This article describes the ORBCOMM system, a wide area packet switched and global two-way data transfer network providing mobile satellite communication (MSC), tracking, monitoring, control and logistics services between mobile, remote, semi-fixed units and other mobile or fixed subscribers via ORBCOMM space and ground segments. It includes the concept of the ORBCOMM Little low earth orbit (LEO) MSC System as well as the architecture of the ORBCOMM Little LEO MSC Network Space, Ground and User segments. ORBCOMM satellite communication, tracking and monitoring terminals, heavy equipment management terminals and ORBCOMM maritime satellite automatic identification system (S-AIS) terminals are also described.

The ORBCOMM MSC system concept originated in 1989 by Orbital Sciences Corporation. The $810 million ORBCOMM Company became operational in 1998 and then filed for Chapter 11 bankruptcy protection in September 2000. Shortly thereafter, ORBCOMM Company was purchased by a new group of investors in April 2001 for an estimated $5 to $10 million.

The ORBCOMM Global, L.P. Company, Dulles, Va., U.S., equally owned by Teleglobe and the Orbital Sciences Corporation, provides global services via the world's first Little LEO satellite-based data and messaging satellite communications system. The U.S. Federal Communications Commission granted ORBCOMM a commercial license in October 1994 and commercial service began in 1998. Orbital Sciences is the prime contractor for satellite design.

The ORBCOMM Company owns and operates a network consisting of Little LEO satellites and several ground earth stations (GES) deployed around the world, connecting small, low power and commercially proven subscriber terminals to private and public networks, including the Global System for Mobile Communication (GSM), cellular systems and the internet.

ORBCOMM is one of the first LEO commercial communications satellite systems to reach orbit and begin service. Offering paging, messaging and data transfer services, the first two of a planned 36-satellite constellation were launched in April 1995.

The constellation was designed to maximize coverage over heavily populated regions, particularly between 60 degrees North and 60 degrees South latitudes. Trade studies were performed to evaluate an optimal constellation configuration for coverage of this region. A total of 35 first generation satellites (OG1) were launched between 1995 and 1999 using the Pegasus and Taurus launch vehicles, establishing the operational satellite constellation for the ORBCOMM Global communications infrastructure. The unlaunched satellite, original designation ORBCOMM FM-29, was cannibalized for parts for a capability demonstration satellite and then rebuilt as TacSat-1 for the U.S. military. 

ORBCOMM Generation 2 (OG2) second generation satellites supplement and will eventually replace the first generation constellation. Eighteen satellites were ordered by 2008 nominally intended to be launched in three groups of six from 2010 to 2014, and by 2015 have all 17 satellites launched. These satellites were launched by SpaceX on the Falcon 9 launch vehicle.

ORBCOMM provides constellations of Little LEO communication satellites for mobile applications, such as maritime, land (road and rail) and aeronautical communications. Apart from service for mobile applications, ORBCOMM provides service for fixed applications, industrial IoT, machine-to-machine (M2M) communications hardware, software and services designed to track, monitor and control fixed and mobile assets in markets including transportation, heavy equipment, maritime, containers, oil and gas, utilities and government. The company provides hardware devices, modems, web applications and data services delivered over multiple satellite and cellular networks.1

ORBCOMM SYSTEM

As of 30 June 2021, ORBCOMM had more than 2.3 million billable subscriber communicators, serving original equipment manufacturers such as Caterpillar Inc., Doosan Infracore America, Hitachi Construction Machinery Co., Ltd., John Deere, Komatsu Limited and Volvo Construction Equipment, as well as other corporate and private customers, such as J. B. Hunt, C&S Wholesale Grocers, Canadian National Railways, C.R. England, Hub Group, KLLM Transport Services, Marten Transport, Swift Transportation, Target, Tropicana, Tyson Foods, Walmart and Werner Enterprises. ORBCOMM Company is headquartered in Fort Lee, New Jersey and has a Network Control Center in Dulles, Va.

By means of a global network of LEO satellites and accompanying ground infrastructure, ORBCOMM’s low-cost and reliable two-way data communications products and services track, monitor and control mobile and fixed assets in four core markets: commercial transportation, heavy equipment, industrial fixed assets and marine/homeland security. The company’s products are installed on trucks, containers, marine vessels, locomotives, backhoes, pipelines, oil wells, utility meters, storage tanks, small craft, camera cargo sensors, tractor ID sensors for trailers, wireless door sensors, wireless temperature sensors, next generation of cellular and IoT telematics and other assets.

