CN102226843B - Method for utilizing forwarding range finding value and pseudo range value to determine GEO navigation satellite clock error - Google Patents

Abstract

The invention relates to a method for utilizing forwarding range finding value and pseudo range value to determine GEO navigation satellite clock error. The method comprises the following steps: obtaining GEO navigation satellite transponder time delay value, forwarding range finding value, pseudo range finding value and synchronization forwarding range finding value through laser measurement and definitive orbit calculation, converting the synchronization forwarding range finding value as original satellite ground distance value, and carrying out ionosphere correction on the original satellite ground distance value and the pseudo range finding value to respectively obtain ionosphere corrected satellite ground distance value and ionosphere corrected pseudo range measured value; figuring out real-time GEO navigation satellite clock error; and obtaining satellite transponder time-delayed actual value and after precise GEO navigation satellite clock error through after precision definitive orbit calculation. According to the method, clock error product with second time interval can be provided to improve real-time precision of a navigation positioning system. Also the calculating method used in the invention is simple, thus error in the calculating process is effectively minimized.

Description

Utilize forwarding distance measurement value and pseudorange value to confirm the method for GEO Navsat clock correction

Technical field

The present invention relates to a kind of method of utilizing forwarding distance measurement value and pseudorange value to confirm the clock correction of atomic clock on the GEO Navsat, relate to Navsat and measure the orbit determination field, belong to the Astrometry and Celestial Mechanics subject.

Background technology

The key issue of the bearing accuracy of navigational satellite system is to confirm satellite atomic clock clock correction and variation thereof.

The method of confirming Navsat clock correction at present mainly contains three kinds: 1) one way telemetry, and satellite that pseudorange value that this method utilization is measured and tracks positioned obtain and the distance value between the synchronizing station, both ask poor, can obtain satellite clock correction.2) round trip telemetry obtains satellite orbit thereby adopt some radar measurement stations and minority laser station to measure, and adopts then with the identical method of one way range finding and obtains satellite clock correction.3) direct time ratio is to method.Main method when adopting two-way survey realizes, send markers to satellite from land station, on satellite, measure time of arrival, and satellites transmits markers simultaneously, in ground survey time of arrival, relatively these two pseudo-random code ranging values can obtain satellite clock correction.

The GEO Navsat since the trace geometry condition of satellite receive local restriction of surveying the rail net, satellite with respect to the dynamics constraint information on ground a little less than.Reason owing to measurement mechanism; Even observing simultaneously, a plurality of research stations also are difficult to satellite clock correction is separated with survey station clock correction; Confirm that satellite clock correction becomes a technical barrier, the method for employing group difference obtains satellite clock correction usually, and this can reduce definite precision of satellite clock correction.

Said method exists that scope quantity is many, computing method are complicated, result of calculation receives the Satellite Orbit Determination precision to influence, obtain the slow shortcoming of Navsat clock correction result.

Summary of the invention

The technical matters that solves

For fear of the weak point of prior art, the present invention proposes a kind of method that can obtain GEO Navsat clock correction in real time.Forwarding distance measurement value through not containing GEO Navsat clock correction with comprise GEO satellite clock correction pseudorange value and subtract each other and obtain Navsat clock correction.Utilize the present invention to calculate satellite clock correction and can realize the definite in real time GEO Navsat clock correction in separate unit station; Have calculate simple, clock correction result is irrelevant with satellite orbit, can realize round-the-clock uninterrupted observation, and can reduce the quantity of scope, reduces the advantage of the cost of structure measuring system.

Technical scheme

Technical characterictic of the present invention is: with the forwarding distance measurement value that does not contain GEO Navsat clock correction is reference value; With the pseudorange value that comprises GEO Navsat clock correction is measured value; Adopt following method to handle transmitting distance measurement value and pseudorange value, obtain GEO Navsat clock correction, concrete steps are following:

Step 1: calculate GEO Navsat transponder time delay value R through laser measurement or orbit determination, its value is the distance value of signal from satellite earth antenna phase center arrival satellite transmitting antenna phase center after transponder is transmitted, unit: m;

Step 2: will transmit distance-measuring equipment, pseudorange distance-measuring equipment and obtain transmitting distance measurement value C (t) with sampling constantly according to 1 second/inferior carrying out of sampling rate; The measuring-signal per second triggers; Its value goes upward to satellite for transmitting distance measuring signal from transmitting the distance-measuring equipment antenna phase center;, satellite repeater comes downwards to the distance value of transmitting the distance-measuring equipment antenna phase center, unit: m after transmitting; Pseudorange distance measurement value L (t), the measuring-signal per second triggers, and its value is sent the distance value that comes downwards to pseudorange distance-measuring equipment antenna phase center for the pseudorange distance measuring signal from GEO Navsat antenna phase center, unit: m;

