Trimble Navigation Limited

Other

Eric B Rodal

Chung Y Lau

James M Janky

John F Schipper

Mark Edward Nichols

Gary L Wagner

Dominic G Farmer

Reed A Parker

David J Cowl

David R Gildea

Kreg A Martin

Michael C Detro

A GPS receiver and an RF GPS integrated circuit for receiving a GPS signal. The GPS integrated circuit includes a synthesizer for generating LO signals, first and second downconverters for using the LO signals for downconverting the GPS signal, and a sampler for providing in-phase and quadrature phase sampled output signals representative of the GPS signal. The synthesizer includes a multi-mode divider for providing substantially the same first LO frequency at about the midpoint of the L and L GPS lo frequencies for either of two reference frequencies. The RF GPS integrated circuit uses an entirely on-chip voltage controlled oscillator (VCO) having a resonator for generating the LO signals and an entirely on-chip filter for filtering a first intermediate frequency signal.

RF integrated circuit for downconverting a GPS signal

A system for monitoring location and speed of a vehicle, using a location determination system such as GPS, GLONASS or LORAN and an optional odometer or speedometer, for determining and recording the locations and times at which vehicle speed is less than a threshold speed for at least a threshold time (called a &ldquo;vehicle arrest event&rdquo;). Vehicle arrest event locations, times and time intervals are stored and/or printed to provide trip and mileage records and for efficiency monitoring. A vehicle odometer and/or speedometer can also be calibrated and/or corrected using this approach.

Vehicle tracker, mileage-time monitor and calibrator

A GPS/GSM receiver combination for receiving GSM and GPS signals using an RF GPS integrated circuit for downconverting the GPS signal. The GPS integrated circuit includes a synthesizer for generating LO signals, first and second downconverters for using the LO signals for downconverting the GPS signal, and a sampler for providing in-phase and quadrature phase sampled output signals representative of the GPS signal. The synthesizer includes a multi-mode divider for providing substantially the same first LO frequency at about the midpoint of the L1 and L2 GPS frequencies when either of a standard GSM reference frequency or historically common GPS reference frequency is selected. A standby mode in the integrated circuit is controlled by a power logic circuit using a power supply input as a logic control signal. The GSM/GPS receiver combination includes a GSM reference oscillator and a microprocessor system including a GSM frequency correction code for correcting the GSM reference frequency based upon a frequency correction beacon (FCB) signal received in the GSM signal. The GSM-based correction is then used for correcting the GSM reference frequency in order to center a frequency search for acquiring the GPS signal.

GSM cellular telephone and GPS receiver combination

A GPS receiver including an RF GPS integrated circuit downconverter having a standby mode controlled by a power supply input used as a logic signal. The RF GPS integrated circuit includes a synthesizer for generating LO signals, first and second downconverters for using the LO signals for downconverting the GPS signal, and a sampler for using a clock signal for providing in-phase and quadrature phase sampled output signals representative of the GPS signal. The synthesizer includes a multi-mode divider for providing substantially the same first LO frequency at about the midpoint of the L1 and L2 GPS frequencies when either of an external or internally generated reference frequency is selected. A GPS digital signal processor integrated circuit issues the logic signal and the clock signal from a single pin.

Integrated circuit using a power supply input for digital logic

A system for monitoring location and speed of a vehicle, using a location determination system such as GPS, GLONASS or LORAN and an optional odometer or speedometer, for determining and recording the locations and times at which vehicle speed is less than a threshold speed for at least a threshold time (called a 'vehicle arrest event'). Vehicle arrest event locations, times and time intervals are stored and/or printed to provide trip and mileage records and for efficiency monitoring. A vehicle odometer and/or speedometer can also be calibrated and/or corrected using this approach.

Vehicle tracker mileage-time monitor and calibrator

A GPS timing receiver for providing a GPS-derived time signal. The GPS timing receiver includes a filter for filtering a GPS signal to a certain information bandwidth, a reference clock for generating a reference clock signal having a clock rate at least ten times the information bandwidth, a sampler using the reference clock signal for oversampling the filtered GPS signal, a correlation subsystem including a microprocessor for correlating the sampled GPS signal to the reference clock signal to measure a time difference between the GPS signal and the reference clock signal, and a time clock to issue a GPS-derived time signal based upon the reference clock signal and adjusted by the measured time difference in increments of the period of the reference clock signal. An optional frequency multiplier multiplies the reference clock rate enabling the time clock to adjust the GPS-derived time signal in increments of the period of the frequency multiplied reference clock signal.

