CA2633051A1 - Apparatus for satellite telecommunications - Google Patents

Apparatus for satellite telecommunications Download PDF

Info

Publication number
CA2633051A1
CA2633051A1 CA002633051A CA2633051A CA2633051A1 CA 2633051 A1 CA2633051 A1 CA 2633051A1 CA 002633051 A CA002633051 A CA 002633051A CA 2633051 A CA2633051 A CA 2633051A CA 2633051 A1 CA2633051 A1 CA 2633051A1
Authority
CA
Canada
Prior art keywords
satellite
satellites
low
earth orbit
elevation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CA002633051A
Other languages
French (fr)
Other versions
CA2633051C (en
Inventor
Thomas Ronald Tessier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to CA2633051A priority Critical patent/CA2633051C/en
Publication of CA2633051A1 publication Critical patent/CA2633051A1/en
Application granted granted Critical
Publication of CA2633051C publication Critical patent/CA2633051C/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18563Arrangements for interconnecting multiple systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18539Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
    • H04B7/18541Arrangements for managing radio, resources, i.e. for establishing or releasing a connection for handover of resources
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18545Arrangements for managing station mobility, i.e. for station registration or localisation
    • H04B7/18547Arrangements for managing station mobility, i.e. for station registration or localisation for geolocalisation of a station
    • H04B7/18554Arrangements for managing station mobility, i.e. for station registration or localisation for geolocalisation of a station using the position provided by an existing geolocalisation system
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W4/00Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/02Services making use of location information

Abstract

A portable communication device has a first system for receiving signals from GPS satellites and a second system for communication with multiple satellites of a low orbit communications system. The device is arranged, at a time of required transmission, to monitor the elevation and azimuth of the GPS satellites in view so as to generate an elevation mask of where the sky is open at the tim e and to commence a required transmission only if the calculation prediction indicate s that at least one of the satellites of the low earth orbit communication satellite system is in view.

Description

APPARATUS FOR SATELLITE TELECOMMUNICATIONS

This invention relates to an apparatus for satellite telecommunications and particularly to an apparatus which is arranged to reduce the ratio of unsuccessful transmissions as compared to the total number of transmission attempts primarily for purposes of power saving.

BACKGROUND OF THE INVENTION

It is known that problems are encountered in using satellite communication devices in mountainous areas where a view of the sky can be blocked to where the satellites are located as they move across the sky.

This is particularly applicable to low-earth orbit satellite communication systems, including Orbcomm, Iridium and Globalstar, where the satellites change position relative to observers on the ground. Thus, even though a satellite is expected to be in view above the horizon, it is in fact blocked due to the presence of a mountain in the direction concerned.

This can lead to many failed communication attempts which are inconvenient and more importantly use significant power leading to drain on portable equipment where the power supply is a significant part of the weight and volume of the equipment.

SUMMARY OF THE INVENTION

It is one object of the invention to provide an apparatus for satellite telecommunications which is arranged to reduce the ratio of unsuccessful transmissions as compared to the total number of transmission attempts.
According to one aspect of the invention there is provided an apparatus for satellite telecommunications comprising:

a mobile communication device for movement over the Earth to different locations;

the mobile communication device having a first system for receiving signals from the Global Positioning System (GPS) satellites;

the mobile communication device having a second system for communication with a low-earth orbit communication satellite system that contains multiple satellites that each pass overhead, in and out of view to the communication device;

the first and second systems being arranged such that, at a time of required transmission on the second system, the first system operates to monitor the elevation and azimuth of at least some of those GPS satellites in view so as to generate an elevation mask of where the sky is open at the time;

the first and second systems being arranged such that, using the elevation mask of where the sky is open at the time, the second system operates to calculate from data available for the (ow-earth orbit communication satellite system and the elevation mask a prediction of whether at least one of the satellites of the low earth orbit communication satellite system is in view;

and the first and second systems being arranged such that the required transmission is commenced only if the calculation prediction indicates that at least one of the satellites of the low earth orbit communication satellite system is in view.

Although the above refers to two systems, the apparatus may comprise a single processor programmed with both systems as two separate protocols operated by the same processor.

