Abstract: Performance anomalies in complex systems can be difficult to identify and diagnose. In an example, CPU-usage associated with one or more of the systems can be determined. An anomalous event can be determined based on the determined CPU-usage. In some examples, based at least in part on determining the event, the system may be controlled in a safe state and/or reconfigured to obviate the anomalous event.

Abstract: A global positioning system (GPS) receiver that is configured to rapidly acquire GPS signals in space applications and a method for rapidly acquiring GPS signals in space applications is disclosed. In an embodiment, the GPS receiver includes, but is not limited to, a GPS signal acquisition component. The GPS signal acquisition component is adapted to acquire a GPS signal by receiving data from the GPS signal and processing the data to detect the GPS signal.

Abstract: A global positioning system (GPS) receiver that is configured to rapidly acquire GPS signals in space applications and a method for rapidly acquiring GPS signals in space applications is disclosed. In an embodiment, the GPS receiver includes, but is not limited to, a GPS signal acquisition component comprising a time domain correlation module. The GPS signal acquisition component is adapted to acquire a GPS signal by receiving data from the GPS signal and processing the data to detect the GPS signal.

Abstract: A method in a mobile satellite positioning system receiver operating in cold-start mode, including searching for and detecting (310) a first satellite in a constellation of orbiting satellites, searching (320) for a second satellite based on detection probability information for non-detected satellites, the detection probability information obtained using information about one of satellites not detected or the first satellite detected. In one embodiment, the detection probability information is based on a measure of range between the non-detected satellites and the first satellite detected, and in another embodiment the detection probability information is based on a measure of angle between the non-detected satellites and the first satellite detected.

Abstract: A multiple channel receiver (200) includes a communications receiver synthesizer (204) and at least one numerically controlled oscillator (NCO) (406) that produce local oscillator signals that are derived from a common reference oscillator (202). A DSP (212) and CPU (214) perform automatic frequency control (AFC) by adjustment of the reference oscillator (202) based upon a signal received by a receive channel using the local oscillator signal produced by the communications receiver synthesizer (204). The CPU (214) also provides a synchronous indication of adjustments to the reference oscillator (202) to control circuitry for the at least one NCO (406) so that the configuration of the NCO (406) can be altered so as to maintain a substantially constant frequency output during the adjustment of the reference oscillator (202).

Abstract: A method in a location enabled mobile wireless receiver having an oscillator, including determining a change in cellular network based frequency error of the oscillator (250), based on a difference (230) between a cellular network based frequency error of the oscillator and a reference cellular network based frequency error (210) of the oscillator, determining a first frequency error of the oscillator by summing (250) a reference satellite positioning system receiver based oscillator frequency error (220) with the change in cellular network based frequency error of the oscillator.

Abstract: Method in a Global Positioning System (GPS) receivers, including determining pseudorange (PNR) measurements for at least four satellites (210), determining a coarse time (220) corresponding to the pseudorange measurement, determining an offset time (240) between a periodic GPS event of one of the four satellites and the coarse time, determining a time correction delta (250) based upon the period of the Periodic GPS event, the offset time and the coarse time if an error of the coarse time is less than ½ the period of the periodic GPS event, and determining corrected time (260) based upon the coarse time and the time correction delta if the error of the coarse time is less than ½ the period of the periodic GPS event.

Abstract: Methods and architectures for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits. In one embodiment, an adjusted bit sync offset time is determined for each of a plurality of signals for which bit sync offset time is not known based on a corresponding clock error corrected propagation time for each signal, based on a known bit synch offset time and based on a clock error corrected propagation time of the signal for which bit synch offset time is known.

Abstract: A multiple channel receiver (200) includes a communications receiver synthesizer (204) and at least one numerically controlled oscillator (NCO) (406) that produce local oscillator signals that are derived from a common reference oscillator (202). A DSP (212) and CPU (214) perform automatic frequency control (AFC) by adjustment of the reference oscillator (202) based upon a signal received by a receive channel using the local oscillator signal produced by the communications receiver synthesizer (204). The CPU (214) also provides a synchronous indication of adjustments to the reference oscillator (202) to control circuitry for the at least one NCO (406) so that the configuration of the NCO (406) can be altered so as to maintain a substantially constant frequency output during the adjustment of the reference oscillator (202).

Abstract: Methods and architectures for code phase searching spread spectrum signals having a repeating sequence of bits. The signals are searched virtually in parallel by segmenting with a divider (314) received signals by sequentially, partially correlating signal segments with a corresponding replica signal segments for a predetermined number of phase delays during a time interval not greater than that required to form the next signal segment. Multiplexors (322) and (330) provide Doppler and replica signal segments data from Doppler signal and replica signal generators (318) and (320) to corresponding multipliers (326) and (332), respectively, for multiplication with corresponding signal segments in a segment register (316). The partial correlation results for each phase delay and at each Doppler frequency are stored in corresponding memory locations in a coherent accumulation RAM (334). The signals may be searched over one or more phase delays and at one or more Doppler frequencies.

Abstract: A method and apparatus for determining position in a GPS receiver (FIG. 4) is provided according to the invention. The apparatus includes a first switch (402), the first switch (402) receiving a digital GPS data, a first memory (409), a second memory (410) in parallel with the first memory, with the first memory and the second memory selectable by the first switch (402) for filling with the digital GPS data, and a second switch (416) selectable between the first memory (409) and the second memory (410) in order to extract the digital GPS data therefrom, wherein DSP signal processing (140) extracts digital GPS data from the first memory (409) while the second memory (410) is being filled and extracts digital GPS data from the second memory (410) while the first memory is being filled, and wherein the first memory (409) and the second memory (410) allow the digital GPS data to be processed in real time.