Step 3: it is synchronous with the moment of pseudorange value to transmit distance measurement value, utilize following formula calculate with the synchronous forwarding distance measurement value C ' of pseudorange value synchronization (t), wherein c is the light velocity,

$C^{\′}\left(t\right)=C\left(t\right)+(C(t-1)-C\left(t\right))\×\frac{C\left(t\right)}{c}$

Step 4: formula will be transmitted distance measurement value C ' synchronously and (t) convert original star ground distance value C to " (t), below utilizing

$C^{\′\′}\left(t\right)=\frac{C^{\′}\left(t\right)-R}{2}$

Step 5: with original star ground distance value C " (t) with pseudorange value L (t) carry out ionosphere correct obtain the star ground distance value C that correct in ionosphere respectively " ' the pseudorange value L ' that (t) corrects with ionosphere (t) utilizes following formula to obtain real-time GEO Navsat clock correction S (t),

S(t)＝C″′(t)-L′(t)

Wherein: C " ' (t)=C " (t)+Δ C is " (t)

L(t)＝L(t)+ΔL(t)

${\mathrm{\ΔC}}^{\′\′}\left(t\right)=\frac{40.28}{f_C^2}\×\sec [\arcsin \left(\frac{C^{\′\′}\left(t\right)}{C^{\′\′}\left(t\right)+h}\cos E\right)\×\mathrm{VTEC}\left(t\right)$

$\mathrm{\ΔL}\left(t\right)=\frac{40.28}{f_L^2}\×\sec [\arcsin \left(\frac{L\left(t\right)}{L\left(t\right)+h}\cos E\right)\×\mathrm{VTEC}\left(t\right)$

f _CFor transmitting the frequency of the used radio carrier of range finding, unit: Hz;

f _LBe the find range frequency of used radio carrier of pseudorange, unit: Hz;

H is a height of site value, unit: rice;

E is the observation angle of pitch, unit: degree;

VTEC is the electron content concentration of radiowave point of puncture, unit: TECU;

Step 6: the actual value R ' that calculates the satellite repeater time delay through precise orbit determination afterwards (t), formula obtains accurate afterwards GEO Navsat clock correction S ' (t) below utilizing,

$S^{\′}\left(t\right)=\frac{C^{\′}\left(t\right)}{2}+{\mathrm{\ΔC}}^{\′\′}\left(t\right)-L^{\′}\left(t\right)-\frac{R^{\′}\left(t\right)}{2}$

Beneficial effect

The method that utilization forwarding distance measurement value that the present invention proposes and pseudorange value are confirmed GEO Navsat clock correction; Do not receive the trace geometry condition restriction and the restriction more weak of GEO satellite of satellite with respect to the dynamics constraint information on ground; Can confirm GEO Navsat clock correction in real time; IGS is 15 minutes to the real-time clock correction product time interval of gps satellite at present, and through this method can be provided the time interval is the clock correction product of per second, improves the real-time precision of navigation positioning system.The used computing method of the present invention are simple in addition, can effectively reduce the error that computation process is brought.

Embodiment

Combine embodiment that the present invention is further described at present:

The measuring system of present embodiment comprises seven parts: ground clock system, forwarding distance-measuring equipment, pseudorange distance-measuring equipment, GEO Navsat, data processing centre (DPC) and operation the present invention confirm the software of Navsat clock correction.

The principle of work of transmitting distance-measuring equipment is identical to principle of work with the two-way time ratio of satellite.The principle of work of pseudorange distance-measuring equipment is identical with GPS pseudorange operation of receiver principle.

The ground clock system provides unified time and frequency signal for transmitting distance-measuring equipment and pseudorange distance-measuring equipment.

Transmit distance-measuring equipment and comprise modulator, detuner, antenna system, data acquisition computer five parts.Modulator produces intermediate frequency pseudo-code spread-spectrum signal; Antenna equipment is sent to the GEO Navsat after intermediate frequency pseudo-code spread-spectrum signal is mixed to radiofrequency signal, receives the radiofrequency signal that the GEO Navsat is transmitted, and is mixed to intermediate-freuqncy signal; The intermediate-freuqncy signal that detuner demodulation antenna receives obtains transmitting distance measurement value through the pseudo-code related operation; Distance measurement value is transmitted in data acquisition computer record and storage.

The pseudorange distance-measuring equipment comprises navigation receiving antenna, navigation neceiver; The navigation receiving antenna receives the satellite pseudo range signals and generates pseudorange value by navigation neceiver.

The GEO Navsat comprises pseudorange generating unit and satellite repeater; The pseudorange generating unit produces pseudo range signals, satellite repeater and is used to receive transmit and sends downgoing signal to the earth after distance-measuring equipment is sent to the upward signal frequency conversion of satellite repeater.