If the remote unit processor was too slow or otherwise not capable of doing the communication system ephemeris calculation, a small file with prediction times and positions can be communicated to the devices in the field from time to time. This table could be compared to the visibility mask generated from the GPS

when it is time to transmit. There are ways to encode the table data that are extremely efficient and would take very little air time.

However, preferably the device includes a memory arranged such that each low-earth orbit satellite in the low-earth orbit communication satellite system has an ephemeris stored in the memory wherein the ephemeris of each satellite is used by a satellite visibility prediction subroutine to determine when the next visible pass of each satellite will be, and what the azimuth and elevation of each pass will be.

Preferably the first and second systems are arranged such that, when the apparatus is activated, the first system operates to constantly monitor the elevation and azimuth of at least some of those GPS satellites in view so as to be ready to generate the transmissions when required.
This concept is thus based on problems encountered in using satellite communication device in mountainous areas but can also be applied to situations where a view of the sky where satellites are located is blocked for example by buildings, equipment or even the body of the user.

Thus, for any equipment portable or fixed, it will increase the ratio of successful transmissions as compared to the total number of transmission attempts.
In addition, this increases system efficiency by reducing the number of partial transmissions and lost acknowledgement transmissions.

The system uses two separate satellite systems. The mobile communicator on the ground can receive signals from (1) the Global Positioning System (GPS) satellites, and can communicate with (2) a low-earth orbit communication satellite system that contains multiple satellites that each pass overhead, in and out of view to the user on the ground with the communication device.

Although it is possible to predict, using conventional systems, when communication satellites are above the horizon and thus available for communications, conventional systems cannot predict how much of the sky is obscured by obstacles such as mountains, buildings, or even a user's body.

Therefore, in situations where the view of the sky is blocked, many satellite communication attempts fail. With battery powered equipment, this is a particularly important problem, as a significant portion of battery capacity is wasted with transmission retries. This eliminates this wasted power by ensuring there is a view of the sky in the direction of the communication satellite before transmission attempts are made.

Secondly, in any type of system, be they battery powered or hard-wired to vehicle electrical systems and thus have "unlimited" power, transmitting 5 when there is a clear view of the communications satellite improves satellite and overall system use efficiency. This increase in efficiency is due to a lower number of partial transmissions, fewer lost transmission acknowledgements and reduced transmission retries.

GPS satellite receivers and receiver chipsets are much more power efficient than they used to be. Using a GPS receiver as a "sounding" system that provides the satellite communicator with a way to know where the sky is visible is much more power efficient than turning on a satellite communication receiver subsystem and listening for satellites, or making satellite communication transmissions "blind" in the hope they get through.

Since the GPS system has many satellites that are continuously in view at any location, the satellite communicator can monitor the elevation and azimuth of each GPS satellite in view. This shows the communicator where the sky is visible at that particular instant. Elevation and azimuth data is available from the GPS receiver on board the satellite communicator device.

The satellite communicator will also have the ephemeris of each low-earth orbit satellite in the low-earth orbit communication satellite system in memory.
The ephemeris of each satellite is used by a satellite visibility prediction subroutine in the satellite communicator to determine when the next visible pass of each satellite will be, and what the azimuth and elevation of each pass will be.

Since the satellite communicator has an "elevation mask" of where the sky is open at the present time due to the constant monitoring of GPS
satellites, the satellite communicator can now begin communication transmissions to the low-earth orbit communication satellite when it is predicted to be within the "mask"
previously calculated. This will result in a very high probability of the transmission being successful on the first try. This results in reduction in power use and increased efficiency of satellite resources.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:

Figure 1 is a schematic illustration of a person carrying an apparatus for satellite telecommunications according to the present invention.

Figure 2 is a schematic illustration the apparatus of Figure 1 for satellite telecommunications according to the present invention.

Figure 3 is a flow chart for the calculations for the apparatus for satellite telecommunications of Figures 1 and 2.

In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION

The apparatus as shown in Figures 1 and 2 includes a portable device which includes an antenna or antennas 11 for communications with the GPS and telecommunications systems, a processor 12 for carrying out the communications 5 protocols described hereinafter, a power supply 13 which is ~generaily a battery, a memory 14 of the processor, an input 15 for the user to enter or enable communications to be transmitted and an output 16 for communicating the received communications to the user. Communications may be initiated on user command or may be initiated by an automatic system using a trigger condition such as a timer. In 10 such case, there may be no user interface at all, other than a power switch.

