JPS61200484A - Satellite navigation apparatus - Google Patents

Abstract

PURPOSE:To certainly perform the demodulation of navigation data at a high speed even when a moving body having a mobile station mounted thereto runs an area having much obstruction such as an urban area or a mountain district by making it possible to transmit and receive navigation data between a mobile station and a fixed station. CONSTITUTION:When the power source of the display apparatus 16 of the mobile station 1 mounted to a moving body such as a car is closed, a processing circuit 13 investigates the newness of the navigation data of memory 14 and, if said data is old, a data command is sent to a fixed station through a transmitting and receiving circuit 17. In the fixed station, a processing circuit 23 receiving the command through a transmitting and receiving circuit 27 reads the navigation data of the memory 24 to send the same to the mobile station 1 through the transmitting and receiving circuit 27. In the mobile station 1, the processing circuit 13 selects a satellite on the basis of the new navigation data received through the transmitting and receiving circuit 17 and the signal of the satellite inputted from an antenna 11 is received by a receiving circuit to measure a dummy distance which is, in turn, processed in the combination with the navigation data to calculate the position of the mobile station, that is, the moving body.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a satellite navigation system capable of receiving signals from a satellite in a moving vehicle such as a car or train, and calculating and displaying the position of the vehicle.

[Conventional technology]

Satellite navigation equipment has traditionally been GPS (Global
There is something called a navigation device (Posit-ioning System), in which a moving vehicle such as a car or train receives four high-frequency signals from four artificial satellites, and demodulates navigation data and calculates pseudorange from the four signals. It measures the vehicle's current position and displays the vehicle's current position obtained from navigation data and pseudoranges. Of this navigation data, it takes 18 seconds to demodulate ephemeris data (orbital data and clock characteristic data for individual satellites). Also, it takes 12 seconds per page to demodulate almanac data (compressed orbital data and clock characteristic data for all satellites).

All pages (25 pages) will take about 300 seconds to view. Furthermore, when the vehicle travels in urban areas, the signals from the satellite are blocked by buildings and other obstacles, interrupting the reception of data signals, and it takes an enormous amount of time to demodulate complete data. I end up. During this time, there was a drawback that positioning could not be performed and the displayed position of the vehicle was inaccurate.

[Problem that the invention seeks to solve]

The present invention was made in order to eliminate the above-mentioned drawbacks of conventional satellite navigation devices, and enables high-speed demodulation of navigation data even when the vehicle is traveling in areas with many obstacles such as urban areas and mountainous areas. The purpose of the present invention is to provide a satellite navigation device that enables reliable navigation.

[Means for solving problems]

Means for solving the above problems will be explained using the accompanying drawings corresponding to the embodiments.

The satellite navigation device of the present invention includes a mobile station 1 mounted on a moving vehicle (not shown) and a fixed station 2 having an antenna 21 installed in a place free of obstacles. and mobile station l
Inside and fixed station z are circuits 12 and 22 that receive high-frequency signals sent from one artificial satellite, circuits 13 and 23 that process the received signals, and four circuits 13 and 23 that process and output the signals. It has interface circuits 15 and 25 that convert parallel data into serial data, and circuits 17 and 27 that transmit and receive serial data.

[Effect]

The navigation data (parallel data) received by the mobile station 1 and the fixed station 2 and demodulated is sent to the interface circuit 1.
5 and 25 are converted into serial data, the navigation data can be transmitted and received between the mobile station 1 and the fixed station 2 through the transmitting/receiving circuits 17 and 27, respectively.

〔Example〕

The drawing is a block diagram of one embodiment of the present invention.

The mobile station 1 is mounted on a vehicle such as a car, and an antenna 11 for receiving signals from a satellite is attached to the outside of the vehicle, for example on the roof. The fixed station 2 transmits and receives navigation data to and from a mobile station 1 of a moving body traveling within its communication territory. The fixed station 2 is provided with an antenna 21 that is installed in a place with a good view and receives signals from an artificial satellite. The mobile station 1 and the fixed station 2 include receiving circuits 12 and 22, processing circuits 13 and 23, respectively. Memories 14 and 24, parallel-serial interface circuits 15 and 25, display devices 16 and 26, and transmitting/receiving circuits 17 and 27 are installed as shown.