ORBCOMM is continuously updating its network to improve global coverage and enhance its performance and reliability for customers around the world. With the launch of new and more capable next generation OG2 satellites, ORBCOMM took its service to the next level. Each OG2 satellite is the equivalent of six OG1 satellites, providing faster message delivery, larger message sizes and better coverage at higher latitudes, while significantly increasing network capacity.

ORBCOMM owns and currently operates a global network of 31 LEO communications satellites and accompanying ground infrastructure including 16 GESs, or gateways, in 13 countries to track and establish two-way satellite communications, tracking and monitoring systems.

From robust web reporting applications to turnkey IoT solutions and enablement, ORBCOMM’s portfolio includes the tools developers, system integrators, value added reseller (VAR) partners and enterprise users need to remotely monitor and control fixed and mobile assets around the world. These include trailers, reefers, containers, cargo ships, fishing vessels, cargo security and fleet management.

In addition, ORBCOMM’s Satellite Automatic Identification System (S-AIS) is an important solution for ship tracking and safety and security in navigation. Taking into consideration all mentioned services, the ORBCOMM system could be classified as a subsystem of the Global Maritime Distress and Safety network and its equipment.

A framework for opportunistic navigation with the multi-constellation ORBCOMM Little LEO satellite signals is proposed via Doppler. A receiver architecture suitable for processing both time division multiple access (TDMA) and frequency division multiple access (FMDA) signals from ORBCOMM can produce Doppler frequency measurements from multi-constellation LEO satellites. An extended Kalman filter based estimator is formulated to solve for a stationary receiver’s position using the resulting Doppler measurements.1,2

LITTLE LEO MSC NETWORK ARCHITECTURE

The ORBCOMM system and network is a wide area packet switched network with two-way data transfer and messaging providing satellite communication, tracking and monitoring services between mobile, remote, semi-fixed or fixed satellite communication units (SCUs), GESs or gateway control centers (GCCs) accomplished via the constellation of Little LEO satellites and network control centers (NCCs).

An ORBCOMM mobile or fixed terminal delivers information to and from virtually anywhere in the world on a nearly real-time basis via ground and space segments to the terrestrial telecommunication network and its ground subscribers. The ORBCOMM OG1 ground segment and subscriber transmitters (Tx) are capable of providing a continuous 4.8 Kb/s stream of uplink packet data and 9.6 Kb/s stream of downlink packet data to the receivers (Rx) and vice versa.

At first, the OG2 satellites operated at an uplink speed of 4.8 Kb/s and a downlink speed of 7.2 Kb/s, while the currently the OG2 satellites can provide higher data rate transmission capabilities, with subscriber downlink speeds of up to 86.4 Kb/s in the uplink and up to 172.8 Kb/s in the downlink. More importantly, a proposed modified OG2 satellite deployment plan will improve overall network coverage and capacity (particularly in mid and higher latitude coverage areas), so ORBCOMM can meet an expected increased demand for its services.

RF communication within the ORBCOMM network operates in the very high frequency (VHF) portion of the frequency spectrum between 137 and 150 MHz. The system can send and receive two-way alphanumeric packet messages, like well-known two-way paging, SMS or e-mail transmissions.

The ORBCOMM network enables two-way monitoring, tracking and messaging services through the world’s first commercial Little LEO satellite slow data communications system. Applications include tracking mobile assets such as oceangoing ships, fishing vessels and barges, containers, vehicles, trailers, locomotives and rail cars, heavy equipment and small craft as well as monitoring and controlling fixed sites.

Fixed services include supervisory control and data acquisition (SCADA) or M2M of electric utility meters, water levels, oil and gas storage tanks, wells, pipelines and environmental projects and a two-way messaging service for consumers, commercial and government entities.

Small, low power and commercially proven SCUs can connect to private and public networks, including the Internet, via ORBCOMM satellites and gateways. Through this network, ORBCOMM delivers information to and from virtually anywhere in the world on a nearly real-time basis.

Vital messages generated by a variety of applications are collected and transmitted by appropriate mobile or fixed SCU terminals to a satellite in the ORBCOMM constellation. The satellite receives and relays these messages down to one of four U.S. GES terminals. The GES then relays the message via satellite link or dedicated terrestrial line to the NCC station. The NCC routes the message to the final addressee, through the Internet via e-mail to a personal computer or through terrestrial networks to a subscriber communicator, pager, dedicated telephone line or facsimile.

The ORBCOMM space and ground network with GESs, GCCs and SCUs and with the OG1 and OG2 generation of satellites is shown in Figure 1. Messages originating outside the U.S. are routed through international GCCs in the same way to their final destinations. Messages and data sent to a remote SCU can be initiated from any computer using common e-mail systems, internet and X.400. The GCC or NCC then transmits the information using ORBCOMM’s global telecommunications network.

