JPH0425782A - Position measurement system of on-vehicle gps receiver - Google Patents

Abstract

PURPOSE:To carry on position measurement even if one satellite enters an unreceivable state by receiving signals from receivable satellites independently by many channels and selecting a specific number of satellites which are currently most suitable for the position measurement among all the satellites. CONSTITUTION:Multichannel constitution is provided with plural channels #1ch - #3ch each consisting of an antenna, an RF reception part, and a signal processing part. When reception is started, the respective channels #1ch - #3ch perform the inverse diffusion of satellite radio waves received by the antennas 1A - 1C at RF reception parts 2A - 2C respectively to receive all receivable satellites, channel by channel. Those are demodulated by signal processing part 3A - 3C and then sent to an arithmetic control part 4. Thus, a specific number of satellites which are most suitable for the position measurement at this time are selected among all the receivable satellites which are received by the channels #1ch - #3ch and the position measurement is carried out by using their navigation data. Therefore, even if a satellite in the position measurement becomes unreceivable, navigation data on another reception satellite is usable instead for the position measurement.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is a positioning system using an artificial satellite.
Global Positioning
The present invention relates to a positioning method for a vehicle-mounted GPS receiver that performs positioning using a GPS system.

[Conventional technology]

To perform positioning using GPS, at least three, preferably four GPS satellites are required.

In-vehicle GPS receivers have a one-channel configuration,
Some have multi-channel configurations. A receiver with a one-channel configuration has only one receiving channel consisting of one antenna, one RF receiving section, and one signal processing section, and only this one channel can receive all the receiving satellites necessary for positioning. Receive at. On the other hand, a receiver with a multi-channel configuration includes a plurality of the channels, allocates satellites to be received to each channel, and receives satellites necessary for positioning by dividing the satellites into each channel.

[Problem to be solved by the invention]

In the conventional multi-channel in-vehicle GPS receiver, each channel receives the satellites necessary for positioning, as described above. Therefore, if the receiving satellites of a certain channel are blocked by a building or the like and cannot be received, there is a problem in that it becomes impossible to receive the specified number of satellites required for positioning, and positioning may be interrupted.

The present invention was made to solve such problems, and its purpose is to maintain positioning accuracy while maintaining good positioning accuracy even when some satellites become unreceivable during positioning. An object of the present invention is to provide a positioning method for a vehicle-mounted GPS receiver that can continue positioning.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides an in-vehicle GMS having a multi-channel configuration including a plurality of receiving channels each including one antenna, one RF receiving section, and one signal processing section.
The PS receiver independently receives satellites that can be received on each channel, and selects a predetermined number of satellites that are most suitable for positioning at that time from among all the satellites received on each channel. , positioning is performed using the navigation data of the selected satellite.

[Operation] Selects a predetermined number of satellites most suitable for positioning at that time from among all receiving satellites received on all channels,
Positioning is performed using the navigation data. Therefore, even if the satellite that is currently performing positioning is behind a building and becomes unreceivable, it is possible to perform positioning using the navigation data of other receiving satellites in place of that satellite. , positioning will no longer be interrupted as in the past. Note that in order to select the satellite most suitable for positioning at that time, for example, PDOP (geometric precision deterioration coefficient) may be employed and a combination of satellites with the minimum PDOP may be selected.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of an on-vehicle GPS receiver constructed by applying the method of the present invention. This embodiment is an example of a three-channel configuration, and in order to distinguish each channel, the first channel (hereinafter referred to as #1ch) is given a subscript A, and the second
The channel (hereinafter referred to as #2ch) is indicated with a subscript B, and the third channel (hereinafter referred to as #3ch) is indicated with a subscript C.

In Figure 1, LA, IB, and IC are three antennas installed independently, 2A, 2B, and 2C are RF receivers that despread satellite radio waves received by each antenna and receive GPS satellites, and 3A , 3B, and 3C are signal processing units that demodulate the satellite reception data received by each RF receiving unit into original digital data, and 4 is a signal processing unit that selects a predetermined number (for example, four) of satellites that are most suitable for positioning at that time. , is an arithmetic control unit that calculates the current position using the navigation data of the selected satellite. It is preferable that the three antennas IA, IB, and IC are installed separately at appropriate positions inside the vehicle, such as inside the front window and rear window of the vehicle.

When reception of GPS satellites starts, each antenna LA, I
B. The satellite radio waves received by the IC are sent to the RF receiving sections 2A, 2B,
2C, and all receivable satellites are received for each channel. Then, the received signals from each satellite are processed by signal processing units 3A, 3B, and 3C.
After demodulating into the original digital data, it is sent to the arithmetic control section 4.

For example, if each channel is
In other words, #1ch is the satellite 31. S
3, S4, #2ch is satellite S2. S3. Assuming that #3ch was able to receive three satellites S7 and two satellites 35 and 36, signal processing units 3A, 3B, and 3
C demodulates the received signal of each receiving satellite and sends it to the arithmetic control section 4.

The arithmetic control section 4 includes the signal processing sections 3A and 3B.

Using the navigation data of the receiving satellites 31 to S7 sent from 3C, the combination of satellites that gives the smallest PDOP at that time, for example, the satellites Sl, S2, S2, etc. marked with a circle in FIG. 2, is determined. S3. The combination S6 is selected, and the current position of the own army is calculated using the navigation data of the selected satellite. This allows the most accurate positioning at that time to be performed. In addition, in the case of the example in Figure 2, satellite S3
is received on two channels, #1ch and #2ch, but in such a case, positioning may be performed using the received signal of the satellite on the channel side with the higher received signal strength.

The positioning data obtained as described above is sent to a navigation device (not shown) or the like and displayed as position information on a map displayed on a display such as a CRT.

Furthermore, while performing positioning as described above, for example, if the satellite S2 enters the shadow of a building and becomes unreceivable, the arithmetic and control unit 4 sends other satellites other than the satellite S2 which has become unreceivable. Immediately recalculate PDOP using 6 satellites, select a new combination of 4 satellites with the smallest PDOP at that point, and perform positioning using the navigation data of these newly selected 4 satellites. Continue. Therefore, even if some of the satellites are blocked by a building or the like and cannot be received, the combination of satellites with the highest positioning accuracy at that time is selected using the remaining receiving satellites and positioning is continued. You will be able to do this.

Although the above embodiment has been described using a receiver with a three-channel configuration as an example, the present invention is not limited to this, and can be applied to any receiver with two or more channels or a multi-channel configuration.

〔Effect of the invention〕

As is clear from the above, when using the positioning method of the present invention, positioning can be continued even if some of the satellites are behind a building and cannot be received. This eliminates the need for positioning to be interrupted midway, unlike with other receivers. Furthermore, when performing positioning, the satellite that has passed the most positioning at that point is selected from among all receiving satellites by all antennas, so positioning accuracy can be maintained in any reception condition.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of an on-vehicle GPS receiver constructed by applying the method of the present invention, and FIG. 2 is a diagram showing an example of receiving satellites for each channel in the embodiment. IA, 1. B, IC...antenna, 2A, 2B, 2C
...RF receiving section, 3A, 3B, 3C... Signal processing section, 4... Arithmetic control section, 81-S7... Receiving satellite.

Claims (1)

[Claims] In a multi-channel in-vehicle GPS receiver having a plurality of receiving channels each consisting of one antenna, one RF receiving section, and one signal processing section, satellites that can be received on each channel are provided. is received independently on each channel, selects a predetermined number of satellites that are most suitable for positioning at that time from among all the satellites received on each channel, and performs positioning using the navigation data of the selected satellites. A positioning method for a vehicle-mounted GPS receiver.