Data center's processing forward distance measurement value and pseudorange value obtain GEO Navsat clock correction.

Confirm that GEO Navsat clock correction software is the software of on the DELPHI7 platform, developing.

The embodiment of this method:

Utilize and transmit distance-measuring equipment and GEO Navsat generation forwarding distance measurement value; Utilize pseudorange distance-measuring equipment and GEO Navsat to generate pseudorange value; Data processing centre (DPC) and operation the present invention confirm that the software of GEO Navsat clock correction handles the forwarding distance measurement value and the pseudorange value that collect; Obtain Navsat clock correction, concrete steps are following:

Step 1: land station's clock system performance is at least than the high one magnitude of satellite atomic clock performance, as standard frequency source; The ground clock system provides unified time and frequency signal for transmitting distance-measuring equipment with the pseudorange distance-measuring equipment, and it is only relevant with the signal propagation time of reality to transmit the forwarding distance measurement value that distance-measuring equipment collects this moment, does not comprise that satellite clock correction influences; The pseudorange value that the pseudorange distance-measuring equipment collects comprises that not only actual signal propagation time is relevant, also comprises Navsat clock correction;

Step 2: will transmit distance-measuring equipment and the pseudorange distance-measuring equipment carries out the zero base line setting, and be provided with like this to reduce the systematic error that survey station position difference is brought;

Step 3: calculate GEO Navsat transponder time delay value R through laser measurement or orbit determination;

Step 4: simultaneously the GEO Navsat is transmitted range finding, and obtain transmitting distance measurement value C (t), the GEO Navsat is carried out the pseudorange range finding, and obtain pseudorange distance measurement value L (t);

Step 5: will transmit distance measurement value C (t) and be synchronized to the identical moment with pseudorange distance measurement value L (t), and transmitted distance measurement value C ' synchronously (t);

Step 6: will transmit distance measurement value C ' synchronously and (t) convert original star ground distance value C to " (t),

Step 7: with original star ground distance value C " (t) with pseudorange distance measurement value L (t) carry out ionosphere correct obtain the star ground distance value C that correct in ionosphere respectively " ' (t) with the pseudo-range measurements L ' of ionosphere correction (t),

Step 8: calculate real-time GEO Navsat clock correction S (t),

Step 9: the actual value R ' that calculates the satellite repeater time delay through precise orbit determination afterwards (t) calculates accurate afterwards GEO Navsat clock correction S ' (t)

Can find out by the foregoing description; Utilize forwarding distance measurement value and pseudorange value to confirm the method for GEO Navsat clock correction; Mainly utilize transponder and ground relay type range measurement system on the GEO Navsat to generate and the irrelevant forwarding distance measurement value of GEO Navsat clock correction, and the utilization pseudorange value relevant with GEO Navsat clock correction obtain GEO satellite clock correction through related operation.

The satellite atomic clock of GEO Navsat is owing to reasons such as work under bad environment, volume weight restriction strictness cause performance to differ 1～2 one magnitude than the ground atomic clock; Because of the atomic clock poor performance can cause the navigation and positioning accuracy variation; Therefore must proofread and correct Navsat clock correction, one way telemetry in the past must be carried out precise orbit determination to satellite just can obtain satellite clock correction.Utilize this method owing to can be synchronized to synchronization with transmitting distance measurement value and pseudorange value, it is irrelevant to transmit distance measurement value and pseudorange value and GEO satellite orbit this moment, can directly calculate satellite clock correction, has real-time.The radar measurement station precision is low, and the laser station measuring station receives weather effect big; The relay type measuring station does not receive weather effect, adopts the two-forty pseudo-code can improve distance accuracy, can lower ionospheric delay through high-frequency carrier signal.Relay type data acquisition equipment, navigation neceiver data acquisition equipment zero base line are settled the tracking error that can reduce GEO satellite to ground receiving equipment.

Utilize forwarding distance measurement value and pseudorange value to confirm the method for GEO Navsat clock correction; Minimum need one cover ground clock system, forwarding distance-measuring equipment, pseudorange distance-measuring equipment just can carry out whole day observation to the GEO Navsat; So not only can reduce scope quantity, simplify scope, can also obtain GEO satellite clock correction and accurate afterwards GEO Navsat clock correction in real time.

It is thus clear that; Utilize forwarding distance measurement value and pseudorange value to confirm that the method for GEO Navsat clock correction can increase substantially the real-time of GEO satellite clock correction, simplify quantity and the complexity calculating, reduce measuring equipment; And can accurate satellite clock correction result be provided afterwards, back-end processing is more flexible.

