Understanding GPS Intervals

Key Takeaways:

• Choose GPS trackers based on tracking intervals (10 seconds to 5 minutes) and use cases, from real-time tracking to periodic updates.
• Shorter intervals like 10 seconds offer near real-time tracking, ideal for law enforcement or monitoring high-value assets.
• Longer intervals conserve battery life and are suitable for less time-sensitive tracking.
• The 1.5 second interval is crucial for understanding GPS data transmission, as it impacts the timing accuracy and navigation capabilities by helping receivers track the timing of GPS signals and the increment of the truncated TOW count, which represents the 17 most significant bits of the full 19-bit TOW count.
• Features like geofence alerts and speed monitoring vary by interval and device.
• Battery life differs significantly between devices, with longer intervals offering extended usage.

Choose the most appropriate GPS technology tracking option for your application

If your business is in the market for a GPS tracking device to monitor one of your valuable assets, or even a whole fleet of company vehicles, it’s important for you to know what’s available so you can make the best choice to suit your needs. When examining the options, you should consider the tracking intervals, associated features, and most appropriate use cases for each device. Knowing your own needs will help you determine which device is the right choice.

First of all, a GPS tracking interval refers to the amount of time that lapses between moments in which the GPS tracker turns on to capture its location. Intervals can be anywhere from 10 seconds, which is frequent, to up to 5 minutes, which is very spread out.

On demand tracking is an option that bypasses using intervals and only turns on to track its location in response to a user’s location request. GPS receivers play a crucial role in processing signals from satellites to provide accurate position and time measurements. Atomic clocks on GPS satellites ensure precise timing of signals, which is essential for accurate tracking and position calculations.

This post explores these various interval options available, the features that accompany them, and their most appropriate use cases. The navigation message provides critical information such as satellite health, ephemerides, and time corrections, which are vital for accurate positioning and timing.

5 Minute to 30 Second Intervals for GPS signals

The middle range of interval options have a variety of associated use cases. Most often, devices using personal tracking intervals in this range will be placed inside equipment or vehicles that may be often moved. Code chips, which are the binary elements manipulated in the modulation of GPS signals, play a crucial role in encoding information onto carrier waves and impact signal processing in GPS receivers.

Code-phase tracking significantly impacts the accuracy of GPS signals, enhancing the performance of tracking devices. Code-phase only receivers may not be as precise as those utilizing both code and carrier signals, but they still provide valuable location data. Quadrature components, affected by BPSK modulation, are significant in GPS data transmission as they carry specific codes that enhance the technical details of the signal.

	5 Minute Interval	1 Minute Interval	30 Second Interval
Geofence Alerts	Limited	Yes	Yes
Speed Alert	Limited	Yes	Yes
Nano Battery Life	21 Days	14 Days	10 Days
EON Battery Life	140 Days	100 Days	65 Days

An option that may be available in this use category includes “burst mode,” which helps users, and in some cases, law enforcement, find missing items or vehicles. This allows them to track every location of the device while it is in motion. Additionally, these mid-range interval options allow users to have varying levels of control over their asset tracking, including geofence capabilities, and speed alert options, depending on the specific level the user has chosen.

Intervals like these can also be used to track users who are carrying a portable device on their person. Being able to see more to-the-minute tracking data allows the user to see not just movement and location changes, but also monitor direction of travel, pace, route deviations, and more, which might not be visible in more spaced-out location snapshots.

10 Second Intervals

The 10 second interval option is the most versatile option as it can be used to track in nearly real-time, in addition to other options such as fleet tracking, geofence alerts, and speed alerts. A receiver must maintain a lock on at least four satellites to ensure accurate position tracking.

The tracking loop plays a crucial role in maintaining synchronization between the GPS receiver and satellite signals, enabling the receiver to adjust its code states and frequency in response to signals from satellites.

This option is often a great choice for law enforcement officers tracking a suspect as it keeps them aware of the vehicle’s location and movement at all times. It is most often utilized by users who need up-to-the-minute updates, making law enforcement teams some of its most popular users.

The timing of signal reception is essential for receivers to calculate their distance from satellites during trilateration, allowing the receiver to determine its own three-dimensional position. 10-second intervals may also work for users who are tracking an important person, like a parent monitoring their children or security personnel tracking a public figure for their safety.

