Satellite Connectivity

Satellite connectivity provides network access by relaying signals through orbiting spacecraft, enabling communication in locations where terrestrial infrastructure does not exist or has been destroyed. This reference consolidates technical specifications, provider information, equipment requirements, and regulatory considerations for satellite-based field connectivity.

GEO (Geostationary Earth Orbit)

Satellites orbiting at 35,786 km altitude, appearing stationary relative to Earth’s surface. High latency (600+ ms round-trip) but wide coverage from few satellites.

MEO (Medium Earth Orbit)

Satellites orbiting between 2,000 and 35,786 km altitude. Moderate latency (100-150 ms round-trip) with regional coverage patterns.

LEO (Low Earth Orbit)

Satellites orbiting below 2,000 km altitude. Low latency (20-50 ms round-trip) but requiring large constellations for continuous coverage.

VSAT (Very Small Aperture Terminal)

Ground station equipment with dish antennas typically 0.75m to 2.4m diameter, used for two-way satellite communication.

Throughput

Actual data transfer rate achieved, distinct from the theoretical maximum bandwidth of the service plan.

Contention ratio

Number of subscribers sharing a given amount of satellite capacity. A 20:1 ratio means 20 subscribers share bandwidth nominally allocated to one.

Satellite technology comparison

The three orbital altitude categories determine fundamental performance characteristics. GEO satellites dominated commercial satellite communications for decades due to their ability to provide continental coverage from three spacecraft. The physics of their 35,786 km altitude imposes a minimum 240 ms one-way signal delay, resulting in round-trip latencies that degrade interactive applications and TCP performance. MEO constellations reduce this latency at the cost of requiring more satellites for equivalent coverage. LEO constellations achieve near-terrestrial latency but demand hundreds or thousands of satellites with continuous handoffs between spacecraft.

Signal strength decreases with the square of distance, meaning LEO satellites operating at 550 km altitude deliver signals approximately 4,200 times stronger than GEO satellites at equivalent transmission power. This physics advantage enables LEO terminals to use smaller antennas and lower transmission power while achieving higher data rates.

Atmospheric and weather effects impact all satellite links but affect higher frequencies more severely. Ku-band (12-18 GHz) and Ka-band (26.5-40 GHz) services experience rain fade during heavy precipitation, with signal attenuation reaching 10+ dB in tropical downpours. C-band (4-8 GHz) resists rain fade but requires larger antennas for equivalent gain.

Service provider reference

The satellite service market divides into legacy GEO operators, newer high-throughput satellite (HTS) providers, and LEO constellation operators. Mission-driven organisations typically access these services through resellers and managed service providers rather than direct contracts, though direct relationships become economical at scale or for dedicated capacity.

GEO and HTS providers

Traditional GEO operators sell capacity wholesale to service providers who package retail offerings. High-throughput satellites using spot beam technology deliver 10-100 times the capacity of traditional wide-beam satellites by reusing frequencies across geographically separated beams.

LEO constellation operators

LEO providers sell retail services directly or through authorised resellers. Equipment is typically provider-specific and non-interoperable.

Mobile and portable satellite services

L-band and S-band services support handheld terminals and operate independently of the data-focused providers listed above.

Terminal and equipment specifications

Satellite terminals range from handheld satphones through portable BGAN units to fixed VSAT installations. Selection depends on bandwidth requirements, mobility needs, power availability, and budget.

VSAT terminal specifications

Fixed VSAT installations provide the highest throughput but require site preparation, professional installation, and stable power. Antenna diameter correlates directly with signal gain and thus achievable data rates.

The Block Upconverter (BUC) amplifies outbound signals and determines maximum transmit power. BUC power ratings in watts correspond roughly to achievable upstream bandwidth, with diminishing returns above what the satellite transponder can receive.

The Low Noise Block downconverter (LNB) receives signals from the satellite. LNB noise figure, measured in decibels (dB), determines receive sensitivity. Lower noise figures enable reception of weaker signals.

Portable and flyaway terminals

Portable VSAT systems trade throughput for deployability. Auto-acquire antennas locate satellites automatically, while manual-point systems require operator skill.

Satphone specifications

Handheld satellite phones provide voice and limited data where no other connectivity exists. Battery life assumes standby with periodic position updates.

Bandwidth and latency characteristics

Achievable performance depends on the interaction of orbital mechanics, frequency allocation, contention ratios, and protocol behaviour. Advertised speeds represent theoretical maximums under ideal conditions with no contention.

Latency impact by application

Round-trip time (RTT) determines responsiveness for interactive applications. The table below shows measured latency ranges under normal operating conditions, not theoretical minimums.

TCP throughput over high-latency links suffers because the protocol waits for acknowledgments before sending additional data. The theoretical maximum throughput for a single TCP connection equals the TCP window size divided by the round-trip time. A 64 KB window over a 600 ms RTT link yields maximum 107 KB/s (856 kbps) regardless of available bandwidth.