ORBCOMM serves customers through VARs that provide expertise in specific industries. These ORBCOMM VARs provide whole-product solutions and customer support to end-users. Different customers from around the world rely on the ORBCOMM satellite network for a wide range of mobile, farming and fixed site data applications including:

1) Monitoring and controlling assets at remote or rural sites for oil/gas extraction, pipeline operations, storage, custody transfer and electric power generation and distribution;
2) Messaging for truck fleets, owner operators and remote workers;
3) Tracking and managing construction equipment, locomotives, rail cars, trucks, trailers, containers, vessels, small craft and locating and recovering stolen vehicles and cargo and
4) Weather data for general aviation.2,3,4

Figure 1

Figure 1 ORBCOMM system overview.2

SPACE SEGMENT

The ORBCOMM system allows users to track, monitor and control remote assets via a satellite network that provides near global coverage with OG1and OG2 satellite constellations.

First Generation of ORBCOMM OG1 Satellites

Through a network of LEO OG1 satellites and regional GESs, users can communicate with their mobile or fixed assets anywhere in the world (see Figure 2). ORBCOMM offers low-cost and high-quality service dedicated to fulfilling the specific needs of all potential users.

Figure 2

Figure 2 ORBCOMM OG1 satellite coverage.5

The ORBCOMM communication network’s first generation operational OG1 satellites are in Little LEO orbit at about 825 km above the Earth’s surface (see Figure 3a). The main function of ORBCOMM’s satellites is to complete the link between an SCU and the switching capability at the NCC in the U.S. or a licensee’s GCC in other countries.

1) Planes A, B and C are inclined at 45 degrees to the equator and each contains eight satellites in circular orbits at an altitude of approximately 815 km.
2) Plane D is also at 45 degrees containing seven satellites in circular orbits at an altitude of 815 km.
3) Plane F is inclined at 70 degrees and contains two satellites in a near-polar earth orbit (PEO) at an altitude of 740 km.
4) Plane G is inclined at 108 degrees and contains two satellites in a near-PEO at an altitude varying between 785 km and 875 km. Plane E is in circular equatorial orbit.

Figure 3b shows the main parts of a fully deployed OG1 satellite. Each spacecraft carries 17 data processors and seven antennas, designed to handle 50,000 messages per hour.

Figure 3

Figure 3 ORBCOMM OG1 satellite constellation (a) and components of the OG1 satellite (b).2

Undeployed, the ORBCOMM OG1 satellite resembles a circular disk and weighs about 43 kg. It measures approximately 1 m in diameter and 16 cm in depth. Circular panels hinge from each side after launch to expose solar cells. These panels articulate on one axis to track the Sun and provide 160 W.

The satellite’s electrical power system is designed to deliver about 100 W, on an orbit-average basis, near its expected end-of-life in a worst-case orbit. The satellite solar panels and antennas fold up into the disk (also called the “payload shelf”) with the remainder of the payload during launch and deployment. Once fully deployed, the spacecraft length measures about 3.6 m from end-to-end with a 2.3 m span across the solar panel disks. The spacecraft long boom is a 2.6 m VHF/UHF gateway antenna.

The ORBCOMM network depends on the number of satellites and gateways in operation and the user’s location. As the satellites move with the Earth, so does the approximately 5.100 km diameter geometric footprint of each satellite. This system provides redundancy at the system level, due to the number of satellites in the constellation. Thus, in the event of a lost satellite, ORBCOMM will optimize the remaining constellation to minimize time gaps in satellite coverage. Consequently, the constellation is tolerant of degradation in the performance of individual satellites.

ORBCOMM satellites constantly move, so large obstructions do not prohibit available coverage in remote rural areas. In comparison, GSM (cellular) coverage depends on tower location, usually centered on major highways and cities and cannot reach remote areas, and the geostationary earth orbit (GEO) satellite system requires large space constructions and costly/ power-intensive hardware. Due to slow data transfer, however, large data files (such as graphics) or emergency response latencies are not appropriate applications for ORBCOMM.

Its satellite transponder receives 2400 b/s at 148 to 149,9 MHz and transmits 4800 b/s at 137 to 138 MHz and 400.05 to 400.15 MHz. The OG1 satellite system uses X.400 of the Consultative Committee on International Telephony and Telegraphy (CCITT 1988). Addressing and message size is typically 6 to 250 bytes (no maximum).