Claims (5)

1. one kind is utilized and transmits the method that range finding and pseudorange information are confirmed GEO Navsat clock correction, it is characterized in that step is following:

Step 1: calculate GEO Navsat transponder time delay value R through laser measurement or orbit determination; Its value is the distance value of signal from GEO Navsat receiving antenna phase center arrival GEO Navsat emitting antenna phase center after transponder is transmitted, unit: m;

Step 2: will transmit distance-measuring equipment, pseudorange distance-measuring equipment and obtain transmitting distance measurement value C (t) with sampling constantly according to 1 second/inferior carrying out of sampling rate; The measuring-signal per second triggers; Its value goes upward to the GEO Navsat for transmitting distance measuring signal from transmitting the distance-measuring equipment antenna phase center;, GEO Navsat transponder comes downwards to the distance value of transmitting the distance-measuring equipment antenna phase center, unit: m after transmitting; Pseudorange distance measurement value L (t), the measuring-signal per second triggers, and its value is sent the distance value that comes downwards to pseudorange distance-measuring equipment antenna phase center for the pseudorange distance measuring signal from GEO Navsat antenna phase center, unit: m;

Step 3: the moment of transmitting distance measurement value and pseudorange distance measurement value is synchronous, calculate with the synchronous forwarding distance measurement value C ' of pseudorange distance measurement value synchronization (t), wherein c is the light velocity,

$C^{\′}\left(t\right)=C\left(t\right)+(C(t-1)-C\left(t\right))\×\frac{C\left(t\right)}{c}$

Step 4: will transmit distance measurement value C ' synchronously and (t) convert original star ground distance value C to " (t),

$C^{\′\′}\left(t\right)=\frac{C^{\′}\left(t\right)-R}{2}$

Step 5: with original star ground distance value C " (t) with pseudorange distance measurement value L (t) carry out ionosphere correct obtain the star ground distance value C ' that correct in ionosphere respectively " (t) with the pseudorange distance measurement value L ' of ionosphere correction (t), obtain real-time GEO Navsat clock correction S (t),

S(t)＝C′″(t)-L′(t)

Wherein: C ' " (t)=" (t)+Δ C " (t)

L′(t)＝L(t)+ΔL(t)

${\mathrm{\ΔC}}^{\′\′}\left(t\right)=\frac{40.28}{f_C^2}\×\sec \left[\arcsin \left(\frac{C^{\′\′}\left(t\right)}{C^{\′\′}\left(t\right)+h}\cos E\right)\right]\×\mathrm{VTEC}\left(t\right)$

$\mathrm{\ΔL}\left(t\right)=\frac{40.28}{f_L^2}\×\sec \left[\arcsin \left(\frac{L\left(t\right)}{L\left(t\right)+h}\cos E\right)\right]\×\mathrm{VTEC}\left(t\right)$

f _CFor transmitting the frequency of the used radio carrier of range finding, unit: Hz;

f _LBe the find range frequency of used radio carrier of pseudorange, unit: Hz;

H is a height of site value, unit: rice;

E is the observation angle of pitch, unit: degree;

VTEC is the electron content concentration of radiowave point of puncture, unit: TECU;

Step 6: the actual value R ' that calculates GEO Navsat transponder time delay through precise orbit determination afterwards (t) obtains accurate afterwards GEO Navsat clock correction S ' (t),

$S^{\′}\left(t\right)=\frac{C^{\′}\left(t\right)}{2}+\mathrm{\Δ}{C}^{\′\′}\left(t\right)-L^{\′}\left(t\right)-\frac{R^{\′}\left(t\right)}{2}$

2. a kind of method of utilizing forwarding range finding and pseudorange information to confirm GEO Navsat clock correction according to claim 1; It is characterized in that: transmit distance measuring signal and produce and send to the GEO Navsat by the ground forwarding distance-measuring equipment; After GEO Navsat transponder is transmitted, come downwards to the forwarding distance-measuring equipment, obtain distance value through related operation by transmitting distance-measuring equipment.

3. a kind of method of utilizing forwarding range finding and pseudorange information to confirm GEO Navsat clock correction according to claim 1 is characterized in that: the ground clock system provides unified time and frequency signal for transmitting distance-measuring equipment and pseudorange distance-measuring equipment.

4. a kind of method of utilizing forwarding range finding and pseudorange information to confirm GEO Navsat clock correction according to claim 1 is characterized in that: transmit distance-measuring equipment and pseudorange distance-measuring equipment and carry out the zero base line setting.

5. a kind of method of utilizing forwarding range finding and pseudorange information to confirm GEO Navsat clock correction according to claim 1; It is characterized in that:, only need a cover ground clock system, forwarding distance-measuring equipment, pseudorange distance-measuring equipment, data center just can obtain GEO Navsat clock correction for GEO Navsat seat.