CN1332214C - Method for determining full round number funiness of radio guidance system - Google Patents

Abstract

The present invention discloses a new method for eliminating the whole period digital-to-analog ambiguity of whole carrier phase changes. In the method, in a certain distance range, the whole period digital-to-analog ambiguity of whole carrier phase changes is obtained through the phase position capturing and tracking results of spread spectrum codes of local receiving machines and the value of carrier phase not satisfying one period of receiving machines according to the relationship of the transmission distance of the spread spectrum codes and the carrier transmission distance. The method of the present invention has no need of the addition of extra auxiliary signals and no need of the increase of the complexity of systems, can be used for fast, conveniently and reliably realize the high precision positioning of carrier measurement and can also be used for systems carrying out high precision navigational positioning.

Description

A kind of radio-navigation systems complete cycle is counted definite method of blur level

Technical field

The invention belongs to the field of using the electromagnetic wave technology to navigate and locate, as at radio-navigation systems, it is particularly related to uses carrier phase measurement to carry out the system of high precision navigator fix.

Background technology

As everyone knows, in existing navigation and positioning system, extensively adopt a plurality of transmitting station emission navigator fix signals, receiver receives; This principle of position that receiver calculates oneself according to the electric parameter of the navigator fix signal of each transmitting station of receiving is located and is navigated.To receive function and judge which transmitting station the signal of reception is from order to allow, transmitting station adopts the CDMA spread spectrum usually.Owing to the carrier frequency height, wavelength is short, in order to improve the precision of navigator fix, usually uses carrier phase measurement to carry out the high precision navigator fix again.

Navigation positioning system is to utilize the electric parameter (amplitude, frequency, phase place etc.) of the navigator fix signal of receiving and the relation of navigation parameter to come navigator fix.Determine the navigation parameter according to utilizing different electric parameters, navigation positioning system generally is divided into amplitude radio navigation system, frequency wireless navigational system, time radio navigational system, phase place radio navigation system, coupled antenna electricity navigational system etc., detailed content is seen: " radio navigation principle ", work such as Wei Guangshun, Zhang Yumin, publishing house of Southeast China University published in 1989.

The carrier phase measurement principle: carrier phase measurement is to measure the carrier signal of transmitting station emission in the phase change value of propagating on the distance, with the distance of determining that signal is propagated.Transmitting station s sends a carrier signal, and its phase place at transmitting station s place is  when moment t _s, and at this moment through propagate into the signal at receiver k place apart from r, its phase place is  _k, be ( to the phase change of receiver k then by transmitting station s _k- _s).( _k- _s) comprised the complete cycle issue and the fraction part in one week of less than.General calculating for convenience, carrier phase all is unit with the cycle.If can measure ( _k- _s), transmitting station being then to receiver apart from r:

r＝λ( _k- _s)＝λ(N ₀+Δ)?(1)

In the formula, N ₀Be carrier phase ( _k- _s) complete cycle part; Δ  is the less than fraction part in one week; λ is the wavelength of carrier wave, is given value.But actual phase is measured can only measure the less than fraction part in one week, and complete cycle is counted N ₀Be unclear.Therefore exist complete cycle to count N ₀The problem of blur level.

Therefore, have only accurate definite complete cycle to count N ₀Could obtain high-precision positioning result, otherwise, even the observed reading Δ  precision of phase measurement is very high, also be nonsensical.Therefore, the rapid solving complete cycle is counted N ₀It is the key of carrier phase measurement.Common complete cycle is counted N ₀Definite method have:

(1) a kind of simple method is continuously to calculate the complete phase period after the receiver initialization.At this moment carry out complete phase cycle count and phase count in the time of should be with the information of same received, the phase place integral multiple that the complete phase cycle count calculates every 2 π changes.So just determined that complete cycle counts N ₀The shortcoming of this method is a poor reliability, in case lossing signal or the interim power down of equipment etc. all will destroy the accuracy of complete phase cycle count, just can not eliminate the ambiguity of complete cycle number this moment fully.

(2) another kind of method is a transmitting station emission auxiliary signal, after the receiver initialization, when receiving the navigator fix signal, also receives auxiliary signal, and receiver utilizes auxiliary signal and navigation signal to come combined calculation to go out complete cycle and counts N ₀This method has increased the complexity of transmitter and receiver.

Above-mentioned various calculating complete cycle is counted N ₀The method detailed content see: " radio navigation principle ", work such as Wei Guangshun, Zhang Yumin, publishing house of Southeast China University published in 1989.The each have their own shortcoming of these methods, the reliability of method 1 is not high, in case lossing signal or the interim power down of equipment etc. all will destroy the accuracy of complete phase cycle count, just can not eliminate the ambiguity of complete cycle number this moment fully.Using method 2 has increased the complexity of transmitting station and receiver, thereby has increased realization difficulty and system cost.

