. The radio frequency tag emits a reply signal in response to receiving the interrogatory signal. The interrogator receives the reply signal if the rescue radio is proximate to the radio frequency tag.