RU2316112C2 - Method for reducing crosstalk signal in combined gps receivers and communication system - Google Patents

Abstract

FIELD: communication systems.

SUBSTANCE: method for operation of mobile device is disclosed, where the device is combined receiver of satellite positioning system and mobile communication system. On detection of first action two following operations are performed: (i) for a period of time radio transmission of data through data transmission radio line from communication block of mobile device is blocked, and (ii) from communication block into receiver of satellite mobile device positioning system first control signal is transmitted, which permits processing of signal positioning system signals, received by receiver during aforementioned time period. Size of aforementioned time period may be predetermined or adjustable.

EFFECT: reduced crosstalk signal between communication and positioning sections of combined receiver.

5 cl, 6 dwg

Description

FIELD OF THE INVENTION

The present invention relates, in General, to the field of receivers of a satellite positioning system (MPS, SPS), and more particularly to reducing crosstalk in a combined SPS receiver and communication system.

State of the art

In recent years, the use of personal portable communication devices such as cell phones and pagers has increased significantly. The use of portable navigation devices such as satellite positioning system (SPS) receivers has further increased, as these devices have become more affordable. Recent technological developments have made it possible to combine SPS receivers and communication systems in single units, for example, combining an SPS receiver and a cell phone unit. Such integrated devices have many applications, for example, personal safety, emergency response, vehicle tracking and inventory control. Some combined units combine separate SPS receivers and communication systems using appropriate electronic interfaces. Others use shared circuits and housing. These combined units are distinguished by the advantages of convenient use, which provide common enclosures and unified user interfaces. However, such combined units may also exhibit some disadvantages, for example, increased energy consumption and reduced efficiency.

One noted drawback inherent in many combined SPS and communication devices is the reduced efficiency of the combined block SPS receiver section. A common cause of this reduced efficiency is signal interference between the communication stages and the SPS receiver. For example, in a combined cell phone / SPS receiver, cellular transmissions from the cell phone stage generate strong interference that can reduce the efficiency of the SPS receiver.

Existing approaches to overcome crosstalk between SPS and communication stages include the use of complex filters or high dynamic range circuits in the input section of the SPS receiver to limit intracavity interference to acceptable ranges. However, these approaches require the use of complex additional circuits that can increase the cost and energy consumption of the combined units. For example, one way to reduce crosstalk in a combined cell phone / SPS receiver is to use separate bandpass filters in the RF (RF) input stage of the SPS transmitter to eliminate radio frequency (RF) interference from the cellular transmitter. However, there are some problems with this approach. First, in order to provide an adequate reduction in the signal energy input from the cellular transmitter to the RF circuits of the SPS receiver, several filters may be required. This can increase the cost and increase the size of the combined block. Secondly, the use of filters increases the noise figure of the SPS receiver, making it less sensitive to satellite navigation signals.

Therefore, it is required to provide a system that reduces crosstalk between the communication sections and the SPS of the combined SPS receiver / communication receiver.

Additionally, it is required to provide a system that improves the efficiency of SPS reception in the integrated SPS receiver / communication receiver without adversely affecting the cost and sensitivity characteristics of the SPS receiver.

Disclosure of invention

The method of operation of a mobile device is disclosed. The first action of the mobile device is detected. When the first action is detected, the following two operations are performed: (i) for the period of time, the radio transmission of data is blocked through the radio data line from the communication unit of the mobile device and (ii) the first control signal is transmitted from the communication unit to the receiver of the satellite positioning system of the mobile device, which allows processing of the system signals positioning the signal received by the receiver over a specified period of time.

The first action may occur, for example, due to an operation performed by a user of a mobile device, such as pressing a button on a mobile device, or lack of speech received by the microphone of the communication device.

Blocking and permission of a radio transmission can be carried out alternately.

Other features of the present invention will become apparent from the following detailed description and the attached drawings.

Brief Description of the Drawings

The present invention is illustrated by means of options, and not by imposing restrictions, according to the attached drawings, which use end-to-end numbering.

1 is a block diagram of an integrated receiver of a global positioning system (GPS) and a communication system with a communication link to a base station, according to one embodiment of the present invention.

FIG. 2 is a block diagram of the components constituting a GPS receiver and a connected transceiver in a mobile device according to an embodiment of the present invention.

3 illustrates a mobile device used in a cellular telephone network according to one embodiment of the present invention.

4 is a timing chart illustrating one method of operation of a mobile device according to the invention.

5 is a timing diagram illustrating another method of operation of a mobile device according to the invention.

6 is a flowchart illustrating crosstalk reduction operations in a mobile device according to the method of the present invention.

The implementation of the invention

A method and apparatus for reducing crosstalk in a mobile device that combines a satellite positioning system receiver (CCM, SPS) and a communication device are described. For illustrative purposes, the following description sets forth numerous specific details in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without the specified specific details. In other possible embodiments, to facilitate explanation, known structures and devices are shown in block diagram form.

