JP3283585B2 - GPS receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a GPS receiver, and more particularly to a GPS receiver suitable for measuring the position of a vehicle or the like based on radio waves from GPS satellites.

[0002]

2. Description of the Related Art GPS (Global Position)
A single positioning type and an interference measurement type are known as a non-system receiver. These receivers
It is possible to receive radio waves transmitted from a plurality of GPS satellites, measure the distance between two points from the received radio waves, and measure the position of a moving object. Then, in order to generate digital data related to the measurement from the received radio wave, a DSP (Digital
tal SignalProcessor). This DSP is provided with a plurality of channels to generate digital data corresponding to each satellite from radio waves transmitted from a plurality of GPS satellites. That is, a circuit is provided for the number of GPS satellites (including GPS satellites to be added in the future), activated, and provided with a circuit for selecting from which satellite.

[0003]

However, in the conventional GPS receiver, when the number of DSP channels is eight, the number of satellites visible in the field of view, that is, the number of satellites from which measurement information can be obtained is four. However, the power is also turned on for the other four-channel DSPs, and all the channels are in operation. Therefore, the four-channel DSP that does not generate data from the satellite is always in the operating state.
The current consumption for the channels is wasted.

An object of the present invention is to provide a GPS receiver capable of operating only a data generation circuit corresponding to the number of satellites from which measurement information can be obtained.

[0005]

In order to achieve the above object, the present invention provides a high frequency amplifier circuit for amplifying radio waves transmitted from a satellite, and a frequency converter for converting an output signal of the high frequency amplifier circuit into an intermediate frequency signal. A circuit, an intermediate frequency amplification circuit for amplifying the intermediate frequency signal, a plurality of data generation circuits for generating digital data for each channel corresponding to the satellite based on the intermediate frequency signal, and information on measurement from output data of the data generation circuit. Having arithmetic means for arithmetically processing
In the receiver, the plurality of data generation circuits include a first data generation circuit.
The data generation circuit and the second data generation circuit
In addition, the first data generation circuit has four channels,
In addition, channels corresponding to the number of satellites used for measurement
A channel specifying means for specifying, the Chi Yan'neru channel specified by the specified means when within four channels
The power supply only to the first data generation circuit, cut off the supply of power to the second <br/> data generating circuit, said tea
4 channels specified by channel specifying means
Exceeds the first data generation circuit and the second data generation circuit.
Power supply control means for supplying power to the data generation circuit .

[0006]

[0007]

According to the above-mentioned means, the radio wave transmitted from each satellite is amplified, and when this received radio wave is converted into an intermediate frequency signal, digital data is generated based on the intermediate frequency signal. The number of satellites from which measurement information can be obtained is calculated based on the number. Then, a channel corresponding to the calculation result is designated, power is supplied only to the data generation circuit of the channel designated by the channel designation means, and power supply to the other data generation circuits is cut off. That is, only the data generation circuits of the channels corresponding to the number of satellites from which the measurement information can be obtained are activated, and the power supply of the other data generation circuits is turned off, thereby preventing power from being wasted. It is possible to extend the life of the battery mounted on the machine and to reduce the capacity of the battery.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a GPS receiver 10 includes a high-frequency amplifier circuit 12, a frequency conversion circuit 14, and an intermediate-frequency amplifier circuit 1.
6, the first DSP 18, the second DSP 20, the switch 22,
24, a CPU 26, and a battery 28, and an antenna 30
Is connected.

The high frequency amplifier circuit 12 amplifies radio waves from each satellite received by the antenna 30 and outputs the amplified high frequency signal to the frequency conversion circuit 14. The frequency conversion circuit 14 mixes the input high-frequency signal and the local oscillation frequency, generates an intermediate frequency from the mixed signal, and outputs the generated intermediate frequency signal to the intermediate frequency amplifier 16. The intermediate frequency amplifying circuit 16 amplifies the input intermediate frequency signal with a specified amplification factor, and outputs the amplified signal to each of the DSPs 18 and 20.
Each of the DSPs 18 and 20 has four channels, and is provided with an A / D converter, a digital filter, and a digital PLL circuit corresponding to each channel. The phase data and the navigation based on the input intermediate frequency signal are provided. Message data is generated for each channel. The various data are transferred to the CPU 26, and the CPU 26 can calculate the position of the moving body based on the input data and measure the distance between two points. Further, the number of currently receivable satellites is calculated from the almanac data included in the navigation message data, and the channel corresponding to the calculation result is designated, and the D of the designated channel is designated.
A control signal for supplying power only to the SP is output. That is, the CPU 26 includes an arithmetic unit that arithmetically processes information related to measurement based on data from the DSPs 18 and 20 constituting the data generation circuit;
And satellite means for calculating the number of satellites for which the measurement information can be obtained based on the output data from the satellite and channel means for designating a channel corresponding to the calculation result. Configuration. Switches 22 and 24 are CPU 26
The contacts are opened and closed by commands from the
The power from the battery 28 is supplied to each of the DSPs 18 and 20 only when the switch 4 is turned on, and the supply of power to each of the DSPs 18 and 20 is cut off when the switches 22 and 24 are turned off.

