CN1403833A - Whole cycle fuzziness initializing method in short-base line DGPS location - Google Patents

Abstract

The present invention relates to the whole cycle fuzziness initializing method for the carrier phase in short-base line DGPS. The present invention designs the position of mobile GPS receiving antenna and the operation steps of extracting observation data as well as corresponding data processing method. The operation of the present invention is simple and practical and the corresponding data processing method can give out accurate and reliable whole cycle fuzziness estimation of carrier phase. The present invention can raise the operation efficiency in the DGPS positioning measurement.

Description

A kind of method of lacking initialization integer ambiguity in the baseline DGPS location

Technical field:

The present invention relates to carrier phase difference location survey, relate to the method for initialization ambiguity of carrier phase in a kind of short baseline gps carrier phase difference location survey (DGPS) particularly.

Background technology:

GPS is the cover satellite navigation system that the U.S. sets up, and the GPS beacon that it provides has become the shared resource in the whole world, has brought into play revolutionary effect in fields such as navigation, measurements.Adopt two GPS receivers to carry out synchro measure, can accurately obtain the relative coordinate between two secondary gps antennas, this metering system is called differential GPS to be measured, or claims DGPS to measure.If one of them gps antenna is in the motion, then become dynamic DGPS and measure, measure otherwise be called static DGPS.Utilize the observed quantity of GPS receiver carrier phase carry out DGPS dynamically or static immobilization measure and can reach very high precision, (not far from one another between two GPS receiver antennas that promptly are used to measure at short baseline, representative value is between several meters to one kilometer) under the situation, can reach centimetre-sized even millimetre-sized location survey precision.

Utilizing the carrier phase DGPS technology to position in the measurement, a matter of utmost importance that must solve is the integer ambiguity that the carrier phase observed quantity is determined in initialization correctly.On the developing history of carrier phase DGPS location survey technology, the method of a lot of initialization ambiguity of carrier phase was once proposed, at present, the method that often adopts has following several in practice: 1, on two coordinate points of known relative coordinate, place receiver antenna and observe, and then according to the method for known relative coordinate location compute integer ambiguity.This method is reliable, but needs to set in advance the antenna set-point of two known relative coordinates in the operation, has relatively high expectations; 2, on the some position of two unknown relative coordinates, place receiver antenna, carry out 15 minutes to 25 minutes Continuous Observation, use long Continuous Observation data solver integer ambiguity then.This method does not need default known coordinate point, but needs the Continuous Observation of long period, and is very not convenient; 3, in the dynamic carrier phase place DGPS location survey, receiver antenna is gathered observation data while moving, and after accumulation one given data, adopts the mode of handling afterwards or handling in real time to resolve integer ambiguity.This method does not need static observation, but reliability is relatively poor, generally is used for double-frequency GPS receiver.Above-mentioned these methods respectively have characteristics, and application is all arranged in practice.

Except that above-mentioned method commonly used, also have a kind of method of initialization ambiguity of carrier phase very commonly used, be called " exchange antenna method ".The core of this method is to have designed portable antenna step cleverly, concrete operations are as follows: at first select two antenna set-points that need not pre-determine the point-to-point transmission relative coordinate, the antenna of GPS receiver is placed on the observation of carrying out for 8～15 seconds on these two points; Place two antennas in these two some interdigit exchanges then, carry out the observation in 8～15 seconds again; At last, the data of utilizing this twice short time observation to obtain are resolved ambiguity of carrier phase.This method is operated simple relatively with respect to previously described method, and required precognition condition is few, and the result is also very reliable, thereby often is used.But, above-mentioned exchange antenna method also has its weakness, main is must keep the GPS receiver that gps satellite is carried out the continuous uninterrupted tracking observation in the exchange antenna operation, and under the prerequisite that keeps the continuous tracking observation to satellite an antenna moved on the some position that another antenna occupied originally and be not easy, and this mobile needs carry out twice.Therefore, when adopting this method to measure operation, need exchange sky the Line tool of application specific design sometimes.

Summary of the invention:

The objective of the invention is, the method for initialization ambiguity of carrier phase in a kind of carrier phase DGPS location survey is provided.This method can provide the integer ambiguity initialization valuation reliably when simplifying the operation, improve significantly and measure operating efficiency.

