摘要:
Provided is a position information providing system which can reduce a time required for acquiring position information. An indoor transmitter (200-1) is adapted to provide position information by using a second positioning signal compatible with a first positioning signal which is a spread spectrum signal from each of a plurality of satellites. The indoor transmitter (200-1) includes an EEPROM (243) which stores therein position data for identifying an installation location thereof, an FPGA (245) operable to generate a second positioning signal including the position data as a spread spectrum signal, and a transmitting section (251 to 258) operable to transmit the spread spectrum signal. The second positioning signal is generated to repeat the same content in a cycle shorter than that of the first positioning signal.
摘要:
Provided is a navigation signal transmitter capable of ensuring reduction in frequency deviation of a terrestrially transmitted navigation signal at low cost. The navigation signal transmitter is operable to receive a transmission wave, generate a synchronization pulse in synchronization with a predetermined data frame, generate an internal clock fundamental oscillation by a reference signal synchronizing section (550) using the synchronization pulse as a reference signal, generate an IMES signal based on the internal clock fundamental oscillation, and transmit the IMES signal. The reference signal synchronizing section (550) comprises a counter circuit (551), a comparator (553), a low-pass control filter (554), a D/A converter (555) and a voltage controlled oscillator (556). The reference signal synchronizing section (550) is configured to, when a magnitude relationship between the number of clock pulses generated in the voltage controlled oscillator (556) using the synchronization pulse as the reference signal and a reference value falls within a predetermined value and continues a predetermined number of times in one direction, adjust a level of control voltage of the voltage controlled oscillator (556).