Indoor GPS

MOKOSmart provides edge to edge indoor positioning solutions. Our devices integrate BLE, Wifi, LoRa, GPS, and beacon to provides accurate positioning and motion information with sub-meter accuracy of 2.5 cm.

What is indoor GPS?

GPS stands for Global Positioning System. The term GPS has been correctly linked to the location determination of its users. When someone mentions GPS to you, you will most likely consider who or what is being located.

Similarly, an indoor GPS is defined as the location of select elements in an enclosed space – either large or small. Indoor GPS tracking facilitates the active or passive location monitoring of tagged units in a facility or indoor space.

Essentially, indoor GPS functions for location, timing, mapping, and navigation of indoor spaces like malls, airports, and other facilities.



Indoor Navigation Beacon


Location Beacon


Asset Traking Beacon


With indoor GPS, here are some of the attributes that can be expected. These features provide owners with the ability to carry out a plethora of functions with ease. With these available, the user it users will be able to enjoy the numerous benefits accrued with indoor GPS. The features are;

  • Ability to access navigation offline
  • High battery saving capacity
  • Readily accessible
  • Keep your personal data private
  • Can be easily detected by Beacons
  • Data can be saved durable
  • High accuracy rate
  • The signal can be received continuously


There are a variety of advantages that can be enjoyed by using indoor GPS modules. These advantages vary from capabilities to the sheer edge that indoor GPS accuracy offers us. Some of these advantages are highlighted below;

  • Management of the facility is improved
  • It offers a friendly edition meant for the visually impaired
  • Users and customers can be better understood
  • Operation can be made more efficient
  • Provides very accurate location and maximize space coordination
  • It is intractable, lightweight, and scalable
  • Facilitates live monitoring
  • Invaluable for asset tracking
  • Management and event scheduling is convenient
  • Can utilize WiFi


When the need arises to locate and manage the location of assets amongst other functions, an indoor GPS repeater can be very useful. We know that traditional satellite technology and GPS do not function optimally in enclosed spaces and are considerably inaccurate. These spaces include airports, parking garages, multistory buildings, alleys, and other underground locations.
And that is where the indoor GPS comes into play. The fact that the traditional GPS is not efficient indoors doesn’t mean it is not crucial to pinpoint the location of assets indoors too.

Who Can Benefit From Indoor GPS?

Vast indoor spaces can be especially difficult to traverse talk less of actively locating assets and individuals. Even with several years of experience in these spaces, it is not uncommon for people to still get thrown and sometimes lost in many of these spaces. Now consider being a visitor and trying to navigate without the help of a foolproof system. Therefore, indoor GPS is a great help for people in the following places and functions;

Types of Indoor Tracking Technology

Indoor tracking technology varies as a result of user preference, cost of the unit, and installation. Indoor tracking technology utilizes an array of devices that locate objects and people where GPS and satellite technology are not functional. Indoor tracking solutions feature wayfinding, real-time location systems(RTLS), first responder location, and inventory management systems.

There are a number of tracking technologies that are varied but help determine indoor positioning. These are;

Bluetooth-based systems: This technology is a wireless, low-powered, and high-speed link used to connect mobile equipment. It provides a wireless connection for multiple network devices over a short distance.

Ultra-wideband systems: These are also known as UWB systems. They are able to facilitate position location correct up to 20 centimeters or less. They transmit low-power signals that do not disturb other spectrums. It utilizes a special wave in the radio spectrum different from police or cell phones radios.

RFID systems: RFID stand door radio frequency identification systems that utilized radio waves to transfer data. The data is encoded in the RFID smart labels or tags, which makes it more advantageous than barcode asset tracking technology.

Infrared systems: In this system, an object that constantly emits infrared signals is attached to the tracked body. The CPU is able to compute the position of the emitted signal with the use of triangulation and the direction of the receiver.

WiFi-based systems: This is a simple method by which location can be tracked with the use of WiFi. A WiFi tag transfers beacon data to various access points. After which, the location server gathers the timestamps and translates the access point data and time stamp information into a location.

Zigbee technology: This utilizes an RSSI which is the abbreviation of “received signal strength indicator." The Zigbee wireless sensor technology employs RSSI, which makes it effective in determining indoor positioning and LBS (location-based services). The use of fingerprint database can be used to calculate the position of an individual indoors.

Beacon technology: This technology employs the use of small wireless BLE transmitters to send signals to receivers close by. With this system, location-based interaction and positioning can be accurately and easily determined.

Ultrasound technology: This technology utilizes an ultrasound system that is able to track the position of the emitting body. Ultrasound sensors are employed to track the position of the ultrasound signal.

How Does GPS Work?

Global Positioning System functions by initially acquiring satellite signals which are used to compute a position. The frequency uncertainty accompanying a position computation is about ±4.2 kHz from the observed GPS signal. Gps utilizes correlation to detect the signal. The peak signal becomes not existent in the case where the frequency of the code delay is wrong. The signal search is carried out over varying code-delay and frequency, known as bins.

In essence, a receiver is able to pinpoint the location as it evaluates the distance between the satellite in use and you. For your location to be determined in 3 dimensions, you will need a minimum of 4 satellites. And your location is obtained utilizing the atomic clock in the satellite that multiplies the signal rate. One satellite determines the time signal rate, while three of the satellites are for getting the x, y, and z coordinates.