The apparatus uses the protocols described above together with the well known protocols necessary for GPS location detection and for two way telecommunication with a low earth orbit communication satellite system. These protocols are not described herein as they are well known to persons skilled in this art.

The method of the present invention by which transmissions to the low-earth orbit satellite communication systems is commenced only if the above calculation prediction indicates that at least one of the satellites of the low earth orbit communication satellite system is in view is shown in more detail in the flow chart of Figure 3 and described as follows:.

At step 21 the GPS receiver calculates the position of GPS satellites around the earth using the stored ephemeris of each satellite and current time, and GPS receiver receiving GPS satellite signals determines the current position of the GPS receiver based on the GPS satellite signals received.

At step 22 and 23 the GPS receiver calculates the 2 dimensional direction solution to each GPS satellite relative to the GPS receiver position in terms such as elevation degrees above the horizon and azimuth degrees from a reference point such as true north for each GPS satellite determined to be above local horizontal plane of the earth or a specified offset from the local horizontal plane of the earth.

At step 24 the GPS receiver determines which of the satellites that are above the specified local horizontal plane of the earth or the specified offset from the local horizontal plane of the earth are actually being heard by the GPS
receiver.

At step 25 the processor uses the directional data for each satellite that is visible, and possibly in addition to directional data for each satellite 18 that is not visible as obstructed by a an obstruction 19, to construct a sky visibility mask or elevation mask 17.

As shown at steps 26, 27 and 28, if a sky visibility mask has been previously calculated within a reasonable window of time, this previously calculated sky mask is updated with the new solutions, while the oldest solutions may be dropped from the sky mask solution and a new mask created at step 28.

At step 29, using current time, the positions of communication satellites around the earth are determined using the stored ephemeris of each satellite.
At step 30, using current position and current time, the direction solution to each communications satellite relative to the GPS receiver position is determined and the directional solution to each communication satellite is compared to the visibility mask derived from the received GPS satellites.

As shown at steps 31, 32 and 33, if all communication satellites are outside the area of visibility of the visibility mask a transmission will not be attempted and thus a transmission is commenced only if the calculation prediction indicates that at least one of the satellites of the low earth orbit communication satellite system is in view.

If all communication satellites are outside the area of visibility of the visibility mask a transmission will not be attempted and the estimated time to next visibility may be calculated. As satellites are passing regularly, the time to the next available transmission is generally short so that there is little or no interference with the communications verbal or data from the user to the low-earth orbit satellite communication system.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

Claims (4)

1. Apparatus for satellite telecommunications comprising:

a mobile communication device for movement over the earth to different locations;

the mobile communication device having a first system for receiving signals from the Global Positioning System (GPS) satellites;

the mobile communication device having a second system for communication with a low-earth orbit communication satellite system that contains multiple satellites that each pass overhead, in and out of view to the communication device;

the first and second systems being arranged such that, at a time of required transmission on the second system, the first system operates to monitor the elevation and azimuth of at least some of those GPS satellites in view so as to generate an elevation mask of where the sky is open at the time;

the first and second systems being arranged such that, using the elevation mask of where the sky is open at the time, the second system operates to determine from data available for the low-earth orbit communication satellite system and the elevation mask a prediction of whether at least one of the satellites of the low earth orbit communication satellite system is in view;

and the first and second systems being arranged such that the required transmission is commenced only if the calculation prediction indicates that at least one of the satellites of the low earth orbit communication satellite system is in view.
2. The apparatus according to Claim 1 wherein a table containing prediction times and positions of the low-earth orbit satellites in the low-earth orbit communication satellite system is communicated to the device from time to time and is compared to the elevation mask generated from the GPS system.
3. The apparatus according to Claim 1 including a memory and wherein the memory is arranged such that each low-earth orbit satellite in the low-earth orbit communication satellite system has an ephemeris stored in the memory wherein the ephemeris of each satellite is used by a satellite visibility prediction subroutine to determine when the next visible pass of each satellite will be, and what the azimuth and elevation of each pass will be.
4. The apparatus according to Claim 1 wherein the first and second systems are arranged such that, when the apparatus is activated, the first system operates to constantly monitor the elevation and azimuth of at least some of those GPS satellites in view.
CA2633051A 2008-05-12 2008-05-12 Apparatus for satellite telecommunications Expired - Fee Related CA2633051C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA2633051A CA2633051C (en) 2008-05-12 2008-05-12 Apparatus for satellite telecommunications