In the following description, embodiments of the present invention will be described with respect to use in the United States Global Positioning System (GPS). However, it should be clear that these methods are equally applicable to similar satellite positioning systems, such as the Russian GLONASS system. Consequently, the term “GPS” as used herein includes such alternative satellite positioning systems, including the Russian GLONASS system. Similarly, the term "GPS signals" includes signals from an alternative satellite positioning system.

Mobile device

1 is a block diagram of a mobile device 150 that integrates a connected transmitter / receiver (transceiver) with a GPS receiver for use in one embodiment of the present invention. Mobile device 150 is a portable portable unit that includes circuits for performing functions necessary for processing GPS signals, as well as functions necessary for processing communication signals transmitted and received via a communication line. A communication line, for example, communication line 162, is typically a radio frequency communication line to another communication component, such as a base station 160 having a communication antenna 164.

Mobile device 150 includes a GPS receiver 130, which includes a capture (signal) circuit and a processing section. In accordance with conventional GPS methods, the GPS receiver 130 receives GPS signals transmitted from orbiting GPS satellites and determines the arrival times (so-called "pseudoranges") of unique pseudo noise codes (PNs, PNs) by comparing time shifts between received sequences PN code signals and internally generated PN signal sequences. GPS signals are received via GPS antenna 111 and are input to a capture circuit that captures PN codes for various received satellites. The navigation data (e.g., pseudorange) produced by the acquisition circuit is processed by a processor for transmission by a connected transceiver 109.

Mobile device 150 also includes a communications transceiver section 109. The communication transceiver 109 is connected to the communication antenna 100. The communication transceiver 109, via communication signals (typically RF), transmits the navigation data processed by the GPS receiver 130 to a remote base station, such as base station 160. The navigation data may be the actual GPS latitude, longitude and altitude -receiver, or it may be raw or partially processed data. The received communication signals are fed to the input of the connected transceiver 109 and transmitted to the processor for processing and possible output through the speaker.

According to one embodiment of the present invention, in the mobile device 150, the pseudo range data generated by the GPS receiver 130 is transmitted via the communication line 162 to the base station 160. Then, the base station 160 determines the location of the combined receiver 150 based on the pseudorange data from the combined receiver, the time at which measured pseudorange, and ephemeris data received from her own GPS receiver or other sources of such data. Then, the location data may be transmitted back to the mobile device 150 or to other remote locations. A communication line 162 between the mobile device 150 and the base station 160 may be implemented in several different embodiments, including a cellular telephone line or a direct line. In one embodiment of the present invention, the communication transceiver section 109 is implemented as a cell phone.

2 provides a more detailed block diagram of a combined cell phone and GPS receiver according to one embodiment of the present invention. It will be apparent to those skilled in the art that the system illustrated in FIG. 2 is one embodiment, and, according to the principles of the present invention, various changes in the design and structure of the integrated GPS receiver are possible. For example, although it is assumed in the following description that the communication section is implemented by a cellular telephone, it is clear that the present invention can be implemented by other communication devices, such as two-way pagers, and similar two-way communicators.

2, the mobile device 150 comprises a GPS receiver 130 and a GPS antenna 111 (collectively defined as a “GPS section”) and a cell phone 109 and a cell phone antenna 100 (collectively defined as a “communication section”). The cell phone transmits to a remote base station (for example, base station 160 in FIG. 1) and receives signals from it through an antenna 100.

GPS section

In the GPS receiver 130 of the mobile device 150, the received GPS signal is supplied from the GPS antenna 111 via a signal transmission line 120 and a switch 112 to the input of the radio frequency (RF) converter 113 to the intermediate frequency (IF). A frequency converter 113 converts the signal to a corresponding intermediate frequency, for example, 70 MHz. It then provides additional conversion to a lower intermediate frequency, for example, 1 MHz. The output of the RF to IF converter 113 is connected to an input of the GPS signal processing circuit 114. The GPS signal processing circuit 114 includes an analog-to-digital (A / D) converter that digitizes the output signals from the RF to IF converter 113.

In one embodiment of the present invention, the GPS signal processing circuit 114 also includes a digital frame memory, which is coupled to the output of the analog-to-digital converter and may store a record of data to be processed. Frame memory is used to process GPS signals, which are usually stored in a separate storage device connected to the GPS processing circuit 114. The frame memory can also be used for packetized communication signals, that is, signals consisting of packets of data bits, followed by long periods of inactivity. Continuous signaling, such as many cellular-type signals, can also be processed continuously by the processing circuit.

The output from the GPS signal processing circuit 114 is supplied to the microprocessor 115. The microprocessor 115 performs additional processing of satellite signals received at the GPS receiver 130 and outputs the processed signals for transmission directly to the user interface or via a communication line to a remote receiver (not shown) .