In order to achieve the above object, the present invention adopts following technical scheme:

The first step, the antenna of two GPS receivers is numbered #1 and #2 respectively, the relative coordinate of point position A and some position B need not pre-determine, the distance of A and B is 0.7～1.5 meter, the #1 antenna is placed on a position A, the #2 antenna is placed on a position B, after finishing antenna and placing, carry out the observation in 4～8 seconds, obtain t ₁Two GPS receiver double-differential carrier phases observed quantity constantly , p in the subscript and q represent the gps satellite numbering respectively;

Second step, the #2 antenna is moved to a position C from a position B, the coordinate of point position C need not pre-determine, distance between C and A, B is 0.7～1.5 meter, keep the GPS receiver of #2 antenna correspondence that gps satellite is carried out the continuous uninterrupted tracking observation in moving, finish move after, carry out the observation in 4～8 seconds, obtain t ₂Two GPS receiver double-differential carrier phases observed quantity constantly

The 3rd step moved to a position B with the #1 antenna, moved that back #1 antenna is actual to plant oneself and put distance between a B less than 2 centimetres, the GPS receiver that does not require #1 antenna correspondence when mobile carries out tracking observation to satellite, finish move after, carry out 30～60 seconds Continuous Observation, at moment t ₃With moment t ₄Obtain the observed quantity of two GPS receiver double-differential carrier phases respectively

With , moment t ₃With moment t ₄Between the time interval corresponding with observation time, be 30～60 seconds.

The t that obtains according to aforesaid operations ₁, t ₂, t ₃, t ₄Corresponding constantly double-differential carrier phase observed quantity With , can determine required ambiguity of carrier phase by following column count.

At first calculate following two parameters

With

Then, both are subtracted each other and round, can obtain integer ambiguity

Valuation:

Provide the principle of aforementioned calculation method below:

Know the double-differential carrier phase observed quantity by traditional satellite navigation difference location theory Can be expressed as:

Wherein, $d{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}\left(t_1\right)={\mathrm{\ρ}}_A^p\left(t_1\right)-{\mathrm{\ρ}}_A^q\left(t_1\right)-{\mathrm{\ρ}}_B^p\left(t_1\right)+{\mathrm{\ρ}}_B^q\left(t_1\right)---\left(5\right)$ $l_X^{\mathrm{pq}}\left(t_1\right)=[X_B^s\left(t_1\right)-x_p^s\left(t_1\right)]/{\mathrm{\ρ}}_B^p\left(t_1\right)-[X_B^s\left(t_1\right)-x_q^s\left(t_1\right)]/{\mathrm{\ρ}}_B^q\left(t_1\right)---\left(6\right)$ $l_Y^{\mathrm{pq}}\left(t_1\right)=[Y_B^s\left(t_1\right)-y_p^s\left(t_1\right)]/{\mathrm{\ρ}}_B^p\left(t_1\right)-[Y_B^s\left(t_1\right)-y_q^s\left(t_1\right)]/{\mathrm{\ρ}}_B^q\left(t_1\right)---\left(7\right)$ $l_Z^{\mathrm{pq}}\left(t_1\right)=[Z_B^s\left(t_1\right)-z_p^s\left(t_1\right)]/{\mathrm{\ρ}}_B^p\left(t_1\right)-[Z_B^s\left(t_1\right)-z_q^s\left(t_1\right)]/{\mathrm{\ρ}}_B^q\left(t_1\right)---\left(8\right)$ ρ represents the geometric distance between gps satellite and ground point position approximate coordinates; (X ^s, Y ^s, Z ^s) approximate coordinates of expression ground point; (x ^s, y ^s, z ^s) expression gps satellite approximate coordinates (can from the broadcast message of satellite, obtain); (dX, dY, dZ) the base correction amount of two some interdigits of expression; The dN ambiguity of carrier phase; In above each parameter, indicate gps satellite or the ground point bit number that relates to by last subscript.

