CN202351431U - Anti-interference device for global positioning system (GPS) - Google Patents

Abstract

The utility model discloses an anti-interference device for a global positioning system (GPS). The anti-interference device consists of a GPS antenna, a Dipper antenna, a second signal selection module, a phase-locked loop module, a high-stability crystal oscillator and a time difference measurement module, wherein the GPS antenna and the Dipper antenna are used for transmitting signals to the second signal selection module; the second signal selection module is electrically connected with the phase-locked loop module; the phase-locked loop module is connected with the high-stability crystal oscillator; the high-stability crystal oscillator is connected with the time difference measurement module; and the time difference measurement module is connected with the second signal selection module. Second signals output by the high-stability crystal oscillator can reach a degree which is nearly consistent with that of the GPS/Dipper signals after being trained by the phase-locked loop module for a long time, and an output local second hand is further judged relative to the GPS at the moment; if a time difference is less than 1ms, the GPS is not interfered or attacked; if the time difference is more than 1ms, the GPS may be interfered or attached; and the device has a simple structure and is interference-resistant.

Description

A kind of GPS means for anti-jamming

Technical field

The utility model relates to means for anti-jamming, is specifically related to a kind of GPS means for anti-jamming.

Background technology

Needs for precise navigation and measurement; GPS has set up special-purpose time system; Realized long range radio navigation and accurate time transmission, China has also set up the big-dipper satellite positioning system this year, and accurate time service service can be provided under the situation of only observing a satellite.

Most countries all adopts the pattern of this radio remote time service of GPS to obtain second signal accurately in the world at present, but because this pattern is the long distance wireless electrical transmission, is prone to by external interference or attack.

Summary of the invention

In order to overcome the shortcoming of above-mentioned prior art, the utility model provides a kind of GPS means for anti-jamming, can improve the GPS interference free performance; In order to remove the interference of GPS, when GPS lost efficacy or attacked, the pulse signal same with GPS can be provided; Simple in structure, anti-interference.

To achieve these goals, the technical scheme of the utility model employing is:

A kind of GPS means for anti-jamming; Constitute by gps antenna, Big Dipper antenna, second signal selection module, phase-locked loop module, high stability crystal oscillator and time difference measurement module; Said gps antenna and Big Dipper antenna pass to a second signal selection module with signal, and a second signal selection module is electrically connected with phase-locked loop module, and phase-locked loop module and high stability crystal oscillator interconnect; Said high stability crystal oscillator is connected with the time difference measurement module, and said time difference measurement module also is connected with a second signal selection module;

Said high stability crystal oscillator provides local second signal as frequency source;

The local second signal that second signal of signal selection module output in said second and high stability crystal oscillator produce is sent into phase-locked loop module; Phase-locked loop module is constantly adjusted the voltage-controlled voltage of high stability crystal oscillator through the voltage adjustment amount, produces a local second signal that approaches GPS signal second;

The local second signal that said high stability crystal oscillator produces is sent into the time difference measurement module, measures the time difference between local second signal and GPS signal second;

Utilize receiver that gps signal and Big Dipper signal are inserted a second signal selection module, and judge whether these two kinds of time signals are consistent, if consistent, prove that then Current GPS can use, do not disturbed, available GPS is as standard; As inconsistent, prove that then GPS is disturbed or quilt is attacked, GPS can not use.At this moment it is available to judge whether Big Dipper signal continues, and tames local second as standard like the available Big Dipper that then uses; Also unavailable like Big Dipper signal, as then to use high stability crystal oscillator to produce directly output in local second at short notice, is enough to substitute GPS second the local second of not tamed.

The local second signal pin of output is done further judgement for GPS, exist like GPS, the local second signal that then will just export is sent into the time difference measurement module; Measure the time difference of itself and GPS signal second; If this time difference＜1ms, prove that then GPS is disturbed or attacks, and local second precision is very near GPS second; Need not adjustment, continue output and get final product; If the time difference＞1ms; Prove that then GPS possibly disturbed or attacked, perhaps local second precision has been not enough to substitute GPS and has exported as standard, at this moment need do judgement further; Judge at first whether the GPS second and the Big Dipper exist second simultaneously; As the pps pulse per second signal that only detects a kind of wireless transmission exists, and can't judge then whether GPS is disturbed or attacked, so continue to use export local second; Whether all exist simultaneously like two signals, then repeat above all processes, it is available to judge GPS, and choice criteria was tamed local second again.

