CN103645485B - A kind of pseudorange differential method based on the frequency difference passive location of the double star time difference - Google Patents

Abstract

The invention provides a kind of pseudorange differential method based on the frequency difference passive location of the double star time difference, measure two satellites successively poor to the pseudorange of reference station, calculate the differential correctional of satellite, differential correctional is utilized to correct the pseudorange of unknown radiation source poor, the time of arrival obtained close to true value is poor, witness mark station to the arrival rate difference of two satellites is, computing reference station is poor to the arrival rate close to true value of two satellites, the frequency correction number of satellite is utilized to correct unknown radiation source poor to the arrival rate of two satellites, the arrival rate obtained close to true value is poor, utilize earth ellipsoid equation, differ from the time of arrival close to true value and the poor hi-Fix realized unknown radiation source of arrival rate.The present invention can correct the positioning error of system, thus improves the precision of double star passive location system.

Description

A kind of pseudorange differential method based on the frequency difference passive location of the double star time difference

Technical field

The invention belongs to the technical field of passive location, be particularly applied in the Correction of Errors technology of double star passive location, pseudorange differential method.

Background technology

GPS pseudo range difference is current widely used a kind of technology, its ultimate principle is the distance that the receiver of base station records that it arrives satellite, because the existence of ephemeris error and star clock error, the pseudorange measured also is not equal to the pseudorange obtained according to ephemeris computation, think the measured value containing error, using the pseudorange that obtains according to ephemeris computation as true value, true pseudorange is compared with the measured value containing error, utilize a wave filter by this differential filtering and obtain differential correctional, then by the differential correctional broadcast of all satellites in view to user, user utilizes this correction to correct corresponding pseudo range observed quantity.Finally, the pseudorange after user utilizes correction solves self position coordinates, with regard to the common error of cancellation base station and user, reaches the object improving positioning precision.Double star passive location system is for platform with two satellites, adopt the co-located technology arriving mistiming and arrival rate difference, arrive the difference and arrival rate is poor and earth ellipsoid equation determines the position of radiation source time of arrival between 2 observation platforms by measuring radiation source radiation signal.Therefore the measuring error of its positioning precision and TDOA, FDOA and earth ellipsoid error in equation relevant.At present, it is international and domestic that mainly to concentrate on the research of improving one's methods to the positioning calculation of measurement equation more, and positioning precision can only reach 10 ~ 20km, if do not adopt the Correction of Errors method of science to be corrected various positioning error, be just difficult to realize the hi-Fix to radiation source.

Summary of the invention

In order to overcome the deficiencies in the prior art, the invention provides a kind of pseudorange differential method based on the frequency difference passive location of the double star time difference, the positioning precision of double star passive location can be improved.

The technical solution adopted for the present invention to solve the technical problems comprises the following steps:

1) two satellites are measured poor to the pseudorange of reference station

${\mathrm{\ρ}}_0^{s2}-{\mathrm{\ρ}}_0^{s1}=r_0^{s2}-r_0^{s1}+\mathrm{\Δ}{\mathrm{\ρ}}_0^s+\mathrm{\Δ}{\mathrm{\ρ}}_0---\left(1\right)$

In formula be respectively the pseudorange of two satellites to reference station, be respectively the geometric distance of two satellites to reference station, can obtain according to the position at known reference station and satellite broadcasting ephemeris computation, that is:

$r_0^{s2}=\sqrt{{(x_{s2}-x_0)}^2+{(y_{s2}-y_0)}^2+{(z_{s2}-z_0)}^2}---\left(2\right)$

$r_0^{s1}=\sqrt{{(x_{s1}-x_0)}^2+{(y_{s1}-y_0)}^2+{(z_{s1}-z_0)}^2}---\left(3\right)$

(x in formula ₀, y ₀, z ₀) be the coordinate of reference station, (x _si, y _si, z _si), i=1,2 is positions of two satellites, represent the range error relevant with satellite position with ground reference station location, Δ ρ ₀represent the range error relevant with receiver;

2) differential correctional of satellite is calculated:

$\mathrm{\Δ\ρ}=(r_0^{s1}-r_0^{s2})-({\mathrm{\ρ}}_0^{s1}-{\mathrm{\ρ}}_0^{s2})---\left(4\right)$

3) utilize differential correctional Δ ρ to correct the pseudorange of unknown radiation source poor, obtain difference Δ t' time of arrival close to true value:

${\mathrm{c\Δt}}^{\′}={\mathrm{\ρ}}^{s2}-{\mathrm{\ρ}}^{s1}+\mathrm{\Δ\ρ}=\sqrt{{(x_{s1}-x)}^2+{(y_{s1}-y)}^2+{(z_{s1}-z)}^2}-\sqrt{{(x_{s2}-x)}^2+{(y_{s2}-y)}^2+{(z_{s2}-z)}^2}---\left(5\right)$

In formula, (x, y, z) represents the position of unknown radiation source, and c is the light velocity;

4) witness mark station is Δ f to the arrival rate difference of two satellites _r;

5) computing reference station is to the difference of the arrival rate close to the true value Δ f of two satellites ₀,

$\frac{{\mathrm{c\Δf}}_0}{f_0}=\frac{x_{s2}-x_0}{r_2}{v}_{x2}+\frac{y_{s2}-y_0}{r_2}{v}_{y2}+\frac{z_{s2}-z_0}{r_2}{v}_{z2}-\frac{x_{s1}-x_0}{r_1}{v}_{x1}-\frac{y_{s1}-y_0}{r_1}{v}_{y1}-\frac{z_{s1}-z_0}{r_1}{v}_{z1}---\left(6\right)$

(v in formula _xi, v _yi, v _zi), i=1,2 is the speed of satellite;

6) the frequency correction number of satellite is calculated:

ΔF＝Δf ₀-Δf _r（7）

7) unknown radiation source is Δ f to the arrival rate difference of two satellites, utilizes frequency correction number Δ F to correct the arrival rate of unknown radiation source poor, obtains the arrival rate difference Δ f' close to true value:

$\frac{{\mathrm{c\Δf}}^{\′}}{f_0}=\frac{c(\mathrm{\Δf}+\mathrm{\ΔF})}{f_0}=\frac{x_{s2}-x}{r_2}{v}_{x2}+\frac{y_{s2}-y}{r_2}{v}_{y2}+\frac{z_{s2}-z}{r_2}{v}_{z2}-\frac{x_{s1}-x}{r_1}{v}_{x1}-\frac{y_{s1}-y}{r_1}{v}_{y1}-\frac{z_{s1}-z}{r_1}{v}_{z1}---\left(8\right)$

8) earth ellipsoid equation is utilized:

$\frac{x^2}{a^2}+\frac{y^2}{a^2}+\frac{z^2}{b^2}=1---\left(9\right)$

In formula, a is earth semi-major axis, and b is earth semi-minor axis;

9) resolved the position of unknown radiation source by formula (5), (8) and (9), and then realize hi-Fix.

The invention has the beneficial effects as follows: by the known radiation source utilizing position known, utilize the positioning error of the pseudorange differential method of GPS to unknown radiation source to correct, improve the positioning precision of double star passive location system, and precision can be better than 5km.

Embodiment

Below in conjunction with embodiment, the present invention is further described, the present invention includes but be not limited only to following embodiment.

Difference measurements precision time of arrival that the present embodiment adopts is 30ns, and arrival rate difference measurements precision is 10Hz, and H_2O maser precision is 0.3m, and between star, relative position determination precision is 1m, and satellite orbit is low orbit satellite data, and satellite altitude is 800km.In this embodiment with the carrier frequency f of reference station ₀=10GHz, the initial coordinate of unknown radiation source is [100350] is example, carry out random selecting to unknown radiation source on this basis, reference station coordinates is [105350], and based on the double star time difference, the pseudorange differential method of frequency difference passive location specifically comprises the following steps:

1, instrumented satellite 1 and satellite 2 poor to the pseudorange of reference station rice, wherein

${\mathrm{\ρ}}_0^{s2}-{\mathrm{\ρ}}_0^{s1}=r_0^{s2}-r_0^{s1}+\mathrm{\Δ}{\mathrm{\ρ}}_0^s+\mathrm{\Δ}{\mathrm{\ρ}}_0---\left(1\right)$

In formula be respectively satellite 1 and satellite 2 pseudorange to reference station, be respectively satellite 1 and satellite 2 to the geometric distance of reference station, can obtain according to the position at known reference station and satellite broadcasting ephemeris computation, that is:

$r_0^{s2}=\sqrt{{(x_{s2}-x_0)}^2+{(y_{s2}-y_0)}^2+{(z_{s2}-z_0)}^2}---\left(2\right)$

$r_0^{s1}=\sqrt{{(x_{s1}-x_0)}^2+{(y_{s1}-y_0)}^2+{(z_{s1}-z_0)}^2}---\left(3\right)$