Also can with Be written as: Because when a position B moved to a some position C, receiver carried out tracking measurement continuously to gps satellite at the #2 antenna, therefore the integer ambiguity in (9) formula equates with the integer ambiguity of (1) formula, that is: $d{N}_{\mathrm{AB}}^{\mathrm{pq}}=d{N}_{\mathrm{AC}}^{\mathrm{pq}}$ 。Simultaneously,, can replace the approximate coordinates of some position C fully, at this moment, (4) formula and (9) formula be subtracted each other, and put in order and can get with the approximate coordinates of some position B because some position B and some position C are not far from one another: Wherein, $\mathrm{\&epsiv;}=[l_X^{\mathrm{pq}}\left(t_1\right)-l_X^{\mathrm{pq}}\left(t_2\right)]\&CenterDot;{\mathrm{dX}}_{\mathrm{AB}}+[l_r^{\mathrm{pq}}\left(t_1\right)+l_r^{\mathrm{pq}}\left(t_2\right)]\&CenterDot;{\mathrm{dY}}_{\mathrm{AB}}+[l_Z^{\mathrm{pq}}\left(t_1\right)-l_Z^{\mathrm{pq}}\left(t_2\right)]\&CenterDot;{\mathrm{dZ}}_{\mathrm{AB}},$ The analysis showed that further ε satisfies: $\mathrm{\&epsiv;}<7.9\&times;{10}^{-4}\&CenterDot;(t_2-t_1)\&CenterDot;({\mathrm{dX}}_{\mathrm{AB}}^2+{\mathrm{dY}}_{\mathrm{AB}}^2+{\mathrm{dZ}}_{\mathrm{AB}}^2{)}^{1/2}---\left(11\right)$ Wherein, the unit of time t is second; ε and (dX _AB, dY _AB, dZ _AB) unit be GPS L ₁The wavelength of beacon.Therefore, ε is an a small amount of always, can omit from (10).Compare with (1) formula, (10) formula left end is exactly the right-hand member of (1) formula; Therefore, (10) formula can further be written as:

Wherein, (Δ X _BC, Δ Y _BC, Δ Z _BC) be the baseline vector between some position B and some position C.

Investigate again below With Still replace the approximate coordinates of some position C, then have with the approximate coordinates of some position B:

Wherein,

It is exactly the integer ambiguity of wanting initialization to calculate.

Know the coefficient in (12) formula, (13) formula and (14) formula by GPS location theory

The variation of t in time can be with straight line match well, and in the situation of time span less than tens minutes, the systematic error that fitting a straight line brings can be ignored fully.Therefore, available t ₃, t ₄Observed reading constantly Estimate t ₂Constantly

Value, that is to say, can obtain following estimation:

(15) $\&ap;{\mathrm{dN}}_{\mathrm{BC}}^{\mathrm{pq}}+l_X^{\mathrm{pq}}\left(t_2\right)\&CenterDot;\mathrm{\&Delta;}{X}_{\mathrm{BC}}+l_Y^{\mathrm{pq}}\left(t_2\right)\&CenterDot;\mathrm{\&Delta;}{Y}_{\mathrm{BC}}+l_Z^{\mathrm{pq}}\left(t_2\right)\&CenterDot;\mathrm{\&Delta;}{Z}_{\mathrm{BC}}$ Notice that first equal sign provides in (15) formula relational expression is the standard estimation formulas that the fitting a straight line extrapolation is estimated, also just the parameter calculation formula that provides of (2) formula.(15) formula can directly be written as:

Compare (12) formula and (16) formula, and two formulas subtracted each other, can get: Following formula promptly is that the floating number of integer ambiguity is estimated expression formula.In view of integer ambiguity

Have the integer characteristic, thus (17) formula is rounded the estimator that can obtain integer ambiguity, shown in (3) formula.

(3) accuracy of the integer ambiguity initialization value that provides of formula depends on the precision that (12) formula and (16) formula are estimated, the influence of position deviation when also being subjected to simultaneously #1 antenna in the 3rd operation steps and moving to a some position B.As long as the summation of the error of (17) formula integer ambiguity floating number valuation that the position deviation when the #1 antenna moves to a some position B in error of (12) formula and (16) formula and the operation of the 3rd step is brought is no more than GPS L half ₁The wavelength of beacon so just can guarantee the correctness of the integer ambiguity initialization value that (3) formula is made.(12) error of formula is provided by (11) formula, this error with the #2 antenna moved to position C institute's time spent from a position B be directly proportional, be directly proportional with the precision of relative coordinate guestimate value between a position A and some position B.Generally, in the operation of portable antenna, the #2 antenna is moved to a position C from a position B be easy to realize, this is that therefore, the operation of this step can be finished in 50 seconds because some position C can choose arbitrarily; Because distance is very near between some position A and some position B, so the sure fully magnitude of accomplishing rice of the guestimate value of the relative coordinate between these 2; So, the precision of (12) formula can be controlled at the degree that does not influence (3) formula accuracy fully.(16) estimated accuracy of formula can obtain estimation, the error and the observed quantity of (16) formula from (15) formula