Traditional wireless navigation positioning system is made up of transmitting station Fig. 1 and receiver Fig. 2.Transmitting station is made up of coding module 3, spreading code maker 4, modulation module 5, D/A modular converter 6, carrier generator 7, emitting antenna 8, and its receiver is made up of receiving antenna 9, local carrier generator 10, A/D modular converter 11, demodulation module 12, spread spectrum code acquisition and tracking module 13, reception baseband processing module 14.Its course of work is:

The ranging information that transmitting station will need to send is through coding module 3, and through modulating with modulation module 5 behind spreading code maker 4 spread spectrums, through the carrier frequency mixing of D/A modular converter 6 backs with carrier generator 7 generations, process emitting antenna 8 is launched then again.Through after the skyborne propagation, receiver is through receiving antenna 9, signal is received, after passing through the carrier signal mixing that produces with local carrier generator 10, again by 11 samplings of A/D modular converter, pass through demodulation module 12 demodulation then, pass through spread spectrum code acquisition and tracking module 13 again after, through receiving baseband processing module 14 electric parameter is extracted at last.

Its navigator fix principle is: the transmitting station of a plurality of location awares is arranged in the general system, and the structure of each transmitting station is all the same, and the spreading code of different is each transmitting station is different.Receiver after received signal is handled, extracts the electric parameter of each navigation signal with the signal received, then according to these electric parameters, sets up the navigation parametric equation, thereby carries out navigator fix.Detailed content is seen: " radio navigation principle ", work such as Wei Guangshun, Zhang Yumin, publishing house of Southeast China University published and " gps satellite navigation and precision positioning " in 1989, the Xu Qifeng work, publishing house of PLA published in 1989 years.

Summary of the invention

The purpose of this invention is to provide a kind of radio-navigation systems complete cycle and count definite method of blur level, promptly adopt elimination complete cycle of the present invention to count the method for blur level, in certain distance range, do not need to increase extra auxiliary signal, also need not increase the complexity of system, the navigator fix electric parameter of receiving according to local receiver just can be eliminated the complete cycle that carrier phase changes reliably and count blur level.

The present invention mainly is used in the complete cycle of eliminating the carrier phase variation in the navigator fix receiving system of utilizing carrier phase measurement to come navigator fix and counts blur level.Its theory diagram is seen Fig. 3, and it consists of: traditional receiver 2, spreading code time measurement module 15, complete cycle with spread spectrum code acquisition following function are counted computing module 16.

Principle of work of the present invention: the code length of supposing spreading code is N _c(chip), the code check of spreading code is K (chip/s), and carrier frequency is f (Hz), and propagation velocity of electromagnetic wave is C, and the precision that the receiver spread spectrum code acquisition is followed the tracks of is Δ φ ₁(chip), the local receiver acquisition and tracking to the spreading code phase differential be Δ φ _PN(chip), Δ φ _fThe carrier phase in one week of less than of measuring for receiver.Propagating a required distance of complete spreading code so is R:

$R=\frac{N_{c}C}{K}---\left(2\right)$

If range finding from r less than R, so according to acquisition and tracking to the spread spectrum phasometer signal propagation time of calculating be Δ τ _PN:

${\mathrm{\Δ\τ}}_{\mathrm{PN}}=\frac{{\mathrm{\Δ\φ}}_{\mathrm{PN}}}{K}---\left(3\right)$

When

$\frac{{\mathrm{\&Delta;\&phi;}}_1}{K}<\frac{1}{f}---\left(4\right)$

The complete cycle that carrier phase changes is counted N ₀For:

$\left\{\begin{array}{c}\begin{array}{cc}{N}_0=\left[\mathrm{\&Delta;}{\mathrm{\&tau;}}_{\mathrm{PN}}f\right]+i& i=-\mathrm{1,0,1}\end{array}\\ \frac{{\mathrm{\&Delta;\&phi;}}_{\mathrm{PN}}-{\mathrm{\&Delta;\&phi;}}_1}{K}\&le;\frac{N_0+{\mathrm{\&Delta;\&phi;}}_f}{f}\&le;\frac{{\mathrm{\&Delta;\&phi;}}_{\mathrm{PN}}+{\mathrm{\&Delta;\&phi;}}_1}{K}\end{array}\right.---\left(5\right)$

Wherein the maximum integer that is not more than this number is got in [] expression.

When locating with method of difference, range finding is represented the range difference of two transmitting stations to receiving platform, Δ φ from r _PNThe spread-spectrum signal of two transmitting stations recording of expression receiving platform arrives spreading code phase change poor of receiving platform, N ₀Represent the poor of complete cycle number that two transmitting stations change to the carrier phase of receiver.

