Military Navigation

Applications
Title	Military Navigation
Author(s)	GMV.
Level	Medium
Year of Publication	2011

The satellite navigation is applied to military missions for navigation purposes in enemy territories, especially with absence of light, in missions during the night. The military forces rely on GPS over conventional compasses, in order to obtain an accurate positioning of their own missions, as well as the enemy's forces positions and the locations of enemy's facilities or installations. These positions coordinates can be acquired and distributed to other allied forces, in order to enhance the ground picture.

Satellite navigation is used to plan and track the movements of convoys and to operations of search and rescue of injured soldiers, with considerable reduction of response time.

Application Architecture

The GPS was initially developed for military purposes and has proven to be indispensable for several military activities, such as land, air and sea navigation, surveying and geology and accurate positioning for a wide range of military applications. The use of GNSS has reduced the search and rescue operations response times, increasing the survival chances of the wounded soldiers.

The most common military navigation applications in current use are:

• Forces location,
• Forces navigation,
• Forces employment,
• All weather operations,
• Communication network timing.

The military applications use the Precise Positioning Service, which is more robust and encrypted signal, able to deal of jamming attacks.

It employs two signals to reduce radio transmission errors, thus improving accuracy. SPS uses only one signal, but the ongoing GPS modernization program is adding several more civilian signals over the coming years. Detailed descriptions of Precise Positioning Service and Standard Positioning Service are available in GPS Services.

In the future, the accuracy difference between military and civilian GPS services will be mitigated. With the adoption of GNSS augmentation systems, the GNSS signals distributed to the general public will achieve higher accuracy than Precise Positioning Service.

GPS modernization

An important part of the current GPS modernization program, is the new signal that is designed to improve both the security and prevention jamming properties of military navigation using GPS, the M-code. The M-code signal design needed to provide better jamming resistance than the P(Y)-code signal (that defines the Precise Positioning Service), primarily through enabling transmission at much higher power without interference with C/A-code or P(Y)-code receivers.

The design should provide more robust signal acquisition than is achieved today, while offering better security in terms of exclusivity, authentication, and confidentiality, along with streamlined key distribution. The M-code is designed to be autonomous, and so users will be able to calculate their positions using only the M-code signal, unlike the existing military P(Y)-code, which also requires use of the C/A-code, providing at least comparable performance to the P(Y)-code signal, and more flexibility than the P(Y)-code signal offers.

While providing these benefits, the Mcode signal must coexist with current signals on L1 and L2, not interfering with current or future civilian or military user equipment.

Application Characterization

Forces Navigation

The tracking of troops is another useful application, since potential targets, must be tracked and monitored before an attack. This tracking procedures use other technics such as photo reconnaissance combined with GNSS information, to enhance the awareness and providing guidance information to bombing missions.

Forces location are fundamental in military procedures. GNSS systems can turn the locations of allied and enemy units into a simple task, with the proper equipments. With GNSS being ubiquitous in military actions, troops must be constantly moving to avoid interceptions.

Aircraft navigation is used for civil purposes, as it is documented in Aviation Applications article. In Maritime Applications article there are examples of satellite navigation applied to maritime navigation domain.

Mapping

The mapping is a feature used in military domains and consists in the collection of precise location data to update maps. The military forces require to map the locations of installations and weapons, as well as military bases location, which is in many cases a temporary location, as well as the troop forces on the ground. In order to have a detailed map of the base, the military uses GPS/DGPS to quickly update or create a detailed map of the base.

Remotely Operated Vehicles

Nowadays, the Unmanned Aerial Vehicles (UAVs) have a prominent importance in military actions around the world, due to the capabilities of being remotely controlled in military bases, located on a different part of the globe. The UAVs have increased the tracking and insight capabilities of enemy territories, in Intelligence, Surveillance and Reconnaissance activities. The UAVs used in military application have a GNSS receiver installed, along with the cameras installed in vehicle, allowing pilots to operate the vehicle, away from the conflict region. The GPS tracking systems are very effective in guiding the high-altitude UAVs controller in areas where the installed cameras fail, due to clouds or lower vision.

Signal Jamming

Signal jamming is a major thread to military operations based in GPS. The emergence of GPS jamming devices capable of broadcasting a signal in the same frequency used by satellite navigation to obtain location information, can drive to a disruption of satellite transmissions.

There are some military applications like the GPS Jammer Location (JLOC) designed to monitor for GPS interference threats and provide alerts to military users in the field when a threat is detected.