TCP throughput calculation:

Window size:    65,536 bytes (64 KB default)
RTT:            600 ms (0.6 seconds)

Maximum throughput = Window size / RTT
                   = 65,536 / 0.6
                   = 109,227 bytes/second
                   = 874 kbps

With TCP window scaling to 1 MB:
Maximum throughput = 1,048,576 / 0.6
                   = 1,747,627 bytes/second
                   = 13.98 Mbps

Contention and fair access policies

Shared satellite capacity employs contention ratios and fair access policies to distribute bandwidth among subscribers. Higher contention ratios reduce cost but degrade performance during peak usage.

Fair access policies (FAP) throttle individual subscribers who exceed usage thresholds within rolling windows. A typical policy might allow 50 GB at full speed within a 30-day period, then reduce the subscriber to 1 Mbps until usage falls below the threshold.

Service plan structures

Satellite service pricing combines equipment costs, installation, monthly service fees, and often usage-based charges. The total cost of ownership over a three-year period provides better comparison than monthly fees alone.

GEO VSAT service pricing

Traditional VSAT services bundle bandwidth commitments with contention ratios. Committed Information Rate (CIR) guarantees minimum bandwidth; Maximum Information Rate (MIR) specifies the burst ceiling.

LEO service pricing

LEO providers typically offer flat-rate plans without CIR guarantees, relying on constellation capacity to deliver consistent performance.

Portable and mobile service pricing

L-band services charge by airtime or data volume due to severely constrained capacity.

Three-year total cost examples

The following examples illustrate complete costs for representative deployment scenarios, including equipment, installation, and service over 36 months.

Scenario A: Small field office (5-10 users, basic connectivity)

GEO VSAT option:
  Equipment (0.98m auto-acquire):     $8,000
  Installation:                       $2,500
  Monthly service (Standard tier):    $900 x 36 = $32,400
  -----------------------------------------
  Three-year total:                   $42,900
  Per-month equivalent:               $1,192

Starlink Business option:
  Equipment:                          $2,500
  Installation (self or minimal):     $500
  Monthly service:                    $250 x 36 = $9,000
  -----------------------------------------
  Three-year total:                   $12,000
  Per-month equivalent:               $333

Note: Starlink requires coverage availability and stable power;
GEO VSAT available nearly anywhere with sky visibility.

Scenario B: Regional coordination hub (20-30 users, video conferencing)

GEO VSAT option:
  Equipment (1.2m manual flyaway):    $15,000
  Installation:                       $5,000
  Monthly service (Enterprise tier):  $3,500 x 36 = $126,000
  -----------------------------------------
  Three-year total:                   $146,000
  Per-month equivalent:               $4,056

LEO + GEO hybrid option:
  Starlink Business terminal:         $2,500
  Starlink monthly service:           $250 x 36 = $9,000
  GEO backup (Standard tier):         $600 x 36 = $21,600
  GEO equipment:                      $8,000
  Installation:                       $3,000
  -----------------------------------------
  Three-year total:                   $44,100
  Per-month equivalent:               $1,225

Deployment requirements

Successful satellite deployment requires clear sky visibility, stable mounting, adequate power, and compliance with local regulations.

Line of sight requirements

Satellite antennas require unobstructed view to the target spacecraft. GEO satellites occupy fixed positions on the geostationary arc; the required look angle depends on site latitude and the satellite’s orbital slot.

LEO terminals require broader sky visibility because satellites pass overhead rather than remaining fixed. Starlink recommends no obstructions above 25° from horizontal in any direction; partial obstructions cause service interruptions during the affected portion of satellite passes.

Obstruction impact calculation:

Sky hemisphere = 180° azimuth x 90° elevation = 16,200 square degrees
25° obstruction mask = 180° x 25° = 4,500 square degrees
Available sky = 16,200 - 4,500 = 11,700 square degrees (72%)

A building blocking 30° azimuth from 0-40° elevation:
Blocked area = 30° x 40° = 1,200 square degrees
Impact = 1,200 / 11,700 = 10% of passes potentially affected

Mounting specifications

Antenna mounting must maintain pointing accuracy under wind load, thermal expansion, and ground settlement. The table specifies requirements for fixed VSAT installations.

Power requirements

Satellite terminals require stable power within specified voltage tolerances. Power consumption varies with transmit activity, ambient temperature, and equipment configuration.

For solar-powered installations, size the system for active power draw plus 30% margin, with battery capacity for 24-48 hours without generation. A Starlink terminal requiring average 100W continuous needs:

Daily energy requirement:   100W x 24h = 2,400 Wh = 2.4 kWh
With 30% margin:           2.4 x 1.3 = 3.12 kWh/day

Solar panel sizing (5 peak sun hours):
  3,120 Wh / 5h / 0.8 (system efficiency) = 780W panel capacity

Battery sizing (48-hour autonomy):
  3,120 Wh x 2 days / 0.5 (max discharge) = 12,480 Wh = 12.5 kWh
  At 24V: 520 Ah battery bank
  At 48V: 260 Ah battery bank

Performance optimisation

Several techniques improve usable throughput and application responsiveness over satellite links.