Next, the operation of the present invention will be described with reference to the flowchart of FIG. First, when the power of the GPS receiver 10 is turned on, the receiver is initialized by the CPU 26 (step 100). Next, from the almanac data (orbit information of each satellite) stored in the memory of the CPU 26 in advance, the number of satellites for which measurement information can be obtained as currently receivable satellites is calculated (step 102). Next, it is determined whether or not a satellite has been designated by a manual operation (step 104). At this time, when a predetermined satellite is designated by a manual operation, a process for designating channels corresponding to the designated number of satellites is performed, and a process for supplying power only to the DSP of the designated channel is executed (step 106). ). That is, when the number of designated channels is less than four, an ON signal is output only to the switch 22, and when the number of designated channels exceeds four, both the switches 22 and 24 are turned on.

On the other hand, when it is determined in step 104 that the satellite has not been designated by the manual operation, the process of designating the channel corresponding to the number of satellites calculated in step 102 is executed, and the DSP of the designated channel is executed. (Step 108). That is, the number of satellites for which measurement information can be obtained is four.
When the number of channels is less than the number of channels, an ON signal is output only to the switch 22, and when the number of channels is more than four, the switches 22 and 24 are output.
To output an ON signal.

When the DSP 18 or the DSP 20 is activated, the radio wave received by the antenna 30 is amplified and then converted into an intermediate frequency signal, and the intermediate frequency signal is sequentially converted into digital data for each channel. Then, the position and the like of the moving object are measured based on each data (step 110). Thereafter, it is determined whether or not the measurement has been completed for all observation points. If the measurement has not been completed, the process returns to step 102, and if the measurement has been completed, the processing in this routine ends (step 112). .

As described above, according to the present embodiment, when the number of channels for generating digital data is four or less, only the DSP 18 is activated, so that the DSPs 18 and 20 are always activated. Thus, the current consumption can be reduced more than in the case. In the above-described embodiment, the DSP 18 and the DSP 20 each having four channels have been described. However, the DSP 18 has four channels, the DSP 20 has two channels, and other DSPs.
It is also possible to configure a SP having two channels, and the DSP 18 has four channels,
One channel of DSP 20 and one channel of DS
It is also possible to configure P with three DSPs. Furthermore, it is also possible to configure by providing eight DSPs of one channel. Also in these cases, the current consumption can be reduced by bringing only the DSP of the designated channel into the operating state.

[0014]

As described above, according to the present invention,
Since only the data generation circuit of the designated channel among the plurality of data generation circuits is operated, power consumption can be prevented, and the life of the battery mounted on the receiver and the reduction in capacity can be achieved. it can.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the apparatus shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 GPS receiver 12 High frequency amplification circuit 14 Frequency conversion circuit 16 Intermediate frequency amplification circuit 18 1st DSP 20 2nd DSP 22, 24 switch 26 CPU 28 battery

Continuation of the front page (56) References JP-A-61-28881 (JP, A) JP-A-64-7824 (JP, A) JP-A-61-134162 (JP, A) JP-A-3-74954 (JP) , A) Steven M .; Chamberley air, COMBINED GPS / GLONASS NAVIGATION, IEEE National Telesystems Conference, USA, IEEE, Vol. 1, pp. 205-210, 1991 (58) Fields investigated (Int.Cl. ⁷ , DB name) G01S 5/00-5/14 H04B ^7/ 24-7/26 H04Q ⁷ /00-7/38

Claims (1)

(57) [Claims] A high-frequency amplifier for amplifying a radio wave transmitted from a satellite; a frequency converter for converting an output signal of the high-frequency amplifier to an intermediate frequency signal; an intermediate-frequency amplifier for amplifying the intermediate frequency signal; A GP comprising: a plurality of data generation circuits for generating digital data for each channel corresponding to a satellite based on a frequency signal; and arithmetic means for arithmetically processing information relating to measurement from output data of the data generation circuit
In the S receiver, the plurality of data generation circuits include a first data generation circuit and a first data generation circuit.
And a second data generation circuit, and the first data generation circuit.
The data generation circuit has 4 channels, and furthermore, channels corresponding to the number of satellites used for measurement.
A channel specifying means for specifying, said Ji Yan'neru channel specified by the specified means 4 switch
If it is within the channel , power is supplied only to the first data generation circuit, power supply to the second data generation circuit is cut off, and the channel designated by the channel designation means is supplied.
When the number of channels exceeds 4 channels, the first data is generated.
A GPS receiver, comprising: a power supply control unit that supplies power to the circuit and the second data generation circuit .