A kind of radio-navigation systems complete cycle provided by the invention is counted definite method of blur level, the step below it adopts:

The first step: after received signal received through receiving antenna 9, process and the carrier signal mixing that local carrier generator 10 produces utilized carrier tracking technique to measure the fraction part Δ φ in one week of carrier phase deficient change simultaneously _f:

Second step: by 11 samplings of A/D modular converter, pass through demodulation module 12 demodulation then again, pass through spread spectrum code acquisition and tracking module 13 again, in spread spectrum code acquisition and tracking module 13, utilize the spread spectrum code acquisition tracking technique to measure the phase difference φ of spreading code _PN(chip);

The 3rd step: through receiving baseband processing module 14 electric parameter is extracted then;

Its feature technology is further comprising the steps of:

The 4th step: according to the phase difference φ of the local spreading code of in spread spectrum code acquisition and tracking module 13, measuring with the spreading code of the signal of receiving _PN(chip), spreading code time measurement module 15 is according to formula (3): ${\mathrm{\&Delta;\&tau;}}_{\mathrm{PN}}=\frac{{\mathrm{\&Delta;\&phi;}}_{\mathrm{PN}}}{K}$ Calculate the travel-time Δ τ of signal _PN

The 5th step: count the signal propagation time Δ τ that utilizes spreading code time measurement module 15 to calculate in the computing module 16 at complete cycle _PNThe carrier phase that obtains with local carrier generator in the receiver 10 changes the phase difference φ in a discontented week _f, in the formula of satisfying condition (4): $\frac{\mathrm{\&Delta;}{\mathrm{\&phi;}}_1}{K}<\frac{1}{f}$ The time, according to formula (5):

$\left\{\begin{array}{c}\begin{array}{cc}{N}_0=\left[{\mathrm{\&Delta;\&tau;}}_{\mathrm{PN}}f\right]+i& i=-\mathrm{1,0,1}\end{array}\\ \frac{{\mathrm{\&Delta;\&phi;}}_{\mathrm{PN}}-{\mathrm{\&Delta;\&phi;}}_1}{K}\&le;\frac{N_0+{\mathrm{\&Delta;\&phi;}}_f}{f}\&le;\frac{{\mathrm{\&Delta;\&phi;}}_{\mathrm{PN}}+{\mathrm{\&Delta;\&phi;}}_1}{K}\end{array}\right.$ Calculate complete cycle and count N ₀Value.

Through above step, the complete cycle that just can obtain the carrier phase variation is counted N ₀

Need to prove that formula (5) can be found the solution by programming.

Innovation of the present invention is: count the method ratio of blur level with traditional elimination complete cycle, the invention provides the method that complete cycle that the whole carrier phase of a kind of new elimination changes is counted blur level.In certain distance range, do not need to increase extra auxiliary signal, also need not increase the complexity of system, utilize phase capturing and the result of tracking and the value that the carrier phase in the discontented week that receiver obtains changes of local receiver spreading code, according to the relation of spreading code propagation distance and carrier wave propagation distance, the complete cycle that just can obtain reliable carrier phase variation is counted blur level.

In sum, utilize method of the present invention, do not need to increase extra auxiliary signal, also need not increase the complexity of system, the carrier phase in the discontented week that result who follows the tracks of according to the phase capturing of local receiver spreading code and receiver obtain changes, satisfy in the frequency spreading tracking precision under the condition of formula (4),, just can eliminate the complete cycle of carrier phase variation and count blur level according to the relation of spreading code propagation distance and carrier wave propagation distance.Utilize the present invention can realize carrier wave measurement hi-Fix fast, conveniently, reliably, can be used for carrying out the system of high precision navigator fix.

Description of drawings

Fig. 1 is the transmitter of traditional navigation positioning system

Wherein 3 is coding modules; The 4th, spectrum-spreading code generator; The 5th, modulation module; The 6th, the D/A modular converter; The 7th, carrier generator; The 8th, transmitting antenna;

Fig. 2 is the receiver of traditional navigation positioning system

Wherein 9 is receiving antennas; The 10th, the local carrier generator; The 11st, the A/D modular converter; The 12nd, demodulation module; The 13rd, spread spectrum code acquisition and tracking module; The 14th, receive baseband processing module;

Fig. 3 is the principle of work block diagram of the inventive method

Receiver 2 among the figure is exactly a receiver shown in Figure 2; The 15th, spreading code time measurement module; The 16th, complete cycle is counted computing module;

Fig. 4 is the process flow diagram of the inventive method.

