Satellite navigation localization method based on transportation databaseTechnical field
The present invention relates to the Technique of Satellite Navigation and Positioning of road users, mainly is to utilize the prior imformation of transportation database to reduce the necessary number of satellite, thereby realizes that less satellite number realizes the location navigation of road users.
Background technology
Along with the development of transportation, highway, railway and the water route status in national economy and national defense construction is more and more important, realizes that therefore the real-time positioning of road users and navigation have important economy and military value.Technique of Satellite Navigation and Positioning is one of most important new and high technology in the world today, its ultimate principle is to utilize the pseudo range observed quantity of 4 satellites of different tracks to determine user's three dimensional space coordinate and time, thereby realizes autonomous (being commonly called as passive) positioning timing (4 undetermined parameters are found the solution in 4 observed quantities) of user.The system that the GPS that is widely used now comes to this.
GPS is that US military is set up a satellite navigation and location system for realizing the worldwide navigation location.Because economical and military importance, gps system is subjected to the control of US military always.This system can implement control to the positioning timing precision, even close navigation signal at particular locality, special time according to the needs of U.S. army.In order to share the tremendous economic interests of positioning and navigation field, and militarily break away from the control of the U.S., Russia just further improves the own GLONASS system that sets up, and is Europeanly also embarking the GALILIEO system of oneself.
Yet the satellite navigation and location system of setting up a whole world needs tens billion of dollars expense, therefore has only minority developed country to have the ability to realize this goal.Therefore, if can realize user's navigator fix, have important practical significance for developing country with less satellite number." No. one, the Big Dipper " that China sets up is one and replys formula 2 dimensional region satellite navigation and location system, its ultimate principle is that transmit to two geostationary satellite emission navigation signals and by satellite the ground control centre, the user sends Location Request and passes control center back through satellite after receiving signal, user's volume coordinate (two coordinate parameters of longitude and latitude are resolved in two observed quantities) is calculated according to the signal two-way time, satellite position and the user's altimeter that record by control center, notifies the user through satellite then.
Summary of the invention
The objective of the invention is to utilize road can be approximately the physical attribute of a space curve, under the less situation of number of satellites, realize the navigator fix of road users, promptly
(1) utilize 1 geostationary satellite realization road users to reply the formula navigator fix;
(2) utilize 2 geostationary satellites to realize the non-inquiry of road users (autonomous, passive) formula navigator fix.
For achieving the above object, the present invention adopts following technical scheme:
(1) road is considered as a three-dimensional space curve, utilizes GPS or other means to carry out the road location survey, and will build up the road net database along the sample point coordinate of road;
(2) in the real-time satellite navigator fix process of road users, with the user regard as on the three-dimensional space curve a bit.
Because three-dimensional space curve has only an affine parameter, therefore utilize the transportation database of priori the problem of determining user's three dimensional space coordinate can be changed to one-parameter and find the solution.Just can resolve user's coordinate as long as promptly record a satellite to user's distance according to co-ordinates of satellite and transportation database.For replying the formula navigator fix, control center can directly record the distance of satellite to the user, and for user's autonomous positioning, owing to have clock correction between user's clock and the center clock (or satellite clock), must observe the pseudorange of two satellites, just can resolve user's position and clock correction (two fixed two parameters of observed quantities).
Description of drawings
Fig. 1 is the principle schematic of road users satellite navigation localization method of the present invention.
Embodiment
Referring to Fig. 1, a road among the figure in the curve representation three dimensions, great circle represents with the satellite to be the centre of sphere, be the space sphere of radius with the user to the distance of satellite, the point that this sphere and road curve intersect is a customer location.Because road (highway or railway) can be considered as one 3 dimension space curve, has only one degree of freedom, therefore, just can obtain user's coordinate by the coordinate of satellite as long as measure the distance of user's to a satellite.Road is a three-dimensional space curve among the figure, is the centre of sphere with the satellite, and the user is that radius can form a space sphere to the distance of satellite, and this sphere is inevitable to intersect at a point with road curve, and this point is customer location.
Specifically, the present invention is achieved in that promptly:
(1) utilizes transportation database and 1 geostationary satellite to carry out road users and reply the formula navigator fix
The ground control centre to the satellites transmits distance measuring signal through the outside broadcast of satellite, the emission positioning request signal was passed the ground control centre back through satellite after user transceiver was received the back signal, control center is according to the signal two-way time and the satellite position that record, utilize the road network data storehouse of setting up in advance to find the solution user's position coordinates, and notify the user through satellite.
(2) utilize transportation database and 2 geostationary satellites to carry out non-inquiry (autonomous, passive) the formula navigator fix of road users
The ground control centre simultaneously to 2 satellites transmits distance measuring signals and navigation message (being mainly co-ordinates of satellite) through the outside broadcast of satellite, during local clock face when receiver user is measured signal and arrived and the difference (being commonly referred to the pseudorange of satellite) between the signal nominal time, according to two pseudorange observed readings and the satellite position that provides by navigation message, and utilize the entrained road network data storehouse of receiver, independently resolve oneself position coordinates and clock correction.
This method also can directly generate distance measuring signal and navigation message by satellite, and prerequisite is must keep (clock correction is known) synchronously between the satellite clock.