(x in formula ₀, y ₀, z ₀) be the coordinate of reference station, (x _si, y _si, z _si), i=1,2 is satellite positions, represent the range error relevant with satellite position with ground reference station location, Δ ρ ₀represent the range error relevant with receiver;

2, the differential correctional of satellite is calculated, wherein therefore:

$\mathrm{\Δ\ρ}=(r_0^{s1}-r_0^{s2})-({\mathrm{\ρ}}_0^{s1}-{\mathrm{\ρ}}_0^{s2})=9m$

3, utilize differential correctional Δ ρ to correct the pseudorange of unknown radiation source poor, obtain difference Δ t' time of arrival close to true value:

$\begin{array}{c}{\mathrm{c\Δt}}^{\′}=\sqrt{{(x_{s1}-x)}^2+{(y_{s1}-y)}^2+{(z_{s1}-z)}^2}-\sqrt{{(x_{s2}-x)}^2+{(y_{s2}-y)}^2+{(z_{s2}-z)}^2}\\ ={\mathrm{\ρ}}^{s2}-{\mathrm{\ρ}}^{s1}+\mathrm{\Δ\ρ}=18.839\×{10}^3+7=18.846\×{10}^3\end{array}---\left(5\right)$

In formula, (x, y, z) represents the position of unknown radiation source;

4, witness mark station is Δ f to the arrival rate difference of satellite 1 and satellite 2 _r=1.884 × 10 ³hz;

5, computing reference station is to the difference of the arrival rate close to the true value Δ f of satellite 1 and satellite 2 ₀=1.886 × 10 ³hz,

$\frac{{\mathrm{c\Δf}}_0}{f_0}=\frac{x_{s2}-x_0}{r_2}{v}_{x2}+\frac{y_{s2}-y_0}{r_2}{v}_{y2}+\frac{z_{s2}-z_0}{r_2}{v}_{z2}-\frac{x_{s1}-x_0}{r_1}{v}_{x1}-\frac{y_{s1}-y_0}{r_1}{v}_{y1}-\frac{z_{s1}-z_0}{r_1}{v}_{z1}---\left(6\right)$

(v in formula _xi, v _yi, v _zi), i=1,2 is the speed of satellite;

6, the frequency correction number of satellite is calculated:

ΔF＝Δf ₀-Δf _r＝2Hz

7, unknown radiation source is Δ f to the arrival rate difference of satellite 1 and satellite 2, utilizes frequency correction number Δ F to correct the arrival rate of unknown radiation source poor, obtains the arrival rate difference Δ f' close to true value:

$\begin{array}{c}\frac{{\mathrm{c\Δf}}^{\′}}{f_0}=\frac{x_{s2}-x}{r_2}{v}_{x2}+\frac{y_{s2}-y}{r_2}{v}_{y2}+\frac{z_{s2}-z}{r_2}{v}_{z2}-\frac{x_{s1}-x}{r_1}{v}_{x1}-\frac{y_{s1}-y}{r_1}{v}_{y1}-\frac{z_{s1}-z}{r_1}{v}_{z1}\\ =\frac{c(\mathrm{\Δf}+\mathrm{\ΔF})}{f_0}=\frac{c(5.388\×{10}^3+2)}{f_0}=161.7\end{array}---\left(8\right)$

8, earth ellipsoid equation is utilized:

$\frac{x^2}{a^2}+\frac{y^2}{a^2}+\frac{z^2}{b^2}=1---\left(9\right)$

In formula, a is earth semi-major axis, and b is earth semi-minor axis;

9, after resolving difference by formula (5), (8) and (9), the solution of unknown radiation source is

U_A=[5947320.5,2092654.4,961549.4], and the solution of unknown radiation source is U_B=[5946669.3,2092401.4,966086.1] before difference, the initial solution of emulation is U_O=[5948414.5,2089750.9,961099.3], the positioning precision before difference is | U_B-U_O|=5.91 × 10 ³m, differentiated positioning precision is | U_A-U_O|=3.14 × 10 ³m, therefore differentiated positioning precision is better than 5km.

As can be seen from the above embodiments, when unknown radiation source is positioned, to observed quantity time of arrival, the poor and poor pseudorange differential method that utilizes of arrival rate can eliminate some public errors, positioning precision is brought up to by 10 current ~ 20km and is better than 5km, improve the positioning precision of passive location.