In one embodiment of the present invention, the GPS receiver 130 is a standard GPS receiver that uses a plurality of correlators to demodulate GPS signals. In the method of the present invention, the GPS receiver is activated or deactivated by a trigger pulse. When the standard GPS receiver is activated, it can perform all its normal functions, which includes demodulation of 50 bauds of the satellite information message. However, if the transmission periods of the signals become a large part of the data baud period, then demodulation may be difficult or impossible. In this case, an alternative type of GPS receiver may be used. For example, one type of GPS receiver only detects the relative arrival times of several simultaneously received GPS signals and transmits the indicated relative arrival times (the so-called "pseudorange") to a remote location (see, for example, FHRaab, et al., "An Application of the Global Positioning System to Search and Rescue and Remote Tracking ", Journal of the Institute of Navigation, Vol.24, No.3, Fall 1977, pp. 216-227). Then, the position of the mobile device is determined by combining the indicated pseudorange data with the GPS information from the satellite, which it accumulates using its own receivers or through some other source of such data. This configuration is particularly useful in various emergency response and tracking applications.

Although embodiments of the present application have been described with respect to a specific configuration of a GPS receiver, it will be apparent to those skilled in the art that there are several different configurations of a GPS receiver that may take advantage of the crosstalk reduction methods of the present invention.

Furthermore, although embodiments of the present invention have been described with respect to GPS satellites, it is clear that the principles are equally applicable to positioning systems that use pseudolites (pseudolites) or a combination of satellites and pseudolites. Pseudolites are ground-based transmitters that broadcast a PN code (similar to a GPS signal), modulated on an L-band carrier (or other frequency), mostly synchronized with GPS time. Each transmitter can be assigned a unique PN code to allow identification by a remote receiver. Pseudolites are useful in situations where GPS signals from an orbiting satellite may not be available, for example, in tunnels, mines, buildings, or other enclosed areas. It is understood that the term "satellite" as used herein includes pseudolites or equivalents of pseudolites, and the term GPS signals as used herein includes GPS-like signals from pseudolites or equivalents of pseudolites.

Communication section

The communication section of the mobile device 150 comprises a receiver cascade and a transmitter cascade connected to the communication antenna 100 via an antenna switch or a transceiver switch 101. Upon receipt of a communication signal, such as a cell phone signal, from a communication base station (eg, base station 160), the switch 101 directs the input signal to the RF to IF converter 102. The RF to IF converter 102 converts the communication signal to a corresponding intermediate frequency for further processing. The output of the RF to IF converter 102 is coupled to a demodulator 103, which demodulates the communication signal to determine commands in the communication signal or other data in the communication signal (e.g., digitized speech signal, Doppler data or data representing ephemeris of visible satellites). Demodulator 103 may be implemented as a digital demodulator. In this case, before applying to the input of the demodulator 103, the frequency-converted communication signal can be passed through an analog-to-digital (A / D) converter, which digitizes the output signals from the RF converter 102 to IF.

In one embodiment of the present invention, the output from the demodulator 103 is transmitted to the microprocessor 104. The microprocessor 104 performs any processing necessary for the functions of the reception and transmission of communication.

Microprocessor 104 is also connected to the display and microphone. The microphone is configured to convert speech into speech information and delivers speech information to the microprocessor 104. When transmission via a communication line is required, the microprocessor 104 generates data for transmission and digital samples of the main frequency band of the signal (or its representation, such as a mathematical model of the signal). He then uses this data to modulate the carrier signal using modulator 106. Although analog modulation (such as frequency modulation) can also be used, in recent systems the modulation is mainly digital in nature, such as frequency shift keying or phase shift keying. In this case, after modulation, the digital signal is converted into a D / A converter from digital to analog. The carrier frequency at which modulation is performed in modulator 106 may or may not be the final RF frequency of the communication signal; if it is an intermediate frequency (IF), then an additional IF converter 107 to RF is used to convert the signal to the final RF frequency of the communication signal. The power amplifier 108 raises the signal level of the communication signal, and then this amplified signal is transmitted through the switch 101 to the communication antenna 100.

In the method of the present invention, a communication signal containing data representing position information (eg, pseudorange to various satellites or latitude and longitude of mobile device 150) is transmitted via communication line 162 to base station 160. Base station 160 may serve as a processing node for computing position information of the portable GPS unit, or it can serve as a relay node and relay information received from mobile device 150.

In some cellular telephone communication systems, such as time division multiple access (TDMA) systems (including, for example, global mobile communications system (GSM, GSM)), the transmission and reception times of cellular signals are separated. In such cases, a simple switch 101 may be used to isolate the transmitted amplified signal 118 provided by the power amplifier 108 from the path 119 connected to the sensitive input receiving circuits (frequency converter 102). In particular, the receiving circuits 102 may include a low noise amplifier (LNA, LNA), which may be destroyed or otherwise adversely affected if the signal from the power amplifier is transmitted to the LNA without significant attenuation.