The size of middle stochastic error is directly proportional, with the time interval (t ₄-t ₃) be inversely proportional to, with the time interval (t ₄-t ₂) and the time interval (t ₃-t ₂) be directly proportional; The time interval (t ₄-t ₂) and the time interval (t ₃-t ₂) size and #1 antenna to move to position B institute's time spent from a position A relevant, in the antenna of this step moves, though the #1 antenna need be moved to the some position that a specially appointed #2 antenna occupies, but considering does not need to keep receiver that gps satellite is carried out tracking observation continuously when mobile, so, the time of mobile #1 antenna can be controlled within 50 seconds fully The size of middle stochastic error is in the millimeter level.Position deviation when the #1 antenna moves to a some position B in the 3rd step operation is easy to be controlled within 2 centimetres, and the valuation error maximum of the floating number integer ambiguity that brings is no more than 1/10th GPS L ₁The wavelength of beacon is not so as long as according to the operation of aforesaid operations step, this error source can bring influence to final integer ambiguity integer valuation yet.

In sum, adopt the operation steps and (1) formula, (2) formula, (3) formula that provide previously, the integer ambiguity in the location of initialization carrier phase DGPS reliably.

The present invention has the following advantages and good effect:

1, the method for initialization ambiguity of carrier phase is reliable and practical in the carrier phase DGPS location survey of the present invention's proposition, can provide the integer ambiguity initialization valuation reliably in the measurement engineering of reality;

2, compare with the method for existing initialization ambiguity of carrier phase, the present invention is simple to operate, implements easily, can improve the measurement operating efficiency significantly.

Description of drawings:

Each several part annexation synoptic diagram when Fig. 1 is implementation and operation step 1.

Each several part annexation synoptic diagram when Fig. 2 is implementation and operation step 2.

Each several part annexation synoptic diagram when Fig. 3 is implementation and operation step 3.

Below in conjunction with accompanying drawing, the present invention is further illustrated:

The 1-#1GPS receiver: with by the #1GPS antenna reception and follow the tracks of the beacon of gps satellite Signal, the line item of going forward side by side;

The 2-#2GPS receiver: with by the #2GPS antenna reception and follow the tracks of the beacon of gps satellite Signal, the line item of going forward side by side;

The 3-#1GPS antenna: the #1GPS receiver receives the gps satellite beacon signal by it;

The 4-#2GPS antenna: the #2GPS receiver receives the gps satellite beacon signal by it;

5-antenna set-point position A: in the first step and second step operating procedure, be used for placing The #1GPS antenna;

6-antenna set-point position B: in first step operating procedure, be used for placing #2GPS days Line; In the 3rd step operating procedure, be used for placing the #1GPS antenna;

7-antenna set-point position C: in second step and the 3rd step operating procedure, be used for placing The #2GPS antenna;

8-#1 antenna cable: be used for connecting #1GPS receiver and #1GPS antenna;

9-#2 antenna cable: be used for connecting #2GPS receiver and #2GPS antenna;

In the practical operation, receiver 1 is connected with antenna 3 by cable 8; Receiver 2 passes through Cable 9 is connected with antenna 4; Point position 5, some position 6, some position 7 are used for placing gps antenna 3 Or 4, in different operating procedures, the antenna of placement may be different.

Embodiment:

Below further describe in detail with regard to the specific embodiment of the present invention.

Concrete enforcement of the present invention is divided into the observation data acquisition operations and two parts are calculated in the integer ambiguity valuation.

