Patent ID: 8618978

Claim:
A position information providing system capable of providing position information by use of a first positioning signal which is a spread spectrum signal from each of a plurality of satellites, comprising an indoor transmitter, and a position information providing apparatus, wherein: the indoor transmitter includes: a storage section which stores therein position data for identifying an installation location of the indoor transmitter, a generation section for generating an second positioning signal including the position data, as a spread spectrum signal, and a transmitting section for transmitting the generated spread spectrum signal; and the position information providing apparatus includes: a receiving section for receiving a spread spectrum signal, an identifying section for, based on a plurality of code patterns related to the first and second positioning signals, identifying one of the code patterns which corresponds to the spread spectrum signal received by the receiving section, a determining section for, based on a signal obtained by demodulating the received spread spectrum signal using the code pattern identified by the identifying section, determining which of the first and second positioning signals is received, a position information-deriving section for deriving position information of the position information providing apparatus, while switching between processing modes depending on a result of the determination, and an output section for outputting the position information derived by the position information-deriving section, wherein the second positioning signal is configured to repeat a same content message in a cycle shorter than that of the first positioning signal, wherein the second positioning signal comprises a plurality of frames each including a one or more words, each of which is a transmission unit of data to be subjected to error detection, and wherein: the number of the words included in each of the frames is variably set, a leading one of the words in each of the frames includes a preamble for establishing frame synchronization during receiving, the leading one of the words in each of the frames comprises a message-type identification information indicative of the number of the words constituting the frame, and further indicative of whether the frame includes position information or other information, and if the frames include more than one word, the remaining one or more words other than at least the leading word, in each of the frames, include count data which is updated every time the word data is generated.