GPS timing receiver using oversampling

A GPS/radio antenna for receiving a GPS satellite signal and a DGPS radio signal. The GPS/radio antenna includes a GPS antenna using a microstrip antenna element for receiving the GPS signal having GPS location determination information, a radio antenna for receiving a DGPS radio signal in the FM broadcast frequency range having DGPS corrections, an enclosure, and a cable. The GPS/radio antenna may be included in a GPS/DGPS receiver system also including a receiver unit with an FM DGPS receiver for demodulating the DGPS radio signal and providing DGPS corrections, and a differential-ready GPS receiver for providing a differentially-corrected GPS location.

GPS/radio antenna combination

An apparatus including a hybrid digital-to-analog converter (DAC) (10) for converting a combined digital word (23) into a combined analog output level (21) and a GPS receiver (36) for providing the combined digital word (23) and using the combined analog output level (21) for phase locking a voltage controlled oscillator (VCO) (40) to a GPS satellite signal (34). The combined digital word (23) includes a more significant (MS) digital word (13) having N bits and a less significant (LS) digital word (15) having M bits. The hybrid DAC (10) includes a pulse generator DAC (12) for converting the MS digital word (13) into pulse output signal having a duty cycle and an average MS analog level representative of the MS digital word (13) and a second DAC (14) for converting the LS digital word (15) into an average LS analog level representative of the LS digital word (15). The pulse generator DAC (12) uses a counting technique in order to obtain a high degree of precision. A filter/combiner (18) filters and combines the average MS and the LS analog levels into a combined analog output level (21) representative of the combined digital word (21) to control the VCO (40) for providing a GPS-derived frequency signal (41) and a VCO signal to a correlator (38). The correlator (38) provides the combined digital word (23) representative of a difference between the frequency of the VCO signal and the frequency of the GPS satellite signal (34).

Hybrid DAC suitable for use in a GPS receiver

A dual frequency vertical antenna for radiating a first and a second airwave signal in response to a first and a second conducted signal, the first airwave signal having a first frequency and the second airwave signal having a second frequency lower than one-half the first frequency. The antenna includes a horizontal base member and a vertical mast, including a coaxially disposed rod, projecting upward from the base member to a masthead. For feeding the conducted signals, a lower mast extension projecting downward from the base member and a tuning sleeve projecting either upward or downward from the base member are tuned to 1/4 wavelength at the first frequency and a single coaxial cable is connected between the base member and a feedpoint on the rod. The first airwave signal radiates from a dipole formed of an 1/4 wavelength upper rod extension extending upward from said masthead and a concentric 1/4 wavelength upper sleeve external to the mast projecting downward from said masthead. The mast is 1/4 wavelength at the second frequency for radiating the second airwave signal from a dipole formed of the mast and the base member.

Dual frequency vertical antenna

A low power GPS receiver, including an RF section to receive a GPS signal having information for determining a location fix and to issue an IF signal, a correlator system to correlate an internal replica signal to the IF signal and to issue a correlation signal including location and signal strength information, a microprocessor system to receive the correlation signal, to read the signal strength, and to provide a location fix, and an on/off modulator to receive a duty cycle factor from the microprocessor system and to on/off modulate the operating power to the RF section to provide a minimum signal strength for a valid location fix. The off time duration of the modulation is shorter than the time duration of the interval used to correlate the IF signal enabling the GPS receiver to continue to correlate the IF signal and to provide the location fixes while the RF section operating power is reduced by the duty cycle factor.

Low power GPS receiver

A GPS receiver having a rapid acquisition of a GPS satellite signal when a normal operational mode is entered after a low power standby mode. The GPS receiver includes an RF section for receiving the GPS satellite signal and providing an GPS IF signal, a correlator section for providing a correlation signal for the correlation between the GPS IF signal and an internally generated replica signal, and a microprocessor section for receiving the correlation signal and calculating a geographical location of the GPS receiver. The replica signal is based upon a reference frequency from a reference oscillator and a reference time of arrival (TOA) from a timer. In order to increase acquisition speed, the microprocessor section provides the correlator section with an initial frequency adjustment and an initial TOA adjustment to correct for drift in the reference frequency during the standby mode. The initial adjustments are based upon a learned corrections to the initial adjustments that result in acquisition of the GPS satellite signal after alternating one or more times between the standby mode and the normal mode or from stored temperature relationships and measured temperatures of the reference oscillator.

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Morgan Hill, CA, United States of America

Eric B Rodal