Embodiment

The code length of supposing spreading code is N _c(chip)=8191, the code check of spreading code is K=25 (kchip/s), and carrier frequency is f=2 (MHz), and propagation velocity of electromagnetic wave is C=3 * 10 ⁸(m/s), the precision of receiver acquisition tracking spreading code is Δ φ ₁=0.01 (chip), this up-to-date style (4) is set up.Then propagating a required distance of complete spreading code is $R=\frac{N_{c}C}{K}=98292\left(\mathrm{km}\right),$ Now hypothesis measured apart from r less than 98292 (km).Transmitting station will be measured needed signal and emit through after the band spectrum modulation, pass through the propagation of certain distance after, determine that complete cycle counts N ₀Step as follows:

The first step: after received signal received through receiving antenna 9, process and the carrier signal mixing that local carrier generator 10 produces utilized carrier tracking technique to measure the fraction part Δ φ in one week of carrier phase deficient change simultaneously _f=0.1;

Second step: sample by A/D modular converter 11 again, pass through demodulation 12 demodulation then,, in spread spectrum code acquisition and tracking 13, utilize the spread spectrum code acquisition tracking technique to measure the phase difference φ of spreading code again through spread spectrum code acquisition and tracking 13 _PN=100 (chip);

The 3rd step: through receiving Base-Band Processing 14 electric parameter is extracted then;

The 4th step: according to the phase difference φ of the local spreading code of in spread spectrum code acquisition and tracking 13, measuring with the spreading code of the signal of receiving _PN=100 (chip), spreading code time measurement module 15 is calculated the travel-time Δ τ of signal according to formula (3) _PN=4 (ms);

The 5th step: calculate the signal propagation time Δ τ that calculates according to spreading code time measurement 15 in 16 at the complete cycle number _PNThe carrier phase that obtains with receiver changes the phase difference φ in a discontented week _f, calculate complete cycle according to formula (5) and count N ₀=8000.

Above transmitting station and receiver all are traditional, and spreading code time measurement module 15 and complete cycle are counted all available DSP of computing module 16 (Digital Signal Processing) programming and realized.

Claims (2)

1. a radio-navigation systems complete cycle is counted definite method of blur level, the step below its adopts:

The first step: after received signal received through receiving antenna (9), process and the carrier signal mixing that local carrier generator (10) produces utilized carrier tracking technique to measure the fraction part Δ φ in one week of carrier phase deficient change simultaneously _f

Second step: sample by A/D modular converter (11) again, pass through demodulation module (12) demodulation then, pass through spread spectrum code acquisition and tracking module (13) again, in spread spectrum code acquisition and tracking module (13), utilize the spread spectrum code acquisition tracking technique to measure the phase difference φ of spreading code _PN(chip);

The 3rd step: through receiving baseband processing module (14) electric parameter is extracted then;

Its feature technology is further comprising the steps of:

The 4th step: according to the phase difference φ of the local spreading code of in spread spectrum code acquisition and tracking module (13), measuring with the spreading code of the signal of receiving _PN(chip), spreading code time measurement module (15) is according to formula (3): $\mathrm{\&Delta;}{\mathrm{\&tau;}}_{\mathrm{PN}}=\frac{\mathrm{\&Delta;}{\mathrm{\&phi;}}_{\mathrm{PN}}}{K}$ Calculate the travel-time Δ τ of signal _PN, wherein K is the code check (chip/s) of spreading code;

The 5th step: count the signal propagation time Δ τ that utilizes spreading code time measurement module (15) to calculate in the computing module (16) at complete cycle _PNThe carrier phase that obtains with local carrier generator (10) in the receiver changes the phase difference φ in a discontented week _f, in the formula of satisfying condition (4): $\frac{\mathrm{\&Delta;}{\mathrm{\&phi;}}_1}{K}<\frac{1}{f}$ The time, according to formula (5): $\left\{\begin{array}{c}{N}_0=\left[\mathrm{\&Delta;}{\mathrm{\&tau;}}_{\mathrm{PN}}f\right]+i,i=-\mathrm{1,0,1}\\ \frac{\mathrm{\&Delta;}{\mathrm{\&phi;}}_{\mathrm{PN}}-\mathrm{\&Delta;}{\mathrm{\&phi;}}_1}{K}\&le;\frac{N_0+\mathrm{\&Delta;}{\mathrm{\&phi;}}_f}{f}\&le;\frac{\mathrm{\&Delta;}{\mathrm{\&phi;}}_{\mathrm{PN}}+\mathrm{\&Delta;}{\mathrm{\&phi;}}_1}{K}\end{array}\right.$ Calculate complete cycle and count N ₀Value, wherein f is carrier frequency (Hz), Δ φ ₁Precision (chip) for the tracking of receiver spread spectrum code acquisition.

2, a kind of radio-navigation systems complete cycle according to claim 1 is counted definite method of blur level, it is characterized in that described spreading code time measurement module (15) and complete cycle count all available dsp program of computing module (16) and realize.