At the fixed station 2, high-frequency signals are received by an antenna 21 from a plurality of satellites that can be seen, demodulated into navigation data by a receiving circuit 22, subjected to processing such as bit synchronization by a processing circuit 23, and then recorded in a memory 24. be done.

Antenna 11, receiving circuit 12, processing circuit 1 in mobile station l
3. The memory 14 operates in the same way as the corresponding parts of the fixed station 2, but when the vehicle is traveling in a city, the signals from the satellite may be blocked by buildings or other obstacles. Since the navigation data in the memory 14 is not updated, it may become old data.

Therefore, when the display device 16 is powered on, if the processing circuit is old, a data request command is sent from the serial interface 15 to the fixed station 2 through the transmitting/receiving circuit 17.

In the fixed station 2, the processing circuit 23 that receives the command through the transmitting/receiving circuit 27 and the serial interface 25 reads the navigation data from the memory 24, and converts the read parallel signal navigation data into a serial signal by the interface 25. and sends it to the mobile station 1 via the transmitter/receiver circuit 27. The mobile station 1 transmits the navigation data of the serial signal received through the transceiver 17 to the interface 1.
5 into parallel signal navigation data, and the processing circuit 13 records the navigation data in the memory 14. In this way, records are updated from old navigation data to new navigation data. Using this new navigation data, the processing circuit 13 selects a satellite, receives the signal of the selected satellite input from the antenna 11 in the receiving circuit 12, and measures the pseudorange. Furthermore, the processing circuit 13 combines and processes this pseudorange and navigation data, and displays the result on the display device 16 of the mobile station 1, that is, the waiting station 1 of the mobile station 1, that is, the operation tk.

Note that the transceiver 17 of the mobile station 1 and the transceiver 2 of the fixed station 2
For connection with 7, a wireless or a telephone line via wireless is used. Depending on the type of vehicle, connection may be made using a cable. The fixed station 2 is not necessarily a facility fixed on the ground, but may be another mobile station that has already collected or received navigation data, in which case there is a display that displays the position of the mobile station itself A device 26 is required. Furthermore, the fixed station 2 can also be a relay station that does not itself receive signals from satellites but only has the function of transmitting and receiving navigation data.

〔Effect of the invention〕

As explained above, according to the satellite navigation device of the present invention,
Navigation data can be sent and received between the mobile station and the fixed station, so even if the vehicle equipped with the mobile station is traveling in areas with many obstacles, such as urban areas or mountainous areas, Navigation data can be demodulated quickly and reliably.

Therefore, there is an advantage that the time during which positioning cannot be performed due to data collection is extremely shortened, and the position of the vehicle can be accurately displayed at any time.

[Brief explanation of the drawing]

The drawing is a block diagram of an embodiment of a satellite navigation device to which the present invention is applied. 15. Mobile station, 2. Fixed station. 11・211. Antenna, 12/22 Receiving circuit, 13/23, Processing circuit, 14/240. Memory, 15・259. Serial interface, 16.
26 , , , Display device, 17・27. ,,,transmission/reception circuit.

Claims (1)

[Scope of Claims] A circuit that receives a high-frequency signal sent from an artificial satellite in a mobile station, a circuit that processes the received signal, and an interface that converts parallel data that is processed and output into serial data. It has a circuit that transmits and receives serial data, and a circuit that receives high-frequency signals sent from artificial satellites in the fixed station, a circuit that processes the received signals, and a parallel circuit that processes and outputs the signals. A satellite navigation system comprising an interface circuit for converting serial data into serial data and a circuit for transmitting and receiving the serial data, the mobile station and the fixed station being able to mutually transmit and receive serial data. Device.