In other cellular systems, such as the North American IS-95 system based on code division multiple access (CDMA), the reception and transmission of signals through the antenna 100 can be carried out simultaneously. To isolate the RF circuits of 102 from the high power signal of 118, a device called an “antenna switch” is used instead of switch 101. The antenna switch 101 consists of two RF filters, one tuned to the transmit frequency band and the other to the receive frequency band. The output 118 of the power amplifier passes through the transmission filter and then to the antenna 100, while the received signal from the antenna passes through the reception filter. Therefore, the transmissions are isolated from the RF circuits 102 by an amount equal to the isolation provided by the receive filter at the transmission frequency.

Communication Transceiver Signals

In one embodiment of the present invention, the mobile device 150 comprises control circuits that reduce crosstalk between the stages of the GPS receiver and the cellular transceiver. In combined receivers, crosstalk is often a particularly acute problem, as the satellite signals received in the GPS receiver are usually very weak. Typically, crosstalk occurs due to the high degree of interaction between the cell phone signal transmitted through the antenna 100 and the GPS receiving antenna 111. This is especially true for the case where the antenna blocks 100 and 111 are located to save physical space or reduce cost. share or share parts of their mechanical structure.

In one embodiment of the present invention, crosstalk between the communication sections and the GPS of the combined unit is reduced by reducing the transmitter power of the communication section (typically a cell phone). The transmitter power decreases for a period of time during which the signals of the satellite positioning system can be processed, after which the transmitter power again increases. Power control and GPS receiver operation are synchronized via a trigger pulse. The action of the trigger pulse, according to one embodiment of the present invention, is described with respect to the integrated receiver of FIG. 2.

In a cell phone section 109 of the mobile device 150, a power level control signal 105 is transmitted from the microprocessor 104 to the power amplifier 108. In one embodiment of the present invention, the first state of the power level control signal reduces power in the power amplifier, and the second state of the signal restores normal power levels in the power amplifier. Alternatively, two signals are embodied within the power level control signal. The first signal reduces power in the power amplifier, and the second signal restores normal power levels in the power amplifier. Depending on the power level of the amplifier 108 and the desired reduction in crosstalk, the power level control signal 105 may turn off the power amplifier 108 completely or reduce the gain power by a predetermined amount.

The power level control signal 105 is also transmitted to the GPS receiver 130. This signal is programmed to activate the GPS receiver to receive and process GPS signals depending on the power level of the communication power amplifier 108. When the power level control signal 105 reduces or decreases the power of the power amplifier 108, the GPS receiver 130 is activated to receive GPS signals. Conversely, when the power level control signal maintains normal power levels in the power amplifier 108, the GPS receiver 130 is prevented from receiving GPS signals. Alternatively, the GPS receiver 130 may be programmed to receive GPS signals, but ignore such signals in processing circuits when the power level control signal indicates that the transmitter of the cell phone has more power.

At the GPS receiver 130, a trigger pulse 110 corresponds to a power level control signal 105. In one embodiment of the present invention, the enable pulse 110 is transmitted to the microprocessor 115 via line 122, to the GPS processing circuit 114 via line 116, and to switch 112 via line 117. In one embodiment, the switch 112 is controlled by the enable pulse 110 and power level control signal 105 . When the power level control signal 105 reduces the power of the cell phone power amplifier 108, the switch 112 is turned on to allow data to pass from the GPS antenna 111 to the GPS receiver circuitry. Conversely, when the power level control signal 105 supports the high power of the power amplifier 108, the switch 112 is turned off so that the data does not pass through the GPS receiver. Therefore, when transmitting a cell phone at high power, the transmission of GPS signals is absent (or blocked), while at any other time they can be received.

In one embodiment of the present invention, the switch 112 is a gallium arsenide (GaAs) switch. Since the switch 112 is located in the input path of the GPS signal, it causes some attenuation of the input GPS signal. Using a GaAs switch minimizes this attenuation. In addition, current-key devices at the GPS frequency (1575.42 MHz) provide insertion attenuation of about 0.5 dB.

In an alternative embodiment of the present invention, a trigger pulse 110 may be provided only to the input of the microprocessor 115 instead of the switch 117. In this configuration, the microprocessor 115 directly controls the switch 117 or the GPS signal processing circuit 114 to transmit incoming GPS signals when transmitting the cellular telephone 109.

In a further alternative embodiment of the present invention, the GPS receiver 130 may not include a GaAs switch 112. The switch may be omitted if the input RF circuits of the GPS receiver 113 can withstand a lot of power from a cell phone transmitter (for example, with some kind of limiting schemes). The exclusion of switch 112 eliminates any potential signal attenuation by the switch. In this alternative embodiment, the unlock pulse 110 is supplied to the input of the GPS signal processing circuit 114 or microprocessor 115, or to the input of both devices. This signal ignores the processing patterns of the input GPS signals during transmission periods by the cellular telephone, even if these signals are received by the GPS receiver 130.

