Abstract: Embodiments of the present invention are directed to a method and apparatus for substituting temperature sensor data for a satellite signal in a GPS receiver. In one embodiment of the present invention, a mathematical model of a GPS receiver's clock's response to temperature change is maintained. In one embodiment, the mathematical model is a third order polynomial. In one embodiment, when a GPS receiver has contact with at least four GPS satellites, the receiver collects data on changes in temperature and resulting changes in the GPS receiver's clock frequency. The data is incorporated into the GPS receiver's mathematical model. In one embodiment, the data is incorporated by modifying one or more coefficients in the mathematical model. In one embodiment, if a GPS receiver only has contact with three GPS satellites, changes in temperature and the mathematical model are used to estimate an adjustment to the signal generated by the clock.

Abstract: A Global Positioning System carries out Doppler correction of a C/A code sequence after a frequency conversion, and calculates a pseudo range by performing correlation calculation between the C/A code, which is obtained by summing up the C/A code sequence beginning from a polarity inversion boundary determined at a correlation peak detecting step ST10, and a C/A code generated in a GPS terminal. When a received electric field detected by a received electric field intensity detector 11 is good, the current position is determined from the pseudo range and the navigation data extracted by the GPS terminal itself, whereas when the received electric field is poor, the current position is determined from the pseudo range and the navigation data sent from an external apparatus.

Abstract: A Global Positioning System carries out Doppler correction of a C/A code sequence after a frequency conversion, and calculates a pseudo range by performing correlation calculation between the C/A code, which is obtained by summing up the C/A code sequence beginning from a polarity inversion boundary determined at a correlation peak detecting step ST10, and a C/A code generated in a GPS terminal. When a received electric field detected by a received electric field intensity detector 11 is good, the current position is determined from the pseudo range and the navigation data extracted by the GPS terminal itself, whereas when the received electric field is poor, the current position is determined from the pseudo range and the navigation data sent from an external apparatus.

Abstract: A receiver of a radio frequency signal having a pseudo-random noise (PRN) code, and techniques of processing such a signal that are especially adapted for ranging applications. A signal corresponding to the PRN code is locally generated and used for decoding the received signal in a manner to reduce ranging errors that can result when multipath (delayed) versions of the radio frequency signal are also present. A significant application of the receiver and signal processing techniques of the present invention is in a Global Positioning System (GPS), wherein a number of such signals from several satellites are simultaneously received and processed in order to obtain information of the position, movement, or the like, of the receiver. A delay locked loop (DLL) correlator, provided in each of the receiver's multiple processing channels, locks onto a line of sight signal from one of the satellites with the effect of any multipath signal(s) being significantly reduced.

Abstract: A Global Positioning System carries out Doppler correction of a C/A code sequence after a frequency conversion, and calculates a pseudo range by performing correlation calculation between the C/A code, which is obtained by summing up the C/A code sequence beginning from a polarity inversion boundary determined at a correlation peak detecting step ST10, and a C/A code generated in a GPS terminal. When a received electric field detected by a received electric field intensity detector 11 is good, the current position is determined from the pseudo range and the navigation data extracted by the GPS terminal itself, whereas when the received electric field is poor, the current position is determined from the pseudo range and the navigation data sent from an external apparatus.

Abstract: A quadrifilar antenna for use in satellite communications comprises four conductive elements arranged to define two separate helical pairs, one slightly differing in electrical length than the other, defined by a cylinder of constant radius supported by itself or by a cylindrical non-conductive substrate. The two separate helical pairs are connected to each other in such a way as to constitute the impedance matching, electrical phasing, coupling and power distribution for the antenna. In place of a conventional balun, the antenna is fed at a tap point on one of the conductive elements determined by an impedance matching network which connects the antenna to a transmission line. The matching network can be built with distributed or lumped electrical elements and can be incorporated into the design of the antenna.

Abstract: A Global Positioning System carries out Doppler correction of a C/A code sequence after a frequency conversion, and calculates a pseudo range by performing correlation calculation between the C/A code, which is obtained by summing up the C/A code sequence beginning from a polarity inversion boundary determined at a correlation peak detecting step ST10, and a C/A code generated in a GPS terminal. When a received electric field detected by a received electric field intensity detector 11 is good, the current position is determined from the pseudo range and the navigation data extracted by the GPS terminal itself, whereas when the received electric field is poor, the current position is determined from the pseudo range and the navigation data sent from an external apparatus.

Abstract: A receiver of a radio frequency signal having a pseudo-random noise (PRN) code modulated on a carrier, and techniques of processing such a signal that are especially adapted for ranging applications. Such an application is in a global positioning system (GPS or GLONASS) receiver. Both of the receiver DLL code and PLL carrier loops include a loop component that senses an error in its main loop caused by the presence of a multipath signal. The main loop is continuously adjusted by this sensed error, thereby causing the loop to track more precisely and minimize the effect of the multipath signal. The result is a more accurate range measurement.

Abstract: A technique of accurately determining the relative position of two points using carrier phase information from receivers capable of making code and carrier phase measurements on the L1 and L2 frequencies of signals from either or both GPS and GLONASS satellites. These signals are processed by a receiving system to determine relative position, for the purpose of surveying or otherwise, with the accuracy of carrier phase measurements being obtained. Signal processing similar to that used in existing GPS carrier phase based relative positioning receivers is used with GLONASS signals as well, with a modification that takes into account the unique and different frequencies of the signals from individual GLONASS satellites. Surface acoustic wave (“SAW”) filters are also employed in an intermediate frequency receiver section in order to avoid imparting different delays to the GLONASS signals of different frequencies.