WAN optimisation

TCP acceleration addresses the window size limitation by terminating TCP connections locally and using optimised protocols over the satellite segment. The accelerator acknowledges packets locally while ensuring reliable delivery across the high-latency link. Effective acceleration requires devices at both ends of the satellite connection.

Compression reduces data volume for compressible content. Typical compression ratios range from 2:1 for mixed web traffic to 5:1 for text-heavy content. Already-compressed content (images, video, encrypted data) shows no improvement.

Caching stores frequently accessed content locally, eliminating repeated satellite transfers. A local cache containing operating system updates, common software packages, and frequently accessed web content reduces satellite usage by 20-40% in typical field office environments.

Quality of Service configuration

Limited satellite bandwidth requires prioritisation to ensure critical applications receive adequate capacity. Traffic classification and queuing prevent bulk transfers from starving interactive traffic.

Security considerations

Satellite links present specific security characteristics that differ from terrestrial connectivity.

Link security

Commercial satellite services encrypt the radio link between terminal and satellite using proprietary or standard encryption. This link-layer encryption protects against casual interception but does not provide end-to-end security.

Organisations handling sensitive data should implement VPN tunnels over satellite links regardless of provider link encryption. This protects against compromise of the satellite network itself and provides visibility and control over traffic.

Physical security

Satellite terminals represent high-value, easily identified assets. The antenna identifies the location as having external connectivity, potentially attracting attention in sensitive contexts.

Considerations for physical security planning:

Jurisdictional and interception concerns

Different satellite providers operate under different jurisdictional frameworks affecting lawful interception obligations and data handling.

Regulatory requirements

Satellite terminal operation requires licensing in most jurisdictions. Requirements vary significantly by country and change frequently.

Licensing frameworks

Frequency coordination

Satellite terminals share spectrum with other services. Operating on unapproved frequencies or at excessive power levels causes interference and legal consequences.

Import and export considerations

Satellite equipment faces export controls in many jurisdictions and import restrictions in destination countries.

Regional regulatory notes

Technology selection decision support

The following diagram summarises the selection process based on primary requirements.

                            +------------------+
                            | Primary          |
                            | requirement?     |
                            +--------+---------+
                                     |
         +---------------------------+---------------------------+
         |                           |                           |
         v                           v                           v
+--------+--------+        +---------+-------+         +---------+-------+
| Lowest latency  |        | Widest coverage |         | Lowest cost     |
| (interactive    |        | (any location)  |         | (budget         |
|  applications)  |        |                 |         |  constrained)   |
+--------+--------+        +---------+-------+         +---------+-------+
         |                           |                           |
         v                           v                           v
+-----------------+        +-----------------+         +-----------------+
| LEO available?  |        | LEO/MEO         |         | LEO available   |
|                 |        | available?      |         | and sufficient? |
+----+-------+----+        +----+-------+----+         +----+-------+----+
     |       |                  |       |                   |       |
     v       v                  v       v                   v       v
   Yes      No                Yes      No                  Yes      No
     |       |                  |       |                   |       |
     v       v                  v       v                   v       v
+---------+ +--------+    +---------+ +--------+     +---------+ +--------+
|Starlink | |MEO     |    |LEO/MEO  | |GEO     |     |LEO      | |GEO     |
|or       | |(O3b)   |    |primary  | |VSAT    |     |service  | |shared  |
|OneWeb   | |if      |    |GEO      | |        |     |         | |VSAT    |
|         | |avail.  |    |backup   | |        |     |         | |        |
+---------+ +--------+    +---------+ +--------+     +---------+ +--------+

                            +------------------+
                            | Mobility         |
                            | requirement?     |
                            +--------+---------+
                                     |
         +---------------------------+---------------------------+
         |                           |                           |
         v                           v                           v
+--------+--------+        +---------+-------+         +---------+-------+
| Fixed site      |        | Relocatable     |         | True mobile     |
| (permanent      |        | (semi-permanent |         | (vehicle,       |
|  installation)  |        |  or deployable) |         |  maritime, air) |
+--------+--------+        +---------+-------+         +---------+-------+
         |                           |                           |
         v                           v                           v
+--------+--------+        +---------+-------+         +---------+-------+
| Standard VSAT   |        | Auto-acquire    |         | Flat panel      |
| or flat panel   |        | flyaway VSAT    |         | (Starlink) or   |
| LEO terminal    |        | or flat panel   |         | maritime VSAT   |
+-----------------+        | LEO terminal    |         | or L-band       |
                           +-----------------+         +-----------------+

See also

• Mobile Network Utilisation
• Last-Mile Connectivity
• Emergency Communications
• Satellite Deployment
• Solar and Off-Grid Power
• Low-Bandwidth Optimisation
• Field Hardware Selection