The UK is "dangerously dependent" on the GPS satellite navigation system, a report warns.
Back-up systems are often inadequate, while equipment which can illegally jam systems is easily and cheaply available, the report from the Royal Academy of Engineering says.
With Global Navigation Space Systems (GNSS) affecting things such as road, rail and shipping equipment, a system failure could "just conceivably cause loss of life", says Dr Martyn Thomas, chairman of the academy's GNSS working group.
"The UK is already dangerously dependent on GPS. GPS and other GNSS are so useful and so cheap to build into equipment that we have become almost blindly reliant on the data they give us.
"A significant failure of GPS could cause lots of services to fail at the same time, including many that are thought to be completely independent of each other," Thomas says.
The report says that GNSS is vulnerable to deliberate or accidental interference, with people jamming systems or equipment being affected by solar flares.
Sometimes faulty information from a system failure is so wrong that it will be easily spotted, the report says.
But it added the real threat lay in "dangerously misleading" results which may not seem obviously wrong. In such a situation, a ship, say, could be directed only slightly off course by faulty data but could then be steering into danger.
Helping to launch the report, Bob Cockshott, of the Digital Systems Knowledge Transfer Network, says there is a whole generation of road users who could not read maps and could not operate without satnav.
"Dependency on GPS is growing and jammers are getting easier to obtain. We expect this problem to become more severe.
"You can buy jammers for £20. You don't need much power to take out a GPS signal," Cockshott says.
More-powerful jammers were also available which were "easily available to criminals and are being used by criminals", he says.
One of the academy's GNSS working party, Professor Paul Cannon, says a major "space weather event", where sun-flare activity would lead to disruption of satellite systems, had not taken place since 1859.
He says that such events might not occur more often than 200-500 years but there is "a risk".
The report urges the closing of a loophole in the law which forbids jamming device usage but does not outlaw the import of such equipment or its advertising or its possession.
The academy also urges the Government to trial the deliberate jamming of signals for a limited period to allow users to evaluate the impact of the loss of data and the effectiveness of their back-up plans.
The report also recommends the creation of a research and development programme focused on antenna and receiver improvements which will enhance the resilience of GNSS dependent systems against natural and man-made threats.