Abstract: In a microstrip patch antenna, multipath signals from below the horizon can be reduced by forming ground elements along the edge of the dielectric substrate. Additionally, by using lugs and capacitive elements in the patch antenna, the bandwidth of the antenna can be expanded while maintaining all other antenna characteristics as good as possible.

Abstract: The attenuator is applicable to the art of identification, interrogation and communication equipment. The attenuator has particular application to equipment used in conjunction with smart cards, tags and like apparatus and including, in one form, an RF based technology, which has found a use in electronic ticketing, monitoring passenger movement and the identification and sorting of airline baggage and/or other items, such as containers or mail items. The attenuator, in one form, is predicated on the principle of creating a substantially opposing field, and applying this proximate the interrogator to substantially reduce stray field emissions. The attenuator, in another form, combines the physics of conducting tubes and self-cancelling fields and applies them to a tunnel interrogator. The attenuator thus applies a conducting tube which confines the field and the property of a loop generating a self-cancelling field to an interrogator. This combination may be called a "loop tube".

Abstract: A communication system is provided for increasing communication range between at least two radio communication devices without increasing the output power of transmitted radio signals from the devices, and without increasing the antenna gain of the received signals. Each radio device includes an oscillator for generating a carrier reference signal, and an SATPS receiver which receives at least one standard timing reference signal from at least one SATPS satellite. The received standard timing reference signal is used to continuously adjust the timing and synchronization of the oscillator to improve the accuracy of the carrier frequency signal. The improved accuracy in the carrier frequency signal may then be used to reduce the bandwidth of the modulated carrier frequency signals generated by the radio device to thereby increase the effective communication range and sensitivity of the device.

Abstract: A receiver of a radio frequency signal having a pseudo-random noise (PRN) code, and techniques of processing such a signal that are especially adapted for ranging applications. A signal corresponding to the PRN code is locally generated and used for decoding the received signal in a manner to reduce ranging errors that can result when multipath (delayed) versions of the radio frequency signal are also present. A significant application of the receiver and signal processing techniques of the present invention is in a Global Positioning System (GPS), wherein a number of such signals from several satellites are simultaneously received and processed in order to obtain information of the position, movement, or the like, of the receiver. A delay locked loop (DLL) correlator, provided in each of the receiver's multiple processing channels, locks onto a line of sight signal from one of the satellites with the effect of any multipath signal(s) being significantly reduced.

Abstract: A technique of accurately determining the relative position of two points using carrier phase information from receivers capable of making code and carrier phase measurements on the L1 and L2 frequencies of signals from either or both GPS and GLONASS satellites. These signals are processed by a receiving system to determine relative position, for the purpose of surveying or otherwise, with the accuracy of carrier phase measurements being obtained. Signal processing similar to that used in existing GPS carrier phase based relative positioning receivers is used with GLONASS signals as well, with a modification that takes into account the unique and different frequencies of the signals from individual GLONASS satellites. Surface acoustic wave ("SAW") filters are also employed in an intermediate frequency receiver section in order to avoid imparting different delays to the GLONASS signals of different frequencies.

Abstract: A receiver of a radio frequency signal having a pseudo-random noise (PRN) code modulated on a carrier, and techniques of processing such a signal that are especially adapted for ranging applications. Such an application is in a global positioning system (GPS or GLONASS) receiver. Both of the receiver DLL code and PLL carrier loops include a loop component that senses an error in its main loop caused by the presence of a multipath signal. The main loop is continuously adjusted by this sensed error, thereby causing the loop to track more precisely and minimize the effect of the multipath signal. The result is a more accurate range measurement.

Abstract: A quadrifilar helix antenna for use in satellite communications comprises four conductive elements arranged to define two separate helically twisted loops, one slightly differing in electrical length than the other, to define a cylinder of constant radius supported by itself or by a cylindrical non-conductive substrate. The two separate helically twisted loops are connected to each other in such a way as to constitute the impedance matching, electrical phasing, coupling and power distribution for the antenna. In place of a conventional balun, the antenna is fed at a tap point on one of the conductive elements determined by an impedance matching network which connects the antenna to a transmission line. The matching network can be built with distributed or lumped electrical elements and can be incorporated into the design of the antenna.

Abstract: The present invention relates to the areas of communication and/or identification of remote devices (active or passive). The invention has application where there is a need to identify or communicate with more than one remote device. The remote device may be embodied as a transmitter arrangement, transducer, transponder or responder. In particular, the present invention calls for each remote device to include a transmitter means in which, at each transmission, a carrier frequency or medium is newly selected.

Abstract: An identification system comprising a transponder having receiver means adapted to extract powering energy from a surrounding electromagnet field, transponder transmitter means adapted to transmit at least one unique signal from the transponder, frequency generating means for generating a plurality of pre-determined frequencies, each frequency adapted to carry the signal from the transmitter means to an interrogator receiver means adapted to receive said signals to achieve identification of said transponder, said transponder transmitting signals successively or repetitively using at each successive or repetitive transmission a newly selected frequency or set of newly selected frequencies.

Abstract: In switching a CMOS circuit comprising first and second switchable logic elements the first logic element is enabled so as to allow it to reach a steady logic state and the second logic element is not enabled until the first logic element reaches a substantially steady logic state. The current drawn by the circuit at any time is thereby reduced.

Abstract: A synchronous rectifier comprising: switch means responsive to a control signal for selectively providing conduction of an applied AC signal, and driver means responsive to the applied AC signal and adapted to provide said control signal in synchronism with the applied AC signal, wherein the rectifier is integratable into VLSI "chip" form.