JPH0558122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an automotive GPS (Global Position-
ing System) This relates to a GPS navigation device that can continuously display a highly accurate estimated position even when reception of satellite radio waves is interrupted.

(Prior Art) Generally, when a GPS receiver is installed in a car and the position is measured while the car is running, the reception of low-elevation satellite radio waves is often interrupted by obstructions such as buildings, making positioning impossible. In this case, the estimated position calculated from the respective azimuth data and distance data from the on-vehicle magnetic compass and distance meter, starting from the measured position immediately before the interruption of satellite radio waves, is displayed as the position of the GPS navigation device at the time of interruption of satellite radio waves. .

(Problem to be solved by the invention) The estimated position calculated in this way is calculated using magnetic north course and distance data, which is different from the true north course which is the actual direction on the map, so it is difficult to calculate the position as time passes. However, there was a drawback that the error from the actual position of the car was large. Further, when the magnetic deviation amount is read from a magnetic deviation chart or the like and manually inputted into the GPS navigation device, it is a cumbersome and time-consuming method because it is done manually. In addition, since the amount of magnetic deviation changes from year to year, it is difficult to read the exact amount of deviation at the current location from a magnetic deviation chart, and the disadvantage of a magnetic compass is that the amount of magnetic deviation changes depending on the environment of the installation location. It was hot.

(Means for Solving the Problems) In order to solve these drawbacks, the present invention is equipped with a GPS receiver mounted on a car, and while the GPS receiver is capable of positioning, it also uses satellite radio waves. Even if positioning becomes impossible due to interruption of reception, the information can be obtained from the true bearing data obtained by correcting the bearing data from the magnetic direction meter attached to the car using the amount of magnetic deviation, the distance data from the distance meter, and the positioning data immediately before the interruption of reception. An object of the present invention is to provide a GPS navigation device that can display a continuous position without interruption using a more accurate estimated position based on the information obtained by the present invention.

(Embodiment) Below, the basic configuration of the present invention will be described with reference to a block diagram of an embodiment. 1 is a GPS receiver, which is mounted on a car 6, and an antenna 7 reduces the strength of the satellite signal being received. It has the function of outputting an alarm signal when positioning becomes impossible, and the function of measuring and outputting the moving direction of the vehicle with high precision. 2 is a magnetic deviation calculator that detects the direction of travel of the vehicle, and the direction data (magnetic north course) from the magnetic direction meter 8 and the above-mentioned direction.
The GPS receiver 1 has a function of measuring the amount of magnetic deviation from the moving direction, which is the true north course, which was well measured just before the reception was interrupted. 3 is an estimated position calculator, and a magnetic compass 8 that detects the direction of travel of the vehicle.
, distance data from the distance meter 9 that detects the number of rotations of the wheels, magnetic deviation data from the magnetic deviation calculator 2, and the GPS receiver 1.
It has a function to calculate an estimated position based on the measured position immediately before positioning becomes impossible. 4 is a data switching device, which outputs the positioning result from the GPS receiver 1 to the position display 5 when positioning is possible with the GPS receiver 1, and outputs an alarm signal that the GPS receiver is unable to perform positioning; In this case, it has a function of switching to output the position calculation result of the estimated position calculator 3 to the position display 5. Reference numeral 5 denotes a position indicator, which has the function of displaying the position information from the data switch 4 as a numerical display or as a track on a map.

(Operation) Next, the operation of the present device having the above configuration will be explained.

Radio waves from the GPS satellites are received by the GPS receiver 1 via the GPS receiver antenna 7, and the GPS receiver 1 amplifies and demodulates the received data to obtain a positioning result. This positioning result is displayed on the position display 5 through the data switch 4 as a numerical value or as a track on a map.

By the way, if the GPS satellite's radio waves are blocked by a shielding object and the reception is interrupted and positioning becomes impossible, the estimated position calculator 3 starts operating upon receiving the positioning failure alarm signal sent from the GPS receiver 1. Then, the direction data and distance data from the magnetic direction meter 8 and distance meter 9 placed in the car 6, the magnetic deviation data from the magnetic deviation calculator 2 calculated immediately before reception interruption, and the positioning failure alarm of the GPS receiver 1. A highly accurate estimated position is calculated using the measured position immediately before transmission as a starting point until reception is resumed. This estimated position information is output to the position display 5 through the data switch 4 which is switched to the estimated position calculator 3 side by the positioning failure alarm signal output from the GPS receiver 1, and is displayed numerically or as a track on the map. Is displayed.

When GPS receiver 1 resumes reception and starts positioning, the switch of data switch 4 switches to GPS receiver 1.
When switched to the side, the position indicator 5 displays the positioning result of the GPS receiver 1.

(Effect of the invention) As explained above, the present invention is applicable to automobiles.
When equipped with a GPS receiver and used in urban areas or mountainous areas where there are many obstacles such as buildings, mountains, tunnels, etc., when positioning is not possible due to interruptions in satellite radio waves, the on-board magnetic compass and distance meter can be used. When using distance data of azimuth data, the error in the estimated position increases over time because it is not the true north course used on the actual map, but the present invention supplements magnetic azimuth data with magnetic deviation data, By calculating a more accurate estimated position, it becomes possible to perform continuous and highly accurate positioning without interruption.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the apparatus of the present invention. 1...GPS receiver, 2...Magnetic deviation calculator,
3...Estimated position calculator, 4...Data switch, 5
...Position indicator, 6...Car, 7...GPS receiver antenna, 8...Magnetic compass, 9...Distance meter.

Claims (1)

[Claims] 1. A GPS receiver with a function to output an alarm signal when the strength of the satellite signal being received decreases and positioning becomes impossible, and a function to measure and output the vehicle's moving direction (true north course) with high precision, and a vehicle. Magnetic deviation for calculating the amount of magnetic deviation from the azimuth data (magnetic north course) from a magnetic compass that detects the traveling direction of a computing unit; azimuth data from a magnetic compass that detects the traveling direction of the vehicle; distance data from a distance meter; and magnetic deviation data from the magnetic deviation computing unit;
an estimated position calculator that calculates an estimated position based on the measured position immediately before the GPS receiver becomes unable to perform positioning;
If positioning is possible with the GPS receiver, the GPS
Data for switching to output the positioning result from the receiver to the position display, and to output the position calculation result of the estimated position calculator to the position display when the GPS receiver outputs a positioning failure alarm signal. 1. A GPS navigation device comprising: a switch; and a position indicator that displays position information from the data switch as a numerical display or a track on a map.