CN101435860A

CN101435860A - Coherent processing of receiver

Info

Publication number: CN101435860A
Application number: CNA2007101582688A
Authority: CN
Inventors: 王博通
Original assignee: SHENYANG MARS INFORMATION TECHNOLOGIES Co Ltd
Current assignee: SHENYANG MARS INFORMATION TECHNOLOGIES Co Ltd
Priority date: 2007-11-14
Filing date: 2007-11-14
Publication date: 2009-05-20

Abstract

The invention discloses coherent treatment of a receiver, and relates to a receiver device. The aim of the invention is to provide a GPS receiver which can make the coherent treatment before related treatment, correct the polarity reversal of C/A codes without using navigation information externally obtained, and accumulate the C/A codes for addition. The aim of the invention is to provide a GPS receiver which has good stability and reliability and high performance-price ratio, selects a lower medium frequency aiming at the frequency range actually used by GPS and adopts an analog front end structure different from the common high frequency receiver. The receiver consists of a radio frequency analogue front end, an A/D sampling circuit, a frequency synthesizer, a synchronous control circuit and a digital signal processing chip, wherein the radio frequency analogue front end, the A/D sampling circuit and the digital signal processing chip are in electric connection sequentially, the frequency synthesizer is connected with the radio frequency analogue front end, and the synchronous control circuit is connected with the frequency synthesizer and the radio frequency analogue front end.

Description

The relevant processing of receiver

Technical field

The present invention relates to receiver apparatus.

Background technology

In the GPS receiver, for the C/A sign indicating number that constitutes the gps signal that receives, based on the internal clocking of GPS receiver, the C/A sign indicating number that generates is carried out time shifting, add up gradually simultaneously, the line correlation of going forward side by side is handled, and the shift amount of the time when being maximum with the result who adds up is as the time of arrival of gps signal.But, when the intensity of C/A sign indicating number is fainter when the intensity of gps signal is fainter, can not judge which is maximum among the result who adds up.Therefore, in the GPS of high sensitivity receiver, even the intensity of gps signal is fainter, also should judge which maximum among the result of above-mentioned accumulative total, the processing that was concerned with before relevant treatment accumulates the phase adduction to the C/A sign indicating number and makes it become big.But, on the C/A sign indicating number of the object of handling as being concerned with, the navigation message of precise ephemeris data is encoded.And this navigation is one with 20 cycles of C/A sign indicating number.Thereby the C sign indicating number has the possibility of per 20 cycles with regard to reversal of poles, if the C/A sign indicating number is accumulated addition simply, then produces by offseting that this reversal of poles causes, thereby can not obtain high sensitivity.

HF receiver works in the skip band of 3～30MHZ.In this frequency range, external disturbance is serious, in order to satisfy the sensitivity index requirement, and effectively suppresses mirror to interference, adopts the superhet of three frequency conversion structures usually.The GPS operation of receiver that the sea is surveyed is in skip band, and its structure has also adopted and the similar structure of common HF receiver.Generally there are not problems such as passage consistency in communication system mostly with single-channel mode work.The receiver of GPS is usually with much channel communication work, and for multichannel receiver, complicated repeatedly frequency conversion structure requires to result in hand cramps for stability, the passage consistency of receiver.For simplifying the GPS structure, improving the stability of receiver, the HF receiver based on a mixing of software radio thought has appearred, this class receiver adopt intermediate frequency be 40MHZ with the structure frequently that is in high school, work in the shortwave full frequency band.To the over the horizon GPS that the sea is surveyed, its frequency of operation is usually less than 14MHZ, at the characteristics of over the horizon GPS, can suitably reduce intermediate frequency, further simplifies the GPS structure.The GPS receiver is about coherent receiver.In the signal of receiver, transmitting obtains by technology such as frequency division, frequency multiplication, mixing by a clock source, its frequency synthesizer is very complicated.

At present, a kind of like this invention is arranged before the C/A sign indicating number is accumulated addition, proofread and correct the reversal of poles of C from sign indicating number based on the navigation message of received gps signal modulation or the navigation message of obtaining from the outside.But, need spended time for to obtain navigation message according to gps signal.For example, often exist 3G (Third Generation) Moblie mode (3G) etc., can't help the outside situation that navigation message is provided to the GPS receiver.

Summary of the invention

The object of the present invention is to provide a kind of like this GPS receiver, before relevant treatment, be concerned with when handling, need not use the navigation message of obtaining from the outside, with regard to the reversal of poles of recoverable C/A sign indicating number, and can be with C/A sign indicating number accumulation addition.Purpose is the frequency range at the actual use of GPS, selects for use than Low Medium Frequency, adopts the AFE (analog front end) structure that is different from general HF receiver, provides a kind of reliable and stable, has the GPS receiver than high performance-price ratio.

