Smooth satellite selection method for signal source of navigational satellite system

Abstract

The invention discloses a smooth satellite selection method for a signal source of a navigational satellite system. The method comprises the following steps of first satellite selection and subsequent satellite selection, wherein the step of subsequent satellite selection comprises the following substeps of: taking a satellite which is selected last time and is visible this time as a selected satellite this time; selecting NUM satellites and judging a geometric dilution of precision (GDOP) value; modifying newly selected satellites if selection modification is required, and the like; and moreover, in the step of subsequent satellite selection, a judging rule of ascending satellites and descending satellites, a priority sorting rule and a corresponding process flow are newly introduced. Bythe method, the number of variable satellites in two adjacent satellite selection results is reduced, the smoothness of the satellite selection results is kept, a receiver for receiving a navigation signal transmitted by the signal source has high positioning accuracy at a satellite changing moment on the premise of meeting the requirement of positioning accuracy, and a phenomenon that positioning cannot be performed in a short time is avoided basically.

Description

technical field [0001] The invention belongs to the field of signal source design of a satellite navigation system, and in particular relates to a satellite selection method for a signal source of a navigation satellite system. Background technique [0002] The signal source of the navigation satellite system can provide repeatable analog signals for various researches, simulations and tests in the field of satellite navigation, and is an essential tool for the development and verification of single and multi-mode navigation receivers. At the same time, in environments where it is not convenient to install antennas, such as remote mountainous areas and areas with harsh climates, the signal source can also ensure the normal operation of the navigation terminal, which greatly reduces the construction and maintenance costs of installing antennas. [0003] In order to reduce the cost of signal source implementation, several satellites that meet the positioning accuracy requireme...

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Problems solved by technology

[0033] We found that there is no big problem when applying the above method of fast star selection to the signal source of the navigation satellite system for the first star selection, but in actual application, with the change of time / position, the information of visible stars also Therefore, it is necessary to re-select stars at regular intervals, and when this method is used for continuous star selection, there will be the following problems: the patent method only discloses how to perform one-time star selection. If you want to use this method for continuous For star selection, all the steps can only be repeated every time. The result is: the result of each star selection is relatively independent, and the result of the previous star selection will not affect the result of the next star selection, which is likely to cause In the two star selection results before and after, the number of changed satellites is too much

For the application of the signal source, due to the limited number of simulated satellites (which can effectively reduce the realization cost of the signal source), this may lead to too many changes in the selected satellites between the two satellite selections, making the use of the signal source The receiver needs to reacquisition and track, which will cause the receiver to be unable to locate or locate abnormally during this period. For some receivers that use a certain star selection strategy, the positioning accuracy will be low and the positioning time will be long. long wait phenomenon

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