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA2633051A CA2633051C (en) 2008-05-12 2008-05-12 Apparatus for satellite telecommunications

Publications (2)

Publication Number Publication Date
CA2633051A1 true CA2633051A1 (en) 2009-11-12
CA2633051C CA2633051C (en) 2016-05-03

Family

ID=41297222

Family Applications (1)

Application Number Title Priority Date Filing Date
CA2633051A Expired - Fee Related CA2633051C (en) 2008-05-12 2008-05-12 Apparatus for satellite telecommunications

Country Status (1)

Country Link
CA (1) CA2633051C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020074747A1 (en) * 2018-10-12 2020-04-16 Oq Technology S.À R.L. Method and system for non-terrestrial cellular wireless communication networks

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020074747A1 (en) * 2018-10-12 2020-04-16 Oq Technology S.À R.L. Method and system for non-terrestrial cellular wireless communication networks
EP3907904A1 (en) * 2018-10-12 2021-11-10 OQ Technology S.à r.l. Frequency synchronization for non-terrestrial cellular wireless communication networks
EP3907905A1 (en) * 2018-10-12 2021-11-10 OQ Technology S.à r.l. Timing synchronization for non-terrestrial cellular wireless communication networks
EP3934127A1 (en) * 2018-10-12 2022-01-05 OQ Technology S.à r.l. Method and system for non-terrestrial cellular wireless communication networks
US11309957B2 (en) 2018-10-12 2022-04-19 OQ Technology S.á.r.l. Method and system for non-terrestrial cellular wireless communication networks
US11546050B2 (en) 2018-10-12 2023-01-03 OQ Technology S.á.r.l. Frequency synchronization for non-terrestrial cellular wireless communication networks
US11546051B2 (en) 2018-10-12 2023-01-03 OQ Technology S.á.r.l. Timing synchronization for non-terrestrial cellular wireless communication networks
US11894913B2 (en) 2018-10-12 2024-02-06 OQ Technology S.á.r.l. Airborne or spaceborne base station for a non-terrestrial cellular data communication system
US11894912B2 (en) 2018-10-12 2024-02-06 OQ Technology S.á.r.l. Estimating terminal device localization data

Also Published As

Publication number Publication date
CA2633051C (en) 2016-05-03

Similar Documents

Publication Publication Date Title
US8120528B2 (en) Apparatus for satellite telecommunications
US8554173B2 (en) Position locating device and position determining system
US6272316B1 (en) Mobile satellite user information request system and methods
JP5726420B2 (en) Method and apparatus for operating a satellite positioning system receiver
US5812932A (en) Mobile satellite user information request system and methods
US10110463B2 (en) Personal communications device for multiple communications systems
KR100716518B1 (en) Wireless distress signal device with gps and wireless rescue system thereof
CN100549721C (en) Global position system is utilized the method and system of elevation information
EP2087367A2 (en) Determining position without current broadcast ephemeris
JP2020532238A (en) Systems and methods for predicting communication link quality
CA2588619A1 (en) Rtk-gps survey system
US20060017612A1 (en) Emergency reporting device
US20070200757A1 (en) Positioning system for portable electronic devices
US20160374047A1 (en) Personal communications device with relia-ble satellite communications
JP2010014485A (en) Gps signal generator and relay system
CN111510196B (en) Space-based search and rescue system based on Lora technology
CN104215986A (en) Seaborne remote iridium bidirectional communication/location system of underwater glider
CA2633051C (en) Apparatus for satellite telecommunications
JP2001230722A (en) Automatic mobile radio communication relay method and system
JP2853670B2 (en) Position detection system
US20020154060A1 (en) System and method for providing worldwide seamless location coverage
GB2395079A (en) Laptop PC tagging device
WO2018230227A1 (en) Timing signal generating device, electronic instrument provided with same, and timing signal generating method
KR100588382B1 (en) Positioning estimated system of ultra wide band
JP5682930B2 (en) Tracking antenna device and tracking antenna control method

Legal Events

Date Code Title Description
EEER Examination request
MKLA Lapsed

Effective date: 20210512