In relatable terms, signals from satellites orbiting the earth are transmitted to the earth’s surface some 20,000km away. It is obvious that due to the distance, free space loss will reduce the power level of the signal. This is why regular GPS signals cannot be dependable in enclosed or indoor spaces because the signal loss becomes greater still. That is why indoor GPS repeaters are utilized for GPS indoor positioning systems.


For a GPS to function correctly, there is the need for a special kind of antenna. The traditional GPS antenna that is utilized as a receiver is circular and functions as a polarized microstrip patch. It operates at an L1 band of 1575 MHz. It is quite small, having a 25mm x 25mm dimension because of the substrate material's dielectric constant (Ɛr = 25). Essentially, the antenna is a conductive metal that becomes electrically active when hit with an electromagnetic wave.

Integrated system

The combination of multiple system sub-components brings this about to activate the system. It contains different electronics that pursue the aims of the GPS, such as reading relevant signals and screening out unwanted ones. In the most basic form, the integrated system would incorporate a signal decoder, a filter, and a communications output.

Communication protocol

A system has to be able to transfer information between its multiple components with the aim of achieving a goal. Therefore, the communication protocol is put in place so that multiple entities are involved in GPS. The communication protocol informs the end system or user. An example is a protocol that retrieves a format of information containing the signal quality, coordinates, and speed.

Hardware of Indoor Positioning System

The hardware (physical components) of the IPS makes up the Indoor GPS system as a whole. These components are:

The Directional GPS Antenna

Just as stated earlier on antennas, this is gotten from the traditional patched GPS. It is made up of an aluminum conical reflector that helps increase the direction or positioning.

Low Noise Amplifiers

This hardware component for the IPS makes uses of a few low noise amplifiers that are able to reduce loud sounds.

Indoor Loss Compensation

This comes in handy when there is loss of signal, and it calculates how beneficial the amplifier is in the Indoor GPS system.

Worldwide Network Implementation

This is the ability of a GPS network to function optimally indoors and the server’s computation function for positions. GPS satellites usually send data that can be translated by the available receiver clearly in the sight of the satellite. The GPS constellation presently features a number of 28 satellites in orbit. To get all the live data, a receiver only has to sight all 28 satellites in orbit at the same time.

To do this, the cheapest and most efficient way would be to access a worldwide network having GPS reference stations. These GPS reference stations act as a data conduit to a server. This network can attend to any amount of A-GPS devices that may need it and from anywhere. Mokosmart has developed this network and implemented it.

What makes this network and server innovative are:It constitutes a completely redundant network having stations all over the globe. This is so that every GPS server is “seen” by a minimum of two different stations at any given time.

With this system, the server will need fewer satellite measurements to compute the position fully. This is done by a worldwide terrain model, which helps improve accuracy even with undulating terrain. It utilizes discrete points featuring grids numbering up to one billion that offer accuracy up to 18 meters in height.

The server does not need accurate GPS time tags to compute position because of GPS pseudorange measurements. It can also function on any device whatsoever, irrespective of the manufacturer.

Indoor GPS Hardware Processing Approach

This is a novel approach to indoor GPS that utilizes live convolutions of GPS signals functioning over a variety of probable code delays. How does this work? A traditional GPS receiver can monitor just one chip for possible code delay at a time. The receiver will have to scan, then acquire the signal before tracking can commence.
This new design discards the need for separate tracking and acquisition stages because it carries out live computations. These computations process over 2000 correlators for each satellite, making it compute a complete, real-time convolution. When used outdoors, it can acquire the signal in an almost instantaneous manner. The fading present in indoor spaces makes regular GPS tracking very weak, but this new design will enable continuous integration even with a fading signal.

Indoor GPS Hardware Processing Approach

Further measures should be taken to get the best out of an indoor GPS to get results. For instance, an antenna will have to be placed on the roof of the indoor space. The highest points in the building will hold the antenna, which will be connected to an indoor repeater. This connection will be made possible by employing a coaxial feeder cable used to transport the signal.

The repeater function as a re-radiator for the signal in the indoor environment. GPS repeater transmits live GPS signal from the exterior of a facility to the interior. Be it a regular building or a facility; the enclosed space will be able to provide a real-time sky view. This live sky view will make the indoors accessible to any GPS receiver in the environment.

Indoor GPS Hardware Processing Approach

There is basically one major challenge facing indoor GPS, and it is weak signal processing. The first aspect of this challenge is the acquisition, the second being multipath, and the third is weak/strong signal interaction.

Acquisition: Incoming signal can be searched for in two dimensions that entail code delay and Doppler frequency. Searching involves a Doppler value which is down-converted by multiplying it by the satellite’s CDMA code that is locally generated. The delay is varied; hence the process is referred to as “correlating.” Integration periods are groups of incoming signals on which the search is performed. When the signals are weak, the correlation period has to be extended so that the signal-to-noise ratio at the result is improved.

Multipath: When outdoor GPS is in use, multipath is only experienced mildly, if at all. Multipath is a reflection of that product, a weaker copy of the direct and original line-of-sight signal. This occurrence gets considerably worse when GPS is used indoors. The reflection could be so bad that it surpasses the direct signal when used indoors.

Weak/strong signal interaction: This is a situation that occurs when the receiver locks into a cross-correlation peak or a wrong signal as opposed to the auto-correlation peak of the right signal. Avoiding this is possible when the strong signal is directly acquired and removed before subsequently acquiring the weak signal.