Most advanced digital cell phone systems have the ability to transmit at full power only a fraction of the time. Accordingly, the gate pulse method described herein is applicable to many different digital cell phones. If cellular communications in these phones occur with a duty cycle of 1/8 (as in the case of digital cellular GSM or CDMA in the mode of reduced data bandwidth), then the loss in sensitivity of the GPS receiver due to such transmission (signal) is only about 0.5 dB

4 illustrates one possible embodiment of a possible operation of a mobile device. Figure 4 is a time chart with time points T1, T2, T3, etc. on the abscissa axis and actions such as "conversation", "voice data transmission" and "GPS data processing" on the ordinate axis.

Starting at time T1, a person can speak into the microphone until time T2 is reached. During this time, voice information is continuously transmitted from the mobile device.

Then there may be a break in speech from time T2 to time T3, after which speech continues again. Since the break from T2 to T3 is less than a predetermined minimum, for example, in half a second, the transmission of voice information is not interrupted.

Then again, at time T4, there may be a break (i.e., a pause) in speech. A break in speech can last until time T7. Since a break or a pause in speech is greater than a minimum break in half a second, at time T5, after a minimum break, the transmission of speech information is blocked. At time T5, a control signal is transmitted that enables the processing of GPS data. GPS data processing continues until time point T6. The gap between time T6 and time T5 is large enough to allow the processing of the required minimum amount of GPS data, usually from one to two seconds. The minimum amount of GPS data is sufficient to triangulate the position of the mobile device.

At time T7, speech continues, which can continue until time T8, after which there is a break in speech from time T8 to time T10. A minimum break in speech in half a second is achieved at time T9, at which the transmission of voice information is blocked. At time T9, GPS data processing is permitted. At time T10, the user can speak into the microphone again and continue talking until time T12. However, the transmission of voice information is deactivated until time T11. The gap between time T11 and time T9 is, for example, about two seconds and is large enough to process a sufficient amount of GPS data. At time T9, a signal is transmitted that permits the processing of GPS data, and at time T11, another signal is transmitted that blocks the reception and processing of GPS. At time T11, voice information is again allowed. In this possible embodiment, the speaker's voice information unit (between T10 and T11) is cut off due to the requirement to complete GPS processing. In other embodiments, the action of the resumed speech could lead to the end of the GPS processing period, thereby enabling continuous speech. However, this can lead to an unsuccessful completion of GPS processing.

It should be noted that the time intervals used to process GPS data are not required to be equal. For example, in the aforementioned possible embodiment, the time intervals T5-T6 and T9-T11 are not required to be equal. This may be the case, since information obtained from processing a previous time period (for example, T5-T6) can help reduce the processing time required for subsequent processing of GPS signals (for example, T9-T11). For example, previous GPS processing determines the arrival times of various GPS signals. The indicated arrival times can be projected forward in time to estimate the arrival times of such signals at a later point in time. Such estimates shorten the processing required to determine the exact time of arrival of GPS signals, which is required for accurate geolocation. It should also be noted that the time periods during which GPS processing is performed (T5-T6 and T9-T11 in the possible embodiment discussed above) can be predefined or can be essentially customizable. According to a simple procedure, periods should be used to ensure successful GPS processing, which are fixed and predefined. A more complicated procedure will be the procedure according to which the GPS processing time interval will be adjustable depending on various conditions. Once completed, voice transmission can be resumed. The conditions governing the duration of the time period should include the intensity of the received signal of the received SPS signals and a priori information regarding the parameters of such signals, for example, the uncertainty region of Doppler frequencies and the arrival times of such signals. As indicated above, previous processing operations of the SPS signal can lead to a reduction in the lengths of time required for subsequent processing. Alternatively, as described previously, the length of time may determine speech inactivity.

During periods when the transmission of voice information is blocked, the communication section of the mobile device may enter half-duplex mode. Therefore, it can receive voice information and, having an acoustic speaker, which is part of a mobile device, create an audio signal. Therefore, as shown in FIG. 4, it can receive voice information over a period of time starting at T5 and ending at T6 when the transmission of voice information is blocked. In other embodiments, implementation over a specified period of time should be prevented and the transmission and reception of voice information.

5 illustrates another method according to which a mobile device can operate. It is assumed that a person speaks into the microphone continuously from time T1 to time T9. The transmission of voice information is initiated at time T1 and continues until time T2.

At time T2, the person presses a button, or, in another embodiment, the person may perform some other action on the mobile device. The button is pressed from time T2 and is released at time T3. At time T3, when the button is released, the transmission of voice information is blocked. A control signal is transmitted that enables the processing of GPS data.

Then the transmission of voice information is alternately blocked and allowed, alternating depending on time. Voice information is blocked at 7/8 frames and then resolved at 1/8 of a frame. Each time when the transmission of voice information is blocked, a control signal is transmitted that allows the processing of GPS data, and each time when the transmission of voice information is enabled, a control signal is transmitted that blocks the processing of GPS data. In this possible embodiment, the transmission of voice information is blocked at time points T3, T5 and T7 and is allowed at time points T4, T6 and T8. GPS data is processed from time T3 to time T4, from time T5 to time T6 and from time T7 to time T8. The amount of GPS data accumulated and processed from releasing the button at time T3 to time T8 is sufficient to triangulate the position of the mobile device. After time T8, the transmission of voice information is not blocked again, unless the button is pressed again. Through this, the user of the mobile device can optionally cause the beginning and further end of GPS processing.