Abstract: Method in a Global Positioning System (GPS) receivers, including determining pseudorange (PNR) measurements for at least four satellites (210), determining a coarse time (220) corresponding to the pseudorange measurement, determining an offset time (240) between a periodic GPS event of one of the four satellites and the coarse time, determining a time correction delta (250) based upon the period of the Periodic GPS event, the offset time and the coarse time if an error of the coarse time is less than ½ the period of the periodic GPS event, and determining corrected time (260) based upon the coarse time and the time correction delta if the error of the coarse time is less than ½ the period of the periodic GPS event.

Abstract: Methods and architectures for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits. In one embodiment, an adjusted bit sync offset time is determined for each of a plurality of signals for which bit sync offset time is not known based on a corresponding clock error corrected propagation time for each signal, based on a known bit synch offset time and based on a clock error corrected propagation time of the signal for which bit synch offset time is known.

Abstract: A method and apparatus for determining position in a GPS receiver (FIG. 4) is provided according to the invention. The apparatus includes a first switch (402), the first switch (402) receiving a digital GPS data, a first memory (409), a second memory (410) in parallel with the first memory, with the first memory and the second memory selectable by the first switch (402) for filling with the digital GPS data, and a second switch (416) selectable between the first memory (409) and the second memory (410) in order to extract the digital GPS data therefrom, wherein DSP signal processing (140) extracts digital GPS data from the first memory (409) while the second memory (410) is being filled and extracts digital GPS data from the second memory (410) while the first memory is being filled, and wherein the first memory (409) and the second memory (410) allow the digital GPS data to be processed in real time.

Abstract: Methods and architectures for code phase searching spread spectrum signals having a repeating sequence of bits. The signals are searched virtually in parallel by segmenting with a divider (314) received signals by sequentially, partially correlating signal segments with a corresponding replica signal segments for a predetermined number of phase delays during a time interval not greater than that required to form the next signal segment. Multiplexors (322) and (330) provide Doppler and replica signal segments data from Doppler signal and replica signal generators (318) and (320) to corresponding multipliers (326) and (332), respectively, for multiplication with corresponding signal segments in a segment register (316). The partial correlation results for each phase delay and at each Doppler frequency are stored in corresponding memory locations in a coherent accumulation RAM (334). The signals may be searched over one or more phase delays and at one or more Doppler frequencies.

Abstract: A method in a location enabled mobile wireless receiver having an oscillator, including determining a change in cellular network based frequency error of the oscillator (250), based on a difference (230) between a cellular network based frequency error of the oscillator and a reference cellular network based frequency error (210) of the oscillator, determining a first frequency error of the oscillator by summing (250) a reference satellite positioning system receiver based oscillator frequency error (220) with the change in cellular network based frequency error of the oscillator.

Abstract: A method of determining the position of a satellite in a near geosynchronous orbit includes receiving at least one main lobe signal from an antenna on a first GPS satellite. A GPS signal, including GPS time and Doppler, is received from a pseudolite positioned on the Earth and an approximate position of each of a plurality of second GPS satellites is determined from an onboard almanac. Side lobe signals and accompanying noise are received from antennas on the plurality of second GPS satellites. The GPS signal and known sequential data bits are used for sorting or integrating the side lobe signals from the accompanying noise and the position of the satellite in a near geosynchronous orbit is determined using the one or more main lobe signals and the sorted side lobe signals.

Abstract: Methods and architectures for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits. In one embodiment, an adjusted bit sync offset time is determined for each of a plurality of signals for which bit sync offset time is not known based on a corresponding clock error corrected propagation time for each signal, based on a known bit synch offset time and based on a clock error corrected propagation time of the signal for which bit synch offset time is known.

Abstract: A method and apparatus for determining position in a GPS receiver (FIG. 4) is provided according to the invention. The apparatus includes a first switch (402), the first switch (402) receiving a digital GPS data, a first memory (409), a second memory (410) in parallel with the first memory, with the first memory and the second memory selectable by the first switch (402) for filling with the digital GPS data, and a second switch (416) selectable between the first memory (409) and the second memory (410) in order to extract the digital GPS data therefrom, wherein DSP signal processing (140) extracts digital GPS data from the first memory (409) while the second memory (410) is being filled and extracts digital GPS data from the second memory (410) while the first memory is being filled, and wherein the first memory (409) and the second memory (410) allow the digital GPS data to be processed in real time.

Abstract: A method and apparatus for determining position in a GPS receiver (FIG. 4) is provided according to the invention. The apparatus includes a first switch (402), the first switch (402) receiving a digital GPS data, a first memory (409), a second memory (410) in parallel with the first memory, with the first memory and the second memory selectable by the first switch (402) for filling with the digital GPS data, and a second switch (416) selectable between the first memory (409) and the second memory (410) in order to extract the digital GPS data therefrom, wherein DSP signal processing (140) extracts digital GPS data from the first memory (409) while the second memory (410) is being filled and extracts digital GPS data from the second memory (410) while the first memory is being filled, and wherein the first memory (409) and the second memory (410) allow the digital GPS data to be processed in real time.