Do not exist like GPS, the local second after then directly output locks, in the quite a long time, this this locality second and GPS are identical, can be used as time reference, have so just avoided because the incredible problem of temporal information of the interference of GPS or wrong generation.

Description of drawings

Accompanying drawing is the structured flowchart of the utility model.

Embodiment

Below in conjunction with accompanying drawing the utility model is done detailed description.

With reference to accompanying drawing; The utility model provides a kind of GPS means for anti-jamming; Constitute by gps antenna, Big Dipper antenna, second signal selection module, phase-locked loop module, high stability crystal oscillator and time difference measurement module; Said gps antenna and Big Dipper antenna pass to a second signal selection module with signal, and a second signal selection module is electrically connected with phase-locked loop module, and phase-locked loop module and high stability crystal oscillator interconnect; Said high stability crystal oscillator is connected with the time difference measurement module, and said time difference measurement module also is connected with a second signal selection module;

Said high stability crystal oscillator provides local second signal as frequency source;

The local second signal that second signal of signal selection module output in said second and high stability crystal oscillator produce is sent into phase-locked loop module; Phase-locked loop module is constantly adjusted the voltage-controlled voltage of high stability crystal oscillator through the voltage adjustment amount, produces a local second signal that approaches GPS signal second;

The local second signal that said high stability crystal oscillator produces is sent into the time difference measurement module, measures the time difference between local second signal and GPS signal second;

Gps antenna and Big Dipper antenna are sent a second signal separately into a second signal selection module respectively, judge current available second signal by this module, and with this second signal send into phase-locked loop module.

Phase-locked loop module utilizes above-mentioned second signal through a series of algorithm and operation, and the voltage-controlled voltage of working voltage control signal adjustment high stability crystal oscillator makes the output frequency of high stability crystal oscillator that trickle variation take place.

After signal second of high stability crystal oscillator output was tamed through phase-locked loop module for a long time, the second signal of high stability crystal oscillator output can reach with GPS/ Big Dipper signal and be close to consistent degree, and the local second hand that will export this moment is done further judgement for GPS; Exist like GPS; Sent into the time difference measurement module in local second that then will just export, and measured itself and the time difference of GPS between second, as if this time difference＜1ms; Prove that then GPS is disturbed or attack; And local second precision need not adjustment very near GPS, continues output and gets final product; If the time difference＞1ms; Prove that then GPS possibly disturbed or attacked, perhaps local second precision has been not enough to substitute GPS and has exported as standard, at this moment need do judgement further; Judge at first whether the GPS second and the Big Dipper exist second simultaneously; As the pps pulse per second signal that only detects a kind of wireless transmission exists, and can't judge then whether GPS is disturbed or attacked second, so continue to use export local second; Whether all exist simultaneously like two signals, then repeat above all processes, it is available to judge GPS, and choice criteria was tamed local second again.

Do not exist like GPS, then directly export the local second signal of the generation of high stability crystal oscillator after locking.

Claims (2)

1. GPS means for anti-jamming; Constitute by gps antenna, Big Dipper antenna, second signal selection module, phase-locked loop module, high stability crystal oscillator and time difference measurement module, it is characterized in that said gps antenna and Big Dipper antenna pass to a second signal selection module with signal; Second, signal selection module was electrically connected with phase-locked loop module; Phase-locked loop module and high stability crystal oscillator interconnect, and said high stability crystal oscillator is connected with the time difference measurement module, and said time difference measurement module also is connected with a second signal selection module.

2. a kind of GPS means for anti-jamming according to claim 1 is characterized in that,

Said high stability crystal oscillator provides local second signal as frequency source;

The local second signal that second signal of signal selection module output in said second and high stability crystal oscillator produce is sent into phase-locked loop module; Phase-locked loop module is constantly adjusted the voltage-controlled voltage of high stability crystal oscillator through the voltage adjustment amount, produces a local second signal that approaches GPS signal second;

The local second signal that said high stability crystal oscillator produces is sent into the time difference measurement module, measures the time difference between local second signal and GPS signal second.

Images