The mobile device can also enter half-duplex mode each time when blocking the transmission of voice information so that voice information can be received and processed and an audio signal can be generated. An audio signal is usually transmitted to the speaker in a mobile device that generates audible sound.

6 illustrates the basic actions according to the invention. At 600, communication is established through the communication line. At 602, it is determined whether an action is detected. The action may be, for example, the absence of speech detected by the microphone of the mobile device, as described in accordance with FIG. 4, or a button press, for example, described in accordance with FIG. 5. Other actions are also possible.

If an action is detected in step 602, then step 604 is performed. At step 604 (i) the transmission of voice information is blocked for a period of time and (ii) a control signal is transmitted to enable data processing of the satellite positioning system signal. In FIG. 4, step 604 occurs at time points T5 and T9, and in FIG. 5, step 604 occurs at time point T3. When the indicated period of time has elapsed, step 606 is performed. At step 606 (iii) voice communication is enabled and (iv) signal processing of the satellite positioning system is blocked. In FIG. 4, step 606 occurs at time points T6 and T11, and in FIG. 5, step 606 occurs at time point T4. As indicated previously, the time period 604 may be predefined or customizable depending on the processing strategy used.

In the mobile device 150 of FIG. 2, diagrams within the GPS section and the communication section are illustrated as being allocated and shared between the two sections. However, it should be noted that embodiments of the present invention can be used in mobile devices in which one or more elements are shared between two sections. For example, the functions of microprocessor 104 and 115 can be combined in a single processor or programmable digital circuit, which can be used by the GPS and communication sections together. Similarly, two sections can share one or more frequency converters, switches, or antenna units.

In the above description, a control signal has been described which is transmitted to a GPS receiver and / or processing elements to activate or deactivate the operation of GPS. The control signal was shown passing through a separate path 110, 117 and 116. It should be clear that in some GPS implementations, the GPS signal processing circuitry and the cellphone processing circuitry can be placed within a single integrated circuit. In this case, the unlocking control signal can be completely represented inside the same integrated circuit and not be observed as an external physical communication line. In addition, such control signals can be transmitted via a common microprocessor bus, which is shared by several circuit elements, such as memory blocks, keyboards, etc. The present invention should be interpreted as including these types of control signal. Additionally, as just explained, a cell phone or other communication device may not be completely separated from the SPS receiver, since again they can share common circuits, for example, input RF components, microprocessors, etc. However, the communication function and the SPS function must have some separate blocks of hardware and / or software. Therefore, when a reference is made to the “communication unit” and to the “SPS receiver”, there is no restriction meaning their complete or even preferential separation.

GPS network / cellular telephone network

As described above, one embodiment of the present invention is used in a mobile device in which the communication transceiver is a cellular telephone used in a cellular communication network. FIG. 3 illustrates the use of a mobile device 150, in the context of a cellular telephone network, to form an integrated GPS and cellular communications system 300. Region 306 represents a cellular telephone communication cell that is served by a cellular communication node 304. Cellular communication unit 304 transmits, for example, a mobile device 302 to cellular telephones and receivers, and receives cellular telephone signals from them within cell 306. Mobile device 302 comprises a mobile device, such as mobile device 150 in FIG. The mobile device 302 transmits cellular signals to the cellular node 304 through a communications antenna 100 and receives GPS signals from GPS satellites via a GPS antenna 111. The cellular node 304 transmits cellular communications from mobile devices within cell 306 to a landline telephone network 310 communication through the center 308 switching cellular communications. The cell switching center 308 transmits communication signals received from the mobile device 302 to the corresponding destination. The cell switching center 308, in addition to cell 306, can serve several other cells. If the destination of the signal transmitted by the mobile device 302 is another mobile device, then a connection is established with the cellular communication node covering the area in which the called mobile device is located. If the destination is terrestrial, then the cellular switching center 308 is connected to the terrestrial telephone network 310.

It should be noted that a cellular-based communication system is a communication system having more than one transmitter, each of which serves a distinct geographical area, which is predetermined at any given time. Typically, each transmitter is a radio transmitter serving a cell having a geographic radius of less than 20 miles, however, the coverage area depends on the particular cellular communication system. There are many types of cellular communication systems, such as cell phones, PCS (personal communication system), SMR (specialized radio for communication with mobile objects), one-way and two-way pager systems, RAM, ARDIS and radio communication systems for transmitting packet data. Typically, various predefined geographical areas are defined as cells, and several cells are grouped together in a cellular service area, and these several cells are connected to one or more cellular switching centers that provide connections to terrestrial systems and / or telephone networks. Service areas are often used for billing. Therefore, there may be a connection of cells in more than one service area, with one switching center. As an option, sometimes there is a connection of cells within the same service area with different switching centers, especially in areas of dense population. Basically, a service area is defined as a collection of cells located geographically close to each other. Another class of cellular communication systems, corresponding to the above description, is based on satellites, and the base stations of cellular communication are satellites, which are usually in Earth orbit. In these systems, cell sectors and service areas shift as functions of time. Options for such systems include Iridium, Globalstar, Orbcomm and Odyssey.