The described technical scheme of the present invention of above-mentioned purpose is: the GPS receiver, it comprises rf analog front-end, A/D sample circuit, frequency synthesizer, synchronization control circuit and digital signal processing chip composition, rf analog front-end, A/D sample circuit, digital signal processing chip are electrically connected successively, frequency synthesizer is connected with rf analog front-end, and synchronization control circuit is connected with frequency synthesizer and rf analog front-end.

After the gps signal that receives from gps satellite is accumulated processing, the duplicate of the C/A sign indicating number that use generates in inside carries out in the GPS receiver of relevant treatment (in above-mentioned accumulation is handled, the a plurality of accumulative total signals of accumulative total on the gps signal that receives, and the result that should add up accumulates addition, each accumulative total be prediction based on the modulation of the gps signal of navigation message with signal and at the signal of inside generation).The GPS receiver can be before relevant treatment, and it is the signal of modulating according to navigation message that a plurality of accumulative totals that accumulative total inside generates on the gps signal of reception are used signal, gps signal.When handling, even the intensity of gps signal is fainter, also can use the navigation message of obtaining from the outside, with regard to the reversal of poles of recoverable (revisal) C/A sign indicating number when being concerned with.Therefore, even do not providing under the situation of navigation message, also can provide highly sensitive GPS receiver from the outside.

Beneficial effect of the present invention:

Use intermediate frequency 21.4MHZ as IF-FRE, under than the Low Medium Frequency condition, can adopt, reduced the burden of Digital Down Convert, directly can finish Digital Down Convert work, do not need extra hardware Digital Down Convert circuit by DSP than low sampling rate; The mixing for once of this receiver, analog device is few, the corresponding minimizing of nonlinearity product, the system linear degree is improved.

Description of drawings:

Fig. 1 is the FB(flow block) of GPS receiver;

Fig. 2 is a C/A sign indicating number processing procedure.

Embodiment:

GPS receiver of the present invention comprises: receiving element receives the gps signal by the navigation message modulation; Accumulative total signal generation unit, prediction generate the different mutually a plurality of accumulative totals of bit pattern and use signal, and make each accumulative total respectively depart from predetermined distance respectively with the phase place of signal based on the modulation of the gps signal of navigation message; Accumulated unit reaches the accumulative total signal on adding up respectively on the gps signal of going back the receiving element reception in the utilization; And the accumulation addition unit, accumulate addition for signal from above-mentioned accumulated unit output.Based on the modulation of the gps signal of navigation message, generate the different mutually a plurality of accumulative total signals of bit pattern, each accumulative total respectively departs from predetermined distance respectively with the phase place of signal, adds up a plurality of accumulative total signals of this generation on the gps signal of reception.On reach accumulative total with in the signal arbitrarily one with identical based on the gps signal bit pattern cardinal principle after the navigation message modulation.

Therefore, the signal that the bit pattern of the gps signal that receives according to the present invention is identical substantially, at this moment, and the reversal of poles of recoverable C/A sign indicating number, this C/A sign indicating number constitutes the gps signal that receives.Even from a plurality of signals of accumulated unit output any accumulated addition, also can not produce offseting of C/A sign indicating number.Described rf analog front-end is by duplexer, bandpass filter, and frequency mixer, low noise amplifier, crystal filter, amplifier, crystal filter is formed according to broken the electrical connection.The linear FM signal of frequency synthesizer output is launched identically with the repetition period of linear FM signal, and in the initial moment in each cycle, the initial phase that transmits with this newspaper signal makes zero.The sampling rate of A/D sample circuit is 160KHZ.Adopt a mixing, the structure of the direct bandpass sampling of intermediate frequency; IF-FRE is selected nominal intermediate frequency 21.4MHZ for use, and it is the crystal filter of 21.4MHZ that intermediate-frequency filter is selected the centre frequency nominal value for use; Adopt bandpass filter directly to be connected, do not have traditional radio-frequency amplifier therebetween with frequency mixer; Dsp chip is finished filtering, Digital Down Convert and fft algorithm.

Claims

1, the relevant processing of receiver, it is characterized in that: the GPS receiver, it comprises rf analog front-end, A/D sample circuit, frequency synthesizer, synchronization control circuit and digital signal processing chip composition, rf analog front-end, A/D sample circuit, digital signal processing chip are electrically connected successively, frequency synthesizer is connected with rf analog front-end, and synchronization control circuit is connected with frequency synthesizer and rf analog front-end.

2, according to claim 1, it is characterized in that: after the gps signal that satellite receives accumulates processing, the duplicate of the C/A sign indicating number that use generates in inside carries out in the GPS receiver of relevant treatment (in above-mentioned accumulation is handled, the a plurality of accumulative total signals of accumulative total on the gps signal that receives, and the result that should add up accumulates addition, each accumulative total be prediction based on the modulation of the gps signal of navigation message with signal and at the signal of inside generation).