Denso Corporation

Other

Katsuhiko Mutoh

Toshiyuki Ito

Hideki Tanino

Kohji Katoh

Nobutaka Tauchi

Kenichi Takagi

Hiroshige Asada

Osamu Yamamori

Katsumi Isogimi

Hedeki Tanino

A radio receiver device includes a radio signal processing section and a digital processing section. The radio signal processing section converts a received radio signal into a digital signal, demodulates the digital signal and detects a S/N ratio of the radio signal. The digital processing section digitally processes digital signals and switches over its operation mode based on the detected S/N ratio, thereby controlling a digital noise generated in the digital processing. The radio processing section checks whether the S/N ratio is lowered by a digital noise of the digital processing section or a shielding body external to the radio receiver device. The digital processing section switches over its operation mode to reduce the digital noise only when the cause of the fall of the S/N ratio is caused by the digital noise.

Radio receiver device

A navigation system for use in a vehicle receives a GPS signal for having a GPS time data that rolls over at an interval of 19.7 years with a start time of 0 a.m. Jan. 6th, 1980 from a GPS satellite, and acquires map generation date information that specifies map data generation time from map database in the navigation system. The GPS time data and the map data generation time information are utilized for calculating an accurate current date and time.

Navigation system

A navigation device changes a position determination accuracy of a receiver for satellite navigation to a higher accuracy in the following cases: when the subject vehicle approaches a destination, the subject vehicle runs on a road not described in map information, when the subject vehicle approaches an intersection at which the road is branched at a narrow angle within a predetermined distance, when the subject vehicle is running on a narrow street, when the subject vehicle is running on one of adjacent parallel roads, when self-contained sensors are calibrated, and other like occasions. In the other cases, the navigation device changes the position determination accuracy of the receiver to a low accuracy. When the receiver is caused to execute low-accuracy position determination, power supply to receiver's operation required only for high-accuracy position determination is prohibited.

Satellite navigation controller

A vehicle navigation system has a plurality of maps, measurement modes, and operation modes. When the measurement mode is a standard in an accuracy priority mode, low detail rate map is used to display a current position. When the measurement mode is a precise measurement in the accuracy priority mode, a city map is used to display the current position. When the low detail rate map is used in a map priority mode, the measurement mode is set to the standard. When the city map is used in the map priority mode, the measurement mode is set to the precise measurement.

A map evaluation system is equipped with a car navigation device and a map evaluation device. The car navigation system generates difference data indicating a location where a difference is present between a vehicle position path and a road location obtained from a map database. The car navigation device then sends the difference data along with additional data relating to accuracy of the difference data. The map evaluation device determines accuracy for the difference data based on the additional data. When the accuracy degree of the difference data is determined to be proper, the map evaluation device increments by one a determining count of a group including the difference data. When the determining count exceeds a given count, a portion to be amended on the map database is displayed on a monitor based on the difference data stored in a difference database.

Map evaluation system, collation device, and map evaluation device

A GPS receiver includes a CPU for synchronously acquiring the GPS satellites by using software correlating and a hardware section composed of multiple hardware correlating units that execute a correlating process for tracking the GPS satellites synchronously acquired by the CPU. Increase in a product size due to tracking can be thereby suppressed in the GPS receiver that synchronously acquires the GPS satellites by the software correlating.

GPS receiver using software correlation for acquisition and hardware correlation for tracking

Personal digital assistance (PDA) is set in a second low-power-consumption (LPC) mode if its power switch is OFF, while the PDA is set in a normal mode if its power switch is ON. If it is determined that the PDA is connected to navigation equipment when the PDA is in the second LPC mode, the PDA automatically switches to a first LPC mode in which the functional blocks used for receiving position data from the navigation equipment and storing the received position data are activated but the other functional blocks are not activated. Then the PDA automatically receives the position data from the navigation equipment and stores the received position data. Thus the PDA can receive the latest position data without wasting the power of the PDA, even when its power switch is OFF.

Portable terminal capable of automatically switching into moderate power consumption mode for receiving data

A navigation system is constructed to set up navigation function of a GPS terminal by using radio signals of broadcast station before receiving GPS signals from GPS satellites. A GPS monitor server receives on the ground GPS signals transmitted from GPS satellites, a FM multiplex broadcast station transmits, using the radio signals, GPS supplementary information including the Almanac and Ephemeris data in a navigation message of the GPS signals received by the GPS monitor server. A GPS terminal starts, upon reception of the GPS supplementary information, reception of the GPS signals transmitted from the GPS satellites.

Navigation system, GPS terminal and navigation method using supplementary data in broadcast radio wave signal

A terminal device has a GPS receiver which receives GPS signals from a GPS satellite. The terminal device has an operation unit for instructing operation modes of the GPS receiver, and the GPS receiver has a clock unit, a radio frequency unit and a data extraction unit. The data extraction unit extracts GPS data by scanning signal-to-noise ratios of each frequency over a search frequency band. When a band correction mode is instructed by the operation unit, the data extraction unit switches its search frequency band from a first frequency band determined based on a maximum temperature-dependent change in the frequency of a clock signal to a second frequency band determined based on a maximum aging-dependent change in the frequency of the clock signal.

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Toyota, Japan

Katsuhiko Mutoh