Claims (1)

1., based on a pseudorange differential method for double star time difference frequency difference passive location, it is characterized in that comprising the steps:

1) two satellites are measured poor to the pseudorange of reference station

${\mathrm{\ρ}}_0^{s2}-{\mathrm{\ρ}}_0^{s1}=r_0^{s2}-r_0^{s1}+{\mathrm{\Δ\ρ}}_0^s+{\mathrm{\Δ\ρ}}_0---\left(1\right)$

In formula be respectively the pseudorange of two satellites to reference station, be respectively the geometric distance of two satellites to reference station, can obtain according to the position at known reference station and satellite broadcasting ephemeris computation, that is:

$r_0^{s2}=\sqrt{{(x_{s2}-x_0)}^2+{(y_{s2}-y_0)}^2+{(z_{s2}-z_0)}^2}---\left(2\right)$

$r_0^{s1}=\sqrt{{(x_{s1}-x_0)}^2+{(y_{s1}-y_0)}^2+{(z_{s1}-z_0)}^2}---\left(3\right)$

(x in formula ₀, y ₀, z ₀) be the coordinate of reference station, (x _si, y _si, z _si), i=1,2 is positions of two satellites, represent the range error relevant with satellite position with ground reference station location, Δ ρ ₀represent the range error relevant with receiver;

2) differential correctional of satellite is calculated:

$\mathrm{\Δ}\mathrm{\ρ}=(r_0^{s1}-r_0^{s2})-({\mathrm{\ρ}}_0^{s1}-{\mathrm{\ρ}}_0^{s2})---\left(4\right)$

3) utilize differential correctional Δ ρ to correct the pseudorange of unknown radiation source poor, obtain difference Δ t' time of arrival close to true value:

${\mathrm{c\Δt}}^{\′}={\mathrm{\ρ}}^{s2}-{\mathrm{\ρ}}^{s1}+\mathrm{\Δ}\mathrm{\ρ}=\sqrt{{(x_{s1}-x)}^2{(y_{s1}-y)}^2+{(z_{s1}-z)}^2}-\sqrt{{(x_{s2}-x)}^2{(y_{s2}-y)}^2+{(z_{s2}-z)}^2}---\left(5\right)$

In formula, (x, y, z) represents the position of unknown radiation source, and c is the light velocity;

4) witness mark station is Δ f to the arrival rate difference of two satellites _r;

5) computing reference station is to the difference of the arrival rate close to the true value Δ f of two satellites ₀,

$\frac{{\mathrm{c\Δf}}_0}{f_0}=\frac{x_{s2}-x_0}{r_2}{v}_{x2}+\frac{y_{s2}-y_0}{r_2}{v}_{y2}+\frac{z_{s2}-z_0}{r_2}{v}_{z2}-\frac{x_{s1}-x_0}{r_1}{v}_{x1}-\frac{y_{s1}-y_0}{r_1}{v}_{y1}-\frac{z_{s1}-z_0}{r_1}{v}_{z1}---\left(6\right)$

(v in formula _xi, v _yi, v _zi), i=1,2 is the speed of satellite; Wherein f ₀for the carrier frequency of reference station, r ₁, r ₂be respectively satellite 1 and satellite 2 geometric distance to unknown radiation source;

6) the frequency correction number of satellite is calculated:

ΔF＝Δf ₀-Δf _Y(7)

7) unknown radiation source is Δ f to the arrival rate difference of two satellites, utilizes frequency correction number Δ F to correct the arrival rate of unknown radiation source poor, obtains the arrival rate difference Δ f' close to true value:

$\frac{{\mathrm{c\Δf}}^{\′}}{f_0}=\frac{c(\mathrm{\Δ}f+\mathrm{\Δ}F)}{f_0}=\frac{x_{s2}-x}{r_2}{v}_{x2}+\frac{y_{s2}-y}{r_2}{v}_{y2}+\frac{z_{s2}-z}{r_2}{v}_{z2}-\frac{x_{s1}-x}{r_1}{v}_{x1}-\frac{y_{s1}-y}{r_1}{v}_{y1}-\frac{z_{s1}-z}{r_1}{v}_{z1}---\left(8\right)$

8) earth ellipsoid equation is utilized:

$\frac{x^2}{a^2}+\frac{y^2}{a^2}+\frac{z^2}{b^2}=1---\left(9\right)$

In formula, a is earth semi-major axis, and b is earth semi-minor axis;

9) resolved the position of unknown radiation source by formula (5), (8) and (9), and then realize hi-Fix.