The enforcement of observation data collecting part is divided into three operation stepss:

1, as shown in Figure 1, two GPS receivers 1 that will be used for the carrier phase DGPS location survey are connected with 4 by the self-corresponding antenna 3 of cable and each with 2, and antenna 3 and 4 is placed respectively on two some positions 5 and 6; Carry out the observation in 4～8 seconds, obtain t ₁Two GPS receiver double-differential carrier phases observed quantity constantly , p in the subscript and q represent the gps satellite numbering respectively, and subscript A and B represent two observation station positions 5 and 6, and some position 5 is 0.7～1.5 meter to the distance of some position 6;

2, as can be known by Fig. 1 and Fig. 2, the antenna 4 of receiver 2 correspondences is moved on the new some position 7, point position 7 is 0.7～1.5 meter with the distance of some position 5 or some position 6, need to keep receiver that the Continuous Tracking of satellite beacon is measured in moving, simultaneously, the operation spended time of portable antenna is few more good more, is controlled at 40 seconds with the interior correctness that can guarantee the integer ambiguity initialization result that finally obtains.After mobile finishing, carry out the measurement in 4～8 seconds, obtain t ₂Two GPS receiver double-differential carrier phases observed quantity constantly , subscript C represents the new position 7 that antenna 4 occupies;

3, as can be known by Fig. 2 and Fig. 3, the antenna 3 of receiver 1 correspondence is moved on the position 5, allow receiver that the tracking measurement of satellite is interrupted losing lock in moving, finishing this antenna, to move institute's time spent also be few more good more, was controlled at for 60 seconds with the interior correctness that can guarantee the integer ambiguity initialization result that finally obtains; Move the actual required distance that plants oneself and put 6 of positions of back #1 antenna less than 2 centimetres, that is to say that deviation that antenna moves is less than 2 centimetres.After mobile finishing, carry out one group of measurement, at t ₃Constantly obtain the observed quantity of two GPS receiver double-differential carrier phases

, then, keep receiver that the Continuous Tracking of satellite is measured, about 30 seconds to 1 minute, carry out one group of measurement more later, at t ₄Constantly obtain another group double-differential carrier phase observed quantity

Moment t ₃With moment t ₄Between the big more correctness that helps guaranteeing net result more of the time interval, but get (t ₄-t ₃) can guarantee the correctness of net result to 60 seconds at 30 seconds.

The integer ambiguity valuation is calculated and is divided following three steps:

1, with the observation data that collects

With Bring following formula into, calculate parameter

2, with the observation data that collects

With Bring following formula into, calculate parameter

3, with parameter

With

Bring following formula into, calculate required integer ambiguity valuation

Wherein, Int[] operation of expression round.

Claims (1)

1, a kind of method of lacking initialization integer ambiguity in the baseline DGPS location is characterized in that, this method follows these steps to order and carries out:

(1), the present invention has designed following operation steps portable antenna position and has gathered observation data:

Two GPS receivers that 1. will be used for the carrier phase DGPS location survey are connected with each self-corresponding antenna, and two antennas are placed respectively on a position A and the B; Carry out the measurement in 4～8 seconds, obtain t ₁Two GPS receiver double-differential carrier phases observed quantity constantly , subscript is represented the gps satellite numbering, subscript is represented a position;

2. on the basis of the rapid operation of previous step, moved on the new some position C, and needed to keep receiver that the Continuous Tracking of satellite beacon is measured in moving originally occupying the antenna of position B; The running time of portable antenna is in 40 seconds; Then, carry out the measurement in 4～8 seconds, obtain t ₂Two GPS receiver double-differential carrier phases observed quantity constantly

3. will originally occupy on the antenna transfer point position B of a position A, and allow receiver that the tracking measurement of satellite is interrupted losing lock during antenna moves; The antenna traveling time is in one minute, and the distance between actual some position that occupies of this antenna and some position B is less than 2 centimetres; After mobile the finishing, carry out one group of measurement, at t ₃Constantly obtain the observed quantity of two GPS receiver double-differential carrier phases Wait for 30 seconds to 60 seconds, at t ₄Constantly carry out one group of measurement again, obtain another group double-differential carrier phase observed quantity

(2), the present invention has designed following computing method and has calculated the ambiguity of carrier phase valuation:

1. will With Bring following formula into, calculate parameter

2. will With

Bring following formula into, calculate parameter

3. will With

Bring following formula into, calculate required integer ambiguity valuation

Wherein, Int[] operation of expression round.

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