A Snapshot of Intervals, Features, and Prices for GPS receivers

	On Demand	5 Minute Interval	1 Minute Interval	30 Second Interval	10 Second Interval
Geofence Alerts	No	Limited	Yes	Yes	Yes
Speed Alerts	No	Limited	Yes	Yes	Yes
Nano Battery Life	21+ days	21 days	14 days	10 days	8 days
EON Battery Life	140+ days	140 days	100 days	6 days	40 days

Each of the different interval types offers its own collection of options for various use cases. The BrickHouse Security team can help users determine which device and which tracking interval is best suited to your particular needs. The NAV message plays a crucial role in providing critical information such as satellite health, ephemerides, and time corrections, ensuring accurate positioning and system performance. The telemetry word indicates the status of data uploading from the Control Segment and helps receivers identify the start of each subframe. We invite you to contact our team to learn more.

The GPS week is significant in providing time-sensitive data such as the time of the week (TOW) and the status of the satellite's broadcast. It also plays a crucial role in determining the satellite's ephemerides, which are essential for accurate positioning calculations relative to Earth's coordinates.

FAQ: Understanding GPS Intervals & GPS Tracking Technology

How does a GPS tracker know where it is at any given time?

A GPS tracker determines its position by calculating the time it takes for signals from multiple satellites in the GPS constellation to reach its GPS receiver. This is done using precise timing from atomic clocks onboard satellites and processing data like the ephemeris and almanac to triangulate the receiver’s three-dimensional position on Earth.

What role does 'ephemeris data' play in GPS tracking intervals?

Ephemeris data contains high-precision information about a particular satellite’s orbit. Your GPS tracker downloads this data from each transmitting satellite to calculate accurate locations. The quality and freshness of this data impact how quickly and precisely the tracker can determine its position—especially relevant in shorter GPS intervals.

Why might my GPS tracker take time to connect after being powered off?

When your tracker powers up, it must acquire almanac and ephemeris data and determine the GPS time using signals from visible satellites. This process is called a cold start and can take longer if the satellite positions or time data are outdated. Devices with stored position memory (like telemetry words and handover words) can perform faster warm starts or hot starts, significantly reducing startup time.

What’s the difference between single-frequency and multi-frequency GPS receivers?

A single-frequency GPS receiver only listens to the L1 band, commonly used in consumer devices. It’s fast and efficient but can struggle with signal reception in challenging environments like urban canyons or dense forests. Multi-frequency receivers (often military or survey-grade) can access additional signals like P-code or M-code, improving accuracy and resistance to signal errors caused by atmospheric interference.

Does the frequency of tracking intervals affect satellite signal health or data quality?

No, interval frequency doesn’t affect the health data or quality of signals from the satellites. However, more frequent updates (like 10-second intervals) require more receiver activity, which means more power consumption and processing of code phase, nav messages, and time stamps. It's a trade-off between precision and battery life.

What happens if my tracker loses signal from some satellites?

If a device loses contact with part of the satellite network, it may fall back to dead reckoning (estimating based on last known direction and speed) or delay updates until it re-establishes contact. A minimum of four satellites is needed for accurate 3D positioning. Urban environments can sometimes limit access to all the satellites, affecting tracking performance.

Can GPS track without an internet connection?

Yes. GPS trackers determine position using satellite signals, not internet. However, to send location data to a user interface or platform, they usually require cellular or Wi-Fi connectivity. Devices with on-demand tracking or longer interval settings can store locations and upload when a network is available.

What is the GPS week number and why does it matter?

The GPS week number is a counter that resets every 1024 weeks (about 19.7 years). Older GPS systems can experience issues if they aren’t updated to interpret the week rollover correctly. This matters in interval tracking because accurate GPS time is crucial for position calculation and syncing time of week (TOW) data.

Is GPS tracking affected by leap seconds?

Good question. The Global Positioning System maintains its own continuous time scale, unaffected by leap seconds, unlike Coordinated Universal Time (UTC). GPS devices convert system time to UTC if needed. This matters in high-precision use cases like military code tracking, where time sync accuracy is critical.

Why does my GPS tracker behave differently after firmware updates?

Firmware updates often include enhancements to tracking loop performance, satellite signal decoding (code chips, W-code, Y-code, etc.), and power management. These can change how efficiently your tracker handles short or long intervals, especially under poor signal conditions or after week count resets.