In the system illustrated in FIG. 3, GPS positioning information transmitted by mobile device 302 is transmitted to a serving GPS base station via a landline telephone network 310. The GPS base station 160 serves as a processing node for calculating the position of the GPS receiver in the remote device 302. The GPS base station 160 can also receive GPS information from satellite signals received at the GPS receiver 312 (for example, to provide differential corrections to the GPS information of the mobile device). The GPS base station 160 may be connected directly to the cellular communication node 304 via a land line or radio link to receive corresponding cellular signals. Alternatively, the GPS base station 160 may receive the corresponding cellular signals from the cellular telephone 314, which transmits the signals to the cellular receiver in the GPS base station 160.

It should be noted that the cellular communication network system 300 of FIG. 3 represents one embodiment of the use of the present invention, and other communication systems other than the cellular telephone network can be used to transmit GPS signals from the mobile device to the GPS base station.

Cellular Communication Systems

Embodiments of the present invention can be used in several different cellular telephone systems. The specific cellular communication system or standard depends on the region in which the system is deployed, since cellular communication standards differ in different countries and regions.

In one embodiment of the present invention, the combined mobile device 150 is used in a GSM cellular communication system. GSM is a Pan-European digital cellular communications system that uses time division multiple access (TDMA) methods. When transmitting voice information, the microtelephone transmits a data packet over a time interval of 15/26 milliseconds. Eight time slots are included in one TDMA frame, and the microphone in the primary mode of operation transmits only one of these frames. Consequently, the transmitter is activated only 12.5% of the time. Accordingly, a control communication link for this system (i.e., a trigger pulse 110 in FIG. 2) will indicate an active transmission at 12.5% of the time. This leads to a lack of transmission and / or ignoring by the GPS receiver 130 of the GPS input data for a specified period of time. The “shutdown” periods are very short, less than the period of one GPS code (977.5 microseconds) and only about 1/20 of the GPS data bit length. Actual sensitivity loss is a factor of 0.875 or -0.58 dB.

Another embodiment of the present invention can be used in the North American TDMA IS-136 system. The IS-136 system uses six time slots for a period of 40 millisecond frames. For full-speed signaling, the voice traffic channel takes two such intervals or 13.33 milliseconds. For half-speed signaling, the voice traffic channel occupies one time interval or 6.66 milliseconds. Therefore, for full speed signaling it is not always possible to practically receive a GPS information message together with transmission transmission; however, it remains possible to measure GPS PN periods (to determine the so-called "pseudorange"). In this case, the resulting loss of sensitivity is 0.667 or -1.76 dB. If a half-speed alarm is used, the resulting loss is reduced to 0.833 or -0.76 dB.

An additional embodiment of the present invention can be used in the North American code division multiple access (CDMA) IS-95 system. In the IS-95 system, interference between signals is prevented by each using a different spreading spreading code. Data is organized into 20 millisecond frames. However, when transmitting signals at low data rates (for example, intermittent speech), data is transmitted in packets that occupy only part of the frame. For example, at 1200 baud, data packets occupy only 1/8 of a frame, and for the remainder of the frame, the transmitted signal is transmitted at reduced power levels. During these times of reduced emissions, the GPS receiver 130 can be activated. Similarly, during periods of normal transmission, the GPS receiver 130 can be deactivated, that is, the input stage of the receiver is turned off and / or the input GPS data is ignored by the processing circuits. The actual loss of sensitivity for the GPS receiver in the case of 1200 baud transmission is equivalent to a decrease in the integration time to 7/8 from the possible otherwise, which is equivalent to -0.58 dB. For this case, 1200 baud, the periods of data packet transmission periods are only 1.25 milliseconds, which is a small fraction of the GPS data bit (20 milliseconds). Accordingly, a standard GPS receiver may continue to demodulate information messages from the satellite in the presence of a trigger pulse 110.

The system for reducing crosstalk in a combined GPS receiver and a communications transceiver unit has been described above. Although the present invention has been described with respect to specific possible embodiments, it is obvious that, without departing from the essence of the invention and without leaving its context in the broad sense set forth in the claims, various changes and modifications can be made in these embodiments. Accordingly, the description and drawings are to be regarded as illustrative rather than limiting.

Claims (17)

1. The method of operation of a mobile device, including detecting a condition containing the lack of speech received by the microphone of the mobile device, or pressing a button on the mobile device, upon detection of the specified state: (i) blocking the radio data transmission through the radio data line from the communication unit of the mobile device, and (ii) the transmission from the communication unit to the receiver of the satellite positioning system (GPS) of the mobile device of the first control signal allowing the processing of the signals of the satellite positioning system received by the receiver for a period long enough to process the minimum required amount of GPS data, the transmission data remains locked for the duration of the mentioned period, even when a person speaks into the microphone of a mobile device. 2. The method of claim 1, wherein the state is a button press on a mobile device. 3. The method according to claim 1, in which the aforementioned radio transmission is blocked and allowed in turn. 4. The method according to claim 3, in which data transmission is blocked and allowed on a temporary basis. 5. The method according to claim 4, in which data transmission is blocked and allowed periodically. 6. The method according to claim 1, further comprising (iii) allowing radio data transmission through a radio data transmission line from a communication unit after receiving a sufficient amount of data from a satellite positioning system. 7. The method according to claim 6, further comprising (iv) transmitting the second control signal from the communication unit to the receiver of the satellite positioning system when radio transmission is permitted, the second control signal blocking the processing of signals of the satellite positioning system received by the receiver. 8. The method according to claim 7, in which (i) and (ii) periodically alternate with (iii) and (iv). 9. The method according to claim 1, wherein said period is predetermined. 10. The method according to claim 1, in which said period is customizable, with the determination of the end of said period when said signal processing of a satellite positioning system. 11. The method of operation of a mobile device, including detecting the status of a mobile device, upon detection of the specified state: (i) blocking the radio data transmission through the radio data line from the communication unit of the mobile device, and (ii) the transmission from the communication unit to the receiver of the satellite positioning system (GPS) of the mobile device of the first control signal allowing the processing of the signals of the satellite positioning system received by the receiver for a period long enough to process the minimum required amount of GPS data, the transmission data remains locked for the duration of the mentioned period, even when a person speaks into the microphone of a mobile device, moreover, the data transmission is blocked as a result of the fact that the user of the mobile device speaks into the microphone of the communication unit. 12. A mobile device containing an antenna of a satellite positioning system (GPS) for receiving signals from a satellite positioning system from several satellites of a satellite positioning system, a receiver circuit connected to an antenna of the satellite signal processing system for processing signals of a satellite positioning system, mobile device state detector, a microphone for converting speech into speech information, a radio transmitter configured to transmit voice information through radio communications via a radio data line, an output amplifier connected to the radio transmitter, and a communication unit circuit configured to control an output amplifier for transmitting a signal via radio communication from a radio transmitter and, when a detector detects a specified state: (i) blocking the radio transmission by the output amplifier, and (ii) transmitting to the receiver circuit a first control signal, for starters processing the receiver circuitry of the signals of the satellite positioning system received by the antenna of the satellite positioning system for a period of time long enough to perform processing of the minimum required amount of GPS data, the output amplifier remaining blocked for the said period of time, even when a person speaks into the microphone, moreover, the said period of time is customizable, with the determination of the end of the said period of time during the said signal processing of the satellite positioning system. 13. The mobile device according to item 12, further comprising a button that the user can click on, wherein said state comprises pressing a button. 14. The mobile device according to item 12, in which the radio transmission is alternately blocked and allowed. 15. The mobile device of claim 12, wherein said time period is predetermined. 16. A mobile device containing an antenna of a satellite positioning system (OP8) for receiving signals from a satellite positioning system from several satellites of a satellite positioning system, a receiver circuit connected to an antenna of the satellite signal processing system for processing signals of a satellite positioning system, a detector for a condition containing no speech received by the microphone, microphone for converting speech into speech information, a radio transmitter configured to transmit voice information via radio communication via a radio data line, an output amplifier connected to the radio transmitter, and a communication unit circuit configured to control an output amplifier for transmitting a signal via radio communication from a radio transmitter and, when a detector detects a specified state: (i) blocking the radio transmission by the output amplifier, and (ii) transmitting a first control signal to the receiver circuit to start processing the satellite positioning system signals received by the satellite positioning system antenna for a period of time long enough to process the minimum amount of GPS data, while the output amplifier remains blocked during the mentioned period of time, even when a person speaks into the microphone. 17. A mobile device containing an antenna of a satellite positioning system (OP8) for receiving signals from a satellite positioning system from several satellites of a satellite positioning system, a receiver circuit connected to an antenna of the satellite signal processing system for processing signals of a satellite positioning system, mobile device state detector, microphone for converting speech into speech information, a radio transmitter configured to transmit voice information via radio communication via a radio data line, an output amplifier connected to the radio transmitter, and a communication unit circuit configured to control an output amplifier for transmitting a signal via radio communication from a radio transmitter and, when the detector detects a specified state (i) blocking the radio transmission by the output amplifier, and (ii) transmitting the first control signal to the receiver circuit to start processing the satellite positioning system signals received by the satellite antenna system for a period of time long enough to process the minimum amount of GPS data, while the output amplifier remains blocked during the mentioned period of time, even when a person speaks into the microphone, moreover, the radio data transmission is blocked while the user of the mobile device speaks into the microphone of the communication unit.

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